extern crate ferretro_core;
extern crate ffmpeg_next as ffmpeg;

use std::collections::VecDeque;
use std::io::Read;
use std::path::{Path, PathBuf};
use std::pin::Pin;

use structopt::StructOpt;

use ferretro_core::retro;
use ferretro_core::retro::ffi::{PixelFormat, GameGeometry, SystemAvInfo, SystemInfo};
use ferretro_core::retro::wrapper::{LibretroWrapper, RetroCallbacks};

use ferretro_core::retro::wrapped_types::{Variable2};

use ffmpeg::{ChannelLayout, Packet, codec, filter, format, frame, media};
use ffmpeg::util::rational::Rational;

struct MyEmulator {
    retro: retro::wrapper::LibretroWrapper,
    sys_info: SystemInfo,
    av_info: SystemAvInfo,
    audio_buf: Vec<(i16, i16)>,
    video_pixel_format: format::Pixel,
    prev_video_frame: Option<frame::Video>,
    video_frames: VecDeque<frame::Video>,
    video_encoder: ffmpeg::encoder::Video,
    audio_encoder: ffmpeg::encoder::Audio,
    video_filter: filter::Graph,
    audio_filter: filter::Graph,
    sys_path: Option<PathBuf>,
    frame_properties_locked: bool,
    octx: ffmpeg::format::context::Output,
    frame: u64,
}

fn video_filter(
    video_encoder: &ffmpeg::encoder::video::Video,
    av_info: &SystemAvInfo,
    pix_fmt: PixelFormat,
) -> Result<filter::Graph, ffmpeg::Error> {
    let mut vfilter = filter::Graph::new();
    let pix_fmt = match pix_fmt {
        PixelFormat::ARGB1555 => if cfg!(target_endian = "big") { "rgb555be" } else { "rgb555le" },
        PixelFormat::ARGB8888 => "argb",
        PixelFormat::RGB565 => if cfg!(target_endian = "big") { "rgb565be" } else { "rgb565le" },
    };
    let pixel_aspect = av_info.geometry.aspect_ratio / (av_info.geometry.base_width as f32 / av_info.geometry.base_height as f32);
    let fps = if av_info.timing.fps == 0.0 { 60.0 } else { av_info.timing.fps };
    let args = format!(
        "width={}:height={}:pix_fmt={}:frame_rate={}:pixel_aspect={}:time_base=1/{}",
        av_info.geometry.base_width,
        av_info.geometry.base_height,
        pix_fmt,
        fps,
        pixel_aspect,
        fps,
    );
    eprintln!("🎥 filter args: {}", args);
    vfilter.add(&filter::find("buffer").unwrap(), "in", &args)?;
    //scale?
    vfilter.add(&filter::find("buffersink").unwrap(), "out", "")?;

    {
        let mut out = vfilter.get("out").unwrap();
        out.set_pixel_format(video_encoder.format());
    }

    vfilter.output("in", 0)?
        .input("out", 0)?
        .parse("null")?; // passthrough filter for video

    vfilter.validate()?;
    // human-readable filter graph
    eprintln!("{}", vfilter.dump());

    Ok(vfilter)
}

fn audio_filter(
    audio_encoder: &ffmpeg::codec::encoder::Audio,
    sample_rate: f64,
) -> Result<filter::Graph, ffmpeg::Error> {
    let mut afilter = filter::Graph::new();
    let sample_rate = if sample_rate == 0.0 { 32040.0 } else { sample_rate };
    let args = format!("sample_rate={}:sample_fmt=s16:channel_layout=stereo:time_base=1/60", sample_rate);
    eprintln!("🔊 filter args: {}", args);
    afilter.add(&filter::find("abuffer").unwrap(), "in", &args)?;
    //aresample?
    afilter.add(&filter::find("abuffersink").unwrap(), "out", "")?;

    {
        let mut out = afilter.get("out").unwrap();
        out.set_sample_format(audio_encoder.format());
        out.set_channel_layout(audio_encoder.channel_layout());
        out.set_sample_rate(audio_encoder.rate());
    }

    afilter.output("in", 0)?
        .input("out", 0)?
        .parse("anull")?;
    afilter.validate()?;
    // human-readable filter graph
    eprintln!("{}", afilter.dump());

    if let Some(codec) = audio_encoder.codec() {
        if !codec
            .capabilities()
            .contains(ffmpeg::codec::capabilities::Capabilities::VARIABLE_FRAME_SIZE)
        {
            eprintln!("setting constant frame size {}", audio_encoder.frame_size());
            afilter
                .get("out")
                .unwrap()
                .sink()
                .set_frame_size(audio_encoder.frame_size());
        }
    }

