use std::collections::HashMap;
use std::io::{Stdout, Write};
use std::path::{Path, PathBuf};
use std::sync::mpsc::Receiver;
use std::time::{Duration, Instant};

use structopt::StructOpt;

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

use termion::color::DetectColors;
use termion::event::Key;
use termion::input::TermRead;
use termion::raw::{IntoRawMode, RawTerminal};
use termion::screen::AlternateScreen;
use termion::terminal_size;

use anime_telnet::encoding::Encoder as AnsiArtEncoder;
use anime_telnet::encoding::ProcessorPipeline;
use anime_telnet::metadata::ColorMode;
use fast_image_resize::FilterType;
use image::RgbaImage;

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

#[derive(StructOpt)]
struct Opt {
    /// Emulator core to use.
    #[structopt(short, long, parse(from_os_str))]
    core: PathBuf,
    /// Path to ROM.
    #[structopt(parse(from_os_str))]
    rom: PathBuf,
    /// Directory containing BIOS files
    #[structopt(short, long, parse(from_os_str))]
    system: Option<PathBuf>,
}

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 AnsiArtEncoder 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 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).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(())
    }
}

struct TermiosInputComponent {
    //reader: AsyncReader,
    receiver: Receiver<(Instant, Key)>,
    want_quit: bool,
    preferred_pad: Option<u32>,
    button_map: HashMap<Key, InputDeviceId>,
    axis_maps: [HashMap<Key, (i16, i16)>; 2],
    button_state: HashMap<InputDeviceId, (Instant, i16)>,
    axis_state: [(Instant, [i16; 2]); 2],
}

impl Default for TermiosInputComponent {
    fn default() -> Self {
        let (sender, receiver) = std::sync::mpsc::channel();
        std::thread::spawn(move || {
            for k in std::io::stdin().keys().map(|kr| kr.unwrap()) {
                sender.send((Instant::now(), k)).unwrap();
                if k == Key::Esc {
                    break
                }
            }
        });
        TermiosInputComponent {
            //reader: termion::async_stdin(),
            receiver,
            want_quit: false,
            preferred_pad: None,
            button_map: [
                (Key::Up, InputDeviceId::Joypad(JoypadButton::Up)),
                (Key::Down, InputDeviceId::Joypad(JoypadButton::Down)),
                (Key::Left, InputDeviceId::Joypad(JoypadButton::Left)),
                (Key::Right, InputDeviceId::Joypad(JoypadButton::Right)),
                (Key::Char('x'), InputDeviceId::Joypad(JoypadButton::A)),
                (Key::Char('z'), InputDeviceId::Joypad(JoypadButton::B)),
                (Key::Char('s'), InputDeviceId::Joypad(JoypadButton::X)),
                (Key::Char('a'), InputDeviceId::Joypad(JoypadButton::Y)),
                (Key::Ctrl('x'), InputDeviceId::Joypad(JoypadButton::A)),
                (Key::Ctrl('z'), InputDeviceId::Joypad(JoypadButton::B)),
                (Key::Ctrl('s'), InputDeviceId::Joypad(JoypadButton::X)),
                (Key::Ctrl('a'), InputDeviceId::Joypad(JoypadButton::Y)),
                (Key::Alt('x'), InputDeviceId::Joypad(JoypadButton::A)),
                (Key::Alt('z'), InputDeviceId::Joypad(JoypadButton::B)),
                (Key::Alt('s'), InputDeviceId::Joypad(JoypadButton::X)),
                (Key::Alt('a'), InputDeviceId::Joypad(JoypadButton::Y)),
                (Key::Char('q'), InputDeviceId::Joypad(JoypadButton::L)),
                (Key::Char('w'), InputDeviceId::Joypad(JoypadButton::R)),
                (Key::Ctrl('q'), InputDeviceId::Joypad(JoypadButton::L2)),
                (Key::Ctrl('w'), InputDeviceId::Joypad(JoypadButton::R2)),
                (Key::Alt('q'), InputDeviceId::Joypad(JoypadButton::L3)),
                (Key::Alt('w'), InputDeviceId::Joypad(JoypadButton::R3)),
                (Key::Char('\n'), InputDeviceId::Joypad(JoypadButton::Start)),
                (Key::Backspace, InputDeviceId::Joypad(JoypadButton::Select)),
                (Key::Char('\t'), InputDeviceId::Joypad(JoypadButton::Select)),
            ].into_iter().collect(),
            axis_maps: [
                [
                    (Key::Char('1'), (i16::MIN, i16::MAX)),
                    (Key::Char('2'), (0, i16::MAX)),
                    (Key::Char('3'), (i16::MAX, i16::MAX)),
                    (Key::Char('4'), (i16::MIN, 0)),
                    (Key::Char('5'), (0, 0)),
                    (Key::Char('6'), (i16::MAX, 0)),
                    (Key::Char('7'), (i16::MIN + 1, i16::MIN + 1)), // ???
                    (Key::Char('8'), (0, i16::MIN)),
                    (Key::Char('9'), (i16::MAX, i16::MIN)),
                ].into_iter().collect(),
                [
                    (Key::Char('r'), (0, i16::MIN)),
                    (Key::Char('d'), (0, i16::MAX)),
                    (Key::Char('e'), (i16::MIN, 0)),
                    (Key::Char('f'), (i16::MAX, 0)),
                ].into_iter().collect(),
            ],
            button_state: Default::default(),
            axis_state: [(Instant::now(), [0, 0]); 2],
        }
    }
}

