use skia_safe::{self as skia, Paint, RRect};

use super::{RenderState, SurfaceId};
use crate::math::Rect as MathRect;
use crate::shapes::{Fill, Frame, ImageFill, Rect, Shape, Type};

fn draw_image_fill(
    render_state: &mut RenderState,
    shape: &Shape,
    image_fill: &ImageFill,
    paint: &Paint,
    antialias: bool,
) {
    let image = render_state.images.get(&image_fill.id());
    if image.is_none() {
        return;
    }

    let size = image_fill.size();
    let canvas = render_state.surfaces.canvas(SurfaceId::Fills);
    let container = &shape.selrect;
    let path_transform = shape.to_path_transform();

    let width = size.0 as f32;
    let height = size.1 as f32;

    // Container size
    let container_width = container.width();
    let container_height = container.height();

    let mut scaled_width = container_width;
    let mut scaled_height = container_height;

    if image_fill.keep_aspect_ratio() {
        // Calculate scale to ensure the image covers the container
        let image_aspect_ratio = width / height;
        let container_aspect_ratio = container_width / container_height;
        let scale = if image_aspect_ratio > container_aspect_ratio {
            // Image is wider, scale based on height to cover container
            container_height / height
        } else {
            // Image is taller, scale based on width to cover container
            container_width / width
        };
        // Scaled size of the image
        scaled_width = width * scale;
        scaled_height = height * scale;
    }

    let dest_rect = MathRect::from_xywh(
        container.left - (scaled_width - container_width) / 2.0,
        container.top - (scaled_height - container_height) / 2.0,
        scaled_width,
        scaled_height,
    );

    // Save the current canvas state
    canvas.save();

    // Set the clipping rectangle to the container bounds
    match &shape.shape_type {
        Type::Rect(Rect {
            corners: Some(corners),
        })
        | Type::Frame(Frame {
            corners: Some(corners),
            ..
        }) => {
            let rrect: RRect = RRect::new_rect_radii(container, corners);
            canvas.clip_rrect(rrect, skia::ClipOp::Intersect, antialias);
        }
        Type::Rect(_) | Type::Frame(_) => {
            canvas.clip_rect(container, skia::ClipOp::Intersect, antialias);
        }
        Type::Circle => {
            let mut oval_path = skia::Path::new();
            oval_path.add_oval(container, None);
            canvas.clip_path(&oval_path, skia::ClipOp::Intersect, antialias);
        }
        shape_type @ (Type::Path(_) | Type::Bool(_)) => {
            if let Some(path) = shape_type.path() {
                if let Some(path_transform) = path_transform {
                    canvas.clip_path(
                        path.to_skia_path().transform(&path_transform),
                        skia::ClipOp::Intersect,
                        antialias,
                    );
                }
            }
        }
        Type::SVGRaw(_) => {
            canvas.clip_rect(container, skia::ClipOp::Intersect, antialias);
        }
        Type::Group(_) => unreachable!("A group should not have fills"),
        Type::Text(_) => unimplemented!("TODO"),
    }

    // Draw the image with the calculated destination rectangle
    if let Some(image) = image {
        canvas.draw_image_rect_with_sampling_options(
            image,
            None,
            dest_rect,
            render_state.sampling_options,
            paint,
        );
    }

    // Restore the canvas to remove the clipping
    canvas.restore();
}

/**
 * This SHOULD be the only public function in this module.
 */
pub fn render(render_state: &mut RenderState, shape: &Shape, fill: &Fill, antialias: bool) {
    let paint = &fill.to_paint(&shape.selrect, antialias);

    match (fill, &shape.shape_type) {
        (Fill::Image(image_fill), _) => {
            draw_image_fill(render_state, shape, image_fill, paint, antialias);
        }
        (_, Type::Rect(_) | Type::Frame(_)) => {
            render_state
                .surfaces
                .draw_rect_to(SurfaceId::Fills, shape, paint);
        }
        (_, Type::Circle) => {
            render_state
                .surfaces
                .draw_circle_to(SurfaceId::Fills, shape, paint);
        }
        (_, Type::Path(_)) | (_, Type::Bool(_)) => {
            render_state
                .surfaces
                .draw_path_to(SurfaceId::Fills, shape, paint);
        }
        (_, _) => {
            unreachable!("This shape should not have fills")
        }
    }
}