webRtc/WebApp/src/class/websockethandler.ts

/**
 * WebSocket处理器
 * 负责管理WebSocket连接和信令消息处理
 */
import Offer from './offer';
import Answer from './answer';
import Candidate from './candidate';

/**
 * 是否为私有模式
 */
let isPrivate: boolean;

/**
 * 客户端连接映射
 * 键: WebSocket实例
 * 值: 该WebSocket的连接ID集合
 */
const clients: Map<WebSocket, Set<string>> = new Map<WebSocket, Set<string>>();

/**
 * 连接组结构
 * host: 主机WebSocket实例（第一个连接的客户端）
 * participants: 参与者WebSocket集合（后续连接的客户端）
 */
interface ConnectionGroup {
  host: WebSocket;
  participants: Set<WebSocket>;
}

/**
 * 连接组映射
 * 键: connectionId
 * 值: ConnectionGroup（1个host + 多个participants）
 */
const connectionGroup: Map<string, ConnectionGroup> = new Map<string, ConnectionGroup>();

/**
 * 获取或创建WebSocket会话的连接ID集合
 * @param session WebSocket会话实例
 * @returns 连接ID的Set集合
 */
function getOrCreateConnectionIds(session: WebSocket): Set<string> {
  let connectionIds = null;
  // 检查客户端是否已存在
  if (!clients.has(session)) {
    // 如果不存在，创建新的连接ID集合
    connectionIds = new Set<string>();
    // 将新的连接ID集合与客户端关联
    clients.set(session, connectionIds);
  }
  // 获取客户端的连接ID集合
  connectionIds = clients.get(session);
  // 返回连接ID集合
  return connectionIds;
}

/**
 * 重置处理器状态
 * @param mode 通信模式（public或private）
 */
function reset(mode: string): void {
  // 设置是否为私有模式
  isPrivate = mode == "private";
}

/**
 * 添加新的WebSocket连接
 * @param ws WebSocket连接实例
 */
function add(ws: WebSocket): void {
  // 为新连接创建空的连接ID集合
  const id = new Set<string>();
  clients.set(ws, id);
  // 记录添加WebSocket连接的日志
  console.log(`Add WebSocket: ${id}`);
}

/**
 * 判断WebSocket是否为指定连接组的host
 * @param ws WebSocket连接实例
 * @param connectionId 连接ID
 * @returns 是否为host
 */
function isHost(ws: WebSocket, connectionId: string): boolean {
  const group = connectionGroup.get(connectionId);
  return group != null && group.host === ws;
}

/**
 * 向连接组中除发送者外的所有成员发送消息
 * @param connectionId 连接ID
 * @param senderWs 发送者WebSocket实例
 * @param message 要发送的消息对象
 */
function broadcastToGroup(connectionId: string, senderWs: WebSocket, message: any): void {
  const group = connectionGroup.get(connectionId);
  if (!group) return;
  // 如果发送者是host，转发给所有participants
  if (senderWs === group.host) {
    group.participants.forEach(participantWs => {
      participantWs.send(JSON.stringify(message));
    });
  } else {
    // 如果发送者是participant，转发给host
    group.host.send(JSON.stringify(message));
  }
}

/**
 * 移除WebSocket连接
 * @param ws WebSocket连接实例
 */
function remove(ws: WebSocket): void {
  // 获取连接的所有连接ID
  const connectionIds = clients.get(ws);
  if (!connectionIds) return;

  // 遍历所有连接ID
  connectionIds.forEach(connectionId => {
    const group = connectionGroup.get(connectionId);
    if (group) {
      if (group.host === ws) {
        // host断开连接，通知所有participants房间已关闭
        group.participants.forEach(participantWs => {
          participantWs.send(JSON.stringify({ type: "disconnect", connectionId: connectionId, reason: "host-left" }));
        });
        // 删除整个连接组
        connectionGroup.delete(connectionId);
      } else {
        // participant断开连接，从participants中移除并通知host
        group.participants.delete(ws);
        group.host.send(JSON.stringify({ type: "participant-left", connectionId: connectionId }));
      }
    }
    // 记录删除连接ID的日志
    console.log(`Remove connectionId: ${connectionId}`);
  });

  // 从客户端映射中删除
  clients.delete(ws);
}

/**
 * 处理连接请求（1对多模式）
 * 第一个连接的客户端成为host，后续连接的客户端成为participants
 * @param ws WebSocket连接实例
 * @param connectionId 连接ID
 */
function onConnect(ws: WebSocket, connectionId: string): void {
  let polite = true;
  // 处理私有模式
  if (isPrivate) {
    if (connectionGroup.has(connectionId)) {
      const group = connectionGroup.get(connectionId);
      // 已有host，新连接作为participant加入
      group.participants.add(ws);
      console.log(`Participant joined connectionId: ${connectionId}, total participants: ${group.participants.size}`);
    } else {
      // 第一个连接成为host
      connectionGroup.set(connectionId, { host: ws, participants: new Set<WebSocket>() });
      polite = false;
      console.log(`Host created connectionId: ${connectionId}`);
    }
  }