impl RetroCallbacks for TermiosInputComponent {
    fn input_poll(&mut self) {
        while let Ok((now, k)) = self.receiver.try_recv() {
            if k == Key::Esc {
                self.want_quit = true;
            }

            if let Some(mapping) = self.button_map.get(&k) {
                self.button_state.insert(mapping.to_owned(), (now, 1));
            }

            for (axis_map, axis_state) in self.axis_maps.iter().zip(self.axis_state.iter_mut()) {
                let (mut sum_x, mut sum_y) = (0, 0);
                let mut count = 0;
                if let Some((x, y)) = axis_map.get(&k) {
                    sum_x += *x as i32;
                    sum_y += *y as i32;
                    count += 1;
                }
                if count != 0 {
                    let average_x = (sum_x / count) as i16;
                    let average_y = (sum_y / count) as i16;
                    *axis_state = (now, [average_x, average_y]);
                }
            }
        }
    }

    fn input_state(&mut self, port: u32, device: InputDeviceId, index: InputIndex) -> i16 {
        if port != 0 {
            return 0;
        }
        if let Some((inst, val)) = self.button_state.get(&device) {
            // TODO: consult kbdrate.c (and X11?) for durations (can't detect key-up/held, only repeat)
            if Instant::now().duration_since(*inst) < Duration::from_millis(300) {
                return *val;
            }
        }
        match device {
            InputDeviceId::Analog(axis_id) => {
                let (inst, axes) = self.axis_state[index as u32 as usize];
                let since = Instant::now().duration_since(inst);
                let ratio = if since < Duration::from_millis(100) {
                    1.0
                } else if since < Duration::from_millis(300) {
                    (0.3 - since.as_secs_f32()) * 5.0
                } else {
                    0.0
                };
                (axes[axis_id as u32 as usize] as f32 * ratio) as i16
            }
            // TODO: mouse?
            _ => 0,
        }
    }

    fn get_variable(&mut self, key: &str) -> Option<String> {
        match key {
            "beetle_saturn_analog_stick_deadzone" => Some("15%".to_string()),
            "parallel-n64-astick-deadzone" => Some("15%".to_string()),
            _ => None,
        }
    }

    fn get_input_device_capabilities(&mut self) -> Option<u64> {
        let bits = (1 << (DeviceType::Joypad as u32)) | (1 << (DeviceType::Analog as u32));
        Some(bits as u64)
    }

    fn set_controller_info(&mut self, controller_info: &[ControllerDescription2]) -> Option<bool> {
        for ci in controller_info {
            // so we can have analog support in beetle/mednafen saturn
            if ci.name.as_str() == "3D Control Pad" {
                self.preferred_pad = Some(ci.device_id());
                break;
            }
        }
        Some(true)
    }
}

impl RetroComponent for TermiosInputComponent {
    fn post_run(&mut self, _: &mut LibretroWrapper) -> ControlFlow {
        if self.want_quit {
            ControlFlow::Break
        } else {
            ControlFlow::Continue
        }
    }

    fn post_load_game(&mut self, retro: &mut LibretroWrapper, _rom: &Path) -> ferretro_components::base::Result<()> {
        if let Some(device) = self.preferred_pad {
            retro.set_controller_port_device(0, device);
        }
        Ok(())
    }
}

fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let opt: Opt = Opt::from_args();
    let mut emu = RetroComponentBase::new(&opt.core);
    emu.register_component(AnsiVideoComponent::default())?;
    emu.register_component(TermiosInputComponent::default())?;
    emu.register_component(StatefulInputComponent::default())?;
    emu.register_component(PathBufComponent {
        sys_path: opt.system.clone(),
        libretro_path: Some(opt.core.to_path_buf()),
        core_assets_path: None,
        save_path: Some(std::env::temp_dir()),
    })?;
    let mut vars_comp = VariableStoreComponent::default();
    vars_comp.insert("mgba_skip_bios", "ON");
    vars_comp.insert("mgba_sgb_borders", "OFF");
    emu.register_component(vars_comp)?;
    emu.register_component(SleepFramerateLimitComponent::default())?;

    emu.init()?;
    emu.load_game(&opt.rom)?;

    while let ControlFlow::Continue = emu.run() {
    }

    Ok(())
}