Lightningbeam/lightningbeam-ui/lightningbeam-editor/src/main.rs

#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]

use eframe::egui;
use lightningbeam_core::layer::{AnyLayer, AudioLayer};
use lightningbeam_core::layout::{LayoutDefinition, LayoutNode};
use lightningbeam_core::pane::PaneType;
use lightningbeam_core::tool::Tool;
use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use clap::Parser;
use uuid::Uuid;

mod panes;
use panes::{PaneInstance, PaneRenderer, SharedPaneState};

mod widgets;

mod menu;
use menu::{MenuAction, MenuSystem};

mod theme;
use theme::{Theme, ThemeMode};

mod waveform_gpu;
mod cqt_gpu;

mod config;
use config::AppConfig;

mod default_instrument;

mod export;

mod preferences;

mod notifications;

mod effect_thumbnails;
use effect_thumbnails::EffectThumbnailGenerator;

mod debug_overlay;

/// Lightningbeam Editor - Animation and video editing software
#[derive(Parser, Debug)]
#[command(name = "Lightningbeam Editor")]
#[command(author, version, about, long_about = None)]
struct Args {
    /// Use light theme
    #[arg(long, conflicts_with = "dark")]
    light: bool,

    /// Use dark theme
    #[arg(long, conflicts_with = "light")]
    dark: bool,
}

fn main() -> eframe::Result {
    println!("🚀 Starting Lightningbeam Editor...");

    // Configure rayon thread pool to use fewer threads, leaving cores free for video playback
    let num_cpus = std::thread::available_parallelism()
        .map(|n| n.get())
        .unwrap_or(4);
    let waveform_threads = (num_cpus.saturating_sub(2)).max(2); // Leave 2 cores free, minimum 2 threads
    rayon::ThreadPoolBuilder::new()
        .num_threads(waveform_threads)
        .thread_name(|i| format!("waveform-{}", i))
        .build_global()
        .expect("Failed to build rayon thread pool");
    println!("✅ Configured waveform generation to use {} threads (leaving {} cores for video)",
        waveform_threads, num_cpus - waveform_threads);

    // Parse command line arguments
    let args = Args::parse();

    // Load config to get theme preference
    let config = AppConfig::load();

    // Determine theme mode: command-line args override config
    let theme_mode = if args.light {
        ThemeMode::Light
    } else if args.dark {
        ThemeMode::Dark
    } else {
        // Use theme from config
        ThemeMode::from_string(&config.theme_mode)
    };

    // Load theme
    let mut theme = Theme::load_default().expect("Failed to load theme");
    theme.set_mode(theme_mode);
    println!("✅ Loaded theme with {} selectors (mode: {:?})", theme.len(), theme_mode);

    // Debug: print theme info
    theme.debug_print();

    // Load layouts from JSON
    let layouts = load_layouts();
    println!("✅ Loaded {} layouts", layouts.len());
    for layout in &layouts {
        println!("   - {}: {}", layout.name, layout.description);
    }

    // Initialize native menus for macOS (app-wide, doesn't need window)
    #[cfg(target_os = "macos")]
    {
        if let Ok(menu_system) = MenuSystem::new() {
            menu_system.init_for_macos();
            println!("✅ Native macOS menus initialized");
        }
    }

    // Load window icon
    let icon_data = include_bytes!("../../../src-tauri/icons/icon.png");
    let icon_image = match image::load_from_memory(icon_data) {
        Ok(img) => {
            let rgba = img.to_rgba8();
            let (width, height) = (rgba.width(), rgba.height());
            println!("✅ Loaded window icon: {}x{}", width, height);
            Some(egui::IconData {
                rgba: rgba.into_raw(),
                width,
                height,
            })
        }
        Err(e) => {
            eprintln!("❌ Failed to load window icon: {}", e);
            None
        }
    };

    let mut viewport_builder = egui::ViewportBuilder::default()
        .with_inner_size([1920.0, 1080.0])
        .with_title("Lightningbeam Editor")
        .with_app_id("lightningbeam-editor"); // Set app_id for Wayland

    if let Some(icon) = icon_image {
        viewport_builder = viewport_builder.with_icon(icon);
    }

    let options = eframe::NativeOptions {
        viewport: viewport_builder,
        ..Default::default()
    };

    eframe::run_native(
        "Lightningbeam Editor",
        options,
        Box::new(move |cc| Ok(Box::new(EditorApp::new(cc, layouts, theme)))),
    )
}

fn load_layouts() -> Vec<LayoutDefinition> {
    let json = include_str!("../assets/layouts.json");
    serde_json::from_str(json).expect("Failed to parse layouts.json")
}

/// Path to a node in the layout tree (indices of children)
type NodePath = Vec<usize>;

#[derive(Default)]
struct DragState {
    is_dragging: bool,
    node_path: NodePath,
    is_horizontal: bool,
}

/// Action to perform on the layout tree
enum LayoutAction {
    SplitHorizontal(NodePath, f32), // path, percent
    SplitVertical(NodePath, f32),   // path, percent
    RemoveSplit(NodePath),
    EnterSplitPreviewHorizontal,
    EnterSplitPreviewVertical,
}

#[derive(Default)]
enum SplitPreviewMode {
    #[default]
    None,
    Active {
        is_horizontal: bool,
        hovered_pane: Option<NodePath>,
        split_percent: f32,
    },
}

/// Rasterize an embedded SVG and upload it as an egui texture
fn rasterize_svg(svg_data: &[u8], name: &str, render_size: u32, ctx: &egui::Context) -> Option<egui::TextureHandle> {
    let tree = resvg::usvg::Tree::from_data(svg_data, &resvg::usvg::Options::default()).ok()?;
    let pixmap_size = tree.size().to_int_size();
    let scale_x = render_size as f32 / pixmap_size.width() as f32;
    let scale_y = render_size as f32 / pixmap_size.height() as f32;
    let scale = scale_x.min(scale_y);

    let final_size = resvg::usvg::Size::from_wh(
        pixmap_size.width() as f32 * scale,
        pixmap_size.height() as f32 * scale,
    ).unwrap_or(resvg::usvg::Size::from_wh(render_size as f32, render_size as f32).unwrap());

    let mut pixmap = resvg::tiny_skia::Pixmap::new(
        final_size.width() as u32,
        final_size.height() as u32,
    )?;
    let transform = resvg::tiny_skia::Transform::from_scale(scale, scale);
    resvg::render(&tree, transform, &mut pixmap.as_mut());

    let rgba_data = pixmap.data();
    let size = [pixmap.width() as usize, pixmap.height() as usize];
    let color_image = egui::ColorImage::from_rgba_unmultiplied(size, rgba_data);
    Some(ctx.load_texture(name, color_image, egui::TextureOptions::LINEAR))
}

/// Embedded pane icon SVGs
mod pane_icons {
    pub static STAGE: &[u8] = include_bytes!("../../../src/assets/stage.svg");
    pub static TIMELINE: &[u8] = include_bytes!("../../../src/assets/timeline.svg");
    pub static TOOLBAR: &[u8] = include_bytes!("../../../src/assets/toolbar.svg");
    pub static INFOPANEL: &[u8] = include_bytes!("../../../src/assets/infopanel.svg");
    pub static PIANO_ROLL: &[u8] = include_bytes!("../../../src/assets/piano-roll.svg");
    pub static PIANO: &[u8] = include_bytes!("../../../src/assets/piano.svg");
    pub static NODE_EDITOR: &[u8] = include_bytes!("../../../src/assets/node-editor.svg");
}

/// Embedded tool icon SVGs
mod tool_icons {
    pub static SELECT: &[u8] = include_bytes!("../../../src/assets/select.svg");
    pub static DRAW: &[u8] = include_bytes!("../../../src/assets/draw.svg");
    pub static TRANSFORM: &[u8] = include_bytes!("../../../src/assets/transform.svg");
    pub static RECTANGLE: &[u8] = include_bytes!("../../../src/assets/rectangle.svg");
    pub static ELLIPSE: &[u8] = include_bytes!("../../../src/assets/ellipse.svg");
    pub static PAINT_BUCKET: &[u8] = include_bytes!("../../../src/assets/paint_bucket.svg");
    pub static EYEDROPPER: &[u8] = include_bytes!("../../../src/assets/eyedropper.svg");
    pub static LINE: &[u8] = include_bytes!("../../../src/assets/line.svg");
    pub static POLYGON: &[u8] = include_bytes!("../../../src/assets/polygon.svg");
    pub static BEZIER_EDIT: &[u8] = include_bytes!("../../../src/assets/bezier_edit.svg");
    pub static TEXT: &[u8] = include_bytes!("../../../src/assets/text.svg");
}

/// Embedded focus icon SVGs
mod focus_icons {
    pub static ANIMATION: &[u8] = include_bytes!("../../../src/assets/focus-animation.svg");
    pub static MUSIC: &[u8] = include_bytes!("../../../src/assets/focus-music.svg");
    pub static VIDEO: &[u8] = include_bytes!("../../../src/assets/focus-video.svg");
}

/// Icon cache for pane type icons
struct IconCache {
    icons: HashMap<PaneType, egui::TextureHandle>,
}

impl IconCache {
    fn new() -> Self {
        Self {
            icons: HashMap::new(),
        }
    }

    fn get_or_load(&mut self, pane_type: PaneType, ctx: &egui::Context) -> Option<&egui::TextureHandle> {
        if !self.icons.contains_key(&pane_type) {
            let svg_data = match pane_type {
                PaneType::Stage | PaneType::Outliner | PaneType::PresetBrowser | PaneType::AssetLibrary => pane_icons::STAGE,
                PaneType::Timeline => pane_icons::TIMELINE,
                PaneType::Toolbar => pane_icons::TOOLBAR,
                PaneType::Infopanel => pane_icons::INFOPANEL,
                PaneType::PianoRoll => pane_icons::PIANO_ROLL,
                PaneType::VirtualPiano => pane_icons::PIANO,
                PaneType::NodeEditor | PaneType::ShaderEditor => pane_icons::NODE_EDITOR,
            };
            if let Some(texture) = rasterize_svg(svg_data, pane_type.icon_file(), 64, ctx) {
                self.icons.insert(pane_type, texture);
            }
        }
        self.icons.get(&pane_type)
    }
}

/// Icon cache for tool icons
struct ToolIconCache {
    icons: HashMap<Tool, egui::TextureHandle>,
}

impl ToolIconCache {
    fn new() -> Self {
        Self {
            icons: HashMap::new(),
        }
    }

    fn get_or_load(&mut self, tool: Tool, ctx: &egui::Context) -> Option<&egui::TextureHandle> {
        if !self.icons.contains_key(&tool) {
            let svg_data = match tool {
                Tool::Select => tool_icons::SELECT,
                Tool::Draw => tool_icons::DRAW,
                Tool::Transform => tool_icons::TRANSFORM,
                Tool::Rectangle => tool_icons::RECTANGLE,
                Tool::Ellipse => tool_icons::ELLIPSE,
                Tool::PaintBucket => tool_icons::PAINT_BUCKET,
                Tool::Eyedropper => tool_icons::EYEDROPPER,
                Tool::Line => tool_icons::LINE,
                Tool::Polygon => tool_icons::POLYGON,
                Tool::BezierEdit => tool_icons::BEZIER_EDIT,
                Tool::Text => tool_icons::TEXT,
            };
            if let Some(texture) = rasterize_svg(svg_data, tool.icon_file(), 180, ctx) {
                self.icons.insert(tool, texture);
            }
        }
        self.icons.get(&tool)
    }
}

/// Icon cache for focus card icons (start screen)
struct FocusIconCache {
    icons: HashMap<FocusIcon, egui::TextureHandle>,
}

impl FocusIconCache {
    fn new() -> Self {
        Self {
            icons: HashMap::new(),
        }
    }

    fn get_or_load(&mut self, icon: FocusIcon, icon_color: egui::Color32, ctx: &egui::Context) -> Option<&egui::TextureHandle> {
        if !self.icons.contains_key(&icon) {
            let (svg_bytes, svg_filename) = match icon {
                FocusIcon::Animation => (focus_icons::ANIMATION, "focus-animation.svg"),
                FocusIcon::Music => (focus_icons::MUSIC, "focus-music.svg"),
                FocusIcon::Video => (focus_icons::VIDEO, "focus-video.svg"),
            };

            // Replace currentColor with the actual color
            let svg_data = String::from_utf8_lossy(svg_bytes);
            let color_hex = format!(
                "#{:02x}{:02x}{:02x}",
                icon_color.r(), icon_color.g(), icon_color.b()
            );
            let svg_with_color = svg_data.replace("currentColor", &color_hex);

            if let Some(texture) = rasterize_svg(svg_with_color.as_bytes(), svg_filename, 120, ctx) {
                self.icons.insert(icon, texture);
            }
        }
        self.icons.get(&icon)
    }
}

/// Command sent to file operations worker thread
enum FileCommand {
    Save {
        path: std::path::PathBuf,
        document: lightningbeam_core::document::Document,
        layer_to_track_map: std::collections::HashMap<uuid::Uuid, u32>,
        progress_tx: std::sync::mpsc::Sender<FileProgress>,
    },
    Load {
        path: std::path::PathBuf,
        progress_tx: std::sync::mpsc::Sender<FileProgress>,
    },
}

/// Progress updates from file operations worker
#[allow(dead_code)] // EncodingAudio/DecodingAudio planned for granular progress reporting
enum FileProgress {
    SerializingAudioPool,
    EncodingAudio { current: usize, total: usize },
    WritingZip,
    LoadingProject,
    DecodingAudio { current: usize, total: usize },
    Complete(Result<lightningbeam_core::file_io::LoadedProject, String>), // For loading
    Error(String),
    Done,
}

/// Active file operation state
enum FileOperation {
    Saving {
        path: std::path::PathBuf,
        progress_rx: std::sync::mpsc::Receiver<FileProgress>,
    },
    Loading {
        path: std::path::PathBuf,
        progress_rx: std::sync::mpsc::Receiver<FileProgress>,
    },
}

/// Information about an imported asset (for auto-placement)
#[derive(Debug, Clone)]
#[allow(dead_code)] // name/duration populated for future import UX features
struct ImportedAssetInfo {
    clip_id: uuid::Uuid,
    clip_type: panes::DragClipType,
    name: String,
    dimensions: Option<(f64, f64)>,
    duration: f64,
    linked_audio_clip_id: Option<uuid::Uuid>,
}

/// Worker thread for file operations (save/load)
struct FileOperationsWorker {
    command_rx: std::sync::mpsc::Receiver<FileCommand>,
    audio_controller: std::sync::Arc<std::sync::Mutex<daw_backend::EngineController>>,
}

impl FileOperationsWorker {
    /// Create a new worker and spawn it on a background thread
    fn spawn(audio_controller: std::sync::Arc<std::sync::Mutex<daw_backend::EngineController>>)
        -> std::sync::mpsc::Sender<FileCommand>
    {
        let (command_tx, command_rx) = std::sync::mpsc::channel();

        let worker = FileOperationsWorker {
            command_rx,
            audio_controller,
        };

        std::thread::spawn(move || {
            worker.run();
        });

        command_tx
    }

    /// Main worker loop - processes file commands
    fn run(self) {
        while let Ok(command) = self.command_rx.recv() {
            match command {
                FileCommand::Save { path, document, layer_to_track_map, progress_tx } => {
                    self.handle_save(path, document, &layer_to_track_map, progress_tx);
                }
                FileCommand::Load { path, progress_tx } => {
                    self.handle_load(path, progress_tx);
                }
            }
        }
    }

    /// Handle save command
    fn handle_save(
        &self,
        path: std::path::PathBuf,
        document: lightningbeam_core::document::Document,
        layer_to_track_map: &std::collections::HashMap<uuid::Uuid, u32>,
        progress_tx: std::sync::mpsc::Sender<FileProgress>,
    ) {
        use lightningbeam_core::file_io::{save_beam, SaveSettings};

        let save_start = std::time::Instant::now();
        eprintln!("📊 [SAVE] Starting save operation...");

        // Step 1: Serialize audio pool
        let _ = progress_tx.send(FileProgress::SerializingAudioPool);
        let step1_start = std::time::Instant::now();

        let audio_pool_entries = {
            let mut controller = self.audio_controller.lock().unwrap();
            match controller.serialize_audio_pool(&path) {
                Ok(entries) => entries,
                Err(e) => {
                    let _ = progress_tx.send(FileProgress::Error(format!("Failed to serialize audio pool: {}", e)));
                    return;
                }
            }
        };
        eprintln!("📊 [SAVE] Step 1: Serialize audio pool took {:.2}ms", step1_start.elapsed().as_secs_f64() * 1000.0);

        // Step 2: Get project
        let step2_start = std::time::Instant::now();
        let mut audio_project = {
            let mut controller = self.audio_controller.lock().unwrap();
            match controller.get_project() {
                Ok(p) => p,
                Err(e) => {
                    let _ = progress_tx.send(FileProgress::Error(format!("Failed to get project: {}", e)));
                    return;
                }
            }
        };
        eprintln!("📊 [SAVE] Step 2: Get audio project took {:.2}ms", step2_start.elapsed().as_secs_f64() * 1000.0);

        // Step 3: Save to file
        let _ = progress_tx.send(FileProgress::WritingZip);
        let step3_start = std::time::Instant::now();

        let settings = SaveSettings::default();
        match save_beam(&path, &document, &mut audio_project, audio_pool_entries, layer_to_track_map, &settings) {
            Ok(()) => {
                eprintln!("📊 [SAVE] Step 3: save_beam() took {:.2}ms", step3_start.elapsed().as_secs_f64() * 1000.0);
                eprintln!("📊 [SAVE] ✅ Total save time: {:.2}ms", save_start.elapsed().as_secs_f64() * 1000.0);
                println!("✅ Saved to: {}", path.display());
                let _ = progress_tx.send(FileProgress::Done);
            }
            Err(e) => {
                let _ = progress_tx.send(FileProgress::Error(format!("Save failed: {}", e)));
            }
        }
    }

    /// Handle load command
    fn handle_load(
        &self,
        path: std::path::PathBuf,
        progress_tx: std::sync::mpsc::Sender<FileProgress>,
    ) {
        use lightningbeam_core::file_io::load_beam;

        let load_start = std::time::Instant::now();
        eprintln!("📊 [LOAD] Starting load operation...");

        // Step 1: Load from file
        let _ = progress_tx.send(FileProgress::LoadingProject);
        let step1_start = std::time::Instant::now();

        let loaded_project = match load_beam(&path) {
            Ok(p) => p,
            Err(e) => {
                let _ = progress_tx.send(FileProgress::Error(format!("Load failed: {}", e)));
                return;
            }
        };
        eprintln!("📊 [LOAD] Step 1: load_beam() took {:.2}ms", step1_start.elapsed().as_secs_f64() * 1000.0);

        // Check for missing files
        if !loaded_project.missing_files.is_empty() {
            eprintln!("⚠️ {} missing files", loaded_project.missing_files.len());
            for missing in &loaded_project.missing_files {
                eprintln!("   - {}", missing.original_path.display());
            }
        }

        eprintln!("📊 [LOAD] ✅ Total load time: {:.2}ms", load_start.elapsed().as_secs_f64() * 1000.0);

        // Send the loaded project back to UI thread for processing
        let _ = progress_tx.send(FileProgress::Complete(Ok(loaded_project)));
    }
}

/// Result from background audio extraction thread
#[derive(Debug)]
enum AudioExtractionResult {
    Success {
        video_clip_id: Uuid,
        audio_clip: lightningbeam_core::clip::AudioClip,
        pool_index: usize,
        video_name: String,
        channels: u32,
        sample_rate: u32,
    },
    NoAudio {
        video_clip_id: Uuid,
    },
    Error {
        video_clip_id: Uuid,
        error: String,
    },
}

/// Application mode - controls whether to show start screen or editor
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum AppMode {
    /// Show the start screen (recent projects, new project options)
    StartScreen,
    /// Show the main editor interface
    Editor,
}

/// Icons for the focus cards on the start screen
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
enum FocusIcon {
    Animation,
    Music,
    Video,
}

/// Recording arm mode - determines how tracks are armed for recording
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
enum RecordingArmMode {
    /// Armed state follows active track (simple single-track workflow)
    #[default]
    Auto,
    /// User explicitly arms tracks (multi-track recording workflow)
    #[allow(dead_code)]
    Manual,
}

struct EditorApp {
    layouts: Vec<LayoutDefinition>,
    current_layout_index: usize,
    current_layout: LayoutNode, // Mutable copy for editing
    drag_state: DragState,
    hovered_divider: Option<(NodePath, bool)>, // (path, is_horizontal)
    selected_pane: Option<NodePath>, // Currently selected pane for editing
    split_preview_mode: SplitPreviewMode,
    icon_cache: IconCache,
    tool_icon_cache: ToolIconCache,
    focus_icon_cache: FocusIconCache, // Focus card icons (start screen)
    selected_tool: Tool, // Currently selected drawing tool
    fill_color: egui::Color32, // Fill color for drawing
    stroke_color: egui::Color32, // Stroke color for drawing
    active_color_mode: panes::ColorMode, // Which color (fill/stroke) was last interacted with
    pane_instances: HashMap<NodePath, PaneInstance>, // Pane instances per path
    menu_system: Option<MenuSystem>, // Native menu system for event checking
    pending_view_action: Option<MenuAction>, // Pending view action (zoom, recenter) to be handled by hovered pane
    theme: Theme, // Theme system for colors and dimensions
    action_executor: lightningbeam_core::action::ActionExecutor, // Action system for undo/redo
    active_layer_id: Option<Uuid>, // Currently active layer for editing
    selection: lightningbeam_core::selection::Selection, // Current selection state
    tool_state: lightningbeam_core::tool::ToolState, // Current tool interaction state
    // Draw tool configuration
    draw_simplify_mode: lightningbeam_core::tool::SimplifyMode, // Current simplification mode for draw tool
    rdp_tolerance: f64, // RDP simplification tolerance (default: 10.0)
    schneider_max_error: f64, // Schneider curve fitting max error (default: 30.0)
    // Audio engine integration
    #[allow(dead_code)] // Must be kept alive to maintain audio output
    audio_stream: Option<cpal::Stream>,
    audio_controller: Option<std::sync::Arc<std::sync::Mutex<daw_backend::EngineController>>>,
    audio_event_rx: Option<rtrb::Consumer<daw_backend::AudioEvent>>,
    audio_events_pending: std::sync::Arc<std::sync::atomic::AtomicBool>,
    #[allow(dead_code)] // Stored for future export/recording configuration
    audio_sample_rate: u32,
    #[allow(dead_code)]
    audio_channels: u32,
    // Video decoding and management
    video_manager: std::sync::Arc<std::sync::Mutex<lightningbeam_core::video::VideoManager>>, // Shared video manager
    // Track ID mapping (Document layer UUIDs <-> daw-backend TrackIds)
    layer_to_track_map: HashMap<Uuid, daw_backend::TrackId>,
    track_to_layer_map: HashMap<daw_backend::TrackId, Uuid>,
    /// Generation counter - incremented on project load to force UI components to reload
    project_generation: u64,
    // Clip instance ID mapping (Document clip instance UUIDs <-> backend clip instance IDs)
    clip_instance_to_backend_map: HashMap<Uuid, lightningbeam_core::action::BackendClipInstanceId>,
    // Playback state (global for all panes)
    playback_time: f64, // Current playback position in seconds (persistent - save with document)
    is_playing: bool,   // Whether playback is currently active (transient - don't save)
    // Recording state
    #[allow(dead_code)] // Infrastructure for Manual recording mode
    recording_arm_mode: RecordingArmMode,
    #[allow(dead_code)]
    armed_layers: HashSet<Uuid>,
    is_recording: bool,                   // Whether recording is currently active
    recording_clips: HashMap<Uuid, u32>,  // layer_id -> backend clip_id during recording
    recording_start_time: f64,            // Playback time when recording started
    recording_layer_id: Option<Uuid>,     // Layer being recorded to (for creating clips)
    // Asset drag-and-drop state
    dragging_asset: Option<panes::DraggingAsset>, // Asset being dragged from Asset Library
    // Clipboard
    clipboard_manager: lightningbeam_core::clipboard::ClipboardManager,
    // Shader editor inter-pane communication
    effect_to_load: Option<Uuid>, // Effect ID to load into shader editor (set by asset library)
    // Effect thumbnail invalidation queue (persists across frames until processed)
    effect_thumbnails_to_invalidate: Vec<Uuid>,
    // Import dialog state
    last_import_filter: ImportFilter, // Last used import filter (remembered across imports)
    // Tool-specific options (displayed in infopanel)
    stroke_width: f64,               // Stroke width for drawing tools (default: 3.0)
    fill_enabled: bool,              // Whether to fill shapes (default: true)
    paint_bucket_gap_tolerance: f64, // Fill gap tolerance for paint bucket (default: 5.0)
    polygon_sides: u32,              // Number of sides for polygon tool (default: 5)