  // 获取或创建连接ID集合
  const connectionIds = getOrCreateConnectionIds(ws);
  // 添加连接ID
  connectionIds.add(connectionId);
  // 发送连接成功消息（包含角色信息）
  const role = polite ? 'participant' : 'host';
  ws.send(JSON.stringify({ type: "connect", connectionId: connectionId, polite: polite, role: role }));
  //启用心跳包
  //AddHeartbeat(ws, connectionId);
}

/**
 * 处理断开连接请求（1对多模式）
 * @param ws WebSocket连接实例
 * @param connectionId 连接ID
 */
function onDisconnect(ws: WebSocket, connectionId: string): void {
  // 获取连接的连接ID集合
  const connectionIds = clients.get(ws);
  if (connectionIds) {
    // 从集合中删除连接ID
    connectionIds.delete(connectionId);
  }

  // 处理连接组
  const group = connectionGroup.get(connectionId);
  if (group) {
    if (group.host === ws) {
      // host断开连接，通知所有participants房间已关闭，并删除连接组
      group.participants.forEach(participantWs => {
        participantWs.send(JSON.stringify({ type: "disconnect", connectionId: connectionId, reason: "host-left" }));
      });
      connectionGroup.delete(connectionId);
      console.log(`Host disconnected, room ${connectionId} deleted, notified ${group.participants.size} participants`);
    } else {
      // participant断开连接，从组中移除并通知host（使用participant-left类型，host不会关闭房间）
      group.participants.delete(ws);
      group.host.send(JSON.stringify({ type: "participant-left", connectionId: connectionId }));
      console.log(`Participant left connectionId: ${connectionId}, remaining participants: ${group.participants.size}`);
    }
  }

  // 向当前连接发送断开连接消息
  ws.send(JSON.stringify({ type: "disconnect", connectionId: connectionId }));
  //RemoveHeartbeat(ws);
  // 记录断开连接的日志
  console.log(`Disconnect connectionId: ${connectionId}`);
}

/**
 * 处理offer信令（1对多模式）
 * host的offer转发给所有participants，participant的offer转发给host
 * @param ws WebSocket连接实例
 * @param message 消息数据
 */
function onOffer(ws: WebSocket, message: any): void {
  // 获取连接ID
  const connectionId = message.connectionId as string;
  // 创建新的offer
  const newOffer = new Offer(message.sdp, Date.now(), false);

  // 处理私有模式
  if (isPrivate) {
    if (connectionGroup.has(connectionId)) {
      const group = connectionGroup.get(connectionId);
      if (group.host === ws) {
        // host发送offer，转发给所有participants
        newOffer.polite = true;
        group.participants.forEach(participantWs => {
          participantWs.send(JSON.stringify({ from: connectionId, to: "", type: "offer", data: newOffer }));
        });
      } else {
        // participant发送offer，转发给host
        newOffer.polite = true;
        group.host.send(JSON.stringify({ from: connectionId, to: "", type: "offer", data: newOffer }));
      }
    }
    return;
  }

  // 公共模式：创建新的连接组（如果不存在）
  if (!connectionGroup.has(connectionId)) {
    connectionGroup.set(connectionId, { host: ws, participants: new Set<WebSocket>() });
  }
  // 向所有其他客户端广播offer
  clients.forEach((_v, k) => {
    if (k == ws) {
      return;
    }
    k.send(JSON.stringify({ from: connectionId, to: "", type: "offer", data: newOffer }));
  });
}

/**
 * 处理answer信令（1对多模式）
 * participant的answer转发给host
 * @param ws WebSocket连接实例
 * @param message 消息数据
 */
function onAnswer(ws: WebSocket, message: any): void {
  // 获取连接ID
  const connectionId = message.connectionId as string;
  // 获取或创建连接ID集合
  const connectionIds = getOrCreateConnectionIds(ws);
  // 添加连接ID
  connectionIds.add(connectionId);
  // 创建新的answer
  const newAnswer = new Answer(message.sdp, Date.now());

  // 检查连接组是否存在
  if (!connectionGroup.has(connectionId)) {
    return;
  }

  const group = connectionGroup.get(connectionId);

  if (group.host === ws) {
    // host发送answer，转发给所有participants（通常host不发送answer）
    group.participants.forEach(participantWs => {
      participantWs.send(JSON.stringify({ from: connectionId, to: "", type: "answer", data: newAnswer }));
    });
  } else {
    // participant发送answer，转发给host
    group.host.send(JSON.stringify({ from: connectionId, to: "", type: "answer", data: newAnswer }));
  }
}

/**
 * 处理candidate信令（1对多模式）
 * host的candidate转发给所有participants，participant的candidate转发给host
 * @param ws WebSocket连接实例
 * @param message 消息数据
 */
function onCandidate(ws: WebSocket, message: any): void {
  // 获取连接ID
  const connectionId = message.connectionId;
  // 创建新的candidate
  const candidate = new Candidate(message.candidate, message.sdpMLineIndex, message.sdpMid, Date.now());

