/*
    Hurry Curry! - a game about cooking
    Copyright 2024 metamuffin

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, version 3 of the License only.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.

*/
use anyhow::{anyhow, Context};
use async_compression::tokio::{bufread::ZstdDecoder, write::ZstdEncoder};
use clap::Parser;
use futures_util::{SinkExt, StreamExt};
use hurrycurry_protocol::{PacketC, PacketS};
use log::{debug, info, warn, LevelFilter};
use serde::{Deserialize, Serialize};
use std::{
    path::{Path, PathBuf},
    time::{Duration, Instant, SystemTime},
};
use tokio::{
    fs::File,
    io::{AsyncBufReadExt, AsyncWriteExt, BufReader, BufWriter},
    net::TcpListener,
    time::sleep,
};
use tokio_tungstenite::tungstenite::Message;

#[derive(Parser)]
enum Args {
    /// Connects as a spectator and saves the protocol packets for replay
    Record {
        /// Dont stop after the first game but restart instead
        #[arg(short, long)]
        r#loop: bool,
        url: String,
        output: PathBuf,
    },
    /// Starts a local server that replays previously recorded sessions
    Replay { input: PathBuf },
}

#[derive(Serialize, Deserialize)]
struct Event {
    ts: f64,
    packet: PacketC,
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    env_logger::builder()
        .filter_level(LevelFilter::Info)
        .parse_env("LOG")
        .init();

    rustls::crypto::ring::default_provider()
        .install_default()
        .unwrap();

    let args = Args::parse();

    match args {
        Args::Record {
            url,
            output,
            r#loop,
        } => loop {
            let out = if r#loop {
                output.join(format!(
                    "replay-{}",
                    SystemTime::now()
                        .duration_since(SystemTime::UNIX_EPOCH)
                        .unwrap()
                        .as_secs()
                ))
            } else {
                output.clone()
            };
            if let Err(e) = do_record(&out, &url).await {
                warn!("recording failed: {e}");
                sleep(Duration::from_secs(1)).await;
            }
            if r#loop {
                info!("restarting...");
            } else {
                break;
            }
        },
        Args::Replay { input } => {
            let ws_listener = TcpListener::bind("0.0.0.0:27032").await?;
            info!("listening for websockets on {}", ws_listener.local_addr()?);

            loop {
                let mut file =
                    BufReader::new(ZstdDecoder::new(BufReader::new(File::open(&input).await?)))
                        .lines();

                let mut next_event =
                    serde_json::from_str::<Event>(&file.next_line().await?.ok_or(anyhow!("eof"))?)?;
                let mut time = 0.;

                info!("ready");
                let (sock, addr) = ws_listener.accept().await?;
                let Ok(mut sock) = tokio_tungstenite::accept_async(sock).await else {
                    warn!("invalid ws handshake");
                    continue;
                };
                info!("{addr} connected via ws");

                sock.send(tokio_tungstenite::tungstenite::Message::Text(
                    serde_json::to_string(&PacketC::ReplayStart).unwrap(),
                ))
                .await?;
                'outer: while let Some(Ok(message)) = sock.next().await {
                    match message {
                        Message::Text(line) => {
                            let packet: PacketS = match serde_json::from_str(&line) {
                                Ok(p) => p,
                                Err(e) => {
                                    warn!("invalid packet: {e}");
                                    break;
                                }
                            };
                            debug!("<- {packet:?}");

                            match packet {
                                PacketS::Join { .. } => {
                                    sock.send(tokio_tungstenite::tungstenite::Message::Text(
                                        serde_json::to_string(&PacketC::ServerMessage {
                                            text: "Replays cannot be joined".to_string(),
                                        })
                                        .unwrap(),
                                    ))
                                    .await?;
                                }
                                PacketS::ReplayTick { dt } => {
                                    time += dt;
                                    while next_event.ts < time {
                                        debug!("<- {:?}", next_event.packet);
                                        sock.send(tokio_tungstenite::tungstenite::Message::Text(
                                            serde_json::to_string(&next_event.packet).unwrap(),
                                        ))
                                        .await?;

                                        let Some(next) = &file.next_line().await? else {
                                            info!("reached end");
                                            break 'outer;
                                        };
                                        next_event = serde_json::from_str::<Event>(next)?;
                                    }
                                }
                                x => warn!("unhandled client packet: {x:?}"),
                            }
                        }
                        Message::Close(_) => break,
                        _ => (),
                    }
                }
                info!("{addr} left");
            }
        }
    }
    Ok(())
}

pub async fn do_record(output: &Path, url: &str) -> anyhow::Result<()> {
    let mut file = BufWriter::new(ZstdEncoder::new(BufWriter::new(
        File::create(&output).await?,
    )));
    info!("connecting to {url:?}...");
    let (mut sock, _) = tokio_tungstenite::connect_async(url).await?;
    info!("starting recording.");
    let start = Instant::now();

    while let Some(Ok(message)) = sock.next().await {
        match message {
            Message::Text(line) => {
                let packet: PacketC = serde_json::from_str(&line).context("invalid packet")?;
                debug!("<- {packet:?}");

                let is_end = matches!(packet, PacketC::SetIngame { state: false, .. });

                file.write_all(
                    format!(
                        "{}\n",
                        serde_json::to_string(&Event {
                            ts: start.elapsed().as_secs_f64(),
                            packet
                        })
                        .unwrap()
                    )
                    .as_bytes(),
                )
                .await?;

                if is_end {
                    info!("stopping replay...");
                    break;
                }
            }
            Message::Close(_) => break,
            _ => (),
        }
    }
    file.flush().await?;
    let mut file = file.into_inner();
    file.flush().await?;
    let mut file = file.into_inner();
    file.flush().await?;
    let mut file = file.into_inner();
    file.flush().await?;
    info!("done");
    Ok(())
}