/* LICENSE BEGIN
    This file is part of the SixtyFPS Project -- https://sixtyfps.io
    Copyright (c) 2020 Olivier Goffart <olivier.goffart@sixtyfps.io>
    Copyright (c) 2020 Simon Hausmann <simon.hausmann@sixtyfps.io>

    SPDX-License-Identifier: GPL-3.0-only
    This file is also available under commercial licensing terms.
    Please contact info@sixtyfps.io for more information.
LICENSE END */

use std::{cell::RefCell, rc::Rc};

use sixtyfps_corelib::eventloop::ComponentWindow;
use sixtyfps_corelib::graphics::{
    Color, GraphicsBackend, GraphicsWindow, Point, Rect, RenderingCache, Resource,
};
use sixtyfps_corelib::item_rendering::{CachedRenderingData, ItemRenderer};
use sixtyfps_corelib::items::Item;
use sixtyfps_corelib::{Property, SharedVector};

type CanvasRc = Rc<RefCell<femtovg::Canvas<femtovg::renderer::OpenGl>>>;
type RenderingCacheRc = Rc<RefCell<RenderingCache<Option<GPUCachedData>>>>;

struct CachedImage {
    id: femtovg::ImageId,
    canvas: CanvasRc,
}

impl Drop for CachedImage {
    fn drop(&mut self) {
        self.canvas.borrow_mut().delete_image(self.id)
    }
}

#[derive(Clone)]
enum GPUCachedData {
    Image(Rc<CachedImage>),
}

impl GPUCachedData {
    fn as_image(&self) -> &Rc<CachedImage> {
        match self {
            GPUCachedData::Image(image) => image,
            //_ => panic!("internal error. image requested for non-image gpu data"),
        }
    }
}

pub struct GLRenderer {
    canvas: CanvasRc,

    #[cfg(target_arch = "wasm32")]
    window: Rc<winit::window::Window>,
    #[cfg(target_arch = "wasm32")]
    event_loop_proxy:
        Rc<winit::event_loop::EventLoopProxy<sixtyfps_corelib::eventloop::CustomEvent>>,
    #[cfg(not(target_arch = "wasm32"))]
    windowed_context: Option<glutin::WindowedContext<glutin::NotCurrent>>,

    gpu_cache: RenderingCacheRc,
    current_scale_factor: f32,
}

impl GLRenderer {
    pub fn new(
        event_loop: &winit::event_loop::EventLoop<sixtyfps_corelib::eventloop::CustomEvent>,
        window_builder: winit::window::WindowBuilder,
        #[cfg(target_arch = "wasm32")] canvas_id: &str,
    ) -> GLRenderer {
        #[cfg(not(target_arch = "wasm32"))]
        let (windowed_context, renderer) = {
            let windowed_context = glutin::ContextBuilder::new()
                .with_vsync(true)
                .build_windowed(window_builder, &event_loop)
                .unwrap();
            let windowed_context = unsafe { windowed_context.make_current().unwrap() };

            let renderer = femtovg::renderer::OpenGl::new(|symbol| {
                windowed_context.get_proc_address(symbol) as *const _
            })
            .unwrap();

            #[cfg(target_os = "macos")]
            {
                use cocoa::appkit::NSView;
                use winit::platform::macos::WindowExtMacOS;
                let ns_view = windowed_context.window().ns_view();
                let view_id: cocoa::base::id = ns_view as *const _ as *mut _;
                unsafe {
                    NSView::setLayerContentsPlacement(view_id, cocoa::appkit::NSViewLayerContentsPlacement::NSViewLayerContentsPlacementTopLeft)
                }
            }

            (windowed_context, renderer)
        };

        #[cfg(target_arch = "wasm32")]
        let event_loop_proxy = Rc::new(event_loop.create_proxy());

        #[cfg(target_arch = "wasm32")]
        let (window, renderer) = {
            let canvas = web_sys::window()
                .unwrap()
                .document()
                .unwrap()
                .get_element_by_id(canvas_id)
                .unwrap()
                .dyn_into::<web_sys::HtmlCanvasElement>()
                .unwrap();

            use winit::platform::web::WindowBuilderExtWebSys;
            use winit::platform::web::WindowExtWebSys;

            let existing_canvas_size = winit::dpi::LogicalSize::new(
                canvas.client_width() as u32,
                canvas.client_height() as u32,
            );

            let window =
                Rc::new(window_builder.with_canvas(Some(canvas)).build(&event_loop).unwrap());