    /// Cache for MIDI event data (keyed by backend midi_clip_id)
    /// Prevents repeated backend queries for the same MIDI clip
    /// Format: (timestamp, note_number, velocity, is_note_on)
    midi_event_cache: HashMap<u32, Vec<(f64, u8, u8, bool)>>,
    /// Cache for audio file durations to avoid repeated queries
    /// Format: pool_index -> duration in seconds
    audio_duration_cache: HashMap<usize, f64>,
    /// Track which audio pool indices got new raw audio data this frame (for thumbnail invalidation)
    audio_pools_with_new_waveforms: HashSet<usize>,
    /// Raw audio sample cache for GPU waveform rendering
    /// Format: pool_index -> (samples, sample_rate, channels)
    raw_audio_cache: HashMap<usize, (Arc<Vec<f32>>, u32, u32)>,
    /// Pool indices that need GPU texture upload (set when raw audio arrives, cleared after upload)
    waveform_gpu_dirty: HashSet<usize>,
    /// Consumer for recording audio mirror (streams recorded samples to UI for live waveform)
    recording_mirror_rx: Option<rtrb::Consumer<f32>>,
    /// Current file path (None if not yet saved)
    current_file_path: Option<std::path::PathBuf>,
    /// Application configuration (recent files, etc.)
    config: AppConfig,

    /// File operations worker command sender
    file_command_tx: std::sync::mpsc::Sender<FileCommand>,
    /// Current file operation in progress (if any)
    file_operation: Option<FileOperation>,

    /// Audio extraction channel for background thread communication
    audio_extraction_tx: std::sync::mpsc::Sender<AudioExtractionResult>,
    audio_extraction_rx: std::sync::mpsc::Receiver<AudioExtractionResult>,

    /// Export dialog state
    export_dialog: export::dialog::ExportDialog,
    /// Export progress dialog
    export_progress_dialog: export::dialog::ExportProgressDialog,
    /// Preferences dialog
    preferences_dialog: preferences::dialog::PreferencesDialog,
    /// Export orchestrator for background exports
    export_orchestrator: Option<export::ExportOrchestrator>,
    /// GPU-rendered effect thumbnail generator
    effect_thumbnail_generator: Option<EffectThumbnailGenerator>,

    /// Debug overlay (F3) state
    debug_overlay_visible: bool,
    debug_stats_collector: debug_overlay::DebugStatsCollector,
    gpu_info: Option<wgpu::AdapterInfo>,
    /// Surface texture format for GPU rendering (Rgba8Unorm or Bgra8Unorm depending on platform)
    target_format: wgpu::TextureFormat,
    /// Current application mode (start screen vs editor)
    app_mode: AppMode,
    /// Pending auto-reopen file path (set on startup if reopen_last_session is enabled)
    pending_auto_reopen: Option<std::path::PathBuf>,
}

/// Import filter types for the file dialog
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
enum ImportFilter {
    #[default]
    All,
    Images,
    Audio,
    Video,
    Midi,
}

impl EditorApp {
    fn new(cc: &eframe::CreationContext, layouts: Vec<LayoutDefinition>, theme: Theme) -> Self {
        let current_layout = layouts[0].layout.clone();

        // Disable egui's "Unaligned" debug overlay (on by default in debug builds)
        #[cfg(debug_assertions)]
        cc.egui_ctx.style_mut(|style| style.debug.show_unaligned = false);

        // Load application config
        let config = AppConfig::load();

        // Check if we should auto-reopen last session
        let pending_auto_reopen = if config.reopen_last_session {
            config.get_recent_files().into_iter().next()
        } else {
            None
        };

        // Initialize native menu system
        let mut menu_system = MenuSystem::new().ok();

        // Populate recent files menu
        if let Some(ref mut menu_sys) = menu_system {
            let recent_files = config.get_recent_files();
            menu_sys.update_recent_files(&recent_files);
        }

        // Create default document with a simple test scene
        let mut document = lightningbeam_core::document::Document::with_size("Untitled Animation", 1920.0, 1080.0)
            .with_duration(10.0)
            .with_framerate(60.0);

        // Add a test layer with a simple shape to visualize
        use lightningbeam_core::layer::{AnyLayer, VectorLayer};
        use lightningbeam_core::object::ShapeInstance;
        use lightningbeam_core::shape::{Shape, ShapeColor};
        use vello::kurbo::{Circle, Shape as KurboShape};

        // Create circle centered at origin, position via instance transform
        let circle = Circle::new((0.0, 0.0), 50.0);
        let path = circle.to_path(0.1);
        let shape = Shape::new(path).with_fill(ShapeColor::rgb(100, 150, 250));
        let object = ShapeInstance::new(shape.id).with_position(200.0, 150.0);

        let mut vector_layer = VectorLayer::new("Layer 1");
        vector_layer.add_shape(shape);
        vector_layer.add_object(object);
        let layer_id = document.root.add_child(AnyLayer::Vector(vector_layer));

        // Wrap document in ActionExecutor
        let action_executor = lightningbeam_core::action::ActionExecutor::new(document);

        // Initialize audio system and destructure it for sharing
        let (audio_stream, audio_controller, audio_event_rx, audio_sample_rate, audio_channels, file_command_tx, recording_mirror_rx) =
            match daw_backend::AudioSystem::new(None, config.audio_buffer_size) {
                Ok(mut audio_system) => {
                    println!("✅ Audio engine initialized successfully");

                    // Extract components
                    let mirror_rx = audio_system.take_recording_mirror_rx();
                    let stream = audio_system.stream;
                    let sample_rate = audio_system.sample_rate;
                    let channels = audio_system.channels;
                    let event_rx = audio_system.event_rx;

                    // Wrap controller in Arc<Mutex<>> for sharing with worker thread
                    let controller = std::sync::Arc::new(std::sync::Mutex::new(audio_system.controller));

                    // Spawn file operations worker
                    let file_command_tx = FileOperationsWorker::spawn(controller.clone());

                    (Some(stream), Some(controller), event_rx, sample_rate, channels, file_command_tx, mirror_rx)
                }
                Err(e) => {
                    eprintln!("❌ Failed to initialize audio engine: {}", e);
                    eprintln!("   Playback will be disabled");

                    // Create a dummy channel for file operations (won't be used)
                    let (tx, _rx) = std::sync::mpsc::channel();
                    (None, None, None, 48000, 2, tx, None)
                }
            };

        // Create audio extraction channel for background thread communication
        let (audio_extraction_tx, audio_extraction_rx) = std::sync::mpsc::channel();

        // Extract GPU info for debug overlay
        let gpu_info = cc.wgpu_render_state.as_ref().map(|rs| rs.adapter.get_info());

        // Get surface format (defaults to Rgba8Unorm if render_state not available)
        let target_format = cc.wgpu_render_state.as_ref()
            .map(|rs| rs.target_format)
            .unwrap_or(wgpu::TextureFormat::Rgba8Unorm);

        Self {
            layouts,
            current_layout_index: 0,
            current_layout,
            drag_state: DragState::default(),
            hovered_divider: None,
            selected_pane: None,
            split_preview_mode: SplitPreviewMode::default(),
            icon_cache: IconCache::new(),
            tool_icon_cache: ToolIconCache::new(),
            focus_icon_cache: FocusIconCache::new(),
            selected_tool: Tool::Select, // Default tool
            fill_color: egui::Color32::from_rgb(100, 100, 255), // Default blue fill
            stroke_color: egui::Color32::from_rgb(0, 0, 0), // Default black stroke
            active_color_mode: panes::ColorMode::default(), // Default to fill color
            pane_instances: HashMap::new(), // Initialize empty, panes created on-demand
            menu_system,
            pending_view_action: None,
            theme,
            action_executor,
            active_layer_id: Some(layer_id),
            selection: lightningbeam_core::selection::Selection::new(),
            tool_state: lightningbeam_core::tool::ToolState::default(),
            draw_simplify_mode: lightningbeam_core::tool::SimplifyMode::Smooth, // Default to smooth curves
            rdp_tolerance: 10.0, // Default RDP tolerance
            schneider_max_error: 30.0, // Default Schneider max error
            audio_stream,
            audio_controller,
            audio_event_rx,
            audio_events_pending: std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)),
            audio_sample_rate,
            audio_channels,
            video_manager: std::sync::Arc::new(std::sync::Mutex::new(
                lightningbeam_core::video::VideoManager::new()
            )),
            layer_to_track_map: HashMap::new(),
            track_to_layer_map: HashMap::new(),
            project_generation: 0,
            clip_instance_to_backend_map: HashMap::new(),
            playback_time: 0.0, // Start at beginning
            is_playing: false,  // Start paused
            recording_arm_mode: RecordingArmMode::default(), // Auto mode by default
            armed_layers: HashSet::new(),     // No layers explicitly armed
            is_recording: false,              // Not recording initially
            recording_clips: HashMap::new(),  // No active recording clips
            recording_start_time: 0.0,        // Will be set when recording starts
            recording_layer_id: None,         // Will be set when recording starts
            dragging_asset: None, // No asset being dragged initially
            clipboard_manager: lightningbeam_core::clipboard::ClipboardManager::new(),
            effect_to_load: None, // No effect to load initially
            effect_thumbnails_to_invalidate: Vec::new(), // No thumbnails to invalidate initially
            last_import_filter: ImportFilter::default(), // Default to "All Supported"
            stroke_width: 3.0,               // Default stroke width
            fill_enabled: true,              // Default to filling shapes
            paint_bucket_gap_tolerance: 5.0, // Default gap tolerance
            polygon_sides: 5,                // Default to pentagon
            midi_event_cache: HashMap::new(), // Initialize empty MIDI event cache
            audio_duration_cache: HashMap::new(), // Initialize empty audio duration cache
            audio_pools_with_new_waveforms: HashSet::new(), // Track pool indices with new raw audio
            raw_audio_cache: HashMap::new(),
            waveform_gpu_dirty: HashSet::new(),
            recording_mirror_rx,
            current_file_path: None, // No file loaded initially
            config,
            file_command_tx,
            file_operation: None, // No file operation in progress initially
            audio_extraction_tx,
            audio_extraction_rx,
            export_dialog: export::dialog::ExportDialog::default(),
            export_progress_dialog: export::dialog::ExportProgressDialog::default(),
            preferences_dialog: preferences::dialog::PreferencesDialog::default(),
            export_orchestrator: None,
            effect_thumbnail_generator: None, // Initialized when GPU available

            // Debug overlay (F3)
            debug_overlay_visible: false,
            debug_stats_collector: debug_overlay::DebugStatsCollector::new(),
            gpu_info,
            target_format,
            // Start screen vs editor mode
            app_mode: AppMode::StartScreen, // Always start with start screen (auto-reopen handled separately)
            pending_auto_reopen,
        }
    }

    /// Render the start screen with recent projects and new project options
    fn render_start_screen(&mut self, ctx: &egui::Context) {
        egui::CentralPanel::default().show(ctx, |ui| {
            let available = ui.available_rect_before_wrap();

            // Calculate content dimensions
            let card_size: f32 = 180.0;
            let card_spacing: f32 = 24.0;
            let left_width: f32 = 350.0;
            let right_width = (card_size * 3.0) + (card_spacing * 2.0);
            let content_width = (left_width + right_width + 80.0).min(available.width() - 100.0);
            let content_height: f32 = 450.0; // Approximate height of content

            // Center content both horizontally and vertically
            let content_rect = egui::Rect::from_center_size(
                available.center(),
                egui::vec2(content_width, content_height),
            );

            ui.scope_builder(egui::UiBuilder::new().max_rect(content_rect), |ui| {
                ui.vertical_centered(|ui| {
                    // Title
                    ui.heading(egui::RichText::new("Welcome to Lightningbeam!")
                        .size(42.0)
                        .strong());

                    ui.add_space(50.0);

                    // Main content area - two columns side by side
                    let recent_files = self.config.get_recent_files();

                    // Use columns for proper two-column layout
                    ui.columns(2, |columns| {
                        // Left column: Recent projects (stacked vertically)
                        columns[0].vertical(|ui| {
                            // Reopen last session section
                            ui.label(egui::RichText::new("Reopen last session")
                                .size(18.0)
                                .strong());
                            ui.add_space(16.0);

                            if let Some(last_file) = recent_files.first() {
                                let file_name = last_file.file_name()
                                    .map(|s| s.to_string_lossy().to_string())
                                    .unwrap_or_else(|| "Unknown".to_string());
                                if self.render_file_item(ui, &file_name, left_width) {
                                    self.load_from_file(last_file.clone());
                                    self.app_mode = AppMode::Editor;
                                }
                            } else {
                                ui.label(egui::RichText::new("No recent session")
                                    .color(egui::Color32::from_gray(120)));
                            }

                            ui.add_space(32.0);

                            // Recent projects section
                            ui.label(egui::RichText::new("Recent projects")
                                .size(18.0)
                                .strong());
                            ui.add_space(16.0);

                            if recent_files.len() > 1 {
                                for file in recent_files.iter().skip(1).take(5) {
                                    let file_name = file.file_name()
                                        .map(|s| s.to_string_lossy().to_string())
                                        .unwrap_or_else(|| "Unknown".to_string());
                                    if self.render_file_item(ui, &file_name, left_width) {
                                        self.load_from_file(file.clone());
                                        self.app_mode = AppMode::Editor;
                                    }
                                    ui.add_space(8.0);
                                }
                            } else {
                                ui.label(egui::RichText::new("No other recent projects")
                                    .color(egui::Color32::from_gray(120)));
                            }
                        });

                        // Right column: Create new project
                        columns[1].vertical_centered(|ui| {
                            ui.label(egui::RichText::new("Create a new project")
                                .size(18.0)
                                .strong());
                            ui.add_space(24.0);

                            // Focus cards in a horizontal row
                            ui.horizontal(|ui| {
                                // Animation
                                let (rect, response) = ui.allocate_exact_size(
                                    egui::vec2(card_size, card_size + 40.0),
                                    egui::Sense::click(),
                                );
                                self.render_focus_card_with_icon(ui, rect, response.hovered(), "Animation", FocusIcon::Animation);
                                if response.clicked() {
                                    self.create_new_project_with_focus(0);
                                }

                                ui.add_space(card_spacing);

                                // Music
                                let (rect, response) = ui.allocate_exact_size(
                                    egui::vec2(card_size, card_size + 40.0),
                                    egui::Sense::click(),
                                );
                                self.render_focus_card_with_icon(ui, rect, response.hovered(), "Music", FocusIcon::Music);
                                if response.clicked() {
                                    self.create_new_project_with_focus(2);
                                }

                                ui.add_space(card_spacing);

                                // Video editing
                                let (rect, response) = ui.allocate_exact_size(
                                    egui::vec2(card_size, card_size + 40.0),
                                    egui::Sense::click(),
                                );
                                self.render_focus_card_with_icon(ui, rect, response.hovered(), "Video editing", FocusIcon::Video);
                                if response.clicked() {
                                    self.create_new_project_with_focus(1);
                                }
                            });
                        });
                    });
                });
            });
        });
    }

    /// Render a clickable file item (for recent projects list)
    fn render_file_item(&self, ui: &mut egui::Ui, name: &str, width: f32) -> bool {
        let height = 36.0;
        let (rect, response) = ui.allocate_exact_size(egui::vec2(width, height), egui::Sense::click());

        let bg_color = if response.hovered() {
            egui::Color32::from_rgb(70, 75, 85)
        } else {
            egui::Color32::from_rgb(55, 60, 70)
        };

        let painter = ui.painter();
        painter.rect_filled(rect, 4.0, bg_color);

        painter.text(
            rect.left_center() + egui::vec2(12.0, 0.0),
            egui::Align2::LEFT_CENTER,
            name,
            egui::FontId::proportional(14.0),
            egui::Color32::from_gray(220),
        );

        response.clicked()
    }

    /// Render a focus card with icon for project creation
    fn render_focus_card_with_icon(&mut self, ui: &egui::Ui, rect: egui::Rect, hovered: bool, title: &str, icon: FocusIcon) {
        let bg_color = if hovered {
            egui::Color32::from_rgb(55, 60, 70)
        } else {
            egui::Color32::from_rgb(45, 50, 58)
        };

        let border_color = egui::Color32::from_rgb(80, 85, 95);

        let painter = ui.painter();

        // Card background
        painter.rect_filled(rect, 8.0, bg_color);
        painter.rect_stroke(rect, 8.0, egui::Stroke::new(1.5, border_color), egui::StrokeKind::Inside);

        // Icon area - render SVG texture
        let icon_color = egui::Color32::from_gray(200);
        let icon_center = rect.center_top() + egui::vec2(0.0, 50.0);
        let icon_display_size = 60.0;

        // Get or load the SVG icon texture
        let ctx = ui.ctx().clone();
        if let Some(texture) = self.focus_icon_cache.get_or_load(icon, icon_color, &ctx) {
            let texture_size = texture.size_vec2();
            let scale = icon_display_size / texture_size.x.max(texture_size.y);
            let scaled_size = texture_size * scale;

            let icon_rect = egui::Rect::from_center_size(icon_center, scaled_size);
            painter.image(
                texture.id(),
                icon_rect,
                egui::Rect::from_min_max(egui::pos2(0.0, 0.0), egui::pos2(1.0, 1.0)),
                egui::Color32::WHITE,
            );
        }

        // Title at bottom
        painter.text(
            rect.center_bottom() - egui::vec2(0.0, 20.0),
            egui::Align2::CENTER_CENTER,
            title,
            egui::FontId::proportional(14.0),
            egui::Color32::WHITE,
        );
    }

    /// Render a focus card for project creation (legacy, kept for compatibility)
    #[allow(dead_code)]
    fn render_focus_card(&self, ui: &mut egui::Ui, rect: egui::Rect, hovered: bool, title: &str, description: &str, _layout_index: usize) {
        let bg_color = if hovered {
            egui::Color32::from_rgb(60, 70, 90)
        } else {
            egui::Color32::from_rgb(45, 50, 60)
        };

        let painter = ui.painter();

        // Background with rounded corners
        painter.rect_filled(rect, 8.0, bg_color);

        // Border
        if hovered {
            painter.rect_stroke(
                rect,
                8.0,
                egui::Stroke::new(2.0, egui::Color32::from_rgb(100, 140, 200)),
                egui::StrokeKind::Inside,
            );
        }

        // Title
        painter.text(
            rect.center_top() + egui::vec2(0.0, 40.0),
            egui::Align2::CENTER_CENTER,
            title,
            egui::FontId::proportional(18.0),
            egui::Color32::WHITE,
        );

        // Description
        painter.text(
            rect.center_top() + egui::vec2(0.0, 70.0),
            egui::Align2::CENTER_CENTER,
            description,
            egui::FontId::proportional(12.0),
            egui::Color32::from_gray(180),
        );
    }

    /// Create a new project with the specified focus/layout
    fn create_new_project_with_focus(&mut self, layout_index: usize) {
        use lightningbeam_core::layer::{AnyLayer, AudioLayer, VectorLayer, VideoLayer};

        // Create a new blank document
        let mut document = lightningbeam_core::document::Document::with_size(
            "Untitled",
            self.config.file_width as f64,
            self.config.file_height as f64,
        )
        .with_duration(60.0) // 1 minute default
        .with_framerate(self.config.framerate as f64);

        // Add default layer based on focus type
        // Layout indices: 0 = Animation, 1 = Video editing, 2 = Music
        let layer_id = match layout_index {
            0 => {
                // Animation focus -> VectorLayer
                let layer = VectorLayer::new("Layer 1");
                document.root.add_child(AnyLayer::Vector(layer))
            }
            1 => {
                // Video editing focus -> VideoLayer
                let layer = VideoLayer::new("Video 1");
                document.root.add_child(AnyLayer::Video(layer))
            }
            2 => {
                // Music focus -> MIDI AudioLayer
                let layer = AudioLayer::new_midi("MIDI 1");
                document.root.add_child(AnyLayer::Audio(layer))
            }
            _ => {
                // Fallback to VectorLayer
                let layer = VectorLayer::new("Layer 1");
                document.root.add_child(AnyLayer::Vector(layer))
            }
        };

        // Reset action executor with new document
        self.action_executor = lightningbeam_core::action::ActionExecutor::new(document);

        // Apply the layout
        if layout_index < self.layouts.len() {
            self.current_layout_index = layout_index;
            self.current_layout = self.layouts[layout_index].layout.clone();
            self.pane_instances.clear(); // Clear old pane instances
        }

        // Clear file path (new unsaved document)
        self.current_file_path = None;

        // Reset selection and set active layer to the newly created one
        self.selection = lightningbeam_core::selection::Selection::new();
        self.active_layer_id = Some(layer_id);

        // For Music focus, sync the MIDI layer with daw-backend
        if layout_index == 2 {
            self.sync_audio_layers_to_backend();
        }

        // Switch to editor mode
        self.app_mode = AppMode::Editor;
    }

    /// Synchronize all existing MIDI layers in the document with daw-backend tracks
    ///
    /// This function should be called:
    /// - After loading a document from file
    /// - After creating a new document with pre-existing MIDI layers
    ///
    /// For each audio layer (MIDI or Sampled):
    /// 1. Creates a daw-backend track (MIDI or Audio)
    /// 2. For MIDI: Loads the default instrument
    /// 3. Stores the bidirectional mapping
    /// 4. Syncs any existing clips on the layer
    fn sync_audio_layers_to_backend(&mut self) {
        use lightningbeam_core::layer::{AnyLayer, AudioLayerType};

        // Iterate through all layers in the document
        for layer in &self.action_executor.document().root.children {
            // Only process Audio layers
            if let AnyLayer::Audio(audio_layer) = layer {
                let layer_id = audio_layer.layer.id;
                let layer_name = &audio_layer.layer.name;

                // Skip if already mapped (shouldn't happen, but be defensive)
                if self.layer_to_track_map.contains_key(&layer_id) {
                    continue;
                }

                // Handle both MIDI and Sampled audio tracks
                match audio_layer.audio_layer_type {
                    AudioLayerType::Midi => {
                        // Create daw-backend MIDI track
                        if let Some(ref controller_arc) = self.audio_controller {
                            let mut controller = controller_arc.lock().unwrap();
                            match controller.create_midi_track_sync(layer_name.clone()) {
                                Ok(track_id) => {
                                    // Store bidirectional mapping
                                    self.layer_to_track_map.insert(layer_id, track_id);
                                    self.track_to_layer_map.insert(track_id, layer_id);

                                    // Load default instrument
                                    if let Err(e) = default_instrument::load_default_instrument(&mut *controller, track_id) {
                                        eprintln!("⚠️  Failed to load default instrument for {}: {}", layer_name, e);
                                    } else {
                                        println!("✅ Synced MIDI layer '{}' to backend (TrackId: {})", layer_name, track_id);
                                    }

                                    // TODO: Sync any existing clips on this layer to the backend
                                    // This will be implemented when we add clip synchronization
                                }
                                Err(e) => {
                                    eprintln!("⚠️  Failed to create daw-backend track for MIDI layer '{}': {}", layer_name, e);
                                }
                            }
                        }
                    }
                    AudioLayerType::Sampled => {
                        // Create daw-backend Audio track
                        if let Some(ref controller_arc) = self.audio_controller {
                            let mut controller = controller_arc.lock().unwrap();
                            match controller.create_audio_track_sync(layer_name.clone()) {
                                Ok(track_id) => {
                                    // Store bidirectional mapping
                                    self.layer_to_track_map.insert(layer_id, track_id);
                                    self.track_to_layer_map.insert(track_id, layer_id);
                                    println!("✅ Synced Audio layer '{}' to backend (TrackId: {})", layer_name, track_id);

                                    // TODO: Sync any existing clips on this layer to the backend
                                    // This will be implemented when we add clip synchronization
                                }
                                Err(e) => {
                                    eprintln!("⚠️  Failed to create daw-backend audio track for '{}': {}", layer_name, e);
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    /// Split clip instances at the current playhead position
    ///
    /// Only splits clips on the active layer, plus any clips linked to them
    /// via instance groups. For video clips with linked audio, the newly
    /// created instances are added to a new group to maintain the link.
    fn split_clips_at_playhead(&mut self) {
        use lightningbeam_core::layer::AnyLayer;
        use lightningbeam_core::actions::SplitClipInstanceAction;
        use lightningbeam_core::instance_group::InstanceGroup;
        use std::collections::HashSet;

        let split_time = self.playback_time;
        let active_layer_id = match self.active_layer_id {
            Some(id) => id,
            None => return, // No active layer, nothing to split
        };

        let document = self.action_executor.document();

        // Helper to find clips that span the playhead in a specific layer
        fn find_splittable_clips(
            clip_instances: &[lightningbeam_core::clip::ClipInstance],
            split_time: f64,
            document: &lightningbeam_core::document::Document,
        ) -> Vec<uuid::Uuid> {
            let mut result = Vec::new();
            for instance in clip_instances {
                if let Some(clip_duration) = document.get_clip_duration(&instance.clip_id) {
                    let effective_duration = instance.effective_duration(clip_duration);
                    let timeline_end = instance.timeline_start + effective_duration;

                    const EPSILON: f64 = 0.001;
                    if split_time > instance.timeline_start + EPSILON
                        && split_time < timeline_end - EPSILON
                    {
                        result.push(instance.id);
                    }
                }
            }
            result
        }