    Ok(afilter)
}

impl MyEmulator {
    pub fn new(
        core_path: impl AsRef<Path>,
        sys_path: &Option<impl AsRef<Path>>,
        video_path: impl AsRef<Path>,
        mut octx: ffmpeg::format::context::Output,
    ) -> Pin<Box<Self>> {
        let lib = libloading::Library::new(core_path.as_ref()).unwrap();
        let raw_retro = retro::loading::LibretroApi::from_library(lib).unwrap();
        let retro = retro::wrapper::LibretroWrapper::from(raw_retro);

        let sys_info = retro.get_system_info();
        let mut av_info = retro.get_system_av_info();

        let fps_int = av_info.timing.fps.round() as i32;
        let fps_int = if fps_int == 0 { 60 } else { fps_int };

        let detected_vcodec = octx.format().codec(&video_path, media::Type::Video);
        //let detected_acodec = octx.format().codec(&video_path, media::Type::Audio);
let wavname  = Path::new("out.wav");
        let detected_acodec = octx.format().codec(&wavname, media::Type::Audio);

        let vcodec = ffmpeg::encoder::find(detected_vcodec).unwrap().video().unwrap();
        let acodec = ffmpeg::encoder::find(detected_acodec).unwrap().audio().unwrap();

        let mut video_output = octx.add_stream(vcodec).unwrap();
        video_output.set_time_base(Rational::new(1, 60));
        let mut video_encoder = video_output.codec().encoder().video().unwrap();

        video_encoder.set_bit_rate(2560000);
        video_encoder.set_format(video_encoder.codec().unwrap().video().unwrap().formats().unwrap().nth(0).unwrap());

        video_encoder.set_time_base(Rational::new(1, 60));
        video_encoder.set_frame_rate(Some(Rational::new(fps_int, 1)));
        
        //video_encoder.set_frame_rate(av_info.timing.fps.into());

        if av_info.geometry.base_height == 0 && av_info.geometry.base_width == 0 {
            av_info.geometry.base_width = 320;
            av_info.geometry.base_height = 224;
            av_info.geometry.aspect_ratio = 4.33;
        }
        if av_info.timing.sample_rate == 0.0 {
            av_info.timing.sample_rate = 44100.0;
        }
        video_encoder.set_width(av_info.geometry.base_width);
        video_encoder.set_height(av_info.geometry.base_height);
        //video_encoder.set_aspect_ratio(av_info.geometry.aspect_ratio as f64);

        let pix_fmt = PixelFormat::ARGB1555; // temporary until env call is made
        let video_filter = video_filter(&video_encoder, &av_info, pix_fmt).unwrap();

        let video_encoder = video_encoder.open_as(vcodec).unwrap();
        //video_output.set_parameters(&video_encoder);

        let mut audio_output = octx.add_stream(acodec).unwrap();
        let mut audio_encoder = audio_output.codec().encoder().audio().unwrap();

        //let mut video_encoder = octx.add_stream(vcodec).unwrap().codec().encoder().video().unwrap();
    /*
        let mut audio_output = octx.add_stream(acodec).unwrap();
        let mut audio_encoder = audio_output.codec().encoder().audio().unwrap();
        */
        /*
        retroarch inits
static bool ffmpeg_init_config(struct ff_config_param *params,
   if (!ffmpeg_init_muxer_pre(handle))
   if (!ffmpeg_init_video(handle))
   av_frame_alloc
   */


        audio_encoder.set_bit_rate(640000);
        audio_encoder.set_max_bit_rate(990000);

        //audio_encoder.set_rate(44100);
        audio_encoder.set_rate(av_info.timing.sample_rate.round() as i32);
        audio_encoder.set_channels(2);
        audio_encoder.set_channel_layout(ChannelLayout::STEREO);
        audio_encoder.set_format(audio_encoder.codec().unwrap().audio().unwrap().formats().unwrap().nth(0).unwrap());
        audio_encoder.set_time_base(Rational::new(1, 60));
        audio_output.set_time_base(Rational::new(1, 60));

        let audio_encoder = audio_encoder.open_as(acodec).unwrap();
        //audio_output.set_parameters(&audio_encoder);

        let audio_filter = audio_filter(&audio_encoder, av_info.timing.sample_rate).unwrap();