            // Try to maintain the existing size of the canvas element. A window created with winit
            // on the web will always have 1024x768 as size otherwise.

            let resize_canvas = {
                let event_loop_proxy = event_loop_proxy.clone();
                let canvas = web_sys::window()
                    .unwrap()
                    .document()
                    .unwrap()
                    .get_element_by_id(canvas_id)
                    .unwrap()
                    .dyn_into::<web_sys::HtmlCanvasElement>()
                    .unwrap();
                let window = window.clone();
                move |_: web_sys::Event| {
                    let existing_canvas_size = winit::dpi::LogicalSize::new(
                        canvas.client_width() as u32,
                        canvas.client_height() as u32,
                    );

                    window.set_inner_size(existing_canvas_size);
                    window.request_redraw();
                    event_loop_proxy
                        .send_event(sixtyfps_corelib::eventloop::CustomEvent::WakeUpAndPoll)
                        .ok();
                }
            };

            let resize_closure =
                wasm_bindgen::closure::Closure::wrap(Box::new(resize_canvas) as Box<dyn FnMut(_)>);
            web_sys::window()
                .unwrap()
                .add_event_listener_with_callback("resize", resize_closure.as_ref().unchecked_ref())
                .unwrap();
            resize_closure.forget();

            {
                let default_size = window.inner_size().to_logical(window.scale_factor());
                let new_size = winit::dpi::LogicalSize::new(
                    if existing_canvas_size.width > 0 {
                        existing_canvas_size.width
                    } else {
                        default_size.width
                    },
                    if existing_canvas_size.height > 0 {
                        existing_canvas_size.height
                    } else {
                        default_size.height
                    },
                );
                if new_size != default_size {
                    window.set_inner_size(new_size);
                }
            }

            let renderer = femtovg::renderer::OpenGl::new_from_html_canvas(window.canvas());
            (window, renderer)
        };

        let canvas = femtovg::Canvas::new(renderer).unwrap();

        let mut renderer = GLRenderer {
            canvas: Rc::new(RefCell::new(canvas)),
            #[cfg(target_arch = "wasm32")]
            window,
            #[cfg(target_arch = "wasm32")]
            event_loop_proxy,
            #[cfg(not(target_arch = "wasm32"))]
            windowed_context: Some(unsafe { windowed_context.make_not_current().unwrap() }),
            gpu_cache: Default::default(),
            current_scale_factor: 0.0,
        };

        renderer.refresh_window_scale_factor();

        renderer
    }
}

impl GraphicsBackend for GLRenderer {
    type ItemRenderer = GLItemRenderer;

    fn new_renderer(&mut self, clear_color: &Color) -> GLItemRenderer {
        let size = self.window().inner_size();

        #[cfg(not(target_arch = "wasm32"))]
        let current_windowed_context =
            unsafe { self.windowed_context.take().unwrap().make_current().unwrap() };

        let dpi_factor = current_windowed_context.window().scale_factor();
        {
            let mut canvas = self.canvas.borrow_mut();
            canvas.set_size(size.width, size.height, dpi_factor as f32);
            canvas.clear_rect(0, 0, size.width, size.height, clear_color.into());
        }

        GLItemRenderer {
            canvas: self.canvas.clone(),
            windowed_context: current_windowed_context,
            clip_rects: Default::default(),
            gpu_cache: self.gpu_cache.clone(),
            scale_factor: dpi_factor as f32,
        }
    }

    fn flush_renderer(&mut self, renderer: GLItemRenderer) {
        self.canvas.borrow_mut().flush();

        #[cfg(not(target_arch = "wasm32"))]
        {
            renderer.windowed_context.swap_buffers().unwrap();

            self.windowed_context =
                Some(unsafe { renderer.windowed_context.make_not_current().unwrap() });
        }
    }

    fn release_item_graphics_cache(&self, data: &CachedRenderingData) {
        data.release(&mut self.gpu_cache.borrow_mut())
    }

    fn refresh_window_scale_factor(&mut self) {
        let (size, dpi_factor) = {
            let window = self.window();
            (window.inner_size(), window.scale_factor() as f32)
        };

        if dpi_factor == self.current_scale_factor {
            return;
        }

        self.current_scale_factor = dpi_factor;