  // 处理私有模式
  if (isPrivate) {
    if (connectionGroup.has(connectionId)) {
      const group = connectionGroup.get(connectionId);
      if (group.host === ws) {
        // host发送candidate，转发给所有participants
        group.participants.forEach(participantWs => {
          participantWs.send(JSON.stringify({ from: connectionId, to: "", type: "candidate", data: candidate }));
        });
      } else {
        // participant发送candidate，转发给host
        group.host.send(JSON.stringify({ from: connectionId, to: "", type: "candidate", data: candidate }));
      }
    }
    return;
  }
}
  function onCallConnectionId(ws: WebSocket, message: any): void {
    // 获取连接ID
    const connectionId = message.connectionId;
    const clientId = message.clientId;
    // 在1对多模式下，通知host有新的呼叫请求
    if (connectionGroup.has(connectionId)) {
      const group = connectionGroup.get(connectionId);
      if (group.host !== ws) {
        // participant发起呼叫，通知host
        group.host.send(JSON.stringify({ from: connectionId, to: "", type: "call-request", data: connectionId }));
      }
    } else {
      // 兼容旧的广播方式
      clients.forEach((_v, k) => {
        if (k === ws) {
          return;
        }
        if (_v == clientId) {
          k.send(JSON.stringify({ from: connectionId, to: "", type: "call-request", data: connectionId }));
        }
      });
    }
  }


    /**
     * 处理广播消息请求（1对多模式）
     * @param ws WebSocket连接实例
     * @param message 消息数据
     */
    function onBroadcast(ws: WebSocket, message: any): void {
      const broadcastMessage = message.message;
      const targetConnectionId = message.targetConnectionId;

      if (targetConnectionId) {
        // 向指定连接组广播
        if (connectionGroup.has(targetConnectionId)) {
          const group = connectionGroup.get(targetConnectionId);
          // 向组内所有成员发送消息
          group.host.send(JSON.stringify({
            type: "broadcast",
            message: broadcastMessage,
            from: "server"
          }));
          group.participants.forEach(participantWs => {
            participantWs.send(JSON.stringify({
              type: "broadcast",
              message: broadcastMessage,
              from: "server"
            }));
          });
        }
      } else {
        // 全局广播：向所有客户端发送消息
        clients.forEach((_v, k) => {
          k.send(JSON.stringify({
            type: "broadcast",
            message: broadcastMessage,
            from: "server"
          }));
        });
      }
    }
    function AddHeartbeat(ws: WebSocket, connectionId: string) {
      // 初始化心跳检测
      (ws as any).lastActivity = Date.now();

      // 设置心跳检测定时器，每30秒发送一次ping
      (ws as any).heartbeatTimer = setInterval(() => {
        const now = Date.now();
        // 检查上次活动时间，如果超过60秒没有活动，关闭连接
        if (now - (ws as any).lastActivity > 10000) {
          console.log('WebSocket connection timeout, closing...');
          clearInterval((ws as any).heartbeatTimer);
          //ws.close();
          onDisconnect(ws, connectionId);
        } else {
          // 发送ping消息
          ws.send(JSON.stringify({ from: connectionId, to: "", type: "on-message", data: { type: "ping"} }));
          console.log('WebSocket connection heartbeat, lastActivity: ', (ws as any).lastActivity);
        }
      }, 3000);
    }
    function RemoveHeartbeat(ws: WebSocket) {
      // 清除心跳检测定时器
      if ((ws as any).heartbeatTimer) {
        clearInterval((ws as any).heartbeatTimer);
      }
    }
    /**
     * 处理获取所有连接ID的请求
     * @param ws WebSocket连接实例
     */
    function onGetAllConnectionIds(): string[] {
      // 获取所有connectionId
      const connectionIds = Array.from(connectionGroup.keys());
      return connectionIds;
    }
    /**
     * 处理chat-message信令（1对多模式）
     * host的消息转发给所有participants，participant的消息转发给host
     * @param ws WebSocket连接实例
     * @param message 消息数据
     */
    function onMessage(ws: WebSocket, message: any): void {
      // 获取连接ID
      const connectionId = message.connectionId;
      const chatMessage = message.message;
      if (connectionGroup.has(connectionId)) {
        const group = connectionGroup.get(connectionId);
        if (group.host === ws) {
          // host发送消息，转发给所有participants
          group.participants.forEach(participantWs => {
            participantWs.send(JSON.stringify({ from: connectionId, to: "", type: "on-message", data: chatMessage }));
          });
        } else {
          // participant发送消息，转发给host
          group.host.send(JSON.stringify({ from: connectionId, to: "", type: "on-message", data: chatMessage }));
        }
      }
    }
    /**
     * 导出WebSocket处理器函数
     */
    export { reset, add, remove, onConnect, onDisconnect, onOffer, onAnswer, onCandidate, onCallConnectionId, onBroadcast, onGetAllConnectionIds, AddHeartbeat, RemoveHeartbeat, onMessage, isHost, broadcastToGroup, connectionGroup };