        //audio_encoder.set_rate(av_info.timing.sample_rate.round() as i32);

        octx.write_header().unwrap();
        ffmpeg::format::context::output::dump(&octx, 0, None);

        let emu = MyEmulator {
            retro,
            sys_info,
            av_info: av_info.clone(),
            audio_buf: Default::default(),
            video_pixel_format: format::Pixel::RGB555,
            prev_video_frame: None,
            video_frames: Default::default(),
            video_encoder,
            audio_encoder,
            video_filter,
            audio_filter,
            sys_path: sys_path.as_ref().map(|x| x.as_ref().to_path_buf()),
            frame_properties_locked: false,
            octx,
            frame: 0
        };

        let mut pin_emu = Box::pin(emu);
        retro::wrapper::set_handler(pin_emu.as_mut());
        pin_emu.retro.init();
        pin_emu.set_system_av_info(&av_info);
        pin_emu
    }
    
    fn receive_and_write_packets(&mut self, encoder: EncoderToWriteFrom)
    {
        let stream_index = match encoder {
            EncoderToWriteFrom::Video => 0,
            EncoderToWriteFrom::Audio => 1,
        };
        let mut encoded_packet = ffmpeg::Packet::empty();
        loop
        {
            match match encoder {
                EncoderToWriteFrom::Video => self.video_encoder.receive_packet(&mut encoded_packet),
                EncoderToWriteFrom::Audio => self.audio_encoder.receive_packet(&mut encoded_packet),
            } {
                Ok(..) => {
                    //if encoded_packet.size() > 0 {
                        encoded_packet.set_stream(stream_index);
                        eprintln!("📦 Writing packet, pts {:?} dts {:?} size {}", encoded_packet.pts(), encoded_packet.dts(), encoded_packet.size());
                        if stream_index == 0 {
                            encoded_packet.rescale_ts(Rational(1, 60), self.octx.stream(stream_index).unwrap().time_base());
                        }
                        eprintln!("📦 rescaled , pts {:?} dts {:?} size {}", encoded_packet.pts(), encoded_packet.dts(), encoded_packet.size());

                        match encoded_packet.write_interleaved(&mut self.octx) {
                            Ok(..) => eprintln!("Write OK"),
                            Err(e) => eprintln!("Error writing: {}", e),
                        }
                        //encoded_packet.write_interleaved(&mut self.octx).unwrap(); // AAA
                    //}
                    //else {
                        //eprintln!("Did not try to write 0-length packet");
                    //}
                },
                Err(e) => {
                    eprintln!("Error writing packet: {:?}", e);
                    break;
                }
            }
        }
    }

    pub fn run(&mut self, frame: i64) {
        self.frame += 1;
        self.retro.run();

        match self.video_frames.pop_front() {
            Some(mut vframe) => {
                vframe.set_pts(Some(frame));
                eprintln!("🎞 queue frame pts {:?}", vframe.pts());
                self.video_filter.get("in").unwrap().source().add(&vframe).unwrap();
                let mut filtered_vframe = frame::Video::empty();

                loop {
                    match self.video_filter.get("out").unwrap().sink().frame(&mut filtered_vframe) {
                        Ok(..) => {
                            eprintln!("🎥 Got filtered video frame {}x{} pts {:?}", filtered_vframe.width(), filtered_vframe.height(), filtered_vframe.pts());
                            if self.video_filter.get("in").unwrap().source().failed_requests() > 0 {
                                println!("🎥 failed to put filter input frame");
                            }
                            //filtered_vframe.set_pts(Some(frame));
                            self.video_encoder.send_frame(&filtered_vframe).unwrap();

                            self.receive_and_write_packets(EncoderToWriteFrom::Video);
                        },
                        Err(e) => {
                            eprintln!("Error getting filtered video frame: {:?}", e);
                            break;
                        }
                    }
                }
                
                let mut aframe = frame::Audio::new(
                    format::Sample::I16(format::sample::Type::Packed),
                    self.audio_buf.len(),
                    ChannelLayout::STEREO
                );
                if aframe.planes() > 0 {
                    aframe.set_channels(2);
                    aframe.set_rate(44100);
                    aframe.set_pts(Some(frame));
                    let aplane: &mut [(i16, i16)] = aframe.plane_mut(0);
                    eprintln!("Audio buffer length {} -> {}", self.audio_buf.len(), aplane.len());
                    aplane.copy_from_slice(self.audio_buf.as_ref());
                    //eprintln!("src: {:?}, dest: {:?}", self.audio_buf, aplane);
                    self.audio_buf.clear();

