import { createServer } from 'http';
import { Server } from 'socket.io';
import { GameState, Player, GameMove } from '@/lib/types';
import { dealTiles, findStartingPlayer, executeMove, canPlayerMove, isGameBlocked, determineBlockedWinner } from '@/lib/gameLogic';

const httpServer = createServer();
const io = new Server(httpServer, {
  cors: {
    origin: process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3000',
    methods: ['GET', 'POST'],
  },
});

// Store active game rooms
const gameRooms = new Map<string, GameState>();
const playerRooms = new Map<string, string>(); // playerId -> roomId

// Generate unique room ID
function generateRoomId(): string {
  return Math.random().toString(36).substring(2, 8).toUpperCase();
}

// Create a new game state
function createGameState(roomId: string): GameState {
  return {
    id: roomId,
    players: [],
    currentPlayerIndex: 0,
    board: [],
    boneyard: [],
    boardEnds: [],
    winner: null,
    isGameOver: false,
    turnsPassed: 0,
    gameMode: 'waiting',
  };
}

// Initialize game when all players are ready
function startGame(roomId: string): GameState {
  const gameState = gameRooms.get(roomId);
  if (!gameState) throw new Error('Game not found');

  const { playerTiles, boneyard } = dealTiles(gameState.players.length);
  
  const updatedPlayers = gameState.players.map((player, index) => ({
    ...player,
    tiles: playerTiles[index],
    score: 0,
  }));

  const startingPlayerIndex = findStartingPlayer(updatedPlayers);

  const newGameState: GameState = {
    ...gameState,
    players: updatedPlayers,
    currentPlayerIndex: startingPlayerIndex,
    boneyard,
    gameMode: 'playing',
  };

  gameRooms.set(roomId, newGameState);
  return newGameState;
}

io.on('connection', (socket) => {
  console.log('Client connected:', socket.id);

  // Create room
  socket.on('create-room', () => {
    const roomId = generateRoomId();
    const gameState = createGameState(roomId);
    gameRooms.set(roomId, gameState);
    
    socket.join(roomId);
    socket.emit('room-created', roomId);
    console.log('Room created:', roomId);
  });

  // Join room
  socket.on('join-room', (roomId: string, playerName: string) => {
    const gameState = gameRooms.get(roomId);
    
    if (!gameState) {
      socket.emit('error', 'Room not found');
      return;
    }

    if (gameState.players.length >= 4) {
      socket.emit('error', 'Room is full');
      return;
    }

    if (gameState.gameMode !== 'waiting') {
      socket.emit('error', 'Game already started');
      return;
    }

    const player: Player = {
      id: socket.id,
      name: playerName,
      tiles: [],
      score: 0,
      isAI: false,
      isReady: false,
    };

    gameState.players.push(player);
    playerRooms.set(socket.id, roomId);
    
    socket.join(roomId);
    socket.emit('room-joined', gameState, socket.id);
    socket.to(roomId).emit('player-joined', player);
    
    console.log(`Player ${playerName} joined room ${roomId}`);
  });

  // Player ready
  socket.on('player-ready', (roomId: string) => {
    const gameState = gameRooms.get(roomId);
    if (!gameState) return;

    const player = gameState.players.find(p => p.id === socket.id);
    if (!player) return;

    player.isReady = true;
    gameRooms.set(roomId, gameState);

    // Start game if all players are ready and at least 2 players
    const allReady = gameState.players.length >= 2 && gameState.players.every(p => p.isReady);
    
    if (allReady) {
      const startedGame = startGame(roomId);
      io.to(roomId).emit('game-started', startedGame);
      console.log('Game started in room:', roomId);
    } else {
      io.to(roomId).emit('game-state-updated', gameState);
    }
  });

  // Make move
  socket.on('make-move', (roomId: string, move: GameMove) => {
    const gameState = gameRooms.get(roomId);
    if (!gameState) return;

    const currentPlayer = gameState.players[gameState.currentPlayerIndex];
    
    if (currentPlayer.id !== socket.id) {
      socket.emit('invalid-move', 'Not your turn');
      return;
    }

    try {
      const newGameState = executeMove(gameState, move);
      
      // Check if game is blocked
      if (isGameBlocked(newGameState)) {
        const winnerId = determineBlockedWinner(newGameState);
        newGameState.winner = winnerId;
        newGameState.isGameOver = true;
        newGameState.gameMode = 'finished';
      }

      gameRooms.set(roomId, newGameState);
      io.to(roomId).emit('game-state-updated', newGameState);
    } catch {
      socket.emit('invalid-move', 'Invalid move');
    }
  });

  // Draw tile
  socket.on('draw-tile', (roomId: string) => {
    const gameState = gameRooms.get(roomId);
    if (!gameState) return;

    const currentPlayer = gameState.players[gameState.currentPlayerIndex];
    
    if (currentPlayer.id !== socket.id) {
      socket.emit('invalid-move', 'Not your turn');
      return;
    }

    if (gameState.boneyard.length === 0) {
      socket.emit('invalid-move', 'No tiles left to draw');
      return;
    }

    const drawnTile = gameState.boneyard.pop()!;
    currentPlayer.tiles.push(drawnTile);

    // Check if player can move now
    if (!canPlayerMove(currentPlayer, gameState.boardEnds)) {
      gameState.currentPlayerIndex = (gameState.currentPlayerIndex + 1) % gameState.players.length;
    }

    gameRooms.set(roomId, gameState);
    io.to(roomId).emit('game-state-updated', gameState);
  });

  // Leave room
  socket.on('leave-room', (roomId: string) => {
    handlePlayerLeave(socket.id, roomId);
  });

  // Disconnect
  socket.on('disconnect', () => {
    const roomId = playerRooms.get(socket.id);
    if (roomId) {
      handlePlayerLeave(socket.id, roomId);
    }
    console.log('Client disconnected:', socket.id);
  });
});

function handlePlayerLeave(playerId: string, roomId: string) {
  const gameState = gameRooms.get(roomId);
  if (!gameState) return;

  gameState.players = gameState.players.filter(p => p.id !== playerId);
  playerRooms.delete(playerId);

  if (gameState.players.length === 0) {
    gameRooms.delete(roomId);
    console.log('Room deleted:', roomId);
  } else {
    gameRooms.set(roomId, gameState);
    io.to(roomId).emit('player-left', playerId);
    io.to(roomId).emit('game-state-updated', gameState);
  }
}

const PORT = process.env.SOCKET_PORT || 3001;

httpServer.listen(PORT, () => {
  console.log(`Socket.IO server running on port ${PORT}`);
});

export { io };