/**
 * 消息去重服务
 * 处理消息去重逻辑，防止重复处理相同的消息
 */

import type { IMessageDeduplication } from './types';
import {
  PROCESSED_MESSAGE_ID_EXPIRY,
  PROCESSED_MESSAGE_ID_MAX_SIZE,
} from './constants';

export class MessageDeduplication implements IMessageDeduplication {
  // 已处理消息ID集合（用于去重，防止ACK消息和正常消息重复处理）
  private processedMessageIds: Set<string> = new Set();
  private processedMessageIdsExpiry: Map<string, number> = new Map();

  /**
   * 检查消息是否已处理
   */
  isMessageProcessed(messageId: string): boolean {
    return this.processedMessageIds.has(messageId);
  }

  /**
   * 标记消息已处理
   */
  markMessageAsProcessed(messageId: string): void {
    this.processedMessageIds.add(messageId);
    this.processedMessageIdsExpiry.set(messageId, Date.now());
    
    // 定期清理
    if (this.processedMessageIds.size > PROCESSED_MESSAGE_ID_MAX_SIZE) {
      this.cleanupProcessedMessageIds();
    }
  }

  /**
   * 清理过期的消息ID（防止内存泄漏）
   */
  cleanupProcessedMessageIds(): void {
    const now = Date.now();
    for (const [id, timestamp] of this.processedMessageIdsExpiry.entries()) {
      if (now - timestamp > PROCESSED_MESSAGE_ID_EXPIRY) {
        this.processedMessageIds.delete(id);
        this.processedMessageIdsExpiry.delete(id);
      }
    }
  }

  /**
   * 重置所有已处理的消息ID
   * 用于测试或需要清除缓存的场景
   */
  reset(): void {
    this.processedMessageIds.clear();
    this.processedMessageIdsExpiry.clear();
  }
}

// 单例导出
export const messageDeduplication = new MessageDeduplication();