use crate::prelude::*;

use std::path::Path;

use sdl2::Sdl;
use sdl2::pixels::PixelFormatEnum;
use sdl2::render::WindowCanvas;
use sdl2::video::FullscreenType;

pub(crate) fn paint_frame_on_canvas(frame: &VideoFrame, canvas: &mut WindowCanvas) -> bool {
    if let Ok(surf) = frame_to_surface(frame) {
        let (cw, ch) = canvas.output_size().unwrap();
        let should_intscale = if cw >= surf.width() && ch >= surf.height() {
            sdl2::sys::SDL_bool::SDL_TRUE
        } else {
            sdl2::sys::SDL_bool::SDL_FALSE
        };
        unsafe {
            sdl2::sys::SDL_RenderSetIntegerScale(canvas.raw(), should_intscale);
        }
        if surf.pixel_format_enum() != PixelFormatEnum::Unknown {
            let format = sdl2::pixels::PixelFormat::try_from(canvas.default_pixel_format()).unwrap();
            let surface = surf.convert(&format).unwrap();

            if let Ok(tex) = canvas
                .texture_creator()
                .create_texture_from_surface(surface)
            {
                canvas.copy(&tex, None, None).unwrap();
            }
        }
        canvas.present();
        true
    } else {
        false
    }
}

pub(crate) fn sdl2_pixfmt(retro_fmt: PixelFormat) -> sdl2::pixels::PixelFormatEnum {
    match retro_fmt {
        PixelFormat::ARGB1555 => sdl2::pixels::PixelFormatEnum::ARGB1555,
        PixelFormat::ARGB8888 => sdl2::pixels::PixelFormatEnum::ARGB8888,
        PixelFormat::RGB565 => sdl2::pixels::PixelFormatEnum::RGB565,
    }
}

pub(crate) fn frame_to_surface<'a>(frame: &'a VideoFrame) -> crate::base::Result<sdl2::surface::Surface<'a>> {
    let (width, height) = frame.dimensions();
    if let Some((bytes, pitch)) = frame.data_pitch_as_bytes() {
        let pixel_format = frame
            .pixel_format()
            .map(sdl2_pixfmt)
            .ok_or("Unknown pixel format")?;
        // dirty, but must be &mut for SDL API.
        // safe as long as we don't offer a &mut Surface in the public API.
        let data = unsafe {
            core::slice::from_raw_parts_mut(bytes.as_ptr() as *mut u8, bytes.len())
        };
        sdl2::surface::Surface::from_data(data, width, height, pitch as u32, pixel_format)
            .map_err(Into::into)
    } else {
        let pixel_format = frame
            .pixel_format()
            .map(sdl2_pixfmt)
            .unwrap_or(PixelFormatEnum::Unknown);
        sdl2::surface::Surface::new(width, height, pixel_format)
            .map_err(Into::into)
    }
}

/// Creates a root window in SDL2, then displays each 2D video frame provided by the core
/// by converting it to a [sdl2::render::Texture] and copying it to the window's canvas.
///
/// This component has no public interface and manages the SDL2 window on its own.
pub struct SimpleSdl2CanvasComponent {
    canvas: WindowCanvas,
    win_size: (u32, u32),
}

impl SimpleSdl2CanvasComponent {
    pub fn new(sdl_context: &mut Sdl, ft: FullscreenType) -> crate::base::Result<Self> {
        // default to old libsnes 256x224 window size until load_game (prereq of get_system_av_info)
        let mut window = sdl_context
            .video()?
            .window("ferretro SDL", 256, 224)
            .resizable()
            .hidden()
            .build()?;

        window.set_fullscreen(ft)?;

        let canvas = window
            .into_canvas()
            .build()?;

        let win_size = canvas.output_size().unwrap();

        Ok(SimpleSdl2CanvasComponent {
            canvas,
            win_size,
        })
    }
}

impl RetroComponent for SimpleSdl2CanvasComponent {
    fn post_load_game(&mut self, retro: &mut LibretroWrapper, rom: &Path) -> crate::base::Result<()> {
        let sys_info = retro.get_system_info();
        let title = format!(
            "{} - {} - ferretro SDL",
            sys_info.library_name,
            rom.file_stem().unwrap_or_default().to_string_lossy(),
        );
        self.canvas.window_mut().set_title(&title)?;
        self.canvas.window_mut().show();
        self.set_geometry(&retro.get_system_av_info().geometry);
        Ok(())
    }
}

impl RetroCallbacks for SimpleSdl2CanvasComponent {
    fn video_refresh(&mut self, frame: &VideoFrame) {
        let output_size = self.canvas.output_size().unwrap();
        if output_size != self.win_size {
            self.canvas.clear();
            self.win_size = output_size;
        }
        paint_frame_on_canvas(frame, &mut self.canvas);
    }

    fn set_pixel_format(&mut self, _pix_fmt: PixelFormat) -> Option<bool> {
        Some(true)
    }

    fn get_variable(&mut self, key: &str) -> Option<String> {
        match key {
            "parallel-n64-gfxplugin" => Some("angrylion".to_string()),
            "mupen64plus-rdp-plugin" => Some("angrylion".to_string()),
            "mupen64plus-rsp-plugin" => Some("cxd4".to_string()),
            _ => None,
        }
    }

    fn set_system_av_info(&mut self, av_info: &SystemAvInfo) -> Option<bool> {
        self.set_geometry(&av_info.geometry);
        Some(true)
    }

    fn set_geometry(&mut self, geom: &GameGeometry) -> Option<bool> {
        let _ = self.canvas.window_mut().set_size(geom.base_width, geom.base_height);
        let _ = self.canvas.set_logical_size(geom.base_width, geom.base_height);
        Some(true)
    }
}