/**
 * WebSocket manager for hot reload
 * Generates a unique instance ID on startup and broadcasts it to connected clients.
 * When the server restarts, clients detect the new ID and reload the page.
 */
export class ReloadSocketManager {
  private instanceId: string;
  private clients: Set<WebSocket> = new Set();

  constructor() {
    this.instanceId = crypto.randomUUID();
    console.log(`[ReloadSocket] Instance ID: ${this.instanceId}`);
  }

  /**
   * Get the current instance ID
   */
  getInstanceId(): string {
    return this.instanceId;
  }

  /**
   * Handle WebSocket upgrade request
   */
  handleUpgrade(request: Request): Response {
    const { socket, response } = Deno.upgradeWebSocket(request);

    socket.onopen = () => {
      this.clients.add(socket);
      console.log(`[ReloadSocket] Client connected (${this.clients.size} total)`);
      // Send instance ID immediately
      socket.send(JSON.stringify({ type: 'instance', id: this.instanceId }));
    };

    socket.onclose = () => {
      this.clients.delete(socket);
      console.log(`[ReloadSocket] Client disconnected (${this.clients.size} remaining)`);
    };

    socket.onerror = (error) => {
      console.error('[ReloadSocket] WebSocket error:', error);
    };

    return response;
  }

  /**
   * Broadcast a message to all connected clients
   */
  broadcast(message: object): void {
    const msg = JSON.stringify(message);
    for (const client of this.clients) {
      if (client.readyState === WebSocket.OPEN) {
        client.send(msg);
      }
    }
  }

  /**
   * Get the number of connected clients
   */
  getClientCount(): number {
    return this.clients.size;
  }
}