/*
    Undercooked - 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, Result};
use futures_util::{SinkExt, StreamExt};
use log::{debug, info, warn, LevelFilter};
use std::{env::args, path::PathBuf, process::exit, str::FromStr, sync::Arc, time::Duration};
use tokio::{
    net::TcpListener,
    spawn,
    sync::{broadcast, mpsc::channel, RwLock},
    time::interval,
};
use tokio_tungstenite::tungstenite::Message;
use undercooked::{
    data::DATA_DIR,
    protocol::{PacketC, PacketS, PlayerID},
    state::State,
};

fn main() -> Result<()> {
    env_logger::builder()
        .filter_level(LevelFilter::Info)
        .parse_env("LOG")
        .init();

    if let Some(arg) = args().nth(1) {
        match arg.as_str() {
            "version" => println!("{}", env!("CARGO_PKG_VERSION")),
            _ => panic!("unknown subcommand"),
        }
        exit(0);
    }

    let data_dir = PathBuf::from_str(
        [
            "/usr/local/share/undercooked/data",
            "/usr/share/undercooked/data",
            "./data",
        ]
        .into_iter()
        .find(|p| PathBuf::from_str(p).unwrap().join("index.yaml").exists())
        .ok_or(anyhow!("no data dir detected"))?,
    )
    .unwrap();
    info!("Detected data dir to be {data_dir:?}");
    *DATA_DIR.lock().unwrap() = Some(data_dir);

    tokio::runtime::Builder::new_multi_thread()
        .enable_all()
        .build()?
        .block_on(run())?;
    Ok(())
}

async fn run() -> anyhow::Result<()> {
    let ws_listener = TcpListener::bind("0.0.0.0:27032").await?;
    info!("listening for websockets on {}", ws_listener.local_addr()?);

    let (tx, rx) = broadcast::channel::<PacketC>(1024);

    let state = Arc::new(RwLock::new(State::new(tx)?));
    {
        let state = state.clone();
        spawn(async move {
            let dt = 1. / 25.;
            let mut tick = interval(Duration::from_secs_f32(dt));
            loop {
                tick.tick().await;
                state.write().await.tick(dt).await;
            }
        });
    }

    for id in (1..).map(PlayerID) {
        let (sock, addr) = ws_listener.accept().await?;
        let Ok(sock) = tokio_tungstenite::accept_async(sock).await else {
            warn!("invalid ws handshake");
            continue;
        };
        let (mut write, mut read) = sock.split();
        let state = state.clone();
        let mut rx = rx.resubscribe();
        let (error_tx, mut error_rx) = channel::<PacketC>(8);
        info!("{addr} connected via ws");
        let mut init = state.write().await.game.prime_client();
        init.insert(0, PacketC::Init { id });
        spawn(async move {
            for p in init {
                if let Err(e) = write
                    .send(tokio_tungstenite::tungstenite::Message::Text(
                        serde_json::to_string(&p).unwrap(),
                    ))
                    .await
                {
                    warn!("ws error on init: {e}");
                    return;
                }
            }
            loop {
                let Some(packet) = tokio::select!(
                   p = rx.recv() => p.ok(),
                   p = error_rx.recv() => p,
                ) else {
                    break;
                };
                if let Err(e) = write
                    .send(tokio_tungstenite::tungstenite::Message::Text(
                        serde_json::to_string(&packet).unwrap(),
                    ))
                    .await
                {
                    warn!("ws error: {e}");
                    break;
                }
            }
        });
        spawn(async move {
            info!("{id:?} joined");
            while let Some(Ok(message)) = read.next().await {
                match message {
                    Message::Text(line) => {
                        let Ok(packet): Result<PacketS, _> = serde_json::from_str(&line) else {
                            warn!("invalid json over ws");
                            break;
                        };
                        debug!("<- {id:?} {packet:?}");
                        if let Err(e) = state.write().await.packet_in(id, packet).await {
                            warn!("client error: {e}");
                            let _ = error_tx
                                .send(PacketC::Error {
                                    message: format!("{e}"),
                                })
                                .await;
                        }
                    }
                    Message::Close(_) => break,
                    _ => (),
                }
            }
            info!("{id:?} left");
            state.write().await.packet_in(id, PacketS::Leave).await.ok();
        });
    }
    Ok(())
}