        // First, find clips on the active layer that span the playhead
        let mut clips_to_split: Vec<(uuid::Uuid, uuid::Uuid)> = Vec::new();
        let mut processed_instances: HashSet<uuid::Uuid> = HashSet::new();

        // Get clips on active layer
        if let Some(layer) = document.get_layer(&active_layer_id) {
            let active_layer_clips = match layer {
                AnyLayer::Vector(vl) => find_splittable_clips(&vl.clip_instances, split_time, document),
                AnyLayer::Audio(al) => find_splittable_clips(&al.clip_instances, split_time, document),
                AnyLayer::Video(vl) => find_splittable_clips(&vl.clip_instances, split_time, document),
                AnyLayer::Effect(el) => find_splittable_clips(&el.clip_instances, split_time, document),
            };

            for instance_id in active_layer_clips {
                clips_to_split.push((active_layer_id, instance_id));
                processed_instances.insert(instance_id);

                // Check if this instance is in a group - if so, add all group members
                if let Some(group) = document.find_group_for_instance(&instance_id) {
                    for (member_layer_id, member_instance_id) in group.get_members() {
                        if !processed_instances.contains(member_instance_id) {
                            // Verify this member also spans the playhead
                            if let Some(member_layer) = document.get_layer(member_layer_id) {
                                let member_splittable = match member_layer {
                                    AnyLayer::Vector(vl) => find_splittable_clips(&vl.clip_instances, split_time, document),
                                    AnyLayer::Audio(al) => find_splittable_clips(&al.clip_instances, split_time, document),
                                    AnyLayer::Video(vl) => find_splittable_clips(&vl.clip_instances, split_time, document),
                                    AnyLayer::Effect(el) => find_splittable_clips(&el.clip_instances, split_time, document),
                                };
                                if member_splittable.contains(member_instance_id) {
                                    clips_to_split.push((*member_layer_id, *member_instance_id));
                                    processed_instances.insert(*member_instance_id);
                                }
                            }
                        }
                    }
                }
            }
        }

        if clips_to_split.is_empty() {
            return;
        }

        // Track original instance IDs and which group they belong to (if any)
        // Also pre-generate new instance IDs so we can create groups before executing
        let mut split_info: Vec<(uuid::Uuid, uuid::Uuid, uuid::Uuid, Option<uuid::Uuid>)> = Vec::new();
        // Format: (layer_id, original_instance_id, new_instance_id, original_group_id)

        for (layer_id, instance_id) in &clips_to_split {
            let group_id = document.find_group_for_instance(instance_id).map(|g| g.id);
            let new_instance_id = uuid::Uuid::new_v4();
            split_info.push((*layer_id, *instance_id, new_instance_id, group_id));
        }

        // Execute split actions with pre-generated new instance IDs
        for (layer_id, instance_id, new_instance_id, _) in &split_info {
            let action = SplitClipInstanceAction::with_new_instance_id(
                *layer_id,
                *instance_id,
                split_time,
                *new_instance_id,
            );

            // Execute with backend synchronization
            if let Some(ref controller_arc) = self.audio_controller {
                let mut controller = controller_arc.lock().unwrap();
                let mut backend_context = lightningbeam_core::action::BackendContext {
                    audio_controller: Some(&mut *controller),
                    layer_to_track_map: &self.layer_to_track_map,
                    clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                };

                if let Err(e) = self.action_executor.execute_with_backend(Box::new(action), &mut backend_context) {
                    eprintln!("Split action failed: {}", e);
                    continue;
                }
            } else {
                let boxed_action: Box<dyn lightningbeam_core::action::Action> = Box::new(action);
                if let Err(e) = self.action_executor.execute(boxed_action) {
                    eprintln!("Split action failed: {}", e);
                    continue;
                }
            }
        }

        // Now create groups for the newly created instances to maintain linking
        // Group new instances by their original group membership
        let mut groups_to_create: std::collections::HashMap<uuid::Uuid, Vec<(uuid::Uuid, uuid::Uuid)>> = std::collections::HashMap::new();

        for (layer_id, _, new_instance_id, original_group_id) in &split_info {
            if let Some(group_id) = original_group_id {
                groups_to_create
                    .entry(*group_id)
                    .or_insert_with(Vec::new)
                    .push((*layer_id, *new_instance_id));
            }
        }

        // Create new groups for the split instances
        let document = self.action_executor.document_mut();
        for (_, members) in groups_to_create {
            if members.len() > 1 {
                let mut new_group = InstanceGroup::new();
                for (layer_id, instance_id) in members {
                    new_group.add_member(layer_id, instance_id);
                }
                document.add_instance_group(new_group);
            }
        }
    }

    /// Copy the current selection to the clipboard
    fn clipboard_copy_selection(&mut self) {
        use lightningbeam_core::clipboard::{ClipboardContent, ClipboardLayerType};
        use lightningbeam_core::layer::AnyLayer;

        // Check what's selected: clip instances take priority, then shapes
        if !self.selection.clip_instances().is_empty() {
            let active_layer_id = match self.active_layer_id {
                Some(id) => id,
                None => return,
            };

            let document = self.action_executor.document();
            let layer = match document.get_layer(&active_layer_id) {
                Some(l) => l,
                None => return,
            };

            let layer_type = ClipboardLayerType::from_layer(layer);

            let instances: Vec<_> = match layer {
                AnyLayer::Vector(vl) => &vl.clip_instances,
                AnyLayer::Audio(al) => &al.clip_instances,
                AnyLayer::Video(vl) => &vl.clip_instances,
                AnyLayer::Effect(el) => &el.clip_instances,
            }
            .iter()
            .filter(|ci| self.selection.contains_clip_instance(&ci.id))
            .cloned()
            .collect();

            if instances.is_empty() {
                return;
            }

            // Gather referenced clip definitions
            let mut audio_clips = Vec::new();
            let mut video_clips = Vec::new();
            let mut vector_clips = Vec::new();
            let image_assets = Vec::new();
            let mut seen_clip_ids = std::collections::HashSet::new();

            for inst in &instances {
                if !seen_clip_ids.insert(inst.clip_id) {
                    continue;
                }
                if let Some(clip) = document.get_audio_clip(&inst.clip_id) {
                    audio_clips.push((inst.clip_id, clip.clone()));
                } else if let Some(clip) = document.get_video_clip(&inst.clip_id) {
                    video_clips.push((inst.clip_id, clip.clone()));
                } else if let Some(clip) = document.get_vector_clip(&inst.clip_id) {
                    vector_clips.push((inst.clip_id, clip.clone()));
                }
            }

            // Gather image assets referenced by vector clips
            // (Future: walk vector clip layers for image fill references)

            let content = ClipboardContent::ClipInstances {
                layer_type,
                instances,
                audio_clips,
                video_clips,
                vector_clips,
                image_assets,
            };

            self.clipboard_manager.copy(content);
        } else if !self.selection.shape_instances().is_empty() {
            let active_layer_id = match self.active_layer_id {
                Some(id) => id,
                None => return,
            };

            let document = self.action_executor.document();
            let layer = match document.get_layer(&active_layer_id) {
                Some(l) => l,
                None => return,
            };

            let vector_layer = match layer {
                AnyLayer::Vector(vl) => vl,
                _ => return,
            };

            // Gather selected shape instances and their shape definitions
            let selected_instances: Vec<_> = vector_layer
                .shape_instances
                .iter()
                .filter(|si| self.selection.contains_shape_instance(&si.id))
                .cloned()
                .collect();

            if selected_instances.is_empty() {
                return;
            }

            let mut shapes = Vec::new();
            let mut seen_shape_ids = std::collections::HashSet::new();
            for inst in &selected_instances {
                if seen_shape_ids.insert(inst.shape_id) {
                    if let Some(shape) = vector_layer.shapes.get(&inst.shape_id) {
                        shapes.push((inst.shape_id, shape.clone()));
                    }
                }
            }

            let content = ClipboardContent::Shapes {
                shapes,
                instances: selected_instances,
            };

            self.clipboard_manager.copy(content);
        }
    }

    /// Delete the current selection (for cut and delete operations)
    fn clipboard_delete_selection(&mut self) {
        use lightningbeam_core::layer::AnyLayer;

        if !self.selection.clip_instances().is_empty() {
            let active_layer_id = match self.active_layer_id {
                Some(id) => id,
                None => return,
            };

            // Build removals list
            let removals: Vec<(Uuid, Uuid)> = self
                .selection
                .clip_instances()
                .iter()
                .map(|&id| (active_layer_id, id))
                .collect();

            if removals.is_empty() {
                return;
            }

            let action = lightningbeam_core::actions::RemoveClipInstancesAction::new(removals);

            if let Some(ref controller_arc) = self.audio_controller {
                let mut controller = controller_arc.lock().unwrap();
                let mut backend_context = lightningbeam_core::action::BackendContext {
                    audio_controller: Some(&mut *controller),
                    layer_to_track_map: &self.layer_to_track_map,
                    clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                };
                if let Err(e) = self
                    .action_executor
                    .execute_with_backend(Box::new(action), &mut backend_context)
                {
                    eprintln!("Delete clip instances failed: {}", e);
                }
            } else {
                if let Err(e) = self.action_executor.execute(Box::new(action)) {
                    eprintln!("Delete clip instances failed: {}", e);
                }
            }

            self.selection.clear_clip_instances();
        } else if !self.selection.shape_instances().is_empty() {
            let active_layer_id = match self.active_layer_id {
                Some(id) => id,
                None => return,
            };

            let document = self.action_executor.document();
            let layer = match document.get_layer(&active_layer_id) {
                Some(l) => l,
                None => return,
            };

            let vector_layer = match layer {
                AnyLayer::Vector(vl) => vl,
                _ => return,
            };

            // Collect shape instance IDs and their shape IDs
            let instance_ids: Vec<Uuid> = self.selection.shape_instances().to_vec();
            let mut shape_ids: Vec<Uuid> = Vec::new();
            let mut shape_id_set = std::collections::HashSet::new();

            for inst in &vector_layer.shape_instances {
                if instance_ids.contains(&inst.id) {
                    if shape_id_set.insert(inst.shape_id) {
                        // Only remove shape definition if no other instances reference it
                        let other_refs = vector_layer
                            .shape_instances
                            .iter()
                            .any(|si| si.shape_id == inst.shape_id && !instance_ids.contains(&si.id));
                        if !other_refs {
                            shape_ids.push(inst.shape_id);
                        }
                    }
                }
            }

            let action = lightningbeam_core::actions::RemoveShapesAction::new(
                active_layer_id,
                shape_ids,
                instance_ids,
            );

            if let Err(e) = self.action_executor.execute(Box::new(action)) {
                eprintln!("Delete shapes failed: {}", e);
            }

            self.selection.clear_shape_instances();
            self.selection.clear_shapes();
        }
    }

    /// Paste from clipboard
    fn clipboard_paste(&mut self) {
        use lightningbeam_core::clipboard::ClipboardContent;
        use lightningbeam_core::layer::AnyLayer;

        let content = match self.clipboard_manager.paste() {
            Some(c) => c,
            None => return,
        };

        // Regenerate IDs for the paste
        let (new_content, _id_map) = content.with_regenerated_ids();

        match new_content {
            ClipboardContent::ClipInstances {
                layer_type,
                mut instances,
                audio_clips,
                video_clips,
                vector_clips,
                image_assets,
            } => {
                let active_layer_id = match self.active_layer_id {
                    Some(id) => id,
                    None => return,
                };

                // Verify layer compatibility
                {
                    let document = self.action_executor.document();
                    let layer = match document.get_layer(&active_layer_id) {
                        Some(l) => l,
                        None => return,
                    };
                    if !layer_type.is_compatible(layer) {
                        eprintln!("Cannot paste: incompatible layer type");
                        return;
                    }
                }

                // Add clip definitions to document (they have new IDs from regeneration)
                {
                    let document = self.action_executor.document_mut();
                    for (_id, clip) in &audio_clips {
                        document.audio_clips.insert(clip.id, clip.clone());
                    }
                    for (_id, clip) in &video_clips {
                        document.video_clips.insert(clip.id, clip.clone());
                    }
                    for (_id, clip) in &vector_clips {
                        document.vector_clips.insert(clip.id, clip.clone());
                    }
                    for (_id, asset) in &image_assets {
                        document.image_assets.insert(asset.id, asset.clone());
                    }
                }

                // Position instances at playhead, preserving relative offsets
                if !instances.is_empty() {
                    let min_start = instances
                        .iter()
                        .map(|i| i.timeline_start)
                        .fold(f64::INFINITY, f64::min);
                    let offset = self.playback_time - min_start;
                    for inst in &mut instances {
                        inst.timeline_start = (inst.timeline_start + offset).max(0.0);
                    }
                }

                // Add each instance via action (handles overlap avoidance)
                let new_ids: Vec<Uuid> = instances.iter().map(|i| i.id).collect();

                for instance in instances {
                    let action = lightningbeam_core::actions::AddClipInstanceAction::new(
                        active_layer_id,
                        instance,
                    );

                    if let Some(ref controller_arc) = self.audio_controller {
                        let mut controller = controller_arc.lock().unwrap();
                        let mut backend_context = lightningbeam_core::action::BackendContext {
                            audio_controller: Some(&mut *controller),
                            layer_to_track_map: &self.layer_to_track_map,
                            clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                        };
                        if let Err(e) = self
                            .action_executor
                            .execute_with_backend(Box::new(action), &mut backend_context)
                        {
                            eprintln!("Paste clip failed: {}", e);
                        }
                    } else {
                        if let Err(e) = self.action_executor.execute(Box::new(action)) {
                            eprintln!("Paste clip failed: {}", e);
                        }
                    }
                }

                // Select pasted clips
                self.selection.clear_clip_instances();
                for id in new_ids {
                    self.selection.add_clip_instance(id);
                }
            }
            ClipboardContent::Shapes {
                shapes,
                instances,
            } => {
                let active_layer_id = match self.active_layer_id {
                    Some(id) => id,
                    None => return,
                };

                // Add shapes and instances to the active vector layer
                let document = self.action_executor.document_mut();
                let layer = match document.get_layer_mut(&active_layer_id) {
                    Some(l) => l,
                    None => return,
                };

                let vector_layer = match layer {
                    AnyLayer::Vector(vl) => vl,
                    _ => {
                        eprintln!("Cannot paste shapes: not a vector layer");
                        return;
                    }
                };

                let new_instance_ids: Vec<Uuid> = instances.iter().map(|i| i.id).collect();

                for (id, shape) in shapes {
                    vector_layer.shapes.insert(id, shape);
                }
                for inst in instances {
                    vector_layer.shape_instances.push(inst);
                }

                // Select pasted shapes
                self.selection.clear_shape_instances();
                for id in new_instance_ids {
                    self.selection.add_shape_instance(id);
                }
            }
        }
    }

    /// Duplicate the selected clip instances on the active layer.
    /// Each duplicate is placed immediately after the original clip.
    fn duplicate_selected_clips(&mut self) {
        use lightningbeam_core::layer::AnyLayer;
        use lightningbeam_core::actions::AddClipInstanceAction;

        let active_layer_id = match self.active_layer_id {
            Some(id) => id,
            None => return,
        };

        let document = self.action_executor.document();
        let selection = &self.selection;

        // Find selected clip instances on the active layer
        let clips_to_duplicate: Vec<lightningbeam_core::clip::ClipInstance> = {
            let layer = match document.get_layer(&active_layer_id) {
                Some(l) => l,
                None => return,
            };
            let instances = match layer {
                AnyLayer::Vector(vl) => &vl.clip_instances,
                AnyLayer::Audio(al) => &al.clip_instances,
                AnyLayer::Video(vl) => &vl.clip_instances,
                AnyLayer::Effect(el) => &el.clip_instances,
            };
            instances.iter()
                .filter(|ci| selection.contains_clip_instance(&ci.id))
                .cloned()
                .collect()
        };

        if clips_to_duplicate.is_empty() {
            return;
        }

        // Collect all duplicate instances upfront to release the document borrow
        let duplicates: Vec<lightningbeam_core::clip::ClipInstance> = clips_to_duplicate.iter().map(|original| {
            let mut duplicate = original.clone();
            duplicate.id = uuid::Uuid::new_v4();
            let clip_duration = document.get_clip_duration(&original.clip_id).unwrap_or(1.0);
            let effective_duration = original.effective_duration(clip_duration);
            duplicate.timeline_start = original.timeline_start + effective_duration;
            duplicate
        }).collect();

        let new_ids: Vec<uuid::Uuid> = duplicates.iter().map(|d| d.id).collect();

        for duplicate in duplicates {
            let action = AddClipInstanceAction::new(active_layer_id, duplicate);

            if let Some(ref controller_arc) = self.audio_controller {
                let mut controller = controller_arc.lock().unwrap();
                let mut backend_context = lightningbeam_core::action::BackendContext {
                    audio_controller: Some(&mut *controller),
                    layer_to_track_map: &self.layer_to_track_map,
                    clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                };
                if let Err(e) = self.action_executor.execute_with_backend(Box::new(action), &mut backend_context) {
                    eprintln!("Duplicate clip failed: {}", e);
                }
            } else {
                if let Err(e) = self.action_executor.execute(Box::new(action)) {
                    eprintln!("Duplicate clip failed: {}", e);
                }
            }
        }

        // Select the new duplicates instead of the originals
        self.selection.clear_clip_instances();
        for id in new_ids {
            self.selection.add_clip_instance(id);
        }
    }

    fn switch_layout(&mut self, index: usize) {
        self.current_layout_index = index;
        self.current_layout = self.layouts[index].layout.clone();

        // Clear pane instances so they rebuild with new layout
        self.pane_instances.clear();
    }

    fn apply_layout_action(&mut self, action: LayoutAction) {
        match action {
            LayoutAction::SplitHorizontal(path, percent) => {
                split_node(&mut self.current_layout, &path, true, percent);
            }
            LayoutAction::SplitVertical(path, percent) => {
                split_node(&mut self.current_layout, &path, false, percent);
            }
            LayoutAction::RemoveSplit(path) => {
                remove_split(&mut self.current_layout, &path);
            }
            LayoutAction::EnterSplitPreviewHorizontal => {
                self.split_preview_mode = SplitPreviewMode::Active {
                    is_horizontal: false, // horizontal divider = vertical grid (top/bottom)
                    hovered_pane: None,
                    split_percent: 50.0,
                };
            }
            LayoutAction::EnterSplitPreviewVertical => {
                self.split_preview_mode = SplitPreviewMode::Active {
                    is_horizontal: true, // vertical divider = horizontal grid (left/right)
                    hovered_pane: None,
                    split_percent: 50.0,
                };
            }
        }
    }

    fn handle_menu_action(&mut self, action: MenuAction) {
        match action {
            // File menu
            MenuAction::NewFile => {
                println!("Menu: New File");
                // TODO: Prompt to save current file if modified

                // Create new document
                let mut document = lightningbeam_core::document::Document::with_size("Untitled Animation", 1920.0, 1080.0)
                    .with_duration(10.0)
                    .with_framerate(60.0);

                // Add default layer
                use lightningbeam_core::layer::{AnyLayer, VectorLayer};
                let vector_layer = VectorLayer::new("Layer 1");
                let layer_id = document.root.add_child(AnyLayer::Vector(vector_layer));

                // Replace action executor with new document
                self.action_executor = lightningbeam_core::action::ActionExecutor::new(document);
                self.active_layer_id = Some(layer_id);

                // Reset audio project (send command to create new empty project)
                // TODO: Add ResetProject command to EngineController
                self.layer_to_track_map.clear();
                self.track_to_layer_map.clear();

                // Clear file path
                self.current_file_path = None;
                println!("Created new file");
            }
            MenuAction::NewWindow => {
                println!("Menu: New Window");
                // TODO: Implement new window (requires multi-window support)
            }
            MenuAction::Save => {
                use rfd::FileDialog;

                if let Some(path) = &self.current_file_path {
                    // Save to existing path
                    self.save_to_file(path.clone());
                } else {
                    // No current path, fall through to Save As
                    if let Some(path) = FileDialog::new()
                        .add_filter("Lightningbeam Project", &["beam"])
                        .set_file_name("Untitled.beam")
                        .save_file()
                    {
                        self.save_to_file(path);
                    }
                }
            }
            MenuAction::SaveAs => {
                use rfd::FileDialog;

                let dialog = FileDialog::new()
                    .add_filter("Lightningbeam Project", &["beam"])
                    .set_file_name("Untitled.beam");

                // Set initial directory if we have a current file
                let dialog = if let Some(current_path) = &self.current_file_path {
                    if let Some(parent) = current_path.parent() {
                        dialog.set_directory(parent)
                    } else {
                        dialog
                    }
                } else {
                    dialog
                };

                if let Some(path) = dialog.save_file() {
                    self.save_to_file(path);
                }
            }
            MenuAction::OpenFile => {
                use rfd::FileDialog;

                // TODO: Prompt to save current file if modified

                if let Some(path) = FileDialog::new()
                    .add_filter("Lightningbeam Project", &["beam"])
                    .pick_file()
                {
                    self.load_from_file(path);
                }
            }
            MenuAction::OpenRecent(index) => {
                let recent_files = self.config.get_recent_files();

                if let Some(path) = recent_files.get(index) {
                    // TODO: Prompt to save current file if modified
                    self.load_from_file(path.clone());
                }
            }
            MenuAction::ClearRecentFiles => {
                self.config.clear_recent_files();
                self.update_recent_files_menu();
            }
            MenuAction::Revert => {
                println!("Menu: Revert");
                // TODO: Implement revert
            }
            MenuAction::Import | MenuAction::ImportToLibrary => {
                let auto_place = matches!(action, MenuAction::Import);

                // TODO: Implement auto-placement when auto_place is true

                use lightningbeam_core::file_types::*;
                use rfd::FileDialog;

                // Build file filter from extension constants
                let all_extensions: Vec<&str> = all_supported_extensions();

                // Build dialog with filters in order based on last used filter
                // The first filter added is the default in most file dialogs
                let mut dialog = FileDialog::new().set_title("Import Asset");

                // Add filters in order, with the last-used filter first
                match self.last_import_filter {
                    ImportFilter::All => {
                        dialog = dialog
                            .add_filter("All Supported", &all_extensions)
                            .add_filter("Images", IMAGE_EXTENSIONS)
                            .add_filter("Audio", AUDIO_EXTENSIONS)
                            .add_filter("Video", VIDEO_EXTENSIONS)
                            .add_filter("MIDI", MIDI_EXTENSIONS);
                    }
                    ImportFilter::Images => {
                        dialog = dialog
                            .add_filter("Images", IMAGE_EXTENSIONS)
                            .add_filter("All Supported", &all_extensions)
                            .add_filter("Audio", AUDIO_EXTENSIONS)
                            .add_filter("Video", VIDEO_EXTENSIONS)
                            .add_filter("MIDI", MIDI_EXTENSIONS);
                    }
                    ImportFilter::Audio => {
                        dialog = dialog
                            .add_filter("Audio", AUDIO_EXTENSIONS)
                            .add_filter("All Supported", &all_extensions)
                            .add_filter("Images", IMAGE_EXTENSIONS)
                            .add_filter("Video", VIDEO_EXTENSIONS)
                            .add_filter("MIDI", MIDI_EXTENSIONS);
                    }
                    ImportFilter::Video => {
                        dialog = dialog
                            .add_filter("Video", VIDEO_EXTENSIONS)
                            .add_filter("All Supported", &all_extensions)
                            .add_filter("Images", IMAGE_EXTENSIONS)
                            .add_filter("Audio", AUDIO_EXTENSIONS)
                            .add_filter("MIDI", MIDI_EXTENSIONS);
                    }
                    ImportFilter::Midi => {
                        dialog = dialog
                            .add_filter("MIDI", MIDI_EXTENSIONS)
                            .add_filter("All Supported", &all_extensions)
                            .add_filter("Images", IMAGE_EXTENSIONS)
                            .add_filter("Audio", AUDIO_EXTENSIONS)
                            .add_filter("Video", VIDEO_EXTENSIONS);
                    }
                }

                let file = dialog.pick_file();

                if let Some(path) = file {
                    let _import_timer = std::time::Instant::now();
                    // Get extension and detect file type
                    let extension = path.extension()
                        .and_then(|e| e.to_str())
                        .unwrap_or("");

                    let imported_asset = match get_file_type(extension) {
                        Some(FileType::Image) => {
                            self.last_import_filter = ImportFilter::Images;
                            self.import_image(&path)
                        }
                        Some(FileType::Audio) => {
                            self.last_import_filter = ImportFilter::Audio;
                            self.import_audio(&path)
                        }
                        Some(FileType::Video) => {
                            self.last_import_filter = ImportFilter::Video;
                            self.import_video(&path)
                        }
                        Some(FileType::Midi) => {
                            self.last_import_filter = ImportFilter::Midi;
                            self.import_midi(&path)
                        }
                        None => {
                            println!("Unsupported file type: {}", extension);
                            None
                        }
                    };

                    eprintln!("[TIMING] import took {:.1}ms", _import_timer.elapsed().as_secs_f64() * 1000.0);
                    // Auto-place if this is "Import" (not "Import to Library")
                    if auto_place {
                        if let Some(asset_info) = imported_asset {
                            let _place_timer = std::time::Instant::now();
                            self.auto_place_asset(asset_info);
                            eprintln!("[TIMING] auto_place took {:.1}ms", _place_timer.elapsed().as_secs_f64() * 1000.0);
                        }
                    }
                    eprintln!("[TIMING] total import+place took {:.1}ms", _import_timer.elapsed().as_secs_f64() * 1000.0);
                }
            }
            MenuAction::Export => {
                println!("Menu: Export");
                // Open export dialog with calculated timeline endpoint
                let timeline_endpoint = self.action_executor.document().calculate_timeline_endpoint();
                // Derive project name from the .beam file path, falling back to document name
                let project_name = self.current_file_path.as_ref()
                    .and_then(|p| p.file_stem())
                    .map(|s| s.to_string_lossy().into_owned())
                    .unwrap_or_else(|| self.action_executor.document().name.clone());
                self.export_dialog.open(timeline_endpoint, &project_name);
            }
            MenuAction::Quit => {
                println!("Menu: Quit");
                std::process::exit(0);
            }

