use std::io::{Stdout, Write};
use std::path::Path;
use std::time::Instant;

use ferretro_components::base::ControlFlow;
use ferretro_components::prelude::*;

use termion::color::DetectColors;
use termion::raw::{IntoRawMode, RawTerminal};
use termion::screen::AlternateScreen;
use termion::terminal_size;

use anime_telnet::encoding::{AnsiEncoder, ProcessorPipeline};
use anime_telnet::metadata::ColorMode;
use fast_image_resize::FilterType;
use image::RgbaImage;

use sdl2::pixels::PixelFormatEnum;
use sdl2::surface::Surface;

pub struct AnsiVideoComponent {
    terminal_width: u32,
    terminal_height: u32,
    color_mode: ColorMode,
    screen: AlternateScreen<RawTerminal<Stdout>>,
    fps: f32,
    framerate_sampling_start: Instant,
    frame_count: usize,
    frame_skip: usize,
}

impl AnsiEncoder for AnsiVideoComponent {
    fn needs_width(&self) -> u32 {
        self.terminal_width - 1
    }

    fn needs_height(&self) -> u32 {
        (self.terminal_height - 1) * 2 // half-blocks?
    }

    fn needs_color(&self) -> ColorMode {
        self.color_mode
    }
}

impl Default for AnsiVideoComponent {
    fn default() -> Self {
        let output = std::io::stdout().into_raw_mode().unwrap();
        let mut screen = AlternateScreen::from(output);
        write!(screen, "{}", termion::cursor::Hide).unwrap();

        let (w, h) = terminal_size().unwrap_or((80, 24));
        let (width, height) = (w as u32, h as u32);
        let colors = screen.available_colors().unwrap_or(16);

        let color_mode = if colors > 16 { ColorMode::True } else { ColorMode::EightBit };

        AnsiVideoComponent {
            terminal_width: width,
            terminal_height: height,
            color_mode,
            screen,
            fps: 60.0,
            framerate_sampling_start: Instant::now(),
            frame_count: 0,
            frame_skip: 0,
        }
    }
}

impl Drop for AnsiVideoComponent {
    fn drop(&mut self) {
        write!(self.screen, "{}", termion::cursor::Show).unwrap();
    }
}

impl RetroCallbacks for AnsiVideoComponent {
    fn video_refresh(&mut self, frame: &VideoFrame) {
        match frame {
            VideoFrame::XRGB1555 { width, height, .. }
            | VideoFrame::RGB565 { width, height, .. }
            | VideoFrame::XRGB8888 { width, height, .. } => {
                let (bytes, pitch) = frame.data_pitch_as_bytes().unwrap();
                let pitch = pitch as u32;
                let format = match frame.pixel_format().unwrap() {
                    PixelFormat::ARGB1555 => sdl2::pixels::PixelFormatEnum::RGB555,
                    PixelFormat::ARGB8888 => sdl2::pixels::PixelFormatEnum::ARGB8888,
                    PixelFormat::RGB565 => sdl2::pixels::PixelFormatEnum::RGB565,
                };
                // dirty, but must be &mut for SDL API.
                // safety: we don't actually mutate or leak the Surface we construct here.
                let data = unsafe {
                    core::slice::from_raw_parts_mut(bytes.as_ptr() as *mut u8, bytes.len())
                };

                // has the screen size changed?
                let (w, h) = terminal_size().unwrap_or((80, 24));
                let (w, h) = (w as u32, h as u32);
                let force_redraw = if self.terminal_width != w || self.terminal_height != h {
                    self.terminal_width = w as u32;
                    self.terminal_height = h as u32;
                    self.frame_skip = 0;
                    write!(self.screen, "{}", termion::clear::All).unwrap();
                    true
                } else {
                    false
                };

                if !force_redraw {
                    if self.frame_skip != 0 && self.frame_count % self.frame_skip != 0 {
                        return;
                    }
                }

                if let Ok(surf) = Surface::from_data(data, *width, *height, pitch, format) {
                    let rgba_raw = surf.into_canvas().unwrap().read_pixels(None, PixelFormatEnum::ABGR8888).unwrap();
                    let rgba_img = RgbaImage::from_raw(*width, *height, rgba_raw).unwrap();

                    let processor = ProcessorPipeline {
                        filter: FilterType::Hamming,
                        width: self.needs_width(),
                        height: self.needs_height(),
                        color_modes: Some(self.needs_color()).into_iter().collect(),
                    };

                    let processed = processor.process(&rgba_img).into_iter().next().unwrap().1;
                    write!(self.screen, "{}", termion::cursor::Goto(1, 1)).unwrap();
                    for line in self.encode_frame(&processed).lines() {
                        write!(self.screen, "{}{}\r\n", line, termion::color::Fg(termion::color::Black)).unwrap();
                    }
                    write!(self.screen, "\x1B[0m").unwrap();
                    self.screen.flush().unwrap();
                } else if force_redraw {
                    // TODO: draw last copy
                }
            }
            _ => {}
        }
    }

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

impl RetroComponent for AnsiVideoComponent {
    fn post_run(&mut self, _retro: &mut LibretroWrapper) -> ControlFlow {
        self.frame_count += 1;
        if self.frame_skip < 10 && self.frame_count > 10 {
            let now = Instant::now();
            let period = now.duration_since(self.framerate_sampling_start).as_secs_f32();
            let actual_fps = self.frame_count as f32 / period;
            if actual_fps < self.fps * 2.0 / 3.0 {
                self.frame_skip += 1;
                self.frame_count = 0;
                self.framerate_sampling_start = now;
            }
        }
        ControlFlow::Continue
    }

    fn post_load_game(&mut self, retro: &mut LibretroWrapper, _rom: &Path) -> ferretro_components::base::Result<()> {
        self.fps = retro.get_system_av_info().timing.fps as f32;
        Ok(())
    }
}