import { EventEmitter } from 'events'
import { WebSocketMessage } from './types'

export class WebSocketServer extends EventEmitter {
  private port: number
  private running: boolean = false
  private clients: Map<string, { userId: string; lastSeen: number }> = new Map()
  private subscriptions: Map<string, Set<string>> = new Map()
  private messageQueue: WebSocketMessage[] = []

  constructor(port: number) {
    super()
    this.port = port
  }

  getPort(): number {
    return this.port
  }

  getConnectionCount(): number {
    return this.clients.size
  }

  isRunning(): boolean {
    return this.running
  }

  async start(): Promise<void> {
    this.running = true
    this.emit('ready')
  }

  async close(): Promise<void> {
    this.running = false
    this.clients.clear()
    this.subscriptions.clear()
  }

  async handleClientConnect(clientId: string, userId: string): Promise<void> {
    this.clients.set(clientId, { userId, lastSeen: Date.now() })

    if (!this.subscriptions.has(userId)) {
      this.subscriptions.set(userId, new Set())
    }
    this.subscriptions.get(userId)!.add(clientId)

    this.emit('client-connect', clientId)
  }

  async handleClientDisconnect(clientId: string): Promise<void> {
    const client = this.clients.get(clientId)
    if (client) {
      const subscribers = this.subscriptions.get(client.userId)
      if (subscribers) {
        subscribers.delete(clientId)
      }
      this.clients.delete(clientId)
    }

    this.emit('client-disconnect', clientId)
  }

  async handleMessage(message: WebSocketMessage): Promise<void> {
    const client = this.clients.get(message.clientId)
    if (!client) return

    this.messageQueue.push(message)

    const subscribers = this.subscriptions.get(client.userId)
    if (subscribers) {
      for (const subscriberId of subscribers) {
        if (subscriberId !== message.clientId) {
          this.emit('message-broadcast', {
            message,
            targetClients: [subscriberId]
          })
        }
      }
    }

    this.emit('message-received', message)
  }

  async getMessagesSince(clientId: string, timestamp: number): Promise<WebSocketMessage[]> {
    return this.messageQueue.filter(m => m.timestamp > timestamp)
  }

  getSubscribersForUser(userId: string): string[] {
    const subs = this.subscriptions.get(userId)
    return subs ? Array.from(subs) : []
  }
}