import type { InternalAxiosRequestConfig, Canceler } from 'axios'
import axios from 'axios'
import { isFunction } from '@/utils/is'

// Used to store the identification and cancellation function of each request
let pendingMap = new Map<string, Canceler>()

export const getPendingUrl = (config: InternalAxiosRequestConfig) => [config.method, config.url].join('&')

export class AxiosCanceler {
  /**
   * 添加请求
   * @param {Object} config
   */
  addPending(config: InternalAxiosRequestConfig) {
    this.removePending(config)
    const url = getPendingUrl(config)
    config.cancelToken =
      config.cancelToken ||
      new axios.CancelToken((cancel) => {
        if (!pendingMap.has(url)) {
          // 如果当前没有待处理的请求，添加它
          pendingMap.set(url, cancel)
        }
      })
  }

  /**
   * @description: 清除所有待处理
   */
  removeAllPending() {
    pendingMap.forEach((cancel) => {
      cancel && isFunction(cancel) && cancel()
    })
    pendingMap.clear()
  }

  /**
   * 删除请求
   * @param {Object} config
   */
  removePending(config: InternalAxiosRequestConfig) {
    const url = getPendingUrl(config)

    if (pendingMap.has(url)) {
      // 如果有当前请求标识符处于pending状态，则需要取消当前请求并移除
      const cancel = pendingMap.get(url)
      cancel && cancel(url)
      pendingMap.delete(url)
    }
  }

  /**
   * @description: reset
   */
  reset(): void {
    pendingMap = new Map<string, Canceler>()
  }
}