            // Edit menu
            MenuAction::Undo => {
                let undo_succeeded = if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    let mut backend_context = lightningbeam_core::action::BackendContext {
                        audio_controller: Some(&mut *controller),
                        layer_to_track_map: &self.layer_to_track_map,
                        clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                    };
                    match self.action_executor.undo_with_backend(&mut backend_context) {
                        Ok(true) => {
                            println!("Undid: {}", self.action_executor.redo_description().unwrap_or_default());
                            true
                        }
                        Ok(false) => { println!("Nothing to undo"); false }
                        Err(e) => { eprintln!("Undo failed: {}", e); false }
                    }
                } else {
                    match self.action_executor.undo() {
                        Ok(true) => {
                            println!("Undid: {}", self.action_executor.redo_description().unwrap_or_default());
                            true
                        }
                        Ok(false) => { println!("Nothing to undo"); false }
                        Err(e) => { eprintln!("Undo failed: {}", e); false }
                    }
                };
                // Rebuild MIDI cache after undo (backend_context dropped, borrows released)
                if undo_succeeded {
                    let midi_update = self.action_executor.last_redo_midi_notes()
                        .map(|(id, notes)| (id, notes.to_vec()));
                    if let Some((clip_id, notes)) = midi_update {
                        self.rebuild_midi_cache_entry(clip_id, &notes);
                    }
                }
            }
            MenuAction::Redo => {
                let redo_succeeded = if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    let mut backend_context = lightningbeam_core::action::BackendContext {
                        audio_controller: Some(&mut *controller),
                        layer_to_track_map: &self.layer_to_track_map,
                        clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                    };
                    match self.action_executor.redo_with_backend(&mut backend_context) {
                        Ok(true) => {
                            println!("Redid: {}", self.action_executor.undo_description().unwrap_or_default());
                            true
                        }
                        Ok(false) => { println!("Nothing to redo"); false }
                        Err(e) => { eprintln!("Redo failed: {}", e); false }
                    }
                } else {
                    match self.action_executor.redo() {
                        Ok(true) => {
                            println!("Redid: {}", self.action_executor.undo_description().unwrap_or_default());
                            true
                        }
                        Ok(false) => { println!("Nothing to redo"); false }
                        Err(e) => { eprintln!("Redo failed: {}", e); false }
                    }
                };
                // Rebuild MIDI cache after redo (backend_context dropped, borrows released)
                if redo_succeeded {
                    let midi_update = self.action_executor.last_undo_midi_notes()
                        .map(|(id, notes)| (id, notes.to_vec()));
                    if let Some((clip_id, notes)) = midi_update {
                        self.rebuild_midi_cache_entry(clip_id, &notes);
                    }
                }
            }
            MenuAction::Cut => {
                self.clipboard_copy_selection();
                self.clipboard_delete_selection();
            }
            MenuAction::Copy => {
                self.clipboard_copy_selection();
            }
            MenuAction::Paste => {
                self.clipboard_paste();
            }
            MenuAction::Delete => {
                self.clipboard_delete_selection();
            }
            MenuAction::SelectAll => {
                println!("Menu: Select All");
                // TODO: Implement select all
            }
            MenuAction::SelectNone => {
                println!("Menu: Select None");
                // TODO: Implement select none
            }
            MenuAction::Preferences => {
                self.preferences_dialog.open(&self.config, &self.theme);
            }

            // Modify menu
            MenuAction::Group => {
                println!("Menu: Group");
                // TODO: Implement group
            }
            MenuAction::SendToBack => {
                println!("Menu: Send to Back");
                // TODO: Implement send to back
            }
            MenuAction::BringToFront => {
                println!("Menu: Bring to Front");
                // TODO: Implement bring to front
            }
            MenuAction::SplitClip => {
                self.split_clips_at_playhead();
            }
            MenuAction::DuplicateClip => {
                self.duplicate_selected_clips();
            }

            // Layer menu
            MenuAction::AddLayer => {
                // Create a new vector layer with a default name
                let layer_count = self.action_executor.document().root.children.len();
                let layer_name = format!("Layer {}", layer_count + 1);

                let action = lightningbeam_core::actions::AddLayerAction::new_vector(layer_name);
                let _ = self.action_executor.execute(Box::new(action));

                // Select the newly created layer (last child in the document)
                if let Some(last_layer) = self.action_executor.document().root.children.last() {
                    self.active_layer_id = Some(last_layer.id());
                }
            }
            MenuAction::AddVideoLayer => {
                println!("Menu: Add Video Layer");
                // Create a new video layer with a default name
                let layer_number = self.action_executor.document().root.children.len() + 1;
                let layer_name = format!("Video {}", layer_number);
                let new_layer = lightningbeam_core::layer::AnyLayer::Video(
                    lightningbeam_core::layer::VideoLayer::new(&layer_name)
                );

                // Add the layer to the document
                self.action_executor.document_mut().root.add_child(new_layer.clone());

                // Set it as the active layer
                if let Some(last_layer) = self.action_executor.document().root.children.last() {
                    self.active_layer_id = Some(last_layer.id());
                }
            }
            MenuAction::AddAudioTrack => {
                // Create a new sampled audio layer with a default name
                let layer_count = self.action_executor.document().root.children.len();
                let layer_name = format!("Audio Track {}", layer_count + 1);

                // Create audio layer in document
                let audio_layer = AudioLayer::new_sampled(layer_name.clone());
                let action = lightningbeam_core::actions::AddLayerAction::new(AnyLayer::Audio(audio_layer));
                let _ = self.action_executor.execute(Box::new(action));

                // Get the newly created layer ID
                if let Some(last_layer) = self.action_executor.document().root.children.last() {
                    let layer_id = last_layer.id();
                    self.active_layer_id = Some(layer_id);

                    // Create corresponding daw-backend audio track
                    if let Some(ref controller_arc) = self.audio_controller {
                        let mut controller = controller_arc.lock().unwrap();
                        match controller.create_audio_track_sync(layer_name.clone()) {
                            Ok(track_id) => {
                                // Store bidirectional mapping
                                self.layer_to_track_map.insert(layer_id, track_id);
                                self.track_to_layer_map.insert(track_id, layer_id);
                                println!("✅ Created {} (backend TrackId: {})", layer_name, track_id);
                            }
                            Err(e) => {
                                eprintln!("⚠️  Failed to create daw-backend audio track for {}: {}", layer_name, e);
                                eprintln!("   Layer created but will be silent until backend track is available");
                            }
                        }
                    }
                }
            }
            MenuAction::AddMidiTrack => {
                // Create a new MIDI audio layer with a default name
                let layer_count = self.action_executor.document().root.children.len();
                let layer_name = format!("MIDI Track {}", layer_count + 1);

                // Create MIDI layer in document
                let midi_layer = AudioLayer::new_midi(layer_name.clone());
                let action = lightningbeam_core::actions::AddLayerAction::new(AnyLayer::Audio(midi_layer));
                let _ = self.action_executor.execute(Box::new(action));

                // Get the newly created layer ID
                if let Some(last_layer) = self.action_executor.document().root.children.last() {
                    let layer_id = last_layer.id();
                    self.active_layer_id = Some(layer_id);

                    // Create corresponding daw-backend MIDI track
                    if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                        match controller.create_midi_track_sync(layer_name.clone()) {
                            Ok(track_id) => {
                                // Store bidirectional mapping
                                self.layer_to_track_map.insert(layer_id, track_id);
                                self.track_to_layer_map.insert(track_id, layer_id);

                                // Load default instrument into the track
                                if let Err(e) = default_instrument::load_default_instrument(&mut *controller, track_id) {
                                    eprintln!("⚠️  Failed to load default instrument for {}: {}", layer_name, e);
                                } else {
                                    println!("✅ Created {} (backend TrackId: {}, instrument: {})",
                                             layer_name, track_id, default_instrument::default_instrument_name());
                                }
                            }
                            Err(e) => {
                                eprintln!("⚠️  Failed to create daw-backend MIDI track for {}: {}", layer_name, e);
                                eprintln!("   Layer created but will be silent until backend track is available");
                            }
                        }
                    } else {
                        println!("⚠️  Audio engine not initialized - {} created but will be silent", layer_name);
                    }
                }
            }
            MenuAction::AddTestClip => {
                // Create a test vector clip and add it to the library (not to timeline)
                use lightningbeam_core::clip::VectorClip;
                use lightningbeam_core::layer::{VectorLayer, AnyLayer};
                use lightningbeam_core::shape::{Shape, ShapeColor};
                use lightningbeam_core::object::ShapeInstance;
                use kurbo::{Circle, Rect, Shape as KurboShape};

                // Generate unique name based on existing clip count
                let clip_count = self.action_executor.document().vector_clips.len();
                let clip_name = format!("Test Clip {}", clip_count + 1);

                let mut test_clip = VectorClip::new(&clip_name, 400.0, 400.0, 5.0);

                // Create a layer with some shapes
                let mut layer = VectorLayer::new("Shapes");

                // Create a red circle shape
                let circle_path = Circle::new((100.0, 100.0), 50.0).to_path(0.1);
                let mut circle_shape = Shape::new(circle_path);
                circle_shape.fill_color = Some(ShapeColor::rgb(255, 0, 0));
                let circle_id = circle_shape.id;
                layer.add_shape(circle_shape);

                // Create a blue rectangle shape
                let rect_path = Rect::new(200.0, 50.0, 350.0, 150.0).to_path(0.1);
                let mut rect_shape = Shape::new(rect_path);
                rect_shape.fill_color = Some(ShapeColor::rgb(0, 0, 255));
                let rect_id = rect_shape.id;
                layer.add_shape(rect_shape);

                // Add shape instances
                layer.shape_instances.push(ShapeInstance::new(circle_id));
                layer.shape_instances.push(ShapeInstance::new(rect_id));

                // Add the layer to the clip
                test_clip.layers.add_root(AnyLayer::Vector(layer));

                // Add to document's clip library only (user drags from Asset Library to timeline)
                let _clip_id = self.action_executor.document_mut().add_vector_clip(test_clip);
                println!("Added '{}' to Asset Library (drag to timeline to use)", clip_name);
            }
            MenuAction::DeleteLayer => {
                println!("Menu: Delete Layer");
                // TODO: Implement delete layer
            }
            MenuAction::ToggleLayerVisibility => {
                println!("Menu: Toggle Layer Visibility");
                // TODO: Implement toggle layer visibility
            }

            // Timeline menu
            MenuAction::NewKeyframe => {
                println!("Menu: New Keyframe");
                // TODO: Implement new keyframe
            }
            MenuAction::NewBlankKeyframe => {
                println!("Menu: New Blank Keyframe");
                // TODO: Implement new blank keyframe
            }
            MenuAction::DeleteFrame => {
                println!("Menu: Delete Frame");
                // TODO: Implement delete frame
            }
            MenuAction::DuplicateKeyframe => {
                println!("Menu: Duplicate Keyframe");
                // TODO: Implement duplicate keyframe
            }
            MenuAction::AddKeyframeAtPlayhead => {
                println!("Menu: Add Keyframe at Playhead");
                // TODO: Implement add keyframe at playhead
            }
            MenuAction::AddMotionTween => {
                println!("Menu: Add Motion Tween");
                // TODO: Implement add motion tween
            }
            MenuAction::AddShapeTween => {
                println!("Menu: Add Shape Tween");
                // TODO: Implement add shape tween
            }
            MenuAction::ReturnToStart => {
                println!("Menu: Return to Start");
                // TODO: Implement return to start
            }
            MenuAction::Play => {
                println!("Menu: Play");
                // TODO: Implement play/pause
            }

            // View menu
            MenuAction::ZoomIn => {
                self.pending_view_action = Some(MenuAction::ZoomIn);
            }
            MenuAction::ZoomOut => {
                self.pending_view_action = Some(MenuAction::ZoomOut);
            }
            MenuAction::ActualSize => {
                self.pending_view_action = Some(MenuAction::ActualSize);
            }
            MenuAction::RecenterView => {
                self.pending_view_action = Some(MenuAction::RecenterView);
            }
            MenuAction::NextLayout => {
                println!("Menu: Next Layout");
                let next_index = (self.current_layout_index + 1) % self.layouts.len();
                self.switch_layout(next_index);
            }
            MenuAction::PreviousLayout => {
                println!("Menu: Previous Layout");
                let prev_index = if self.current_layout_index == 0 {
                    self.layouts.len() - 1
                } else {
                    self.current_layout_index - 1
                };
                self.switch_layout(prev_index);
            }
            MenuAction::SwitchLayout(index) => {
                println!("Menu: Switch to Layout {}", index);
                if index < self.layouts.len() {
                    self.switch_layout(index);
                }
            }

            // Help menu
            MenuAction::About => {
                println!("Menu: About");
                // TODO: Implement about dialog
            }

            // Lightningbeam menu (macOS)
            MenuAction::Settings => {
                println!("Menu: Settings");
                // TODO: Implement settings
            }
            MenuAction::CloseWindow => {
                println!("Menu: Close Window");
                // TODO: Implement close window
            }
        }
    }

    /// Prepare document for saving by storing current UI layout
    fn prepare_document_for_save(&mut self) {
        let doc = self.action_executor.document_mut();

        // Store current layout state
        doc.ui_layout = Some(self.current_layout.clone());

        // Store base layout name for reference
        if self.current_layout_index < self.layouts.len() {
            doc.ui_layout_base = Some(self.layouts[self.current_layout_index].name.clone());
        }
    }

    /// Save the current document to a .beam file
    fn save_to_file(&mut self, path: std::path::PathBuf) {
        println!("Saving to: {}", path.display());

        if self.audio_controller.is_none() {
            eprintln!("❌ Audio system not initialized");
            return;
        }

        // Prepare document for save (including layout)
        self.prepare_document_for_save();

        // Create progress channel
        let (progress_tx, progress_rx) = std::sync::mpsc::channel();

        // Clone document for background thread
        let document = self.action_executor.document().clone();

        // Send save command to worker thread
        let command = FileCommand::Save {
            path: path.clone(),
            document,
            layer_to_track_map: self.layer_to_track_map.clone(),
            progress_tx,
        };

        if let Err(e) = self.file_command_tx.send(command) {
            eprintln!("❌ Failed to send save command: {}", e);
            return;
        }

        // Store operation state
        self.file_operation = Some(FileOperation::Saving {
            path,
            progress_rx,
        });
    }

    /// Load a document from a .beam file
    fn load_from_file(&mut self, path: std::path::PathBuf) {
        println!("Loading from: {}", path.display());

        if self.audio_controller.is_none() {
            eprintln!("❌ Audio system not initialized");
            return;
        }

        // Create progress channel
        let (progress_tx, progress_rx) = std::sync::mpsc::channel();

        // Send load command to worker thread
        let command = FileCommand::Load {
            path: path.clone(),
            progress_tx,
        };

        if let Err(e) = self.file_command_tx.send(command) {
            eprintln!("❌ Failed to send load command: {}", e);
            return;
        }

        // Store operation state
        self.file_operation = Some(FileOperation::Loading {
            path,
            progress_rx,
        });
    }

    /// Update the "Open Recent" menu to reflect current config
    fn update_recent_files_menu(&mut self) {
        if let Some(menu_system) = &mut self.menu_system {
            let recent_files = self.config.get_recent_files();
            menu_system.update_recent_files(&recent_files);
        }
    }

    /// Restore UI layout from loaded document
    fn restore_layout_from_document(&mut self) {
        let doc = self.action_executor.document();

        // Restore saved layout if present
        if let Some(saved_layout) = &doc.ui_layout {
            self.current_layout = saved_layout.clone();

            // Try to find matching base layout by name
            if let Some(base_name) = &doc.ui_layout_base {
                if let Some(index) = self.layouts.iter().position(|l| &l.name == base_name) {
                    self.current_layout_index = index;
                } else {
                    // Base layout not found (maybe renamed/removed), default to first
                    self.current_layout_index = 0;
                }
            }

            println!("✅ Restored UI layout from save file");
        } else {
            // No saved layout (old file format or new project)
            // Keep the default (first layout)
            self.current_layout_index = 0;
            self.current_layout = self.layouts[0].layout.clone();
            println!("ℹ️  No saved layout found, using default");
        }

        // Clear existing pane instances so they rebuild with new layout
        self.pane_instances.clear();
    }

    /// Apply loaded project data (called after successful load in background)
    fn apply_loaded_project(&mut self, loaded_project: lightningbeam_core::file_io::LoadedProject, path: std::path::PathBuf) {
        use lightningbeam_core::action::ActionExecutor;

        let apply_start = std::time::Instant::now();
        eprintln!("📊 [APPLY] Starting apply_loaded_project() on UI thread...");

        // Check for missing files
        if !loaded_project.missing_files.is_empty() {
            eprintln!("⚠️ {} missing files", loaded_project.missing_files.len());
            for missing in &loaded_project.missing_files {
                eprintln!("   - {}", missing.original_path.display());
            }
            // TODO Phase 5: Show recovery dialog
        }

        // Replace document
        let step1_start = std::time::Instant::now();
        self.action_executor = ActionExecutor::new(loaded_project.document);
        eprintln!("📊 [APPLY] Step 1: Replace document took {:.2}ms", step1_start.elapsed().as_secs_f64() * 1000.0);

        // Restore UI layout from loaded document
        let step2_start = std::time::Instant::now();
        self.restore_layout_from_document();
        eprintln!("📊 [APPLY] Step 2: Restore UI layout took {:.2}ms", step2_start.elapsed().as_secs_f64() * 1000.0);

        // Load audio pool FIRST (before setting project, so clips can reference pool entries)
        let step3_start = std::time::Instant::now();
        if let Some(ref controller_arc) = self.audio_controller {
            let mut controller = controller_arc.lock().unwrap();
            let audio_pool_entries = loaded_project.audio_pool_entries;

            eprintln!("📊 [APPLY] Step 3: Starting audio pool load...");
            if let Err(e) = controller.load_audio_pool(audio_pool_entries, &path) {
                eprintln!("❌ Failed to load audio pool: {}", e);
                return;
            }
            eprintln!("📊 [APPLY] Step 3: Load audio pool took {:.2}ms", step3_start.elapsed().as_secs_f64() * 1000.0);

            // Now set project (clips can now reference the loaded pool entries)
            let step4_start = std::time::Instant::now();
            if let Err(e) = controller.set_project(loaded_project.audio_project) {
                eprintln!("❌ Failed to set project: {}", e);
                return;
            }
            eprintln!("📊 [APPLY] Step 4: Set audio project took {:.2}ms", step4_start.elapsed().as_secs_f64() * 1000.0);
        }

        // Reset state and restore track mappings
        let step5_start = std::time::Instant::now();
        self.layer_to_track_map.clear();
        self.track_to_layer_map.clear();

        if !loaded_project.layer_to_track_map.is_empty() {
            // Restore saved mapping (connects UI layers to loaded backend tracks with effects graphs)
            for (&layer_id, &track_id) in &loaded_project.layer_to_track_map {
                self.layer_to_track_map.insert(layer_id, track_id);
                self.track_to_layer_map.insert(track_id, layer_id);
            }
            eprintln!("📊 [APPLY] Step 5: Restored {} track mappings from file in {:.2}ms",
                loaded_project.layer_to_track_map.len(), step5_start.elapsed().as_secs_f64() * 1000.0);
        } else {
            eprintln!("📊 [APPLY] Step 5: No saved track mappings (old file format)");
        }

        // Sync any audio layers that don't have a mapping yet (new layers, or old file format)
        let step6_start = std::time::Instant::now();
        self.sync_audio_layers_to_backend();
        eprintln!("📊 [APPLY] Step 6: Sync audio layers took {:.2}ms", step6_start.elapsed().as_secs_f64() * 1000.0);

        // Increment project generation to force node graph pane reload
        self.project_generation += 1;

        // Fetch raw audio for all audio clips in the loaded project
        let step7_start = std::time::Instant::now();
        let pool_indices: Vec<usize> = self.action_executor.document()
            .audio_clips.values()
            .filter_map(|clip| {
                if let lightningbeam_core::clip::AudioClipType::Sampled { audio_pool_index } = &clip.clip_type {
                    Some(*audio_pool_index)
                } else {
                    None
                }
            })
            .collect();

        let mut raw_fetched = 0;
        for pool_index in pool_indices {
            if !self.raw_audio_cache.contains_key(&pool_index) {
                if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    match controller.get_pool_audio_samples(pool_index) {
                        Ok((samples, sr, ch)) => {
                            self.raw_audio_cache.insert(pool_index, (Arc::new(samples), sr, ch));
                            self.waveform_gpu_dirty.insert(pool_index);
                            raw_fetched += 1;
                        }
                        Err(e) => eprintln!("Failed to fetch raw audio for pool {}: {}", pool_index, e),
                    }
                }
            }
        }
        eprintln!("📊 [APPLY] Step 7: Fetched {} raw audio samples in {:.2}ms", raw_fetched, step7_start.elapsed().as_secs_f64() * 1000.0);

        // Rebuild MIDI event cache for all MIDI clips (needed for timeline/piano roll rendering)
        let step8_start = std::time::Instant::now();
        self.midi_event_cache.clear();
        let midi_clip_ids: Vec<u32> = self.action_executor.document()
            .audio_clips.values()
            .filter_map(|clip| clip.midi_clip_id())
            .collect();

        let mut midi_fetched = 0;
        if let Some(ref controller_arc) = self.audio_controller {
            let mut controller = controller_arc.lock().unwrap();
            for clip_id in midi_clip_ids {
                // track_id is unused by the query, pass 0
                match controller.query_midi_clip(0, clip_id) {
                    Ok(clip_data) => {
                        let processed_events: Vec<(f64, u8, u8, bool)> = clip_data.events.iter()
                            .filter_map(|event| {
                                let status_type = event.status & 0xF0;
                                if status_type == 0x90 || status_type == 0x80 {
                                    let is_note_on = status_type == 0x90 && event.data2 > 0;
                                    Some((event.timestamp, event.data1, event.data2, is_note_on))
                                } else {
                                    None
                                }
                            })
                            .collect();
                        self.midi_event_cache.insert(clip_id, processed_events);
                        midi_fetched += 1;
                    }
                    Err(e) => eprintln!("Failed to fetch MIDI clip {}: {}", clip_id, e),
                }
            }
        }
        eprintln!("📊 [APPLY] Step 8: Rebuilt MIDI event cache for {} clips in {:.2}ms", midi_fetched, step8_start.elapsed().as_secs_f64() * 1000.0);

        // Reset playback state
        self.playback_time = 0.0;
        self.is_playing = false;
        self.current_file_path = Some(path.clone());

        // Add to recent files
        self.config.add_recent_file(path.clone());
        self.update_recent_files_menu();

        // Set active layer
        if let Some(first) = self.action_executor.document().root.children.first() {
            self.active_layer_id = Some(first.id());
        }

        eprintln!("📊 [APPLY] ✅ Total apply_loaded_project() time: {:.2}ms", apply_start.elapsed().as_secs_f64() * 1000.0);
        println!("✅ Loaded from: {}", path.display());
    }

    /// Import an image file as an ImageAsset
    fn import_image(&mut self, path: &std::path::Path) -> Option<ImportedAssetInfo> {
        use lightningbeam_core::clip::ImageAsset;

        // Get filename for asset name
        let name = path.file_stem()
            .and_then(|s| s.to_str())
            .unwrap_or("Untitled Image")
            .to_string();