        // The scale factor in the Canvas can only be updated via `set_size`, which requires a current context
        #[cfg(not(target_arch = "wasm32"))]
        let current_windowed_context =
            unsafe { self.windowed_context.take().unwrap().make_current().unwrap() };

        self.canvas.borrow_mut().set_size(size.width, size.height, dpi_factor);

        #[cfg(not(target_arch = "wasm32"))]
        {
            self.windowed_context =
                Some(unsafe { current_windowed_context.make_not_current().unwrap() });
        }
    }

    fn window(&self) -> &winit::window::Window {
        #[cfg(not(target_arch = "wasm32"))]
        return self.windowed_context.as_ref().unwrap().window();
        #[cfg(target_arch = "wasm32")]
        return &self.window;
    }
}

pub struct GLItemRenderer {
    canvas: CanvasRc,

    #[cfg(not(target_arch = "wasm32"))]
    windowed_context: glutin::WindowedContext<glutin::PossiblyCurrent>,

    clip_rects: SharedVector<Rect>,

    gpu_cache: RenderingCacheRc,
    scale_factor: f32,
}

impl GLItemRenderer {
    fn load_image(
        &self,
        item_cache: &CachedRenderingData,
        source_property: core::pin::Pin<&Property<Resource>>,
    ) -> Option<(Rc<CachedImage>, femtovg::ImageInfo)> {
        let canvas_rc = self.canvas.clone();
        let mut canvas = self.canvas.borrow_mut();
        let mut cache = self.gpu_cache.borrow_mut();
        item_cache
            .ensure_up_to_date(&mut cache, || {
                match source_property.get() {
                    Resource::None => None,
                    Resource::AbsoluteFilePath(path) => canvas
                        .load_image_file(
                            std::path::Path::new(&path.as_str()),
                            femtovg::ImageFlags::empty(),
                        )
                        .ok(),
                    Resource::EmbeddedData(data) => {
                        canvas.load_image_mem(data.as_slice(), femtovg::ImageFlags::empty()).ok()
                    }
                    Resource::EmbeddedRgbaImage { .. } => todo!(),
                }
                .map(|id| GPUCachedData::Image(Rc::new(CachedImage { id, canvas: canvas_rc })))
            })
            .map(|gpu_resource| {
                let image = gpu_resource.as_image();
                (image.clone(), canvas.image_info(image.id).unwrap())
            })
    }
}

fn rect_to_path(r: Rect) -> femtovg::Path {
    let mut path = femtovg::Path::new();
    path.rect(r.min_x(), r.min_y(), r.width(), r.height());
    path
}

impl ItemRenderer for GLItemRenderer {
    fn draw_rectangle(
        &mut self,
        pos: Point,
        rect: std::pin::Pin<&sixtyfps_corelib::items::Rectangle>,
    ) {
        // TODO: cache path in item to avoid re-tesselation
        let mut path = rect_to_path(rect.geometry());
        let paint = femtovg::Paint::color(
            sixtyfps_corelib::items::Rectangle::FIELD_OFFSETS.color.apply_pin(rect).get().into(),
        );
        self.canvas.borrow_mut().save_with(|canvas| {
            canvas.translate(pos.x, pos.y);
            canvas.fill_path(&mut path, paint)
        })
    }

