import pLimit from 'p-limit' // 建议使用 v2.2.0 以兼容 CJS

/**
 * 并发管理器，负责动态调整并发数
 */
export class ConcurrencyManager {
  private baseConcurrency: number
  private currentConcurrency: number
  private limit: ReturnType<typeof pLimit>

  constructor(baseConcurrency: number = 2) {
    this.baseConcurrency = baseConcurrency
    this.currentConcurrency = baseConcurrency
    this.limit = pLimit(this.currentConcurrency)
  }

  /**
   * 获取当前的并发限制器
   */
  getLimit() {
    return this.limit
  }

  /**
   * 增加并发数
   */
  increaseConcurrency(): void {
    this.currentConcurrency++
    this.limit = pLimit(this.currentConcurrency)
  }

  /**
   * 减少并发数
   */
  decreaseConcurrency(): void {
    if (this.currentConcurrency > 1) {
      this.currentConcurrency--
      this.limit = pLimit(this.currentConcurrency)
    }
  }

  /**
   * 重置并发数为基准值
   */
  resetConcurrency(): void {
    this.currentConcurrency = this.baseConcurrency
    this.limit = pLimit(this.currentConcurrency)
  }

  /**
   * 根据系统资源动态调整并发数
   */
  adjustConcurrency(): void {
    // 这里可以添加根据系统资源（如CPU、内存使用率）动态调整并发数的逻辑
    // 目前实现一个简单的基于任务类型的调整策略
    this.resetConcurrency()
  }
}

// 导出一个单例实例
export const concurrencyManager = new ConcurrencyManager()