                    eprintln!("frame audio: {:?}", aframe);

                    eprintln!("🎞 queue frame pts {:?}", aframe.pts());
                    self.audio_filter.get("in").unwrap().source().add(&aframe).unwrap();

                    let mut filtered_aframe = frame::Audio::empty();
                    loop {
                        match self.audio_filter.get("out").unwrap().sink().frame(&mut filtered_aframe) {
                            Ok(..) => {
                                eprintln!("🔊 Got filtered audio frame {:?} pts {:?}", filtered_aframe, filtered_aframe.pts());
                                if self.audio_filter.get("in").unwrap().source().failed_requests() > 0 {
                                    println!("🎥 failed to put filter input frame");
                                }
                                //let faplane: &[f32] = filtered_aframe.plane(0);
                                //filtered_aframe.set_pts(Some(frame));

                                self.audio_encoder.send_frame(&filtered_aframe).unwrap();
                                self.receive_and_write_packets(EncoderToWriteFrom::Audio);
                            },
                            Err(e) => {
                                eprintln!("Error getting filtered audio frame: {:?}", e);
                                break;
                            }
                        }
                    }
                }
            },
            None => println!("Video not ready during frame {}", self.frame)
        }



    }

    pub fn load_game(&mut self, rom: impl AsRef<Path>) {
        let path = rom.as_ref();
        let mut data = None;
        let mut v = Vec::new();
        if !self.sys_info.need_fullpath {
            if let Ok(mut f) = std::fs::File::open(path) {
                if f.read_to_end(&mut v).is_ok() {
                    data = Some(v.as_ref());
                }
            }
        }
        self.retro
            .load_game(Some(path), data, None)
            .unwrap();
    }

    pub fn end(&mut self) {
        self.video_encoder.send_eof();
        self.receive_and_write_packets(EncoderToWriteFrom::Video);
        self.audio_encoder.send_eof();
        self.receive_and_write_packets(EncoderToWriteFrom::Audio);
        self.octx.write_trailer().unwrap();
    }

    pub fn unserialize(&mut self, state: impl AsRef<Path>) -> Result<(), Box<dyn std::error::Error>> {
        let path = state.as_ref();
        let mut v = Vec::new();
        if let Ok(mut f) = std::fs::File::open(path) {
            if f.read_to_end(&mut v).is_ok(){
                return self.retro.unserialize(v.as_ref());
            }
        }
        Err("Couldn't read file to unserialize".into())
    }
}

impl retro::wrapper::LibretroWrapperAccess for MyEmulator {
    fn libretro_core(&mut self) -> &mut LibretroWrapper {
        &mut self.retro
    }
}

impl retro::wrapper::RetroCallbacks for MyEmulator {
    fn video_refresh(&mut self, data: &[u8], width: u32, height: u32, pitch: u32) {
        let mut vframe = frame::Video::new(self.video_pixel_format, width, height);

        let stride = vframe.stride(0);
        let pitch = pitch as usize;

        let vplane = vframe.data_mut(0);
        if data.len() == vplane.len() && pitch == stride {
            vplane.copy_from_slice(&data);
        } else {
            for y in 0..(height as usize) {
                let ffbegin = y * stride;
                let lrbegin = y * pitch;
                let min = usize::min(stride, pitch);
                vplane[ffbegin..(ffbegin + min)].copy_from_slice(
                    &data[lrbegin..(lrbegin + min)]
                );
            }
        }

        //vframe.set_pts(Some(self.frame as i64));

        self.prev_video_frame.replace(vframe.clone());
        self.video_frames.push_back(vframe);
    }

    fn video_refresh_dupe(&mut self, width: u32, height: u32, _pitch: u32) {
        if let Some(frame) = &self.prev_video_frame {
            self.video_frames.push_back(frame.clone());
        } else {
            let vframe = frame::Video::new(self.video_pixel_format, width, height);
            self.video_frames.push_back(vframe);
        }
    }

    fn audio_sample(&mut self, left: i16, right: i16) {
        self.audio_buf.push((left, right));
    }

    fn audio_sample_batch(&mut self, stereo_pcm: &[i16]) -> usize {
        let left_iter = stereo_pcm.iter().step_by(2).cloned();
        let right_iter = stereo_pcm.iter().skip(1).step_by(2).cloned();
        self.audio_buf.extend(Iterator::zip(left_iter, right_iter));
        stereo_pcm.len()
    }