        // Load image to get dimensions
        match image::open(path) {
            Ok(img) => {
                let (width, height) = (img.width(), img.height());

                // Read raw file data for embedding
                let data = match std::fs::read(path) {
                    Ok(data) => Some(data),
                    Err(e) => {
                        eprintln!("Warning: Could not embed image data: {}", e);
                        None
                    }
                };

                // Create image asset
                let mut asset = ImageAsset::new(&name, path, width, height);
                asset.data = data;

                // Add to document
                let asset_id = self.action_executor.document_mut().add_image_asset(asset);
                println!("Imported image '{}' ({}x{}) - ID: {}", name, width, height, asset_id);

                Some(ImportedAssetInfo {
                    clip_id: asset_id,
                    clip_type: panes::DragClipType::Image,
                    name,
                    dimensions: Some((width as f64, height as f64)),
                    duration: 0.0, // Images have no duration
                    linked_audio_clip_id: None,
                })
            }
            Err(e) => {
                eprintln!("Failed to load image '{}': {}", path.display(), e);
                None
            }
        }
    }

    /// Import an audio file via daw-backend (async — non-blocking)
    /// to the engine for async import. The engine memory-maps WAV files or sets
    /// up stream decoding for compressed formats. An `AudioFileReady` event is
    /// emitted when the file is playback-ready; the event handler populates the
    /// GPU waveform cache.
    fn import_audio(&mut self, path: &std::path::Path) -> Option<ImportedAssetInfo> {
        use lightningbeam_core::clip::AudioClip;

        let name = path.file_stem()
            .and_then(|s| s.to_str())
            .unwrap_or("Untitled Audio")
            .to_string();

        // Read metadata without decoding (fast — sub-millisecond)
        let metadata = match daw_backend::io::read_metadata(path) {
            Ok(m) => m,
            Err(e) => {
                eprintln!("Failed to read audio metadata '{}': {}", path.display(), e);
                return None;
            }
        };

        let duration = metadata.duration;
        let channels = metadata.channels;
        let sample_rate = metadata.sample_rate;

        if let Some(ref controller_arc) = self.audio_controller {
            // Import synchronously to get the real pool index from the engine.
            // NOTE: briefly blocks the UI thread (sub-ms for PCM mmap; a few ms
            // for compressed streaming init).
            let pool_index = {
                let mut controller = controller_arc.lock().unwrap();
                match controller.import_audio_sync(path.to_path_buf()) {
                    Ok(idx) => idx,
                    Err(e) => {
                        eprintln!("Failed to import audio '{}': {}", path.display(), e);
                        return None;
                    }
                }
            };

            let clip = AudioClip::new_sampled(&name, pool_index, duration);
            let clip_id = self.action_executor.document_mut().add_audio_clip(clip);

            println!("Imported audio '{}' ({:.1}s, {}ch, {}Hz) - ID: {} (pool: {})",
                name, duration, channels, sample_rate, clip_id, pool_index);

            Some(ImportedAssetInfo {
                clip_id,
                clip_type: panes::DragClipType::AudioSampled,
                name,
                dimensions: None,
                duration,
                linked_audio_clip_id: None,
            })
        } else {
            eprintln!("Cannot import audio: audio engine not initialized");
            None
        }
    }

    /// Rebuild a MIDI event cache entry from backend note format.
    /// Called after undo/redo to keep the cache consistent with the backend.
    fn rebuild_midi_cache_entry(&mut self, clip_id: u32, notes: &[(f64, u8, u8, f64)]) {
        let mut events: Vec<(f64, u8, u8, bool)> = Vec::with_capacity(notes.len() * 2);
        for &(start_time, note, velocity, duration) in notes {
            events.push((start_time, note, velocity, true));
            events.push((start_time + duration, note, velocity, false));
        }
        events.sort_by(|a, b| a.0.partial_cmp(&b.0).unwrap());
        self.midi_event_cache.insert(clip_id, events);
    }

    /// Import a MIDI file via daw-backend
    fn import_midi(&mut self, path: &std::path::Path) -> Option<ImportedAssetInfo> {
        use lightningbeam_core::clip::AudioClip;

        let name = path.file_stem()
            .and_then(|s| s.to_str())
            .unwrap_or("Untitled MIDI")
            .to_string();

        // Load MIDI file via daw-backend
        match daw_backend::io::midi_file::load_midi_file(path, 0, 44100) {
            Ok(midi_clip) => {
                let duration = midi_clip.duration;
                let event_count = midi_clip.events.len();

                // Process MIDI events to cache format: (timestamp, note_number, velocity, is_note_on)
                // Filter to note events only (status 0x90 = note-on, 0x80 = note-off)
                let processed_events: Vec<(f64, u8, u8, bool)> = midi_clip.events.iter()
                    .filter_map(|event| {
                        let status_type = event.status & 0xF0;
                        if status_type == 0x90 || status_type == 0x80 {
                            // Note-on is 0x90 with velocity > 0, Note-off is 0x80 or velocity = 0
                            let is_note_on = status_type == 0x90 && event.data2 > 0;
                            Some((event.timestamp, event.data1, event.data2, is_note_on))
                        } else {
                            None // Ignore non-note events (CC, pitch bend, etc.)
                        }
                    })
                    .collect();

                let note_event_count = processed_events.len();

                // Add to backend MIDI clip pool FIRST and get the backend clip ID
                if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    controller.add_midi_clip_to_pool(midi_clip.clone());
                    let backend_clip_id = midi_clip.id; // The backend clip ID

                    // Cache MIDI events in frontend for rendering (thumbnails & timeline piano roll)
                    self.midi_event_cache.insert(backend_clip_id, processed_events);

                    // Create frontend MIDI clip referencing the backend pool
                    let clip = AudioClip::new_midi(&name, backend_clip_id, duration);
                    let frontend_clip_id = self.action_executor.document_mut().add_audio_clip(clip);

                    println!("Imported MIDI '{}' ({:.1}s, {} total events, {} note events) - Frontend ID: {}, Backend ID: {}",
                        name, duration, event_count, note_event_count, frontend_clip_id, backend_clip_id);
                    println!("✅ Added MIDI clip to backend pool and cached {} note events", note_event_count);

                    Some(ImportedAssetInfo {
                        clip_id: frontend_clip_id,
                        clip_type: panes::DragClipType::AudioMidi,
                        name,
                        dimensions: None,
                        duration,
                        linked_audio_clip_id: None,
                    })
                } else {
                    eprintln!("⚠️  Cannot import MIDI: audio system not available");
                    None
                }
            }
            Err(e) => {
                eprintln!("Failed to load MIDI '{}': {}", path.display(), e);
                None
            }
        }
    }

    /// Import a video file (placeholder - decoder not yet ported)
    fn import_video(&mut self, path: &std::path::Path) -> Option<ImportedAssetInfo> {
        use lightningbeam_core::clip::VideoClip;
        use lightningbeam_core::video::probe_video;

        let name = path.file_stem()
            .and_then(|s| s.to_str())
            .unwrap_or("Untitled Video")
            .to_string();

        let path_str = path.to_string_lossy().to_string();

        // Probe video for metadata
        let metadata = match probe_video(&path_str) {
            Ok(meta) => meta,
            Err(e) => {
                eprintln!("Failed to probe video '{}': {}", name, e);
                return None;
            }
        };

        // Create video clip with real metadata
        let clip = VideoClip::new(
            &name,
            path_str.clone(),
            metadata.width as f64,
            metadata.height as f64,
            metadata.duration,
            metadata.fps,
        );

        let clip_id = clip.id;

        // Load video into VideoManager (without building keyframe index)
        let doc_width = self.action_executor.document().width as u32;
        let doc_height = self.action_executor.document().height as u32;

        let mut video_mgr = self.video_manager.lock().unwrap();
        if let Err(e) = video_mgr.load_video(clip_id, path_str.clone(), doc_width, doc_height) {
            eprintln!("Failed to load video '{}': {}", name, e);
            return None;
        }
        drop(video_mgr);

        // Spawn background thread to build keyframe index asynchronously
        let video_manager_clone = Arc::clone(&self.video_manager);
        let keyframe_clip_id = clip_id;
        std::thread::spawn(move || {
            let video_mgr = video_manager_clone.lock().unwrap();
            if let Err(e) = video_mgr.build_keyframe_index(&keyframe_clip_id) {
                eprintln!("Failed to build keyframe index: {}", e);
            } else {
                println!("  Built keyframe index for video clip {}", keyframe_clip_id);
            }
        });

        // Spawn background thread for audio extraction if video has audio
        if metadata.has_audio {
            if let Some(ref audio_controller) = self.audio_controller {
                let path_clone = path_str.clone();
                let video_clip_id = clip_id;
                let video_name = name.clone();
                let audio_controller_clone = Arc::clone(audio_controller);
                let tx = self.audio_extraction_tx.clone();

                std::thread::spawn(move || {
                    use lightningbeam_core::video::extract_audio_from_video;
                    use lightningbeam_core::clip::AudioClip;

                    // Extract audio from video (slow FFmpeg operation)
                    match extract_audio_from_video(&path_clone) {
                        Ok(Some(extracted)) => {
                            // Add audio to daw-backend pool synchronously to get pool index
                            let pool_index = {
                                let mut controller = audio_controller_clone.lock().unwrap();
                                match controller.add_audio_file_sync(
                                    path_clone.clone(),
                                    extracted.samples,
                                    extracted.channels,
                                    extracted.sample_rate,
                                ) {
                                    Ok(index) => index,
                                    Err(e) => {
                                        eprintln!("Failed to add audio file to backend: {}", e);
                                        let _ = tx.send(AudioExtractionResult::Error {
                                            video_clip_id,
                                            error: format!("Failed to add audio to backend: {}", e),
                                        });
                                        return;
                                    }
                                }
                            };

                            // Create AudioClip
                            let audio_clip_name = format!("{} (Audio)", video_name);
                            let audio_clip = AudioClip::new_sampled(
                                &audio_clip_name,
                                pool_index,
                                extracted.duration,
                            );

                            // Send success result
                            let _ = tx.send(AudioExtractionResult::Success {
                                video_clip_id,
                                audio_clip,
                                pool_index,
                                video_name,
                                channels: extracted.channels,
                                sample_rate: extracted.sample_rate,
                            });
                        }
                        Ok(None) => {
                            // Video has no audio stream
                            let _ = tx.send(AudioExtractionResult::NoAudio { video_clip_id });
                        }
                        Err(e) => {
                            // Audio extraction failed
                            let _ = tx.send(AudioExtractionResult::Error {
                                video_clip_id,
                                error: e,
                            });
                        }
                    }
                });
            } else {
                eprintln!("  ⚠️  Video has audio but audio engine not initialized - skipping extraction");
            }
        }

        // Spawn background thread for thumbnail generation
        // Get decoder once, then generate thumbnails without holding VideoManager lock
        let video_manager_clone = Arc::clone(&self.video_manager);
        let duration = metadata.duration;
        let thumb_clip_id = clip_id;
        std::thread::spawn(move || {
            // Get decoder Arc with brief lock
            let decoder_arc = {
                let video_mgr = video_manager_clone.lock().unwrap();
                match video_mgr.get_decoder(&thumb_clip_id) {
                    Some(arc) => arc,
                    None => {
                        eprintln!("Failed to get decoder for thumbnail generation");
                        return;
                    }
                }
            };
            // VideoManager lock released - video can now be displayed!

            let interval = 5.0;
            let mut t = 0.0;
            let mut thumbnail_count = 0;

            while t < duration {
                // Decode frame WITHOUT holding VideoManager lock
                let thumb_opt = {
                    let mut decoder = decoder_arc.lock().unwrap();
                    match decoder.decode_frame(t) {
                        Ok(rgba_data) => {
                            let w = decoder.get_output_width();
                            let h = decoder.get_output_height();
                            Some((rgba_data, w, h))
                        }
                        Err(_) => None,
                    }
                };

                // Downsample without any locks
                if let Some((rgba_data, w, h)) = thumb_opt {
                    use lightningbeam_core::video::downsample_rgba_public;
                    let thumb_w = 128u32;
                    let thumb_h = (h as f32 / w as f32 * thumb_w as f32) as u32;
                    let thumb_data = downsample_rgba_public(&rgba_data, w, h, thumb_w, thumb_h);

                    // Brief lock just to insert
                    {
                        let mut video_mgr = video_manager_clone.lock().unwrap();
                        video_mgr.insert_thumbnail(&thumb_clip_id, t, Arc::new(thumb_data));
                    }
                    thumbnail_count += 1;
                }

                t += interval;
            }

            println!("  Generated {} thumbnails for video clip {}", thumbnail_count, thumb_clip_id);
        });

        // Add clip to document
        let clip_id = self.action_executor.document_mut().add_video_clip(clip);

        println!("Imported video '{}' ({}x{}, {:.2}s @ {:.0}fps) - ID: {}",
            name,
            metadata.width,
            metadata.height,
            metadata.duration,
            metadata.fps,
            clip_id
        );

        if metadata.has_audio {
            println!("  Extracting audio track in background...");
        }

        Some(ImportedAssetInfo {
            clip_id,
            clip_type: panes::DragClipType::Video,
            name,
            dimensions: Some((metadata.width as f64, metadata.height as f64)),
            duration: metadata.duration,
            linked_audio_clip_id: None, // Audio extraction happens async in background thread
        })
    }

    /// Auto-place an imported asset at playhead time
    /// Places images at document center, video/audio clips on appropriate layers
    fn auto_place_asset(&mut self, asset_info: ImportedAssetInfo) {
        use lightningbeam_core::clip::ClipInstance;
        use lightningbeam_core::layer::*;

        let drop_time = self.playback_time;

        // Find or create a compatible layer
        let document = self.action_executor.document();
        let mut target_layer_id = None;

        // Check if active layer is compatible
        if let Some(active_id) = self.active_layer_id {
            if let Some(layer) = document.get_layer(&active_id) {
                if panes::layer_matches_clip_type(layer, asset_info.clip_type) {
                    target_layer_id = Some(active_id);
                }
            }
        }

        // If no compatible active layer, create a new layer
        if target_layer_id.is_none() {
            let layer_name = format!("{} Layer", match asset_info.clip_type {
                panes::DragClipType::Vector => "Vector",
                panes::DragClipType::Video => "Video",
                panes::DragClipType::AudioSampled => "Audio",
                panes::DragClipType::AudioMidi => "MIDI",
                panes::DragClipType::Image => "Image",
                panes::DragClipType::Effect => "Effect",
            });
            let new_layer = panes::create_layer_for_clip_type(asset_info.clip_type, &layer_name);

            // Create and execute add layer action
            let action = lightningbeam_core::actions::AddLayerAction::new(new_layer);
            let _ = self.action_executor.execute(Box::new(action));

            // Get the newly created layer ID (it's the last child in the document)
            let doc = self.action_executor.document();
            if let Some(last_layer) = doc.root.children.last() {
                let layer_id = last_layer.id();
                target_layer_id = Some(layer_id);

                // Update active layer to the new layer
                self.active_layer_id = target_layer_id;

                // Create a backend audio/MIDI track and add the mapping
                if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    match asset_info.clip_type {
                        panes::DragClipType::AudioSampled => {
                            match controller.create_audio_track_sync(layer_name.clone()) {
                                Ok(track_id) => {
                                    self.layer_to_track_map.insert(layer_id, track_id);
                                    self.track_to_layer_map.insert(track_id, layer_id);
                                }
                                Err(e) => eprintln!("Failed to create audio track for auto-place: {}", e),
                            }
                        }
                        panes::DragClipType::AudioMidi => {
                            match controller.create_midi_track_sync(layer_name.clone()) {
                                Ok(track_id) => {
                                    self.layer_to_track_map.insert(layer_id, track_id);
                                    self.track_to_layer_map.insert(track_id, layer_id);
                                }
                                Err(e) => eprintln!("Failed to create MIDI track for auto-place: {}", e),
                            }
                        }
                        _ => {} // Other types don't need backend tracks
                    }
                }
            }
        }

        // Add clip instance or shape to the target layer
        if let Some(layer_id) = target_layer_id {
            // For images, create a shape with image fill instead of a clip instance
            if asset_info.clip_type == panes::DragClipType::Image {
                // Get image dimensions
                let (width, height) = asset_info.dimensions.unwrap_or((100.0, 100.0));

                // Get document center position
                let doc = self.action_executor.document();
                let center_x = doc.width / 2.0;
                let center_y = doc.height / 2.0;

                // Create a rectangle path at the origin (position handled by transform)
                use kurbo::BezPath;
                let mut path = BezPath::new();
                path.move_to((0.0, 0.0));
                path.line_to((width, 0.0));
                path.line_to((width, height));
                path.line_to((0.0, height));
                path.close_path();

                // Create shape with image fill (references the ImageAsset)
                use lightningbeam_core::shape::Shape;
                let shape = Shape::new(path).with_image_fill(asset_info.clip_id);

                // Create shape instance at document center
                use lightningbeam_core::object::ShapeInstance;
                let shape_instance = ShapeInstance::new(shape.id)
                    .with_position(center_x, center_y);

                // Create and execute action
                let action = lightningbeam_core::actions::AddShapeAction::new(
                    layer_id,
                    shape,
                    shape_instance,
                );
                let _ = self.action_executor.execute(Box::new(action));
            } else {
                // For clips, create a clip instance
                let mut clip_instance = ClipInstance::new(asset_info.clip_id)
                    .with_timeline_start(drop_time);

                // For video clips, scale to fit and center in document
                if asset_info.clip_type == panes::DragClipType::Video {
                    if let Some((video_width, video_height)) = asset_info.dimensions {
                        let doc = self.action_executor.document();
                        let doc_width = doc.width;
                        let doc_height = doc.height;

                        // Calculate scale to fit (use minimum to preserve aspect ratio)
                        let scale_x = doc_width / video_width;
                        let scale_y = doc_height / video_height;
                        let uniform_scale = scale_x.min(scale_y);

                        clip_instance.transform.scale_x = uniform_scale;
                        clip_instance.transform.scale_y = uniform_scale;

                        // Center the video in the document
                        let scaled_width = video_width * uniform_scale;
                        let scaled_height = video_height * uniform_scale;
                        let center_x = (doc_width - scaled_width) / 2.0;
                        let center_y = (doc_height - scaled_height) / 2.0;

                        clip_instance.transform.x = center_x;
                        clip_instance.transform.y = center_y;
                    }
                } else {
                    // Audio clips are centered in document
                    let doc = self.action_executor.document();
                    clip_instance.transform.x = doc.width / 2.0;
                    clip_instance.transform.y = doc.height / 2.0;
                }

                // Save instance ID for potential grouping
                let video_instance_id = clip_instance.id;

                // Create and execute action for video/audio with backend sync
                let action = lightningbeam_core::actions::AddClipInstanceAction::new(
                    layer_id,
                    clip_instance,
                );

                // Execute with backend synchronization (same as drag-from-library)
                if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    let mut backend_context = lightningbeam_core::action::BackendContext {
                        audio_controller: Some(&mut *controller),
                        layer_to_track_map: &self.layer_to_track_map,
                        clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                    };

                    if let Err(e) = self.action_executor.execute_with_backend(Box::new(action), &mut backend_context) {
                        eprintln!("❌ Failed to execute AddClipInstanceAction with backend: {}", e);
                    }
                } else {
                    // No audio controller, just execute without backend
                    let _ = self.action_executor.execute(Box::new(action));
                }

                // If video has linked audio, auto-place it and create group
                if let Some(linked_audio_clip_id) = asset_info.linked_audio_clip_id {
                    // Find or create sampled audio track
                    let audio_layer_id = {
                        let doc = self.action_executor.document();
                        panes::find_sampled_audio_track(doc)
                    }.unwrap_or_else(|| {
                        // Create new sampled audio layer
                        let audio_layer = AudioLayer::new_sampled("Audio Track");
                        self.action_executor.document_mut().root.add_child(
                            AnyLayer::Audio(audio_layer)
                        )
                    });

                    // Sync newly created audio layer with backend BEFORE adding clip instances
                    self.sync_audio_layers_to_backend();

                    // Create audio clip instance at same timeline position
                    let audio_instance = ClipInstance::new(linked_audio_clip_id)
                        .with_timeline_start(drop_time);
                    let audio_instance_id = audio_instance.id;

                    // Execute audio action with backend sync
                    let audio_action = lightningbeam_core::actions::AddClipInstanceAction::new(
                        audio_layer_id,
                        audio_instance,
                    );

                    // Execute with backend synchronization
                    if let Some(ref controller_arc) = self.audio_controller {
                        let mut controller = controller_arc.lock().unwrap();
                        let mut backend_context = lightningbeam_core::action::BackendContext {
                            audio_controller: Some(&mut *controller),
                            layer_to_track_map: &self.layer_to_track_map,
                            clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                        };

                        if let Err(e) = self.action_executor.execute_with_backend(Box::new(audio_action), &mut backend_context) {
                            eprintln!("❌ Failed to execute audio AddClipInstanceAction with backend: {}", e);
                        }
                    } else {
                        let _ = self.action_executor.execute(Box::new(audio_action));
                    }

                    // Create instance group linking video and audio
                    let mut group = lightningbeam_core::instance_group::InstanceGroup::new();
                    group.add_member(layer_id, video_instance_id);
                    group.add_member(audio_layer_id, audio_instance_id);
                    self.action_executor.document_mut().add_instance_group(group);
                }
            }
        }
    }

    /// Auto-place extracted audio for a video that was already placed
    fn auto_place_extracted_audio(&mut self, video_clip_id: uuid::Uuid, audio_clip_id: uuid::Uuid) {
        use lightningbeam_core::clip::ClipInstance;
        use lightningbeam_core::layer::*;

        // Find the video clip instance in the document
        let document = self.action_executor.document();
        let mut video_instance_info: Option<(uuid::Uuid, uuid::Uuid, f64)> = None; // (layer_id, instance_id, timeline_start)

        // Search all layers for a video clip instance with matching clip_id
        for layer in &document.root.children {
            if let AnyLayer::Video(video_layer) = layer {
                for instance in &video_layer.clip_instances {
                    if instance.clip_id == video_clip_id {
                        video_instance_info = Some((
                            video_layer.layer.id,
                            instance.id,
                            instance.timeline_start,
                        ));
                        break;
                    }
                }
            }
            if video_instance_info.is_some() {
                break;
            }
        }

        // If we found a video instance, auto-place the audio
        if let Some((video_layer_id, video_instance_id, timeline_start)) = video_instance_info {
            // Find or create sampled audio track
            let audio_layer_id = {
                let doc = self.action_executor.document();
                panes::find_sampled_audio_track(doc)
            }.unwrap_or_else(|| {
                // Create new sampled audio layer
                let audio_layer = AudioLayer::new_sampled("Audio Track");
                self.action_executor.document_mut().root.add_child(
                    AnyLayer::Audio(audio_layer)
                )
            });

            // Sync newly created audio layer with backend BEFORE adding clip instances
            self.sync_audio_layers_to_backend();

            // Create audio clip instance at same timeline position as video
            let audio_instance = ClipInstance::new(audio_clip_id)
                .with_timeline_start(timeline_start);
            let audio_instance_id = audio_instance.id;

            // Execute audio action with backend sync
            let audio_action = lightningbeam_core::actions::AddClipInstanceAction::new(
                audio_layer_id,
                audio_instance,
            );

            // Execute with backend synchronization
            if let Some(ref controller_arc) = self.audio_controller {
                let mut controller = controller_arc.lock().unwrap();
                let mut backend_context = lightningbeam_core::action::BackendContext {
                    audio_controller: Some(&mut *controller),
                    layer_to_track_map: &self.layer_to_track_map,
                    clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                };

                if let Err(e) = self.action_executor.execute_with_backend(Box::new(audio_action), &mut backend_context) {
                    eprintln!("❌ Failed to execute extracted audio AddClipInstanceAction with backend: {}", e);
                }
            } else {
                let _ = self.action_executor.execute(Box::new(audio_action));
            }

            // Create instance group linking video and audio
            let mut group = lightningbeam_core::instance_group::InstanceGroup::new();
            group.add_member(video_layer_id, video_instance_id);
            group.add_member(audio_layer_id, audio_instance_id);
            self.action_executor.document_mut().add_instance_group(group);

            println!("   🔗 Auto-placed audio and linked to video instance");
        }
    }

    /// Handle audio extraction results from background thread
    fn handle_audio_extraction_result(&mut self, result: AudioExtractionResult) {
        match result {
            AudioExtractionResult::Success {
                video_clip_id,
                audio_clip,
                pool_index,
                video_name,
                channels,
                sample_rate,
            } => {
                // Add AudioClip to document
                let audio_clip_id = self.action_executor.document_mut().add_audio_clip(audio_clip);

                // Update VideoClip's linked_audio_clip_id
                if let Some(video_clip) = self.action_executor.document_mut().video_clips
                    .get_mut(&video_clip_id)
                {
                    video_clip.linked_audio_clip_id = Some(audio_clip_id);

                    // Get audio clip duration for logging
                    let duration = self.action_executor.document().audio_clips
                        .get(&audio_clip_id)
                        .map(|c| c.duration)
                        .unwrap_or(0.0);

                    println!("✅ Extracted audio from '{}' ({:.1}s, {}ch, {}Hz) - AudioClip ID: {}",
                        video_name,
                        duration,
                        channels,
                        sample_rate,
                        audio_clip_id
                    );

                    // Fetch raw audio samples for GPU waveform rendering
                    if let Some(ref controller_arc) = self.audio_controller {
                        let mut controller = controller_arc.lock().unwrap();
                        match controller.get_pool_audio_samples(pool_index) {
                            Ok((samples, sr, ch)) => {
                                self.raw_audio_cache.insert(pool_index, (Arc::new(samples), sr, ch));
                                self.waveform_gpu_dirty.insert(pool_index);
                            }
                            Err(e) => eprintln!("Failed to fetch raw audio for extracted audio: {}", e),
                        }
                    }

                    // Auto-place extracted audio if the video was auto-placed
                    self.auto_place_extracted_audio(video_clip_id, audio_clip_id);
                } else {
                    eprintln!("⚠️  Audio extracted but VideoClip {} not found (may have been deleted)", video_clip_id);
                }
            }
            AudioExtractionResult::NoAudio { video_clip_id } => {
                println!("ℹ️  Video {} has no audio stream", video_clip_id);
            }
            AudioExtractionResult::Error { video_clip_id, error } => {
                eprintln!("❌ Failed to extract audio from video {}: {}", video_clip_id, error);
            }
        }
    }
}

impl eframe::App for EditorApp {
    fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
        let _frame_start = std::time::Instant::now();

        // Disable egui's built-in Ctrl+Plus/Minus zoom behavior
        // We handle zoom ourselves for the Stage pane
        ctx.options_mut(|o| {
            o.zoom_with_keyboard = false;
        });

        // Force continuous repaint if we have pending waveform updates
        // This ensures thumbnails update immediately when waveform data arrives
        if !self.audio_pools_with_new_waveforms.is_empty() {
            println!("🔄 [UPDATE] Pending waveform updates for pools: {:?}", self.audio_pools_with_new_waveforms);
            ctx.request_repaint();
        }

        // Poll audio extraction results from background threads
        while let Ok(result) = self.audio_extraction_rx.try_recv() {
            self.handle_audio_extraction_result(result);
        }

        // Check for native menu events (macOS)
        if let Some(menu_system) = &self.menu_system {
            if let Some(action) = menu_system.check_events() {
                self.handle_menu_action(action);
            }
        }

        // Handle pending auto-reopen (first frame only)
        if let Some(path) = self.pending_auto_reopen.take() {
            self.load_from_file(path);
            // Will switch to editor mode when file finishes loading
        }

        // NOTE: Missing raw audio samples for newly imported files will arrive
        // via AudioDecodeProgress events (compressed) or inline with AudioFileReady
        // (PCM). No blocking query needed here.
        // For project loading, audio files are re-imported which also sends events.

