use super::*;

#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum HorizontalAlignment {
    Left,
    Center,
    Right,
}

pub struct LabelText {
    pub font: Font,
    pub text: String,
}

pub struct Label {
    text: LabelText,
    alignment: HorizontalAlignment,
    scale: f32,
    color: Color,
    left: f32,
    right: f32,
    baseline: f32,
    center_y: bool,
    dirty: bool,
    layout: Option<TextLayout>,
    bounds: Rect,
    offset: Vec2,
}

impl Label {
    pub fn new(
        text: LabelText,
        alignment: HorizontalAlignment,
        scale: f32,
        color: Color,
        left: f32,
        right: f32,
        baseline: f32,
        center_y: bool,
    ) -> Self {
        Self {
            text,
            alignment,
            scale,
            color,
            left,
            right,
            baseline,
            center_y,
            dirty: true,
            layout: None,
            bounds: Rect::from_xy_size(Vec2::ZERO, Vec2::ZERO),
            offset: Vec2::ZERO,
        }
    }
}

impl Widget for Label {
    fn draw(&mut self, ctx: &DrawContext) {
        if self.dirty {
            let layout = TextLayout::new(&self.text.font, &self.text.text);
            let bounds = Rect::from(layout.get_bounds()).scale(self.scale);
            self.bounds = bounds;
            let xoff = match self.alignment {
                HorizontalAlignment::Left => self.left - bounds.bl.x,
                HorizontalAlignment::Right => self.right - bounds.tr.x,
                HorizontalAlignment::Center => {
                    let available = self.right - self.left;
                    let halfway = available / 2.0 + self.left;
                    let width = bounds.tr.x - bounds.bl.x;
                    let left = halfway - width / 2.0;
                    left - bounds.bl.x
                }
            };

            let yoff = if self.center_y {
                (bounds.bl.y - bounds.tr.y) / 2.0 - bounds.bl.y
            } else {
                0.0
            };

            self.offset = Vec2::new(xoff, yoff + self.baseline);
            self.dirty = false;
            self.layout = Some(layout);
        }

        if let Some(layout) = self.layout.as_ref() {
            ctx.draw_text_layout(layout, self.offset, self.scale, self.color);
        }
    }
}