import PubNub from 'pubnub';

const pubnub = new PubNub({
  publishKey: 'pub-c-...',
  subscribeKey: 'sub-c-...',
  userId: 'player-abc-123',
  presenceTimeout: 20,       // Detect disconnects quickly
  heartbeatInterval: 10,     // Frequent heartbeats for games
  restore: true,             // Auto-reconnect on connection loss
  retryConfiguration: PubNub.LinearRetryPolicy({
    delay: 1,
    maximumRetry: 10
  })
});

// Subscribe to game lobby
pubnub.subscribe({
  channels: ['game-lobby'],
  withPresence: true
});

async function createGameRoom(pubnub, hostPlayerId, gameConfig) {
  const roomId = `game-room-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
  const roomChannel = `game.${roomId}`;
  const stateChannel = `game.${roomId}.state`;

  // Set room metadata via App Context
  await pubnub.objects.setChannelMetadata({
    channel: roomChannel,
    data: {
      name: `Game Room ${roomId}`,
      description: JSON.stringify({
        host: hostPlayerId,
        maxPlayers: gameConfig.maxPlayers || 4,
        gameType: gameConfig.gameType,
        status: 'waiting',
        createdAt: Date.now()
      })
    }
  });

  // Host subscribes to game channels
  pubnub.subscribe({
    channels: [roomChannel, stateChannel],
    withPresence: true
  });

  // Announce room in lobby
  await pubnub.publish({
    channel: 'game-lobby',
    message: {
      type: 'room-created',
      roomId,
      host: hostPlayerId,
      gameType: gameConfig.gameType,
      maxPlayers: gameConfig.maxPlayers || 4
    }
  });

  return { roomId, roomChannel, stateChannel };
}

// Send delta state updates (only changed properties)
async function sendStateUpdate(pubnub, stateChannel, deltaUpdate) {
  await pubnub.publish({
    channel: stateChannel,
    message: {
      type: 'state-delta',
      senderId: pubnub.getUserId(),
      timestamp: Date.now(),
      sequenceNum: ++localSequence,
      delta: deltaUpdate
    }
  });
}

// Listen for state updates and apply them
pubnub.addListener({
  message: (event) => {
    if (event.channel.endsWith('.state')) {
      const { type, delta, sequenceNum, senderId } = event.message;

      if (type === 'state-delta' && senderId !== pubnub.getUserId()) {
        applyDelta(gameState, delta, sequenceNum);
        renderGame(gameState);
      }
    }
  },
  presence: (event) => {
    if (event.action === 'leave' || event.action === 'timeout') {
      handlePlayerDisconnect(event.uuid, event.channel);
    } else if (event.action === 'join') {
      handlePlayerJoin(event.uuid, event.channel);
    }
  }
});