        // Initialize and update effect thumbnail generator (GPU-based effect previews)
        if let Some(render_state) = frame.wgpu_render_state() {
            let device = &render_state.device;
            let queue = &render_state.queue;

            // Initialize on first GPU access
            if self.effect_thumbnail_generator.is_none() {
                self.effect_thumbnail_generator = Some(EffectThumbnailGenerator::new(device, queue));
                println!("✅ Effect thumbnail generator initialized");
            }

            // Process effect thumbnail invalidations from previous frame
            // This happens BEFORE UI rendering so asset library will see empty GPU cache
            // We only invalidate GPU cache here - asset library will see the list during render
            // and invalidate its own ThumbnailCache
            if !self.effect_thumbnails_to_invalidate.is_empty() {
                if let Some(generator) = &mut self.effect_thumbnail_generator {
                    for effect_id in &self.effect_thumbnails_to_invalidate {
                        generator.invalidate(effect_id);
                    }
                }
                // DON'T clear here - asset library still needs to see these during render
            }

            // Generate pending effect thumbnails (up to 2 per frame to avoid stalls)
            if let Some(generator) = &mut self.effect_thumbnail_generator {
                // Combine built-in effects from registry with custom effects from document
                let mut all_effects: HashMap<Uuid, lightningbeam_core::effect::EffectDefinition> = HashMap::new();
                for def in lightningbeam_core::effect_registry::EffectRegistry::get_all() {
                    all_effects.insert(def.id, def);
                }
                for (id, def) in &self.action_executor.document().effect_definitions {
                    all_effects.insert(*id, def.clone());
                }

                let generated = generator.generate_pending(device, queue, &all_effects, 2);
                if generated > 0 {
                    // Request repaint to continue generating remaining thumbnails
                    if generator.pending_count() > 0 {
                        ctx.request_repaint();
                    }
                }
            }
        }

        // Handle file operation progress
        if let Some(ref mut operation) = self.file_operation {
            // Set wait cursor
            ctx.set_cursor_icon(egui::CursorIcon::Progress);

            // Poll for progress updates
            let mut operation_complete = false;
            let mut loaded_project_data: Option<(lightningbeam_core::file_io::LoadedProject, std::path::PathBuf)> = None;
            let mut update_recent_menu = false; // Track if we need to update recent files menu

            match operation {
                FileOperation::Saving { ref mut progress_rx, ref path } => {
                    while let Ok(progress) = progress_rx.try_recv() {
                        match progress {
                            FileProgress::Done => {
                                println!("✅ Save complete!");
                                self.current_file_path = Some(path.clone());

                                // Add to recent files
                                self.config.add_recent_file(path.clone());
                                update_recent_menu = true;

                                operation_complete = true;
                            }
                            FileProgress::Error(e) => {
                                eprintln!("❌ Save error: {}", e);
                                operation_complete = true;
                            }
                            _ => {
                                // Other progress states - just keep going
                            }
                        }
                    }

                    // Render progress dialog
                    egui::Window::new("Saving Project")
                        .collapsible(false)
                        .resizable(false)
                        .anchor(egui::Align2::CENTER_CENTER, egui::vec2(0.0, 0.0))
                        .show(ctx, |ui| {
                            ui.vertical_centered(|ui| {
                                ui.add(egui::Spinner::new());
                                ui.add_space(8.0);
                                ui.label("Saving project...");
                                ui.label(format!("Path: {}", path.display()));
                            });
                        });
                }
                FileOperation::Loading { ref mut progress_rx, ref path } => {
                    while let Ok(progress) = progress_rx.try_recv() {
                        match progress {
                            FileProgress::Complete(Ok(loaded_project)) => {
                                println!("✅ Load complete!");
                                // Store data to apply after dialog closes
                                loaded_project_data = Some((loaded_project, path.clone()));
                                operation_complete = true;
                            }
                            FileProgress::Complete(Err(e)) => {
                                eprintln!("❌ Load error: {}", e);
                                operation_complete = true;
                            }
                            FileProgress::Error(e) => {
                                eprintln!("❌ Load error: {}", e);
                                operation_complete = true;
                            }
                            _ => {
                                // Other progress states - just keep going
                            }
                        }
                    }

                    // Render progress dialog
                    egui::Window::new("Loading Project")
                        .collapsible(false)
                        .resizable(false)
                        .anchor(egui::Align2::CENTER_CENTER, egui::vec2(0.0, 0.0))
                        .show(ctx, |ui| {
                            ui.vertical_centered(|ui| {
                                ui.add(egui::Spinner::new());
                                ui.add_space(8.0);
                                ui.label("Loading project...");
                                ui.label(format!("Path: {}", path.display()));
                            });
                        });
                }
            }

            // Clear operation if complete
            if operation_complete {
                self.file_operation = None;
            }

            // Apply loaded project data if available
            if let Some((loaded_project, path)) = loaded_project_data {
                self.apply_loaded_project(loaded_project, path);
                // Switch to editor mode after loading a project
                self.app_mode = AppMode::Editor;
            }

            // Update recent files menu if needed
            if update_recent_menu {
                self.update_recent_files_menu();
            }

            // Request repaint to keep updating progress
            ctx.request_repaint();
        }

        let _pre_events_ms = _frame_start.elapsed().as_secs_f64() * 1000.0;
        // Check if audio events are pending and request repaint if needed
        if self.audio_events_pending.load(std::sync::atomic::Ordering::Relaxed) {
            ctx.request_repaint();
        }

        // Drain recording mirror buffer for live waveform display
        if self.is_recording {
            if let Some(ref mut mirror_rx) = self.recording_mirror_rx {
                let mut drained = 0usize;
                if let Some(entry) = self.raw_audio_cache.get_mut(&usize::MAX) {
                    let samples = Arc::make_mut(&mut entry.0);
                    while let Ok(sample) = mirror_rx.pop() {
                        samples.push(sample);
                        drained += 1;
                    }
                }
                if drained > 0 {
                    self.waveform_gpu_dirty.insert(usize::MAX);
                    ctx.request_repaint();
                }
            }
        }

        // Poll audio events from the audio engine
        if let Some(event_rx) = &mut self.audio_event_rx {
            let mut polled_events = false;
            while let Ok(event) = event_rx.pop() {
                polled_events = true;
                    use daw_backend::AudioEvent;
                    match event {
                        AudioEvent::PlaybackPosition(time) => {
                            self.playback_time = time;
                        }
                        AudioEvent::PlaybackStopped => {
                            self.is_playing = false;
                        }
                        AudioEvent::ExportProgress { frames_rendered, total_frames } => {
                            // Update export progress dialog with actual render progress
                            let progress = frames_rendered as f32 / total_frames as f32;
                            self.export_progress_dialog.update_progress(
                                format!("Rendering: {} / {} frames", frames_rendered, total_frames),
                                progress,
                            );
                            ctx.request_repaint();
                        }
                        AudioEvent::ExportFinalizing => {
                            self.export_progress_dialog.update_progress(
                                "Finalizing...".to_string(),
                                1.0,
                            );
                            ctx.request_repaint();
                        }
                        AudioEvent::WaveformChunksReady { pool_index, .. } => {
                            // Skip synchronous audio queries during export (audio thread is blocked)
                            let is_exporting = self.export_orchestrator.as_ref()
                                .map_or(false, |o| o.is_exporting());

                            if !is_exporting && !self.raw_audio_cache.contains_key(&pool_index) {
                                if let Some(ref controller_arc) = self.audio_controller {
                                    let mut controller = controller_arc.lock().unwrap();
                                    match controller.get_pool_audio_samples(pool_index) {
                                        Ok((samples, sr, ch)) => {
                                            self.raw_audio_cache.insert(pool_index, (Arc::new(samples), sr, ch));
                                            self.waveform_gpu_dirty.insert(pool_index);
                                            self.audio_pools_with_new_waveforms.insert(pool_index);
                                        }
                                        Err(e) => eprintln!("Failed to fetch raw audio for pool {}: {}", pool_index, e),
                                    }
                                }
                            }

                            ctx.request_repaint();
                        }
                        // Recording events
                        AudioEvent::RecordingStarted(track_id, backend_clip_id, rec_sample_rate, rec_channels) => {
                            println!("🎤 Recording started on track {:?}, backend_clip_id={}", track_id, backend_clip_id);

                            // Create clip in document and add instance to layer
                            if let Some(layer_id) = self.recording_layer_id {
                                use lightningbeam_core::clip::{AudioClip, ClipInstance};

                                // Create a recording-in-progress clip (no pool index yet)
                                let clip = AudioClip::new_recording("Recording...");
                                let doc_clip_id = self.action_executor.document_mut().add_audio_clip(clip);

                                // Create clip instance on the layer
                                let clip_instance = ClipInstance::new(doc_clip_id)
                                    .with_timeline_start(self.recording_start_time);

                                // Add instance to layer
                                if let Some(layer) = self.action_executor.document_mut().root.children.iter_mut()
                                    .find(|l| l.id() == layer_id)
                                {
                                    if let lightningbeam_core::layer::AnyLayer::Audio(audio_layer) = layer {
                                        audio_layer.clip_instances.push(clip_instance);
                                        println!("✅ Created recording clip instance on layer {}", layer_id);
                                    }
                                }

                                // Store mapping for later updates
                                self.recording_clips.insert(layer_id, backend_clip_id);
                            }

                            // Initialize live waveform cache for recording
                            self.raw_audio_cache.insert(usize::MAX, (Arc::new(Vec::new()), rec_sample_rate, rec_channels));

                            ctx.request_repaint();
                        }
                        AudioEvent::RecordingProgress(_clip_id, duration) => {
                            // Update clip duration as recording progresses
                            if let Some(layer_id) = self.recording_layer_id {
                                // First, find the clip_id from the layer (read-only borrow)
                                let clip_id = {
                                    let document = self.action_executor.document();
                                    document.root.children.iter()
                                        .find(|l| l.id() == layer_id)
                                        .and_then(|layer| {
                                            if let lightningbeam_core::layer::AnyLayer::Audio(audio_layer) = layer {
                                                audio_layer.clip_instances.last().map(|i| i.clip_id)
                                            } else {
                                                None
                                            }
                                        })
                                };

                                // Then update the clip duration (mutable borrow)
                                if let Some(clip_id) = clip_id {
                                    if let Some(clip) = self.action_executor.document_mut().audio_clips.get_mut(&clip_id) {
                                        if clip.is_recording() {
                                            clip.duration = duration;
                                        }
                                    }
                                }
                            }
                            ctx.request_repaint();
                        }
                        AudioEvent::RecordingStopped(_backend_clip_id, pool_index, _waveform) => {
                            println!("🎤 Recording stopped: pool_index={}", pool_index);

                            // Clean up live recording waveform cache
                            self.raw_audio_cache.remove(&usize::MAX);
                            self.waveform_gpu_dirty.remove(&usize::MAX);

                            // Fetch raw audio samples for GPU waveform rendering
                            if let Some(ref controller_arc) = self.audio_controller {
                                let mut controller = controller_arc.lock().unwrap();
                                match controller.get_pool_audio_samples(pool_index) {
                                    Ok((samples, sr, ch)) => {
                                        self.raw_audio_cache.insert(pool_index, (Arc::new(samples), sr, ch));
                                        self.waveform_gpu_dirty.insert(pool_index);
                                        self.audio_pools_with_new_waveforms.insert(pool_index);
                                    }
                                    Err(e) => eprintln!("Failed to fetch raw audio after recording: {}", e),
                                }
                            }

                            // Get accurate duration from backend (not calculated from waveform peaks)
                            let duration = if let Some(ref controller_arc) = self.audio_controller {
                                let mut controller = controller_arc.lock().unwrap();
                                match controller.get_pool_file_info(pool_index) {
                                    Ok((dur, _, _)) => {
                                        println!("✅ Got duration from backend: {:.2}s", dur);
                                        self.audio_duration_cache.insert(pool_index, dur);
                                        dur
                                    }
                                    Err(e) => {
                                        eprintln!("⚠️  Failed to get pool file info: {}", e);
                                        0.0
                                    }
                                }
                            } else {
                                0.0
                            };

                            // Finalize the recording clip with real pool_index and duration
                            // and sync to backend for playback
                            if let Some(layer_id) = self.recording_layer_id {
                                // First, find the clip instance and clip id
                                let (clip_id, instance_id, timeline_start, trim_start) = {
                                    let document = self.action_executor.document();
                                    document.root.children.iter()
                                        .find(|l| l.id() == layer_id)
                                        .and_then(|layer| {
                                            if let lightningbeam_core::layer::AnyLayer::Audio(audio_layer) = layer {
                                                audio_layer.clip_instances.last().map(|instance| {
                                                    (instance.clip_id, instance.id, instance.timeline_start, instance.trim_start)
                                                })
                                            } else {
                                                None
                                            }
                                        })
                                        .unwrap_or((uuid::Uuid::nil(), uuid::Uuid::nil(), 0.0, 0.0))
                                };

                                if !clip_id.is_nil() {
                                    // Finalize the clip (update pool_index and duration)
                                    if let Some(clip) = self.action_executor.document_mut().audio_clips.get_mut(&clip_id) {
                                        if clip.finalize_recording(pool_index, duration) {
                                            clip.name = format!("Recording {}", pool_index);
                                            println!("✅ Finalized recording clip: pool={}, duration={:.2}s", pool_index, duration);
                                        }
                                    }

                                    // Sync the clip instance to backend for playback
                                    if let Some(backend_track_id) = self.layer_to_track_map.get(&layer_id) {
                                        if let Some(ref controller_arc) = self.audio_controller {
                                            let mut controller = controller_arc.lock().unwrap();
                                            use daw_backend::command::{Query, QueryResponse};

                                            let query = Query::AddAudioClipSync(
                                                *backend_track_id,
                                                pool_index,
                                                timeline_start,
                                                duration,
                                                trim_start
                                            );

                                            match controller.send_query(query) {
                                                Ok(QueryResponse::AudioClipInstanceAdded(Ok(backend_instance_id))) => {
                                                    // Store the mapping
                                                    self.clip_instance_to_backend_map.insert(
                                                        instance_id,
                                                        lightningbeam_core::action::BackendClipInstanceId::Audio(backend_instance_id)
                                                    );
                                                    println!("✅ Synced recording to backend: instance_id={}", backend_instance_id);
                                                }
                                                Ok(QueryResponse::AudioClipInstanceAdded(Err(e))) => {
                                                    eprintln!("❌ Failed to sync recording to backend: {}", e);
                                                }
                                                Ok(_) => {
                                                    eprintln!("❌ Unexpected query response when syncing recording");
                                                }
                                                Err(e) => {
                                                    eprintln!("❌ Failed to send query to backend: {}", e);
                                                }
                                            }
                                        }
                                    }
                                }
                            }

                            // Clear recording state
                            self.is_recording = false;
                            self.recording_clips.clear();
                            self.recording_layer_id = None;
                            ctx.request_repaint();
                        }
                        AudioEvent::RecordingError(message) => {
                            eprintln!("❌ Recording error: {}", message);
                            self.is_recording = false;
                            self.recording_clips.clear();
                            self.recording_layer_id = None;
                            ctx.request_repaint();
                        }
                        AudioEvent::MidiRecordingProgress(_track_id, clip_id, duration, notes) => {
                            // Update clip duration in document (so timeline bar grows)
                            if let Some(layer_id) = self.recording_layer_id {
                                let doc_clip_id = {
                                    let document = self.action_executor.document();
                                    document.root.children.iter()
                                        .find(|l| l.id() == layer_id)
                                        .and_then(|layer| {
                                            if let lightningbeam_core::layer::AnyLayer::Audio(audio_layer) = layer {
                                                audio_layer.clip_instances.last().map(|i| i.clip_id)
                                            } else {
                                                None
                                            }
                                        })
                                };

                                if let Some(doc_clip_id) = doc_clip_id {
                                    if let Some(clip) = self.action_executor.document_mut().audio_clips.get_mut(&doc_clip_id) {
                                        clip.duration = duration;
                                    }
                                }
                            }

                            // Update midi_event_cache with notes captured so far
                            // (inlined instead of calling rebuild_midi_cache_entry to avoid
                            // conflicting &mut self borrow with event_rx loop)
                            {
                                let mut events: Vec<(f64, u8, u8, bool)> = Vec::with_capacity(notes.len() * 2);
                                for &(start_time, note, velocity, dur) in &notes {
                                    events.push((start_time, note, velocity, true));
                                    events.push((start_time + dur, note, velocity, false));
                                }
                                events.sort_by(|a, b| a.0.partial_cmp(&b.0).unwrap());
                                self.midi_event_cache.insert(clip_id, events);
                            }
                            ctx.request_repaint();
                        }
                        AudioEvent::MidiRecordingStopped(track_id, clip_id, note_count) => {
                            println!("🎹 MIDI recording stopped: track={:?}, clip_id={}, {} notes",
                                     track_id, clip_id, note_count);

                            // Query backend for the definitive final note data
                            if let Some(ref controller_arc) = self.audio_controller {
                                let mut controller = controller_arc.lock().unwrap();
                                match controller.query_midi_clip(track_id, clip_id) {
                                    Ok(midi_clip_data) => {
                                        // Convert backend MidiEvent format to cache format
                                        let cache_events: Vec<(f64, u8, u8, bool)> = midi_clip_data.events.iter()
                                            .filter_map(|event| {
                                                let status_type = event.status & 0xF0;
                                                if status_type == 0x90 || status_type == 0x80 {
                                                    let is_note_on = status_type == 0x90 && event.data2 > 0;
                                                    Some((event.timestamp, event.data1, event.data2, is_note_on))
                                                } else {
                                                    None
                                                }
                                            })
                                            .collect();
                                        drop(controller);
                                        self.midi_event_cache.insert(clip_id, cache_events);

                                        // Update document clip with final duration and name
                                        if let Some(layer_id) = self.recording_layer_id {
                                            let doc_clip_id = {
                                                let document = self.action_executor.document();
                                                document.root.children.iter()
                                                    .find(|l| l.id() == layer_id)
                                                    .and_then(|layer| {
                                                        if let lightningbeam_core::layer::AnyLayer::Audio(audio_layer) = layer {
                                                            audio_layer.clip_instances.last().map(|i| i.clip_id)
                                                        } else {
                                                            None
                                                        }
                                                    })
                                            };
                                            if let Some(doc_clip_id) = doc_clip_id {
                                                if let Some(clip) = self.action_executor.document_mut().audio_clips.get_mut(&doc_clip_id) {
                                                    clip.duration = midi_clip_data.duration;
                                                    clip.name = format!("MIDI Recording {}", clip_id);
                                                }
                                            }
                                        }

                                        println!("✅ Finalized MIDI recording: {} notes, {:.2}s",
                                                 note_count, midi_clip_data.duration);
                                    }
                                    Err(e) => {
                                        eprintln!("Failed to query MIDI clip data after recording: {}", e);
                                        // Cache was already populated by last MidiRecordingProgress event
                                    }
                                }
                            }

                            // TODO: Store clip_instance_to_backend_map entry for this MIDI clip.
                            // The backend created the instance in create_midi_clip(), but doesn't
                            // report the instance_id back. Needed for move/trim operations later.

