/*
    Hurry Curry! - a game about cooking
    Copyright (C) 2025 Hurry Curry! Contributors

    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::{bail, Result};
use clap::Parser;
use futures_util::{SinkExt, StreamExt};
use hurrycurry_protocol::{PacketC, PacketS, BINCODE_CONFIG, VERSION};
use hurrycurry_server::{
    data::DATA_DIR,
    server::{GameServerExt, Server},
    trm, ConnectionID,
};
use log::{debug, info, trace, warn, LevelFilter};
use std::{
    env::var,
    net::SocketAddr,
    path::PathBuf,
    process::exit,
    str::FromStr,
    sync::{
        atomic::{AtomicBool, Ordering},
        Arc,
    },
    time::Duration,
};
use tokio::{
    net::TcpListener,
    spawn,
    sync::{broadcast, mpsc::channel, RwLock},
    time::interval,
};
use tokio_tungstenite::tungstenite::Message;

#[derive(Parser)]
pub(crate) struct Args {
    /// Print the version, then exit
    #[arg(short, long)]
    version: bool,
    /// Set the path to the game data directory, autodetect if ommitted
    #[arg(short, long)]
    data_dir: Option<PathBuf>,
    /// Set the address on which the server should listen
    #[arg(short, long, default_value = "[::]:27032")]
    listen: SocketAddr,
    /// Enables submissions to the public server registry
    #[arg(long)]
    register: bool,
    /// Enables the mDNS responder for local network discovery
    #[cfg(feature = "mdns")]
    #[arg(long)]
    mdns: bool,
    // Enables automatic gateway port forwarding using UPnP
    #[cfg(feature = "upnp")]
    #[arg(long)]
    upnp: bool,
    /// Server name
    #[cfg(any(feature = "register", feature = "mdns"))]
    #[arg(long, short = 'N', default_value = "A Hurry Curry! Server")]
    server_name: String,
    /// Uri for connecting remotely for registry submission
    #[cfg(feature = "register")]
    #[arg(long)]
    register_uri: Option<String>,
    /// Do not register using IPv4
    #[cfg(feature = "register")]
    #[arg(long)]
    register_disable_ip4: bool,
    /// Do not register using IPv6
    #[cfg(feature = "register")]
    #[arg(long)]
    register_disable_ip6: bool,
}

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

    let args = Args::parse();

    let version = env!("CARGO_PKG_VERSION");
    let distribution = option_env!("HURRYCURRY_DISTRIBUTION").unwrap_or("unknown");
    if args.version {
        println!("{version} ({distribution})");
        exit(0);
    }

    info!("Starting Hurry Curry! Server {version} ({distribution})");

    let data_dir = if let Some(d) = args.data_dir.clone() {
        d
    } else {
        let mut test_order = Vec::new();

        if let Ok(path) = var("HURRYCURRY_DATA_PATH") {
            test_order.push(path);
        }

        if let Some(path) = option_env!("HURRYCURRY_DATA_PATH") {
            test_order.push(path.to_owned());
        }

        #[cfg(debug_assertions)]
        test_order.push("data".to_string());

        #[cfg(windows)]
        match read_windows_reg_datadir() {
            Ok(path) => test_order.push(path),
            Err(e) => warn!("Cannot find read datadir from windows registry: {e}"),
        };

        #[cfg(not(windows))]
        test_order.extend([
            "/usr/local/share/hurrycurry/data".to_string(),
            "/usr/share/hurrycurry/data".to_string(),
            "/opt/hurrycurry/data".to_string(),
        ]);

        let Some(d) = test_order
            .iter()
            .find(|p| PathBuf::from_str(p).unwrap().join("index.yaml").exists())
        else {
            warn!("The following paths were tested without success: {test_order:#?}",);
            bail!(
                "Could not find the data directory. Use the --data-dir option to specify a path."
            );
        };

        info!("Selected data dir {d:?}");
        PathBuf::from_str(d)?
    };
    *DATA_DIR.lock().unwrap() = Some(data_dir);

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

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

    let (tx, rx) = broadcast::channel::<PacketC>(128 * 1024);

    let mut state = Server::new(tx)?;
    state.load(state.index.generate_with_book("lobby")?, None);
    let state = Arc::new(RwLock::new(state));

    #[cfg(feature = "register")]
    if args.register {
        let r = hurrycurry_server::network::register::Register::new(
            args.server_name.clone(),
            args.listen.port(),
            args.register_uri,
            state.clone(),
            args.register_disable_ip4,
            args.register_disable_ip6,
        );
        tokio::task::spawn(r.register_loop());
    }
    #[cfg(feature = "upnp")]
    if args.upnp {
        tokio::task::spawn(hurrycurry_server::network::upnp::upnp_loop(
            args.listen.port(),
        ));
    }
    #[cfg(feature = "mdns")]
    if args.mdns {
        tokio::task::spawn(hurrycurry_server::network::mdns::mdns_loop(
            args.server_name.clone(),
            args.listen,
            state.clone(),
        ));
    }

    {
        let state = state.clone();
        spawn(async move {
            let dt = 1. / 50.;
            let mut tick = interval(Duration::from_secs_f32(dt));
            loop {
                tick.tick().await;
                if let Err(e) = state.write().await.tick_outer(dt) {
                    warn!("Tick failed: {e}");
                }
            }
        });
    }

    for id in (1..).map(ConnectionID) {
        let (sock, addr) = ws_listener.accept().await?;
        let Ok(sock) = tokio_tungstenite::accept_async(sock).await else {
            warn!("Invalid ws handshake");
            continue;
        };
        info!("{addr} connected via websocket");

