import { Server as SocketIOServer } from 'socket.io';
import cookie from 'cookie';
import config from '../config.js';
import { findSessionUser } from '../auth/service.js';
import { lobby } from './lobby.js';
import { getGame, listGames } from './gameRegistry.js';

function broadcastRoom(io, room) {
  io.to(`room:${room.id}`).emit('room:update', room);
}

function broadcastLobby(io, gameSlug) {
  io.to(`lobby:${gameSlug}`).emit('lobby:update', lobby.list(gameSlug));
}

export function attachMultiplayer(httpServer) {
  const io = new SocketIOServer(httpServer, {
    cors: { origin: config.socket.corsOrigin, credentials: true },
  });

  io.use((socket, next) => {
    const raw = socket.handshake.headers.cookie ?? '';
    const cookies = cookie.parse(raw || '');
    const sid = cookies[config.auth.cookieName];
    const user = findSessionUser(sid);
    if (!user) return next(new Error('Not authenticated.'));
    socket.data.user = user;
    next();
  });

  io.on('connection', (socket) => {
    const { user } = socket.data;

    socket.emit('hello', { user, games: listGames() });

    socket.on('lobby:subscribe', (gameSlug) => {
      if (!getGame(gameSlug)) return;
      socket.join(`lobby:${gameSlug}`);
      socket.emit('lobby:update', lobby.list(gameSlug));
    });

    socket.on('lobby:unsubscribe', (gameSlug) => {
      socket.leave(`lobby:${gameSlug}`);
    });

    socket.on('room:create', ({ gameSlug, name }, ack) => {
      try {
        const room = lobby.create({ gameSlug, hostUser: user, name });
        socket.join(`room:${room.id}`);
        broadcastLobby(io, gameSlug);
        ack?.({ ok: true, room });
      } catch (err) {
        ack?.({ ok: false, error: err.message });
      }
    });

    socket.on('room:join', ({ roomId }, ack) => {
      try {
        const room = lobby.join(roomId, user);
        socket.join(`room:${room.id}`);
        broadcastRoom(io, room);
        broadcastLobby(io, room.gameSlug);
        ack?.({ ok: true, room });
      } catch (err) {
        ack?.({ ok: false, error: err.message });
      }
    });

    socket.on('room:leave', ({ roomId }, ack) => {
      const before = lobby.get(roomId);
      const room = lobby.leave(roomId, user.id);
      socket.leave(`room:${roomId}`);
      if (room) broadcastRoom(io, room);
      if (before) broadcastLobby(io, before.gameSlug);
      ack?.({ ok: true });
    });

    socket.on('room:message', ({ roomId, payload }) => {
      const room = lobby.get(roomId);
      if (!room || !room.players.some((p) => p.userId === user.id)) return;
      io.to(`room:${roomId}`).emit('room:message', {
        from: { id: user.id, username: user.username },
        payload,
        at: Date.now(),
      });
    });

    socket.on('disconnect', () => {
      // Drop the user from any rooms they were in.
      for (const room of [...lobby.rooms.values()]) {
        if (room.players.some((p) => p.userId === user.id)) {
          const updated = lobby.leave(room.id, user.id);
          if (updated) broadcastRoom(io, updated);
          broadcastLobby(io, room.gameSlug);
        }
      }
    });
  });

  return io;
}