use egui::emath::NumExt as _;
use egui::epaint::{Color32, Rgba, Stroke};

use crate::transform::{PlotBounds, PlotTransform};

use super::{Orientation, PlotPoint};

/// Trait that abstracts from rectangular 'Value'-like elements, such as bars or boxes
pub(super) trait RectElement {
    fn name(&self) -> &str;

    fn bounds_min(&self) -> PlotPoint;

    fn bounds_max(&self) -> PlotPoint;

    fn bounds(&self) -> PlotBounds {
        let mut bounds = PlotBounds::NOTHING;
        bounds.extend_with(&self.bounds_min());
        bounds.extend_with(&self.bounds_max());
        bounds
    }

    /// At which argument (input; usually X) there is a ruler (usually vertical)
    fn arguments_with_ruler(&self) -> Vec<PlotPoint> {
        // Default: one at center
        vec![self.bounds().center()]
    }

    /// At which value (output; usually Y) there is a ruler (usually horizontal)
    fn values_with_ruler(&self) -> Vec<PlotPoint>;

    /// The diagram's orientation (vertical/horizontal)
    fn orientation(&self) -> Orientation;

    /// Get X/Y-value for (argument, value) pair, taking into account orientation
    fn point_at(&self, argument: f64, value: f64) -> PlotPoint {
        match self.orientation() {
            Orientation::Horizontal => PlotPoint::new(value, argument),
            Orientation::Vertical => PlotPoint::new(argument, value),
        }
    }

    /// Right top of the rectangle (position of text)
    fn corner_value(&self) -> PlotPoint {
        //self.point_at(self.position + self.width / 2.0, value)
        PlotPoint {
            x: self.bounds_max().x,
            y: self.bounds_max().y,
        }
    }

    /// Debug formatting for hovered-over value, if none is specified by the user
    fn default_values_format(&self, transform: &PlotTransform) -> String;
}

// ----------------------------------------------------------------------------
// Helper functions

pub(super) fn highlighted_color(mut stroke: Stroke, fill: Color32) -> (Stroke, Color32) {
    stroke.width *= 2.0;

    let mut fill = Rgba::from(fill);
    if fill.is_additive() {
        // Make slightly brighter
        fill = 1.3 * fill;
    } else {
        // Make more opaque:
        let fill_alpha = (2.0 * fill.a()).at_most(1.0);
        fill = fill.to_opaque().multiply(fill_alpha);
    }

    (stroke, fill.into())
}