                            // Clear recording state
                            self.is_recording = false;
                            self.recording_clips.clear();
                            self.recording_layer_id = None;
                            ctx.request_repaint();
                        }
                        AudioEvent::AudioFileReady { pool_index, path, channels, sample_rate, duration, format } => {
                            println!("Audio file ready: pool={}, path={}, ch={}, sr={}, {:.1}s, {:?}",
                                     pool_index, path, channels, sample_rate, duration, format);
                            // For PCM (mmap'd) files, raw samples are available immediately
                            // via the pool's data() accessor. Fetch them for GPU waveform.
                            if format == daw_backend::io::AudioFormat::Pcm {
                                if let Some(ref controller_arc) = self.audio_controller {
                                    let mut controller = controller_arc.lock().unwrap();
                                    match controller.get_pool_audio_samples(pool_index) {
                                        Ok((samples, sr, ch)) => {
                                            self.raw_audio_cache.insert(pool_index, (Arc::new(samples), sr, ch));
                                            self.waveform_gpu_dirty.insert(pool_index);
                                        }
                                        Err(e) => eprintln!("Failed to fetch raw audio for pool {}: {}", pool_index, e),
                                    }
                                }
                            }
                            // For compressed files, waveform data arrives progressively
                            // via AudioDecodeProgress events.
                            ctx.request_repaint();
                        }
                        AudioEvent::AudioDecodeProgress { pool_index, samples, sample_rate, channels } => {
                            // Samples arrive as deltas — append to existing cache
                            if let Some(entry) = self.raw_audio_cache.get_mut(&pool_index) {
                                Arc::make_mut(&mut entry.0).extend_from_slice(&samples);
                            } else {
                                self.raw_audio_cache.insert(pool_index, (Arc::new(samples), sample_rate, channels));
                            }
                            self.waveform_gpu_dirty.insert(pool_index);
                            ctx.request_repaint();
                        }
                        _ => {} // Ignore other events for now
                    }
                }

            // If we polled events, set the flag to trigger another update
            // (in case more events arrive before the next frame)
            if polled_events {
                self.audio_events_pending.store(true, std::sync::atomic::Ordering::Relaxed);
            } else {
                // No events this frame, clear the flag
                self.audio_events_pending.store(false, std::sync::atomic::Ordering::Relaxed);
            }
        }

        let _post_events_ms = _frame_start.elapsed().as_secs_f64() * 1000.0;

        // Request continuous repaints when playing to update time display
        if self.is_playing {
            ctx.request_repaint();
        }

        // Handle export dialog
        if let Some(export_result) = self.export_dialog.render(ctx) {
            use export::dialog::ExportResult;

            // Create orchestrator if needed
            if self.export_orchestrator.is_none() {
                self.export_orchestrator = Some(export::ExportOrchestrator::new());
            }

            let export_started = if let Some(orchestrator) = &mut self.export_orchestrator {
                match export_result {
                    ExportResult::AudioOnly(settings, output_path) => {
                        println!("🎵 [MAIN] Starting audio-only export: {}", output_path.display());

                        if let Some(audio_controller) = &self.audio_controller {
                            orchestrator.start_audio_export(
                                settings,
                                output_path,
                                Arc::clone(audio_controller),
                            );
                            true
                        } else {
                            eprintln!("❌ Cannot export audio: Audio controller not available");
                            false
                        }
                    }
                    ExportResult::VideoOnly(settings, output_path) => {
                        println!("🎬 [MAIN] Starting video-only export: {}", output_path.display());

                        match orchestrator.start_video_export(settings, output_path) {
                            Ok(()) => true,
                            Err(err) => {
                                eprintln!("❌ Failed to start video export: {}", err);
                                false
                            }
                        }
                    }
                    ExportResult::VideoWithAudio(video_settings, audio_settings, output_path) => {
                        println!("🎬🎵 [MAIN] Starting video+audio export: {}", output_path.display());

                        if let Some(audio_controller) = &self.audio_controller {
                            match orchestrator.start_video_with_audio_export(
                                video_settings,
                                audio_settings,
                                output_path,
                                Arc::clone(audio_controller),
                            ) {
                                Ok(()) => true,
                                Err(err) => {
                                    eprintln!("❌ Failed to start video+audio export: {}", err);
                                    false
                                }
                            }
                        } else {
                            eprintln!("❌ Cannot export with audio: Audio controller not available");
                            false
                        }
                    }
                }
            } else {
                false
            };

            // Open progress dialog if export started successfully
            if export_started {
                self.export_progress_dialog.open();
            }
        }

        // Render export progress dialog and handle cancel
        if self.export_progress_dialog.render(ctx) {
            // User clicked Cancel
            if let Some(orchestrator) = &mut self.export_orchestrator {
                orchestrator.cancel();
            }
        }

        // Keep requesting repaints while export progress dialog is open
        if self.export_progress_dialog.open {
            ctx.request_repaint();
        }

        // Render preferences dialog
        if let Some(result) = self.preferences_dialog.render(ctx, &mut self.config, &mut self.theme) {
            if result.buffer_size_changed {
                println!("⚠️  Audio buffer size will be applied on next app restart");
            }
        }

        // Render video frames incrementally (if video export in progress)
        if let Some(orchestrator) = &mut self.export_orchestrator {
            if orchestrator.is_exporting() {
                // Get GPU resources from eframe's wgpu render state
                if let Some(render_state) = frame.wgpu_render_state() {
                    let device = &render_state.device;
                    let queue = &render_state.queue;

                    // Create temporary renderer and image cache for export
                    // Note: Creating a new renderer per frame is inefficient but simple
                    // TODO: Reuse renderer across frames by storing it in EditorApp
                    let mut temp_renderer = vello::Renderer::new(
                        device,
                        vello::RendererOptions {
                            use_cpu: false,
                            antialiasing_support: vello::AaSupport::all(),
                            num_init_threads: None,
                            pipeline_cache: None,
                        },
                    ).ok();

                    let mut temp_image_cache = lightningbeam_core::renderer::ImageCache::new();

                    if let Some(renderer) = &mut temp_renderer {
                        if let Ok(has_more) = orchestrator.render_next_video_frame(
                            self.action_executor.document_mut(),
                            device,
                            queue,
                            renderer,
                            &mut temp_image_cache,
                            &self.video_manager,
                        ) {
                            if has_more {
                                // More frames to render - request repaint for next frame
                                ctx.request_repaint();
                            }
                        }
                    }
                }
            }
        }

        // Poll export orchestrator for progress
        if let Some(orchestrator) = &mut self.export_orchestrator {
            // Only log occasionally to avoid spam
            use std::sync::atomic::{AtomicU32, Ordering as AtomicOrdering};
            static POLL_COUNT: AtomicU32 = AtomicU32::new(0);
            let count = POLL_COUNT.fetch_add(1, AtomicOrdering::Relaxed) + 1;
            if count % 60 == 0 {
                println!("🔍 [MAIN] Polling orchestrator (poll #{})...", count);
            }
            if let Some(progress) = orchestrator.poll_progress() {
                match progress {
                    lightningbeam_core::export::ExportProgress::Started { total_frames } => {
                        println!("Export started: {} frames", total_frames);
                        self.export_progress_dialog.update_progress(
                            "Starting export...".to_string(),
                            0.0,
                        );
                        ctx.request_repaint(); // Keep repainting during export
                    }
                    lightningbeam_core::export::ExportProgress::FrameRendered { frame, total } => {
                        let progress = frame as f32 / total as f32;
                        self.export_progress_dialog.update_progress(
                            format!("Rendering frame {} of {}", frame, total),
                            progress,
                        );
                        ctx.request_repaint();
                    }
                    lightningbeam_core::export::ExportProgress::AudioRendered => {
                        self.export_progress_dialog.update_progress(
                            "Rendering audio...".to_string(),
                            0.5,
                        );
                        ctx.request_repaint();
                    }
                    lightningbeam_core::export::ExportProgress::Finalizing => {
                        self.export_progress_dialog.update_progress(
                            "Finalizing export...".to_string(),
                            0.9,
                        );
                        ctx.request_repaint();
                    }
                    lightningbeam_core::export::ExportProgress::Complete { ref output_path } => {
                        println!("✅ Export complete: {}", output_path.display());
                        self.export_progress_dialog.update_progress(
                            format!("Export complete: {}", output_path.display()),
                            1.0,
                        );
                        // Close the progress dialog after a brief delay
                        self.export_progress_dialog.close();

                        // Send desktop notification
                        if let Err(e) = notifications::notify_export_complete(output_path) {
                            // Log but don't fail - notifications are non-critical
                            eprintln!("⚠️  Could not send desktop notification: {}", e);
                        }
                    }
                    lightningbeam_core::export::ExportProgress::Error { ref message } => {
                        eprintln!("❌ Export error: {}", message);
                        self.export_progress_dialog.update_progress(
                            format!("Error: {}", message),
                            0.0,
                        );
                        // Keep the dialog open to show the error

                        // Send desktop notification for error
                        if let Err(e) = notifications::notify_export_error(message) {
                            // Log but don't fail - notifications are non-critical
                            eprintln!("⚠️  Could not send desktop notification: {}", e);
                        }
                    }
                }
            }

            // Request repaint while exporting to update progress
            if orchestrator.is_exporting() {
                ctx.request_repaint();
            }
        }

        // Top menu bar (egui-rendered on all platforms)
        egui::TopBottomPanel::top("menu_bar").show(ctx, |ui| {
            if let Some(menu_system) = &self.menu_system {
                let recent_files = self.config.get_recent_files();
                if let Some(action) = menu_system.render_egui_menu_bar(ui, &recent_files) {
                    self.handle_menu_action(action);
                }
            }
        });

        // Render start screen or editor based on app mode
        if self.app_mode == AppMode::StartScreen {
            self.render_start_screen(ctx);
            return; // Skip editor rendering
        }

        // Skip rendering the editor while a file is loading — the loading dialog
        // (rendered earlier) is all the user needs to see. This avoids showing
        // the default empty layout behind the dialog for several seconds.
        if matches!(self.file_operation, Some(FileOperation::Loading { .. })) {
            egui::CentralPanel::default().show(ctx, |_ui| {});
            return;
        }

        // Main pane area (editor mode)
        let mut layout_action: Option<LayoutAction> = None;
        egui::CentralPanel::default().show(ctx, |ui| {
            let available_rect = ui.available_rect_before_wrap();

            // Reset hovered divider each frame
            self.hovered_divider = None;

            // Track fallback pane priority for view actions (reset each frame)
            let mut fallback_pane_priority: Option<u32> = None;

            // Registry for view action handlers (two-phase dispatch)
            let mut pending_handlers: Vec<panes::ViewActionHandler> = Vec::new();

            // Registry for actions to execute after rendering (two-phase dispatch)
            let mut pending_actions: Vec<Box<dyn lightningbeam_core::action::Action>> = Vec::new();

            // Menu actions queued by pane context menus
            let mut pending_menu_actions: Vec<MenuAction> = Vec::new();

            // Queue for effect thumbnail requests (collected during rendering)
            let mut effect_thumbnail_requests: Vec<Uuid> = Vec::new();
            // Empty cache fallback if generator not initialized
            let empty_thumbnail_cache: HashMap<Uuid, Vec<u8>> = HashMap::new();

            // Create render context
            let mut ctx = RenderContext {
                tool_icon_cache: &mut self.tool_icon_cache,
                icon_cache: &mut self.icon_cache,
                selected_tool: &mut self.selected_tool,
                fill_color: &mut self.fill_color,
                stroke_color: &mut self.stroke_color,
                active_color_mode: &mut self.active_color_mode,
                pane_instances: &mut self.pane_instances,
                pending_view_action: &mut self.pending_view_action,
                fallback_pane_priority: &mut fallback_pane_priority,
                pending_handlers: &mut pending_handlers,
                theme: &self.theme,
                action_executor: &mut self.action_executor,
                selection: &mut self.selection,
                active_layer_id: &mut self.active_layer_id,
                tool_state: &mut self.tool_state,
                pending_actions: &mut pending_actions,
                draw_simplify_mode: &mut self.draw_simplify_mode,
                rdp_tolerance: &mut self.rdp_tolerance,
                schneider_max_error: &mut self.schneider_max_error,
                audio_controller: self.audio_controller.as_ref(),
                video_manager: &self.video_manager,
                playback_time: &mut self.playback_time,
                is_playing: &mut self.is_playing,
                is_recording: &mut self.is_recording,
                recording_clips: &mut self.recording_clips,
                recording_start_time: &mut self.recording_start_time,
                recording_layer_id: &mut self.recording_layer_id,
                dragging_asset: &mut self.dragging_asset,
                stroke_width: &mut self.stroke_width,
                fill_enabled: &mut self.fill_enabled,
                paint_bucket_gap_tolerance: &mut self.paint_bucket_gap_tolerance,
                polygon_sides: &mut self.polygon_sides,
                layer_to_track_map: &self.layer_to_track_map,
                midi_event_cache: &mut self.midi_event_cache,
                audio_pools_with_new_waveforms: &self.audio_pools_with_new_waveforms,
                raw_audio_cache: &self.raw_audio_cache,
                waveform_gpu_dirty: &mut self.waveform_gpu_dirty,
                effect_to_load: &mut self.effect_to_load,
                effect_thumbnail_requests: &mut effect_thumbnail_requests,
                effect_thumbnail_cache: self.effect_thumbnail_generator.as_ref()
                    .map(|g| g.thumbnail_cache())
                    .unwrap_or(&empty_thumbnail_cache),
                effect_thumbnails_to_invalidate: &mut self.effect_thumbnails_to_invalidate,
                target_format: self.target_format,
                pending_menu_actions: &mut pending_menu_actions,
                clipboard_manager: &mut self.clipboard_manager,
                waveform_stereo: self.config.waveform_stereo,
                project_generation: &mut self.project_generation,
            };

            render_layout_node(
                ui,
                &mut self.current_layout,
                available_rect,
                &mut self.drag_state,
                &mut self.hovered_divider,
                &mut self.selected_pane,
                &mut layout_action,
                &mut self.split_preview_mode,
                &Vec::new(), // Root path
                &mut ctx,
            );

            // Process collected effect thumbnail requests
            if !effect_thumbnail_requests.is_empty() {
                if let Some(generator) = &mut self.effect_thumbnail_generator {
                    generator.request_thumbnails(&effect_thumbnail_requests);
                }
            }


            // Execute action on the best handler (two-phase dispatch)
            if let Some(action) = &self.pending_view_action {
                if let Some(best_handler) = pending_handlers.iter().min_by_key(|h| h.priority) {
                    // Look up the pane instance and execute the action
                    if let Some(pane_instance) = self.pane_instances.get_mut(&best_handler.pane_path) {
                        match pane_instance {
                            panes::PaneInstance::Stage(stage_pane) => {
                                stage_pane.execute_view_action(action, best_handler.zoom_center);
                            }
                            _ => {} // Other pane types don't handle view actions yet
                        }
                    }
                }
                // Clear the pending action after execution
                self.pending_view_action = None;
            }

            // Sync any new audio layers created during this frame to the backend
            // This handles layers created directly (e.g., auto-created audio tracks for video+audio)
            // Must happen BEFORE executing actions so the layer-to-track mapping is available
            self.sync_audio_layers_to_backend();

            // Execute all pending actions (two-phase dispatch)
            for action in pending_actions {
                // Create backend context for actions that need backend sync
                if let Some(ref controller_arc) = self.audio_controller {
                    let mut controller = controller_arc.lock().unwrap();
                    let mut backend_context = lightningbeam_core::action::BackendContext {
                        audio_controller: Some(&mut *controller),
                        layer_to_track_map: &self.layer_to_track_map,
                        clip_instance_to_backend_map: &mut self.clip_instance_to_backend_map,
                    };

                    // Execute action with backend synchronization
                    if let Err(e) = self.action_executor.execute_with_backend(action, &mut backend_context) {
                        eprintln!("Action execution failed: {}", e);
                    }
                } else {
                    // No audio system available, execute without backend
                    let _ = self.action_executor.execute(action);
                }
            }

            // Process menu actions queued by pane context menus
            for action in pending_menu_actions {
                self.handle_menu_action(action);
            }

            // Set cursor based on hover state
            if let Some((_, is_horizontal)) = self.hovered_divider {
                if is_horizontal {
                    ui.ctx().set_cursor_icon(egui::CursorIcon::ResizeHorizontal);
                } else {
                    ui.ctx().set_cursor_icon(egui::CursorIcon::ResizeVertical);
                }
            }
        });

        // Handle ESC key and click-outside to cancel split preview
        if let SplitPreviewMode::Active { hovered_pane, .. } = &self.split_preview_mode {
            let should_cancel = ctx.input(|i| {
                // Cancel on ESC key
                if i.key_pressed(egui::Key::Escape) {
                    return true;
                }
                // Cancel on click outside any pane
                if i.pointer.primary_clicked() && hovered_pane.is_none() {
                    return true;
                }
                false
            });

            if should_cancel {
                self.split_preview_mode = SplitPreviewMode::None;
            }
        }

        // Apply layout action after rendering to avoid borrow issues
        if let Some(action) = layout_action {
            self.apply_layout_action(action);
        }

        // Check keyboard shortcuts AFTER UI is rendered
        // This ensures text fields have had a chance to claim focus first
        let wants_keyboard = ctx.wants_keyboard_input();

        // Space bar toggles play/pause (only when no text input is focused)
        if !wants_keyboard && ctx.input(|i| i.key_pressed(egui::Key::Space)) {
            self.is_playing = !self.is_playing;
            if let Some(ref controller_arc) = self.audio_controller {
                let mut controller = controller_arc.lock().unwrap();
                if self.is_playing {
                    controller.play();
                } else {
                    controller.pause();
                }
            }
        }

        ctx.input(|i| {
            // Handle clipboard events (Ctrl+C/X/V) — winit converts these to
            // Event::Copy/Cut/Paste instead of regular key events, so
            // check_shortcuts won't see them via key_pressed().
            for event in &i.events {
                match event {
                    egui::Event::Copy => {
                        self.handle_menu_action(MenuAction::Copy);
                    }
                    egui::Event::Cut => {
                        self.handle_menu_action(MenuAction::Cut);
                    }
                    egui::Event::Paste(_) => {
                        self.handle_menu_action(MenuAction::Paste);
                    }
                    _ => {}
                }
            }

            // Check menu shortcuts that use modifiers (Cmd+S, etc.) - allow even when typing
            // But skip shortcuts without modifiers when keyboard input is claimed (e.g., virtual piano)
            if let Some(action) = MenuSystem::check_shortcuts(i) {
                // Only trigger if keyboard isn't claimed OR the shortcut uses modifiers
                if !wants_keyboard || i.modifiers.ctrl || i.modifiers.command || i.modifiers.alt || i.modifiers.shift {
                    self.handle_menu_action(action);
                }
            }

            // Check tool shortcuts (only if no modifiers are held AND no text input is focused)
            if !wants_keyboard && !i.modifiers.ctrl && !i.modifiers.shift && !i.modifiers.alt && !i.modifiers.command {
                use lightningbeam_core::tool::Tool;

                if i.key_pressed(egui::Key::V) {
                    self.selected_tool = Tool::Select;
                } else if i.key_pressed(egui::Key::P) {
                    self.selected_tool = Tool::Draw;
                } else if i.key_pressed(egui::Key::Q) {
                    self.selected_tool = Tool::Transform;
                } else if i.key_pressed(egui::Key::R) {
                    self.selected_tool = Tool::Rectangle;
                } else if i.key_pressed(egui::Key::E) {
                    self.selected_tool = Tool::Ellipse;
                } else if i.key_pressed(egui::Key::B) {
                    self.selected_tool = Tool::PaintBucket;
                } else if i.key_pressed(egui::Key::I) {
                    self.selected_tool = Tool::Eyedropper;
                } else if i.key_pressed(egui::Key::L) {
                    self.selected_tool = Tool::Line;
                } else if i.key_pressed(egui::Key::G) {
                    self.selected_tool = Tool::Polygon;
                } else if i.key_pressed(egui::Key::A) {
                    self.selected_tool = Tool::BezierEdit;
                } else if i.key_pressed(egui::Key::T) {
                    self.selected_tool = Tool::Text;
                }
            }
        });

        // F3 debug overlay toggle (works even when text input is active)
        if ctx.input(|i| i.key_pressed(egui::Key::F3)) {
            self.debug_overlay_visible = !self.debug_overlay_visible;
        }

        // Clear the set of audio pools with new waveforms at the end of the frame
        // (Thumbnails have been invalidated above, so this can be cleared for next frame)
        if !self.audio_pools_with_new_waveforms.is_empty() {
            println!("🧹 [UPDATE] Clearing waveform update set: {:?}", self.audio_pools_with_new_waveforms);
        }
        self.audio_pools_with_new_waveforms.clear();

        // Render F3 debug overlay on top of everything
        if self.debug_overlay_visible {
            let stats = self.debug_stats_collector.collect(
                ctx,
                &self.gpu_info,
                self.audio_controller.as_ref(),
            );
            debug_overlay::render_debug_overlay(ctx, &stats);
        }

        let frame_ms = _frame_start.elapsed().as_secs_f64() * 1000.0;
        if frame_ms > 50.0 {
            eprintln!("[TIMING] SLOW FRAME: {:.1}ms (pre-events={:.1}, events={:.1}, post-events={:.1})",
                frame_ms, _pre_events_ms, _post_events_ms - _pre_events_ms, frame_ms - _post_events_ms);
        }
    }

}

/// Context for rendering operations - bundles all mutable state needed during rendering
/// This avoids having 25+ individual parameters in rendering functions
struct RenderContext<'a> {
    tool_icon_cache: &'a mut ToolIconCache,
    icon_cache: &'a mut IconCache,
    selected_tool: &'a mut Tool,
    fill_color: &'a mut egui::Color32,
    stroke_color: &'a mut egui::Color32,
    active_color_mode: &'a mut panes::ColorMode,
    pane_instances: &'a mut HashMap<NodePath, PaneInstance>,
    pending_view_action: &'a mut Option<MenuAction>,
    fallback_pane_priority: &'a mut Option<u32>,
    pending_handlers: &'a mut Vec<panes::ViewActionHandler>,
    theme: &'a Theme,
    action_executor: &'a mut lightningbeam_core::action::ActionExecutor,
    selection: &'a mut lightningbeam_core::selection::Selection,
    active_layer_id: &'a mut Option<Uuid>,
    tool_state: &'a mut lightningbeam_core::tool::ToolState,
    pending_actions: &'a mut Vec<Box<dyn lightningbeam_core::action::Action>>,
    draw_simplify_mode: &'a mut lightningbeam_core::tool::SimplifyMode,
    rdp_tolerance: &'a mut f64,
    schneider_max_error: &'a mut f64,
    audio_controller: Option<&'a std::sync::Arc<std::sync::Mutex<daw_backend::EngineController>>>,
    video_manager: &'a std::sync::Arc<std::sync::Mutex<lightningbeam_core::video::VideoManager>>,
    playback_time: &'a mut f64,
    is_playing: &'a mut bool,
    // Recording state
    is_recording: &'a mut bool,
    recording_clips: &'a mut HashMap<Uuid, u32>,
    recording_start_time: &'a mut f64,
    recording_layer_id: &'a mut Option<Uuid>,
    dragging_asset: &'a mut Option<panes::DraggingAsset>,
    // Tool-specific options for infopanel
    stroke_width: &'a mut f64,
    fill_enabled: &'a mut bool,
    paint_bucket_gap_tolerance: &'a mut f64,
    polygon_sides: &'a mut u32,
    /// Mapping from Document layer UUIDs to daw-backend TrackIds
    layer_to_track_map: &'a std::collections::HashMap<Uuid, daw_backend::TrackId>,
    /// Cache of MIDI events for rendering (keyed by backend midi_clip_id)
    midi_event_cache: &'a mut HashMap<u32, Vec<(f64, u8, u8, bool)>>,
    /// Audio pool indices with new raw audio data this frame (for thumbnail invalidation)
    audio_pools_with_new_waveforms: &'a HashSet<usize>,
    /// Raw audio samples for GPU waveform rendering (pool_index -> (samples, sample_rate, channels))
    raw_audio_cache: &'a HashMap<usize, (Arc<Vec<f32>>, u32, u32)>,
    /// Pool indices needing GPU texture upload
    waveform_gpu_dirty: &'a mut HashSet<usize>,
    /// Effect ID to load into shader editor (set by asset library, consumed by shader editor)
    effect_to_load: &'a mut Option<Uuid>,
    /// Queue for effect thumbnail requests
    effect_thumbnail_requests: &'a mut Vec<Uuid>,
    /// Cache of generated effect thumbnails
    effect_thumbnail_cache: &'a HashMap<Uuid, Vec<u8>>,
    /// Effect IDs whose thumbnails should be invalidated
    effect_thumbnails_to_invalidate: &'a mut Vec<Uuid>,
    /// Surface texture format for GPU rendering (Rgba8Unorm or Bgra8Unorm depending on platform)
    target_format: wgpu::TextureFormat,
    /// Menu actions queued by panes (e.g. context menus), processed after rendering
    pending_menu_actions: &'a mut Vec<MenuAction>,
    /// Clipboard manager for paste availability checks
    clipboard_manager: &'a mut lightningbeam_core::clipboard::ClipboardManager,
    /// Whether to show waveforms as stacked stereo
    waveform_stereo: bool,
    /// Project generation counter (incremented on load)
    project_generation: &'a mut u64,
}

/// Recursively render a layout node with drag support
fn render_layout_node(
    ui: &mut egui::Ui,
    node: &mut LayoutNode,
    rect: egui::Rect,
    drag_state: &mut DragState,
    hovered_divider: &mut Option<(NodePath, bool)>,
    selected_pane: &mut Option<NodePath>,
    layout_action: &mut Option<LayoutAction>,
    split_preview_mode: &mut SplitPreviewMode,
    path: &NodePath,
    ctx: &mut RenderContext,
) {
    match node {
        LayoutNode::Pane { name } => {
            render_pane(ui, name, rect, selected_pane, layout_action, split_preview_mode, path, ctx);
        }
        LayoutNode::HorizontalGrid { percent, children } => {
            // Handle dragging
            if drag_state.is_dragging && drag_state.node_path == *path {
                if let Some(pointer_pos) = ui.input(|i| i.pointer.interact_pos()) {
                    // Calculate new percentage based on pointer position
                    let new_percent = ((pointer_pos.x - rect.left()) / rect.width() * 100.0)
                        .clamp(10.0, 90.0); // Clamp to prevent too small panes
                    *percent = new_percent;
                }
            }

            // Split horizontally (left | right)
            let split_x = rect.left() + (rect.width() * *percent / 100.0);

            let left_rect = egui::Rect::from_min_max(rect.min, egui::pos2(split_x, rect.max.y));

            let right_rect =
                egui::Rect::from_min_max(egui::pos2(split_x, rect.min.y), rect.max);

            // Render children
            let mut left_path = path.clone();
            left_path.push(0);
            render_layout_node(
                ui,
                &mut children[0],
                left_rect,
                drag_state,
                hovered_divider,
                selected_pane,
                layout_action,
                split_preview_mode,
                &left_path,
                ctx,
            );

            let mut right_path = path.clone();
            right_path.push(1);
            render_layout_node(
                ui,
                &mut children[1],
                right_rect,
                drag_state,
                hovered_divider,
                selected_pane,
                layout_action,
                split_preview_mode,
                &right_path,
                ctx,
            );

            // Draw divider with interaction
            let divider_width = 8.0;
            let divider_rect = egui::Rect::from_min_max(
                egui::pos2(split_x - divider_width / 2.0, rect.min.y),
                egui::pos2(split_x + divider_width / 2.0, rect.max.y),
            );

            let divider_id = ui.id().with(("divider", path));
            let response = ui.interact(divider_rect, divider_id, egui::Sense::click_and_drag());