    fn get_system_directory(&mut self) -> Option<PathBuf> {
        self.sys_path.clone()
    }

    fn set_pixel_format(&mut self, format: PixelFormat) -> Option<bool> {
        if self.frame_properties_locked {
            return Some(true);
        }

        self.video_pixel_format = match format {
            PixelFormat::ARGB1555 => format::Pixel::RGB555,
            PixelFormat::ARGB8888 => format::Pixel::RGB32,
            PixelFormat::RGB565 => format::Pixel::RGB565,
        };
        self.video_filter = video_filter(&self.video_encoder, &self.av_info, format).unwrap();
        Some(true)
    }

    fn set_system_av_info(&mut self, system_av_info: &SystemAvInfo) -> Option<bool> {
        if self.frame_properties_locked {
            return Some(true);
        }

        //self.video_encoder.set_frame_rate(system_av_info.timing.fps.into());
        //self.video_encoder.set_time_base(Rational::new(1, 60));
        //self.video_encoder.set_frame_rate(Some(Rational::new(1, 60)));
        if system_av_info.timing.sample_rate.round() as i32 > 0 {
            self.audio_encoder.set_rate(system_av_info.timing.sample_rate.round() as i32);
        }
        self.av_info.timing = system_av_info.timing.clone();
        self.set_geometry(&system_av_info.geometry);
        Some(true)
    }

    fn set_geometry(&mut self, geometry: &GameGeometry) -> Option<bool> {
        if self.frame_properties_locked {
            return Some(true);
        }

        self.video_encoder.set_width(geometry.base_width);
        self.video_encoder.set_height(geometry.base_height);
        //self.video_encoder.set_aspect_ratio(geometry.aspect_ratio as f64);
        self.av_info.geometry = geometry.clone();
        let pixel_format = match self.video_pixel_format {
            format::Pixel::RGB555 => PixelFormat::ARGB1555,
            format::Pixel::RGB32 => PixelFormat::ARGB8888,
            format::Pixel::RGB565 => PixelFormat::RGB565,
            _ => unimplemented!(),
        };
        self.video_filter = video_filter(&self.video_encoder, &self.av_info, pixel_format).unwrap();
        Some(true)
    }


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

    fn set_variables(&mut self, variables: &Vec<Variable2>) -> Option<bool> {
        for v in variables {
            eprintln!("{:?}", v);
        }
        Some(true)
    }

    fn log_print(&mut self, level: retro::ffi::LogLevel, msg: &str) {
        eprint!("🕹️ [{:?}] {}", level, msg);
    }
}

#[derive(StructOpt)]
struct Opt {
    /// Core module to use.
    #[structopt(short, long, parse(from_os_str))]
    core: PathBuf,
    /// ROM to load using the core.
    #[structopt(short, long, parse(from_os_str))]
    rom: PathBuf,
    /// Recorded video to write.
    #[structopt(short, long, parse(from_os_str))]
    video: PathBuf,
    /// Save state to load at startup.
    #[structopt(long, parse(from_os_str))]
    state: Option<PathBuf>,
    /// System directory, often containing BIOS files
    #[structopt(short, long, parse(from_os_str))]
    system: Option<PathBuf>,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let opt: Opt = Opt::from_args();
    ffmpeg::log::set_level(ffmpeg::log::Level::Trace);
    ffmpeg::init().unwrap();

    let mut octx = format::output(&opt.video)?;
    unsafe {
        (*octx.as_mut_ptr()).debug = 1;
        eprintln!("oformat: {:?}", &((*octx.as_mut_ptr()).oformat));
        eprintln!("flags: {:?}", (*(*octx.as_mut_ptr()).oformat).flags);
    }

    //octx.write_header().unwrap();

    let mut emu = MyEmulator::new(opt.core, &opt.system, &opt.video, octx);
    emu.load_game(opt.rom);

    emu.frame_properties_locked = true;

    if let Some(state) = opt.state {
        emu.unserialize(state)?;
    }

    //for frame in 0..60*10 {
    for frame in 0..800 {
        eprintln!("🖼️ frame: {}", frame);
        emu.run(frame);

    }
    let mut packet = Packet::empty();
    eprintln!("flushed: {:?}", emu.video_encoder.flush(&mut packet)?);

    emu.end();
    //octx.write_trailer().unwrap();
    Ok(())
}

enum EncoderToWriteFrom {
    Video,
    Audio,
}