    fn draw_border_rectangle(
        &mut self,
        pos: Point,
        rect: std::pin::Pin<&sixtyfps_corelib::items::BorderRectangle>,
    ) {
        // TODO: cache path in item to avoid re-tesselation
        let mut path = femtovg::Path::new();
        path.rounded_rect(
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS.x.apply_pin(rect).get(),
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS.y.apply_pin(rect).get(),
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS.width.apply_pin(rect).get(),
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS.height.apply_pin(rect).get(),
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS
                .border_radius
                .apply_pin(rect)
                .get(),
        );
        let fill_paint = femtovg::Paint::color(
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS
                .color
                .apply_pin(rect)
                .get()
                .into(),
        );
        let mut border_paint = femtovg::Paint::color(
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS
                .border_color
                .apply_pin(rect)
                .get()
                .into(),
        );
        border_paint.set_line_width(
            sixtyfps_corelib::items::BorderRectangle::FIELD_OFFSETS
                .border_width
                .apply_pin(rect)
                .get(),
        );
        self.canvas.borrow_mut().save_with(|canvas| {
            canvas.translate(pos.x, pos.y);
            canvas.fill_path(&mut path, fill_paint)
        })
    }

    fn draw_image(&mut self, pos: Point, image: std::pin::Pin<&sixtyfps_corelib::items::Image>) {
        let (cached_image, image_info) = match self.load_image(
            &image.cached_rendering_data,
            sixtyfps_corelib::items::Image::FIELD_OFFSETS.source.apply_pin(image),
        ) {
            Some(image) => image,
            None => return,
        };

        let image_id = cached_image.id;

        let (image_width, image_height) = (image_info.width() as f32, image_info.height() as f32);
        let (source_width, source_height) = (image_width, image_height);
        let fill_paint =
            femtovg::Paint::image(image_id, 0., 0., source_width, source_height, 0.0, 1.0);

        let mut path = femtovg::Path::new();
        path.rect(0., 0., image_width, image_height);

        self.canvas.borrow_mut().save_with(|canvas| {
            canvas.translate(
                pos.x + sixtyfps_corelib::items::Image::FIELD_OFFSETS.x.apply_pin(image).get(),
                pos.y + sixtyfps_corelib::items::Image::FIELD_OFFSETS.y.apply_pin(image).get(),
            );

            let scaled_width =
                sixtyfps_corelib::items::Image::FIELD_OFFSETS.width.apply_pin(image).get();
            let scaled_height =
                sixtyfps_corelib::items::Image::FIELD_OFFSETS.height.apply_pin(image).get();
            if scaled_width > 0. && scaled_height > 0. {
                canvas.scale(scaled_width / image_width, scaled_height / image_height);
            }

            canvas.fill_path(&mut path, fill_paint);
        })
    }

    fn draw_clipped_image(
        &mut self,
        pos: Point,
        clipped_image: std::pin::Pin<&sixtyfps_corelib::items::ClippedImage>,
    ) {
        let (cached_image, image_info) = match self.load_image(
            &clipped_image.cached_rendering_data,
            sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS.source.apply_pin(clipped_image),
        ) {
            Some(image) => image,
            None => return,
        };

        let source_clip_rect = Rect::new(
            [
                sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS
                    .source_clip_x
                    .apply_pin(clipped_image)
                    .get() as _,
                sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS
                    .source_clip_y
                    .apply_pin(clipped_image)
                    .get() as _,
            ]
            .into(),
            [0., 0.].into(),
        );

        let (image_width, image_height) = (image_info.width() as f32, image_info.height() as f32);
        let (source_width, source_height) = if source_clip_rect.is_empty() {
            (image_width, image_height)
        } else {
            (source_clip_rect.width() as _, source_clip_rect.height() as _)
        };
        let fill_paint = femtovg::Paint::image(
            cached_image.id,
            source_clip_rect.min_x(),
            source_clip_rect.min_y(),
            source_width,
            source_height,
            0.0,
            1.0,
        );

        let mut path = femtovg::Path::new();
        path.rect(0., 0., image_width, image_height);

        self.canvas.borrow_mut().save_with(|canvas| {
            canvas.translate(
                pos.x
                    + sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS
                        .x
                        .apply_pin(clipped_image)
                        .get(),
                pos.y
                    + sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS
                        .y
                        .apply_pin(clipped_image)
                        .get(),
            );

            let scaled_width = sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS
                .width
                .apply_pin(clipped_image)
                .get();
            let scaled_height = sixtyfps_corelib::items::ClippedImage::FIELD_OFFSETS
                .height
                .apply_pin(clipped_image)
                .get();
            if scaled_width > 0. && scaled_height > 0. {
                canvas.scale(scaled_width / image_width, scaled_height / image_height);
            }