            // Check if pointer is over divider
            if response.hovered() {
                *hovered_divider = Some((path.clone(), true));
            }

            // Handle drag start
            if response.drag_started() {
                drag_state.is_dragging = true;
                drag_state.node_path = path.clone();
                drag_state.is_horizontal = true;
            }

            // Handle drag end
            if response.drag_stopped() {
                drag_state.is_dragging = false;
            }

            // Context menu on right-click
            response.context_menu(|ui| {
                ui.set_min_width(180.0);

                if ui.button("Split Horizontal ->").clicked() {
                    *layout_action = Some(LayoutAction::EnterSplitPreviewHorizontal);
                    ui.close();
                }

                if ui.button("Split Vertical |").clicked() {
                    *layout_action = Some(LayoutAction::EnterSplitPreviewVertical);
                    ui.close();
                }

                ui.separator();

                if ui.button("< Join Left").clicked() {
                    let mut path_keep_right = path.clone();
                    path_keep_right.push(1); // Remove left, keep right child
                    *layout_action = Some(LayoutAction::RemoveSplit(path_keep_right));
                    ui.close();
                }

                if ui.button("Join Right >").clicked() {
                    let mut path_keep_left = path.clone();
                    path_keep_left.push(0); // Remove right, keep left child
                    *layout_action = Some(LayoutAction::RemoveSplit(path_keep_left));
                    ui.close();
                }

            });

            // Visual feedback
            let divider_color = if response.hovered() || response.dragged() {
                egui::Color32::from_gray(120)
            } else {
                egui::Color32::from_gray(60)
            };

            ui.painter().vline(
                split_x,
                rect.y_range(),
                egui::Stroke::new(2.0, divider_color),
            );
        }
        LayoutNode::VerticalGrid { percent, children } => {
            // Handle dragging
            if drag_state.is_dragging && drag_state.node_path == *path {
                if let Some(pointer_pos) = ui.input(|i| i.pointer.interact_pos()) {
                    // Calculate new percentage based on pointer position
                    let new_percent = ((pointer_pos.y - rect.top()) / rect.height() * 100.0)
                        .clamp(10.0, 90.0); // Clamp to prevent too small panes
                    *percent = new_percent;
                }
            }

            // Split vertically (top / bottom)
            let split_y = rect.top() + (rect.height() * *percent / 100.0);

            let top_rect = egui::Rect::from_min_max(rect.min, egui::pos2(rect.max.x, split_y));

            let bottom_rect =
                egui::Rect::from_min_max(egui::pos2(rect.min.x, split_y), rect.max);

            // Render children
            let mut top_path = path.clone();
            top_path.push(0);
            render_layout_node(
                ui,
                &mut children[0],
                top_rect,
                drag_state,
                hovered_divider,
                selected_pane,
                layout_action,
                split_preview_mode,
                &top_path,
                ctx,
            );

            let mut bottom_path = path.clone();
            bottom_path.push(1);
            render_layout_node(
                ui,
                &mut children[1],
                bottom_rect,
                drag_state,
                hovered_divider,
                selected_pane,
                layout_action,
                split_preview_mode,
                &bottom_path,
                ctx,
            );

            // Draw divider with interaction
            let divider_height = 8.0;
            let divider_rect = egui::Rect::from_min_max(
                egui::pos2(rect.min.x, split_y - divider_height / 2.0),
                egui::pos2(rect.max.x, split_y + divider_height / 2.0),
            );

            let divider_id = ui.id().with(("divider", path));
            let response = ui.interact(divider_rect, divider_id, egui::Sense::click_and_drag());

            // Check if pointer is over divider
            if response.hovered() {
                *hovered_divider = Some((path.clone(), false));
            }

            // Handle drag start
            if response.drag_started() {
                drag_state.is_dragging = true;
                drag_state.node_path = path.clone();
                drag_state.is_horizontal = false;
            }

            // Handle drag end
            if response.drag_stopped() {
                drag_state.is_dragging = false;
            }

            // Context menu on right-click
            response.context_menu(|ui| {
                ui.set_min_width(180.0);

                if ui.button("Split Horizontal ->").clicked() {
                    *layout_action = Some(LayoutAction::EnterSplitPreviewHorizontal);
                    ui.close();
                }

                if ui.button("Split Vertical |").clicked() {
                    *layout_action = Some(LayoutAction::EnterSplitPreviewVertical);
                    ui.close();
                }

                ui.separator();

                if ui.button("^ Join Up").clicked() {
                    let mut path_keep_bottom = path.clone();
                    path_keep_bottom.push(1); // Remove top, keep bottom child
                    *layout_action = Some(LayoutAction::RemoveSplit(path_keep_bottom));
                    ui.close();
                }

                if ui.button("Join Down v").clicked() {
                    let mut path_keep_top = path.clone();
                    path_keep_top.push(0); // Remove bottom, keep top child
                    *layout_action = Some(LayoutAction::RemoveSplit(path_keep_top));
                    ui.close();
                }

            });

            // Visual feedback
            let divider_color = if response.hovered() || response.dragged() {
                egui::Color32::from_gray(120)
            } else {
                egui::Color32::from_gray(60)
            };

            ui.painter().hline(
                rect.x_range(),
                split_y,
                egui::Stroke::new(2.0, divider_color),
            );
        }
    }
}

/// Render a single pane with its content
fn render_pane(
    ui: &mut egui::Ui,
    pane_name: &mut String,
    rect: egui::Rect,
    selected_pane: &mut Option<NodePath>,
    layout_action: &mut Option<LayoutAction>,
    split_preview_mode: &mut SplitPreviewMode,
    path: &NodePath,
    ctx: &mut RenderContext,
) {
    let pane_type = PaneType::from_name(pane_name);

    // Define header and content areas
    let header_height = 40.0;
    let header_rect = egui::Rect::from_min_size(
        rect.min,
        egui::vec2(rect.width(), header_height),
    );
    let content_rect = egui::Rect::from_min_size(
        rect.min + egui::vec2(0.0, header_height),
        egui::vec2(rect.width(), rect.height() - header_height),
    );

    // Draw header background
    ui.painter().rect_filled(
        header_rect,
        0.0,
        egui::Color32::from_rgb(35, 35, 35),
    );

    // Draw content background
    let bg_color = if let Some(pane_type) = pane_type {
        pane_color(pane_type)
    } else {
        egui::Color32::from_rgb(40, 40, 40)
    };
    ui.painter().rect_filled(content_rect, 0.0, bg_color);

    // Draw border around entire pane
    let border_color = egui::Color32::from_gray(80);
    let border_width = 1.0;
    ui.painter().rect_stroke(
        rect,
        0.0,
        egui::Stroke::new(border_width, border_color),
        egui::StrokeKind::Middle,
    );

    // Draw header separator line
    ui.painter().hline(
        rect.x_range(),
        header_rect.max.y,
        egui::Stroke::new(1.0, egui::Color32::from_gray(50)),
    );

    // Render icon button in header (left side)
    let icon_size = 24.0;
    let icon_padding = 8.0;
    let icon_button_rect = egui::Rect::from_min_size(
        header_rect.min + egui::vec2(icon_padding, icon_padding),
        egui::vec2(icon_size, icon_size),
    );

    // Draw icon button background
    ui.painter().rect_filled(
        icon_button_rect,
        4.0,
        egui::Color32::from_rgba_premultiplied(50, 50, 50, 200),
    );

    // Load and render icon if available
    if let Some(pane_type) = pane_type {
        if let Some(icon) = ctx.icon_cache.get_or_load(pane_type, ui.ctx()) {
            let icon_texture_id = icon.id();
            let icon_rect = icon_button_rect.shrink(2.0); // Small padding inside button
            ui.painter().image(
                icon_texture_id,
                icon_rect,
                egui::Rect::from_min_max(egui::pos2(0.0, 0.0), egui::pos2(1.0, 1.0)),
                egui::Color32::WHITE,
            );
        }
    }

    // Make icon button interactive (show pane type menu on click)
    let icon_button_id = ui.id().with(("icon_button", path));
    let icon_response = ui.interact(icon_button_rect, icon_button_id, egui::Sense::click());

    if icon_response.hovered() {
        ui.painter().rect_stroke(
            icon_button_rect,
            4.0,
            egui::Stroke::new(1.0, egui::Color32::from_gray(180)),
            egui::StrokeKind::Middle,
        );
    }

    // Show pane type selector menu on left click using new Popup API
    egui::containers::Popup::menu(&icon_response)
        .show(|ui| {
            ui.set_min_width(200.0);
            ui.label("Select Pane Type:");
            ui.separator();

            for pane_type_option in PaneType::all() {
                // Load icon for this pane type
                if let Some(icon) = ctx.icon_cache.get_or_load(*pane_type_option, ui.ctx()) {
                    ui.horizontal(|ui| {
                        // Show icon
                        let icon_texture_id = icon.id();
                        let icon_size = egui::vec2(16.0, 16.0);
                        ui.add(egui::Image::new((icon_texture_id, icon_size)));

                        // Show label with selection
                        if ui.selectable_label(
                            pane_type == Some(*pane_type_option),
                            pane_type_option.display_name()
                        ).clicked() {
                            *pane_name = pane_type_option.to_name().to_string();
                        }
                    });
                } else {
                    // Fallback if icon fails to load
                    if ui.selectable_label(
                        pane_type == Some(*pane_type_option),
                        pane_type_option.display_name()
                    ).clicked() {
                        *pane_name = pane_type_option.to_name().to_string();
                    }
                }
            }
        });

    // Draw pane title in header
    let title_text = if let Some(pane_type) = pane_type {
        pane_type.display_name()
    } else {
        pane_name.as_str()
    };
    let title_pos = header_rect.min + egui::vec2(icon_padding * 2.0 + icon_size + 8.0, header_height / 2.0);
    ui.painter().text(
        title_pos,
        egui::Align2::LEFT_CENTER,
        title_text,
        egui::FontId::proportional(14.0),
        egui::Color32::from_gray(220),
    );

    // Create header controls area (positioned after title)
    let title_width = 150.0; // Approximate width for title
    let header_controls_rect = egui::Rect::from_min_size(
        header_rect.min + egui::vec2(icon_padding * 2.0 + icon_size + 8.0 + title_width, 0.0),
        egui::vec2(header_rect.width() - (icon_padding * 2.0 + icon_size + 8.0 + title_width), header_height),
    );

    // Render pane-specific header controls (if pane has them)
    if let Some(pane_type) = pane_type {
        // Get or create pane instance for header rendering
        let needs_new_instance = ctx.pane_instances
            .get(path)
            .map(|instance| instance.pane_type() != pane_type)
            .unwrap_or(true);

        if needs_new_instance {
            ctx.pane_instances.insert(path.clone(), panes::PaneInstance::new(pane_type));
        }

        if let Some(pane_instance) = ctx.pane_instances.get_mut(path) {
            let mut header_ui = ui.new_child(egui::UiBuilder::new().max_rect(header_controls_rect).layout(egui::Layout::left_to_right(egui::Align::Center)));
            let mut shared = panes::SharedPaneState {
                tool_icon_cache: ctx.tool_icon_cache,
                icon_cache: ctx.icon_cache,
                selected_tool: ctx.selected_tool,
                fill_color: ctx.fill_color,
                stroke_color: ctx.stroke_color,
                active_color_mode: ctx.active_color_mode,
                pending_view_action: ctx.pending_view_action,
                fallback_pane_priority: ctx.fallback_pane_priority,
                theme: ctx.theme,
                pending_handlers: ctx.pending_handlers,
                action_executor: ctx.action_executor,
                selection: ctx.selection,
                active_layer_id: ctx.active_layer_id,
                tool_state: ctx.tool_state,
                pending_actions: ctx.pending_actions,
                draw_simplify_mode: ctx.draw_simplify_mode,
                rdp_tolerance: ctx.rdp_tolerance,
                schneider_max_error: ctx.schneider_max_error,
                audio_controller: ctx.audio_controller,
                video_manager: ctx.video_manager,
                layer_to_track_map: ctx.layer_to_track_map,
                playback_time: ctx.playback_time,
                is_playing: ctx.is_playing,
                is_recording: ctx.is_recording,
                recording_clips: ctx.recording_clips,
                recording_start_time: ctx.recording_start_time,
                recording_layer_id: ctx.recording_layer_id,
                dragging_asset: ctx.dragging_asset,
                stroke_width: ctx.stroke_width,
                fill_enabled: ctx.fill_enabled,
                paint_bucket_gap_tolerance: ctx.paint_bucket_gap_tolerance,
                polygon_sides: ctx.polygon_sides,
                midi_event_cache: ctx.midi_event_cache,
                audio_pools_with_new_waveforms: ctx.audio_pools_with_new_waveforms,
                raw_audio_cache: ctx.raw_audio_cache,
                waveform_gpu_dirty: ctx.waveform_gpu_dirty,
                effect_to_load: ctx.effect_to_load,
                effect_thumbnail_requests: ctx.effect_thumbnail_requests,
                effect_thumbnail_cache: ctx.effect_thumbnail_cache,
                effect_thumbnails_to_invalidate: ctx.effect_thumbnails_to_invalidate,
                target_format: ctx.target_format,
                pending_menu_actions: ctx.pending_menu_actions,
                clipboard_manager: ctx.clipboard_manager,
                waveform_stereo: ctx.waveform_stereo,
                project_generation: ctx.project_generation,
            };
            pane_instance.render_header(&mut header_ui, &mut shared);
        }
    }

    // Make pane content clickable (use content rect, not header, for split preview interaction)
    let pane_id = ui.id().with(("pane", path));
    let response = ui.interact(content_rect, pane_id, egui::Sense::click());

    // Render pane-specific content using trait-based system
    if let Some(pane_type) = pane_type {
        // Get or create pane instance for this path
        // Check if we need a new instance (either doesn't exist or type changed)
        let needs_new_instance = ctx.pane_instances
            .get(path)
            .map(|instance| instance.pane_type() != pane_type)
            .unwrap_or(true);

        if needs_new_instance {
            ctx.pane_instances.insert(path.clone(), PaneInstance::new(pane_type));
        }

        // Get the pane instance and render its content
        if let Some(pane_instance) = ctx.pane_instances.get_mut(path) {
            // Create shared state
            let mut shared = SharedPaneState {
                tool_icon_cache: ctx.tool_icon_cache,
                icon_cache: ctx.icon_cache,
                selected_tool: ctx.selected_tool,
                fill_color: ctx.fill_color,
                stroke_color: ctx.stroke_color,
                active_color_mode: ctx.active_color_mode,
                pending_view_action: ctx.pending_view_action,
                fallback_pane_priority: ctx.fallback_pane_priority,
                theme: ctx.theme,
                pending_handlers: ctx.pending_handlers,
                action_executor: ctx.action_executor,
                selection: ctx.selection,
                active_layer_id: ctx.active_layer_id,
                tool_state: ctx.tool_state,
                pending_actions: ctx.pending_actions,
                draw_simplify_mode: ctx.draw_simplify_mode,
                rdp_tolerance: ctx.rdp_tolerance,
                schneider_max_error: ctx.schneider_max_error,
                audio_controller: ctx.audio_controller,
                video_manager: ctx.video_manager,
                layer_to_track_map: ctx.layer_to_track_map,
                playback_time: ctx.playback_time,
                is_playing: ctx.is_playing,
                is_recording: ctx.is_recording,
                recording_clips: ctx.recording_clips,
                recording_start_time: ctx.recording_start_time,
                recording_layer_id: ctx.recording_layer_id,
                dragging_asset: ctx.dragging_asset,
                stroke_width: ctx.stroke_width,
                fill_enabled: ctx.fill_enabled,
                paint_bucket_gap_tolerance: ctx.paint_bucket_gap_tolerance,
                polygon_sides: ctx.polygon_sides,
                midi_event_cache: ctx.midi_event_cache,
                audio_pools_with_new_waveforms: ctx.audio_pools_with_new_waveforms,
                raw_audio_cache: ctx.raw_audio_cache,
                waveform_gpu_dirty: ctx.waveform_gpu_dirty,
                effect_to_load: ctx.effect_to_load,
                effect_thumbnail_requests: ctx.effect_thumbnail_requests,
                effect_thumbnail_cache: ctx.effect_thumbnail_cache,
                effect_thumbnails_to_invalidate: ctx.effect_thumbnails_to_invalidate,
                target_format: ctx.target_format,
                pending_menu_actions: ctx.pending_menu_actions,
                clipboard_manager: ctx.clipboard_manager,
                waveform_stereo: ctx.waveform_stereo,
                project_generation: ctx.project_generation,
            };

            // Render pane content (header was already rendered above)
            pane_instance.render_content(ui, content_rect, path, &mut shared);
        }
    } else {
        // Unknown pane type - draw placeholder
        let content_text = "Unknown pane type";
        let text_pos = content_rect.center();
        ui.painter().text(
            text_pos,
            egui::Align2::CENTER_CENTER,
            content_text,
            egui::FontId::proportional(16.0),
            egui::Color32::from_gray(150),
        );
    }

    // Handle split preview mode (rendered AFTER pane content for proper z-ordering)
    if let SplitPreviewMode::Active {
        is_horizontal,
        hovered_pane,
        split_percent,
    } = split_preview_mode
    {
        // Check if mouse is over this pane
        if let Some(pointer_pos) = ui.input(|i| i.pointer.hover_pos()) {
            if rect.contains(pointer_pos) {
                // Update hovered pane
                *hovered_pane = Some(path.clone());

                // Calculate split percentage based on mouse position
                *split_percent = if *is_horizontal {
                    ((pointer_pos.x - rect.left()) / rect.width() * 100.0).clamp(10.0, 90.0)
                } else {
                    ((pointer_pos.y - rect.top()) / rect.height() * 100.0).clamp(10.0, 90.0)
                };

                // Render split preview overlay
                let grey_overlay = egui::Color32::from_rgba_premultiplied(128, 128, 128, 30);

                if *is_horizontal {
                    let split_x = rect.left() + (rect.width() * *split_percent / 100.0);

                    // First half
                    let first_rect = egui::Rect::from_min_max(
                        rect.min,
                        egui::pos2(split_x, rect.max.y),
                    );
                    ui.painter().rect_filled(first_rect, 0.0, grey_overlay);

                    // Second half
                    let second_rect = egui::Rect::from_min_max(
                        egui::pos2(split_x, rect.min.y),
                        rect.max,
                    );
                    ui.painter().rect_filled(second_rect, 0.0, grey_overlay);

                    // Divider line
                    ui.painter().vline(
                        split_x,
                        rect.y_range(),
                        egui::Stroke::new(2.0, egui::Color32::BLACK),
                    );
                } else {
                    let split_y = rect.top() + (rect.height() * *split_percent / 100.0);

                    // First half
                    let first_rect = egui::Rect::from_min_max(
                        rect.min,
                        egui::pos2(rect.max.x, split_y),
                    );
                    ui.painter().rect_filled(first_rect, 0.0, grey_overlay);

                    // Second half
                    let second_rect = egui::Rect::from_min_max(
                        egui::pos2(rect.min.x, split_y),
                        rect.max,
                    );
                    ui.painter().rect_filled(second_rect, 0.0, grey_overlay);

                    // Divider line
                    ui.painter().hline(
                        rect.x_range(),
                        split_y,
                        egui::Stroke::new(2.0, egui::Color32::BLACK),
                    );
                }

                // Create a high-priority interaction for split preview (rendered last = highest priority)
                let split_preview_id = ui.id().with(("split_preview", path));
                let split_response = ui.interact(rect, split_preview_id, egui::Sense::click());

                // If clicked, perform the split
                if split_response.clicked() {
                    if *is_horizontal {
                        *layout_action = Some(LayoutAction::SplitHorizontal(path.clone(), *split_percent));
                    } else {
                        *layout_action = Some(LayoutAction::SplitVertical(path.clone(), *split_percent));
                    }
                    // Exit preview mode
                    *split_preview_mode = SplitPreviewMode::None;
                }
            }
        }
    } else if response.clicked() {
        *selected_pane = Some(path.clone());
    }
}

/// Get a color for each pane type for visualization
fn pane_color(pane_type: PaneType) -> egui::Color32 {
    match pane_type {
        PaneType::Stage => egui::Color32::from_rgb(30, 40, 50),
        PaneType::Timeline => egui::Color32::from_rgb(40, 30, 50),
        PaneType::Toolbar => egui::Color32::from_rgb(50, 40, 30),
        PaneType::Infopanel => egui::Color32::from_rgb(30, 50, 40),
        PaneType::Outliner => egui::Color32::from_rgb(40, 50, 30),
        PaneType::PianoRoll => egui::Color32::from_rgb(55, 35, 45),
        PaneType::VirtualPiano => egui::Color32::from_rgb(45, 35, 55),
        PaneType::NodeEditor => egui::Color32::from_rgb(30, 45, 50),
        PaneType::PresetBrowser => egui::Color32::from_rgb(50, 45, 30),
        PaneType::AssetLibrary => egui::Color32::from_rgb(45, 50, 35),
        PaneType::ShaderEditor => egui::Color32::from_rgb(35, 30, 55),
    }
}

/// Split a pane node into a horizontal or vertical grid with two copies of the pane
fn split_node(root: &mut LayoutNode, path: &NodePath, is_horizontal: bool, percent: f32) {
    if path.is_empty() {
        // Split the root node
        if let LayoutNode::Pane { name } = root {
            let pane_name = name.clone();
            let new_node = if is_horizontal {
                LayoutNode::HorizontalGrid {
                    percent,
                    children: [
                        Box::new(LayoutNode::Pane { name: pane_name.clone() }),
                        Box::new(LayoutNode::Pane { name: pane_name }),
                    ],
                }
            } else {
                LayoutNode::VerticalGrid {
                    percent,
                    children: [
                        Box::new(LayoutNode::Pane { name: pane_name.clone() }),
                        Box::new(LayoutNode::Pane { name: pane_name }),
                    ],
                }
            };
            *root = new_node;
        }
    } else {
        // Navigate to parent and split the child
        navigate_to_node(root, &path[..path.len() - 1], &mut |node| {
            let child_index = path[path.len() - 1];
            match node {
                LayoutNode::HorizontalGrid { children, .. }
                | LayoutNode::VerticalGrid { children, .. } => {
                    if let LayoutNode::Pane { name } = &*children[child_index] {
                        let pane_name = name.clone();
                        let new_node = if is_horizontal {
                            LayoutNode::HorizontalGrid {
                                percent,
                                children: [
                                    Box::new(LayoutNode::Pane { name: pane_name.clone() }),
                                    Box::new(LayoutNode::Pane { name: pane_name }),
                                ],
                            }
                        } else {
                            LayoutNode::VerticalGrid {
                                percent,
                                children: [
                                    Box::new(LayoutNode::Pane { name: pane_name.clone() }),
                                    Box::new(LayoutNode::Pane { name: pane_name }),
                                ],
                            }
                        };
                        children[child_index] = Box::new(new_node);
                    }
                }
                _ => {}
            }
        });
    }
}

/// Remove a split by replacing it with one of its children
/// The path includes the split node path plus which child to keep (0 or 1 as last element)
fn remove_split(root: &mut LayoutNode, path: &NodePath) {
    if path.is_empty() {
        return; // Can't remove if path is empty
    }

    // Last element indicates which child to keep (0 or 1)
    let child_to_keep = path[path.len() - 1];

    // Path to the split node is everything except the last element
    let split_path = &path[..path.len() - 1];

    if split_path.is_empty() {
        // Removing root split - replace root with the chosen child
        if let LayoutNode::HorizontalGrid { children, .. }
        | LayoutNode::VerticalGrid { children, .. } = root
        {
            *root = (*children[child_to_keep]).clone();
        }
    } else {
        // Navigate to parent of the split node and replace it
        let parent_path = &split_path[..split_path.len() - 1];
        let split_index = split_path[split_path.len() - 1];

        navigate_to_node(root, parent_path, &mut |node| {
            match node {
                LayoutNode::HorizontalGrid { children, .. }
                | LayoutNode::VerticalGrid { children, .. } => {
                    // Get the split node's chosen child
                    if let LayoutNode::HorizontalGrid { children: split_children, .. }
                    | LayoutNode::VerticalGrid { children: split_children, .. } =
                        &*children[split_index]
                    {
                        // Replace the split node with the chosen child
                        children[split_index] = split_children[child_to_keep].clone();
                    }
                }
                _ => {}
            }
        });
    }
}

/// Navigate to a node at the given path and apply a function to it
fn navigate_to_node<F>(node: &mut LayoutNode, path: &[usize], f: &mut F)
where
    F: FnMut(&mut LayoutNode),
{
    if path.is_empty() {
        f(node);
    } else {
        match node {
            LayoutNode::HorizontalGrid { children, .. }
            | LayoutNode::VerticalGrid { children, .. } => {
                navigate_to_node(&mut children[path[0]], &path[1..], f);
            }
            _ => {}
        }
    }
}