import axios from 'axios'
import { wxAdatper } from './adapters/index'
import addCompatibleMethods from './compatibleMethods'
import { addInstanceExtendMethod, proxyAxiosMethods } from './helpers'
import { generateMethod } from './methods'
import { AjaxInstance, AjaxOption, AxiosMethods } from './types'
import { canceller } from './canceller'

declare const wx: any;

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

export default function initAjax<CusOpts, ResDataShape = any>(options: AjaxOption & CusOpts): AjaxInstance<CusOpts, ResDataShape> {
  const ajax = {} as AjaxInstance<CusOpts>;
  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) => {
    ajax[name.toLocaleLowerCase()] = generateMethod<CusOpts, ResDataShape>(ajax, name)
  })

  // 挂载取消请求的方法
  ajax.CancelToken = axios.CancelToken

  ajax.canceller = canceller
  // 把ajax实例上的'request', 'interceptors'方法代理到axios上去
  proxyAxiosMethods(ajax, ajax.$engine);

  addCompatibleMethods(ajax)

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

  return ajax;
}