            canvas.fill_path(&mut path, fill_paint);
        })
    }

    fn draw_text(&mut self, _pos: Point, _rect: std::pin::Pin<&sixtyfps_corelib::items::Text>) {
        //todo!()
    }

    fn draw_text_input(
        &mut self,
        _pos: Point,
        _rect: std::pin::Pin<&sixtyfps_corelib::items::TextInput>,
    ) {
        //todo!()
    }

    fn draw_path(&mut self, _pos: Point, _path: std::pin::Pin<&sixtyfps_corelib::items::Path>) {
        //todo!()
    }

    fn combine_clip(&mut self, pos: Point, clip: &std::pin::Pin<&sixtyfps_corelib::items::Clip>) {
        let clip_rect = clip.geometry().translate([pos.x, pos.y].into());
        self.canvas.borrow_mut().intersect_scissor(
            clip_rect.min_x(),
            clip_rect.min_y(),
            clip_rect.width(),
            clip_rect.height(),
        );
        self.clip_rects.push(clip_rect);
    }

    fn clip_rects(&self) -> SharedVector<sixtyfps_corelib::graphics::Rect> {
        self.clip_rects.clone()
    }

    fn reset_clip(&mut self, rects: SharedVector<sixtyfps_corelib::graphics::Rect>) {
        self.clip_rects = rects;
        // ### Only do this if rects were really changed
        let mut canvas = self.canvas.borrow_mut();
        canvas.reset_scissor();
        for rect in self.clip_rects.as_slice() {
            canvas.intersect_scissor(rect.min_x(), rect.min_y(), rect.width(), rect.height())
        }
    }

    fn draw_cached_pixmap(
        &mut self,
        item_cache: &CachedRenderingData,
        pos: Point,
        update_fn: &dyn Fn(&mut dyn FnMut(u32, u32, &[u8])),
    ) {
        let canvas = &self.canvas;
        let mut cache = self.gpu_cache.borrow_mut();

        let image_cache = item_cache.ensure_up_to_date(&mut cache, || {
            let mut image_cache = None;
            update_fn(&mut |width: u32, height: u32, data: &[u8]| {
                use rgb::FromSlice;
                let img = imgref::Img::new(data.as_rgba(), width as usize, height as usize);
                if let Some(image_id) =
                    canvas.borrow_mut().create_image(img, femtovg::ImageFlags::PREMULTIPLIED).ok()
                {
                    image_cache = Some(GPUCachedData::Image(Rc::new(CachedImage {
                        id: image_id,
                        canvas: canvas.clone(),
                    })))
                };
            });
            image_cache
        });
        let image_id = match image_cache {
            Some(x) => x.as_image().id,
            None => return,
        };
        let mut canvas = self.canvas.borrow_mut();

        let image_info = canvas.image_info(image_id).unwrap();
        let (width, height) = (image_info.width() as f32, image_info.height() as f32);
        let fill_paint = femtovg::Paint::image(image_id, pos.x, pos.y, width, height, 0.0, 1.0);
        let mut path = femtovg::Path::new();
        path.rect(pos.x, pos.y, width, height);
        canvas.fill_path(&mut path, fill_paint);
    }

    fn scale_factor(&self) -> f32 {
        self.scale_factor
    }
}

pub fn create_gl_window() -> ComponentWindow {
    ComponentWindow::new(GraphicsWindow::new(|event_loop, window_builder| {
        GLRenderer::new(
            &event_loop.get_winit_event_loop(),
            window_builder,
            #[cfg(target_arch = "wasm32")]
            "canvas",
        )
    }))
}

#[cfg(target_arch = "wasm32")]
pub fn create_gl_window_with_canvas_id(canvas_id: String) -> ComponentWindow {
    ComponentWindow::new(GraphicsWindow::new(move |event_loop, window_builder| {
        GLRenderer::new(&event_loop.get_winit_event_loop(), window_builder, &canvas_id)
    }))
}

#[doc(hidden)]
#[cold]
pub fn use_modules() {
    sixtyfps_corelib::use_modules();
}

pub type NativeWidgets = ();
pub type NativeGlobals = ();
pub mod native_widgets {}
pub const HAS_NATIVE_STYLE: bool = false;