use std::{
    collections::HashMap,
    sync::{Arc, RwLock},
};

use tokio::{
    sync::mpsc::{channel, Receiver, Sender},
    task::JoinHandle,
};

use crate::{
    room::{RoomId, RoomRegistry},
    table::AnonTable,
};

/// Opaque player id
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct PlayerId(u64);

#[derive(Clone)]
pub struct PlayerHandle {
    tx: Sender<PlayerCommand>,
}
impl PlayerHandle {
    pub async fn subscribe(&mut self) -> Receiver<Updates> {
        let (sender, rx) = channel(32);
        self.tx.send(PlayerCommand::AddSocket { sender }).await;
        rx
    }

    pub async fn create_room(&mut self) {
        match self.tx.send(PlayerCommand::CreateRoom).await {
            Ok(_) => {}
            Err(_) => {
                panic!("unexpected err");
            }
        };
    }

    pub async fn send_message(&mut self, room_id: RoomId, body: String) {
        self.tx
            .send(PlayerCommand::SendMessage { room_id, body })
            .await;
    }

    pub async fn join_room(&mut self, room_id: RoomId) {
        self.tx.send(PlayerCommand::JoinRoom { room_id }).await;
    }

    pub async fn receive_message(&mut self, room_id: RoomId, author: PlayerId, body: String) {
        self.tx
            .send(PlayerCommand::IncomingMessage {
                room_id,
                author,
                body,
            })
            .await;
    }
}

pub enum Updates {
    RoomJoined { room_id: RoomId },
    NewMessage { room_id: RoomId, body: String },
}
enum PlayerCommand {
    AddSocket {
        sender: Sender<Updates>,
    },
    CreateRoom,
    JoinRoom {
        room_id: RoomId,
    },
    SendMessage {
        room_id: RoomId,
        body: String,
    },
    IncomingMessage {
        room_id: RoomId,
        author: PlayerId,
        body: String,
    },
}

#[derive(Clone)]
pub struct PlayerRegistry(Arc<RwLock<PlayerRegistryInner>>);
impl PlayerRegistry {
    pub fn empty(room_registry: RoomRegistry) -> PlayerRegistry {
        let inner = PlayerRegistryInner {
            next_id: PlayerId(0),
            room_registry,
            players: HashMap::new(),
        };
        PlayerRegistry(Arc::new(RwLock::new(inner)))
    }

    pub async fn create_player(&mut self) -> (PlayerId, PlayerHandle) {
        let player = Player {
            sockets: AnonTable::new(),
        };
        let mut inner = self.0.write().unwrap();
        let id = inner.next_id;
        inner.next_id.0 += 1;
        let (handle, fiber) = player.launch(id, inner.room_registry.clone());
        inner.players.insert(id, (handle.clone(), fiber));
        (id, handle)
    }
}

struct PlayerRegistryInner {
    next_id: PlayerId,
    room_registry: RoomRegistry,
    players: HashMap<PlayerId, (PlayerHandle, JoinHandle<Player>)>,
}

struct Player {
    sockets: AnonTable<Sender<Updates>>,
}
impl Player {
    fn launch(
        mut self,
        player_id: PlayerId,
        mut rooms: RoomRegistry,
    ) -> (PlayerHandle, JoinHandle<Player>) {
        let (tx, mut rx) = channel(32);
        let handle = PlayerHandle { tx };
        let handle_clone = handle.clone();
        let fiber = tokio::task::spawn(async move {
            while let Some(cmd) = rx.recv().await {
                match cmd {
                    PlayerCommand::AddSocket { sender } => {
                        self.sockets.insert(sender);
                    }
                    PlayerCommand::CreateRoom => {
                        let (room_id, room_handle) = rooms.create_room();
                    }
                    PlayerCommand::JoinRoom { room_id } => {
                        let room = rooms.get_room(room_id);
                        match room {
                            Some(mut room) => {
                                room.subscribe(player_id, handle.clone()).await;
                            }
                            None => {
                                tracing::info!("no room found");
                            }
                        }
                    }
                    PlayerCommand::SendMessage { room_id, body } => {
                        let room = rooms.get_room(room_id);
                        match room {
                            Some(mut room) => {
                                room.send_message(player_id, body).await;
                            }
                            None => {
                                tracing::info!("no room found");
                            }
                        }
                    }
                    PlayerCommand::IncomingMessage {
                        room_id,
                        author,
                        body,
                    } => {
                        tracing::info!("Handling incoming message");
                        for socket in &self.sockets {
                            socket
                                .send(Updates::NewMessage {
                                    room_id,
                                    body: body.clone(),
                                })
                                .await;
                        }
                    }
                }
            }
            self
        });
        (handle_clone, fiber)
    }
}