        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);

        let mut init = state.write().await.game.prime_client();
        init.insert(
            0,
            PacketC::Version {
                major: VERSION.0,
                minor: VERSION.1,
                supports_bincode: true,
            },
        );

        let supports_binary = Arc::new(AtomicBool::new(false));
        let supports_binary2 = supports_binary.clone();

        spawn(async move {
            for p in init {
                if let Err(e) = write
                    .send(tokio_tungstenite::tungstenite::Message::Text(
                        serde_json::to_string(&p).unwrap().into(),
                    ))
                    .await
                {
                    warn!("WebSocket error when sending initial packets: {e}");
                    return;
                }
            }
            loop {
                let Some(packet) = tokio::select!(
                   p = rx.recv() => Some(match p {
                        Ok(e) => e,
                        Err(e) => {
                            rx = rx.resubscribe();
                            warn!("Client was lagging; resubscribed: {e}");
                            PacketC::ServerMessage {
                                message: trm!("s.state.overflow_resubscribe"),
                                error: true,
                            }
                        }
                   }),
                   p = error_rx.recv() => p
                ) else {
                    info!("Client outbound sender dropped. closing connection");
                    break;
                };
                let message = if supports_binary.load(Ordering::Relaxed) {
                    Message::Binary(
                        bincode::encode_to_vec(&packet, BINCODE_CONFIG)
                            .unwrap()
                            .into(),
                    )
                } else {
                    Message::Text(serde_json::to_string(&packet).unwrap().into())
                };
                if let Err(e) = write.send(message).await {
                    warn!("WebSocket error: {e}");
                    break;
                }
            }
        });

        spawn(async move {
            info!("{id:?} connected");
            while let Some(Ok(message)) = read.next().await {
                let packet = match message {
                    Message::Text(line) if line.len() < 8196 => match serde_json::from_str(&line) {
                        Ok(p) => p,
                        Err(e) => {
                            warn!("Invalid json packet: {e}");
                            break;
                        }
                    },
                    Message::Binary(packet) => {
                        supports_binary2.store(true, Ordering::Relaxed);
                        match bincode::decode_from_slice::<PacketS, _>(&packet, BINCODE_CONFIG) {
                            Ok((p, _size)) => p,
                            Err(e) => {
                                warn!("Invalid binary packet: {e}");
                                break;
                            }
                        }
                    }
                    Message::Close(_) => break,
                    _ => continue,
                };

                if matches!(
                    packet,
                    PacketS::Movement { .. } | PacketS::ReplayTick { .. }
                ) {
                    trace!("<- {id:?} {packet:?}");
                } else {
                    debug!("<- {id:?} {packet:?}");
                }
                let packet_out = match state.write().await.packet_in_outer(id, packet).await {
                    Ok(packets) => packets,
                    Err(e) => {
                        warn!("Client error: {e}");
                        vec![PacketC::ServerMessage {
                            message: e.into(),
                            error: true,
                        }]
                    }
                };
                for packet in packet_out {
                    let _ = error_tx.send(packet).await;
                }
            }
            info!("{id:?} disconnected");
            let _ = state.write().await.disconnect(id).await;
        });
    }
    Ok(())
}

#[cfg(test)]
mod test {
    use hurrycurry_protocol::{Character, PacketS, PlayerClass, PlayerID};
    use hurrycurry_server::{data::DATA_DIR, server::Server, ConnectionID};
    use std::future::Future;
    use tokio::sync::broadcast;

    fn harness(body: impl Future) {
        *DATA_DIR.lock().unwrap() = Some("../data".into());
        tokio::runtime::Builder::new_current_thread()
            .enable_all()
            .build()
            .unwrap()
            .block_on(body);
    }

    #[test]
    fn run() {
        harness(async { Server::new(broadcast::channel(1024).0).unwrap() });
    }
    #[test]
    fn map_load() {
        harness(async {
            let mut s = Server::new(broadcast::channel(1024).0).unwrap();
            s.load(s.index.generate("5star").unwrap(), None);
        });
    }
    #[test]
    fn map_load_book() {
        harness(async {
            let mut s = Server::new(broadcast::channel(1024).0).unwrap();
            s.load(s.index.generate_with_book("lobby").unwrap(), None);
        });
    }
    #[test]
    fn tick() {
        harness(async {
            let mut s = Server::new(broadcast::channel(1024).0).unwrap();
            for _ in 0..100 {
                s.tick(0.1);
            }
        });
    }
    #[test]
    fn packet_sender_verif() {
        harness(async {
            let mut s = Server::new(broadcast::channel(1024).0).unwrap();

            for (conn, p) in [
                PacketS::Effect {
                    player: PlayerID(0),
                    name: "test".to_owned(),
                },
                PacketS::Leave {
                    player: PlayerID(0),
                },
                PacketS::ReplayTick { dt: 1. },
            ]
            .into_iter()
            .enumerate()
            {
                s.packet_in_outer(
                    ConnectionID(conn.try_into().unwrap()),
                    PacketS::Join {
                        name: format!("test {conn}"),
                        character: Character::default(),
                        class: PlayerClass::Chef,
                        id: None,
                        position: None,
                    },
                )
                .await
                .unwrap();
                assert!(
                    s.packet_in_outer(ConnectionID(conn.try_into().unwrap()), p)
                        .await
                        .is_err(),
                    "test {}",
                    conn,
                )
            }
        });
    }
}

#[cfg(windows)]
fn read_windows_reg_datadir() -> Result<String> {
    use anyhow::Context;
    Ok(windows_registry::CURRENT_USER
        .open("Software\\Hurry Curry!")
        .context("HKCU\\Hurry Curry!")?
        .get_string("datadir")
        .context("datadir subkey")?)
}