import axios from 'axios'
import { wxAdatper } from './adapters/index'
import addCompatibleMethods from './compatibleMethods'
import { addInstanceExtendMethod, proxyAjaxCanceler, proxyAxiosInstanceAttrs } from './helpers'
import { generateMethod } from './methods'
import type { AjaxInstance, AjaxOption, AxiosMethods, RequestMethods } from './types'
import type * as AxiosTypes from 'axios'
export type { AxiosTypes }
export { axios }

declare const wx: any

function isWxapp(): boolean {
  return typeof wx !== 'undefined' && typeof wx.request === 'function'
}

export default function initAjax<CusOpts extends object, ResDataShape extends object = any>(
  options: AjaxOption & CusOpts
): AjaxInstance<CusOpts, ResDataShape> {
  const ajax = {} as AjaxInstance<CusOpts, ResDataShape>
  ajax.$options = options

  // 检测wx如果没有自定义的适配器，则使用默认适配器
  const adapter = ajax.$options.adapter || (isWxapp() ? wxAdatper : undefined)
  ajax.$options.adapter = adapter
  ajax.$engine = axios.create()

  const requestMethods: AxiosMethods[] = ['POST', 'PUT', 'PATCH', 'DELETE', 'GET', 'HEAD']
  requestMethods.forEach((name: AxiosMethods) => {
    const queryMethods = name.toLocaleLowerCase() as RequestMethods
    ajax[queryMethods] = generateMethod<CusOpts, ResDataShape>(ajax, name)
  })

  // 挂载请求的手动取消函数
  proxyAjaxCanceler(ajax)

  // 把ajax实例上的'request', 'interceptors', defaults属性代理到axios实例上去
  proxyAxiosInstanceAttrs(ajax, ajax.$engine)

  addCompatibleMethods(ajax)

  // 添加extend方法，用于扩展ajax实例
  addInstanceExtendMethod(ajax)

  return ajax
}