use super::core_shapes::*;
use super::styles::{DefinedDashStyle, DefinedStrokeStyle, FillStyle, Pattern};
use super::text::{DefinedFontDescription, FontDescription};
use super::types::DefinedCoreShapeContext;

pub trait Renderer {
    // Must be called once before any drawing happens
    fn set_size(&mut self, width: f64, height: f64);
    fn move_to(&mut self, x: f64, y: f64);
    fn stroke(&mut self);
    fn fill(&mut self);
    fn fill_preserve(&mut self);
    fn set_pattern(&mut self, pattern: &Pattern);
    fn set_dash(&mut self, dash: &DefinedDashStyle);
    fn clear_dash(&mut self);
    fn set_line_width(&mut self, width: f64);
    fn line_to(&mut self, x: f64, y: f64);
    fn rectangle(&mut self, x: f64, y: f64, width: f64, height: f64);
    // For a font of size 1.
    fn text_extents(&self, text: &str, font: &FontDescription) -> (f64, f64);
    fn show_text(&mut self, text: &str, font: &DefinedFontDescription);
}

pub trait Render {
    fn render(&self, context: DefinedCoreShapeContext, renderer: &mut dyn Renderer);
}

impl Render for DefinedCoreShape {
    fn render(&self, context: DefinedCoreShapeContext, renderer: &mut dyn Renderer) {
        match self {
            Self::Rectangle(r) => r.render(context, renderer),
            Self::Text(t) => t.render(context, renderer),
            Self::StraightPath(p) => p.render(context, renderer),
        }
    }
}

fn draw(fill: &FillStyle, stroke: &DefinedStrokeStyle, renderer: &mut dyn Renderer) {
    let stroking = !stroke.pattern.is_none();

    if !fill.pattern.is_none() {
        renderer.set_pattern(&fill.pattern);
        if stroking {
            renderer.fill_preserve();
        } else {
            renderer.fill();
        }
    }

    if !stroke.pattern.is_none() {
        renderer.set_pattern(&stroke.pattern);
        renderer.set_line_width(stroke.line_width);
        if let Some(dash) = &stroke.dash {
            renderer.set_dash(dash);
        }
        renderer.stroke();
        renderer.clear_dash();
    }
}

impl Render for Rectangle {
    fn render(&self, context: DefinedCoreShapeContext, renderer: &mut dyn Renderer) {
        let bounds = &context.bounds;
        renderer.rectangle(bounds.left, bounds.top, bounds.width, bounds.height);
        draw(&context.fill, &context.stroke, renderer);
    }
}

impl Render for DefinedText {
    fn render(&self, context: DefinedCoreShapeContext, renderer: &mut dyn Renderer) {
        // TODO: select font, style, text shaping (renderer specific), etc.
        let bounds = &context.bounds;
        //renderer.move_to(bounds.left, bounds.top + self.font.size);
        renderer.move_to(bounds.left, bounds.top);
        // TODO: ???
        //draw(&context.fill, &context.stroke, renderer);
        renderer.show_text(&self.content, &self.font);
    }
}

impl Render for DefinedStraightPath {
    fn render(&self, context: DefinedCoreShapeContext, renderer: &mut dyn Renderer) {
        let mut iter = self.points.iter();

        let first_point = match iter.next() {
            Some(point) => point,
            None => return,
        };

        renderer.move_to(first_point.x, first_point.y);

        for point in iter {
            renderer.line_to(point.x, point.y);
        }

        draw(&context.fill, &context.stroke, renderer);
    }
}