import EventEmitter from './EventEmitter'
import merge from 'ts-deepmerge'
import { getSign } from './util'

const DEFAULT_CONFIG: EventRequestConfig = {
  maxConcurrent: 10,
  timeout: 0,
  header: {},
  dataType: 'json',
  baseUrl: '',
}

type HttpHeader = Record<string, string>

interface EventRequestConfig {
  maxConcurrent: number
  /** 过期时间（毫秒） */
  timeout: number
  header: HttpHeader
  dataType: 'json' | '其他'
  baseUrl: string
}

interface HttpRequestConfig {
  url: string
  method: 'OPTIONS' | 'GET' | 'HEAD' | 'POST' | 'PUT' | 'DELETE' | 'TRACE' | 'CONNECT' | undefined
  data: Object | string
  header: HttpHeader
  dataType: 'json' | '其他'
}

interface RequestJob {
  config: HttpRequestConfig
  resolve(data: any): void
  reject(data: any): void
  response?: any
}

interface HttpRequestCallBack {
  success(data: HttpResponse): void
  fail(err: HttpRequestErr): void
  complete(): void
}

interface HttpRequestErr {
  /** 错误信息 */
  errMsg: string
  /** 需要基础库： `2.24.0`
   *
   * errno 错误码，错误码的详细说明参考 [Errno错误码](https://developers.weixin.qq.com/miniprogram/dev/framework/usability/PublicErrno.html) */
  errno: number
}

interface HttpResponse<T = any> {
  timeout?: string
  data: T
  errMsg: string
  statusCode: number
  header: Record<string, string>
}

type RequestInterceptorCallback = (config: HttpRequestConfig) => boolean
type ResponseInterceptorCallback = (
  config: HttpRequestConfig,
  response: HttpResponse,
) => Promise<any>

class EventRequest extends EventEmitter {
  private config: EventRequestConfig
  private queue: RequestJob[] = []
  private runningTask: number = 0
  private maxConcurrent = DEFAULT_CONFIG.maxConcurrent
  private requestInterceptor: RequestInterceptorCallback = () => true
  private responseInterceptor: ResponseInterceptorCallback = (_, rsp) =>
    new Promise((resolve) => resolve(rsp.data))

  constructor(_config?: Partial<EventRequestConfig>) {
    super()
    if (_config) {
      this.config = merge({}, DEFAULT_CONFIG, _config)
    } else {
      this.config = DEFAULT_CONFIG
    }
    this.maxConcurrent = this.config.maxConcurrent
  }

  private next(): void {
    const queue = this.queue
    if (!queue.length || this.runningTask >= this.maxConcurrent) return

    const entity = queue.shift()!
    const httpConfig = entity.config

    const { requestInterceptor, responseInterceptor } = this

    if (requestInterceptor.call(this, httpConfig) !== true) {
      let response: HttpResponse = {
        data: null,
        errMsg: `Request Interceptor: Request can\'t pass the Interceptor`,
        statusCode: 0,
        header: {},
      }
      entity.reject(response)
      return
    }

    this.emit('request', httpConfig)

    this.runningTask = this.runningTask + 1

    let timer = -1
    let aborted: boolean = false
    let finished: boolean = false

    const callBack: HttpRequestCallBack = {
      success: (res: HttpResponse): void => {
        if (aborted) return
        finished = true
        timer && clearTimeout(timer)
        entity.response = res
        this.emit('success', httpConfig, res)

        responseInterceptor
          .call(this, httpConfig, res)
          .then((rsp) => {
            entity.resolve(rsp)
          })
          .catch((err) => {
            entity.reject(err)
          })
      },
      fail: (err: HttpRequestErr): void => {
        if (aborted) return
        finished = true
        timer && clearTimeout(timer)
        entity.response = err
        this.emit('fail', httpConfig, err)
        entity.reject(err)
      },
      complete: () => {
        if (aborted) return
        this.emit('complete', httpConfig, entity.response)
        this.next()
        this.runningTask = this.runningTask - 1
      },
    }

    const requestConfig = Object.assign(httpConfig, callBack)
    const task = wx.request(requestConfig)

    if (this.config.timeout > 0) {
      timer = setTimeout(() => {
        if (!finished) {
          aborted = true
          entity.reject({
            timeout: '访问超时',
          })
          task && task.abort()
          this.next()
        }
      }, this.config.timeout)
    }
  }

  request<T = any>(
    method: 'OPTIONS' | 'GET' | 'HEAD' | 'POST' | 'PUT' | 'DELETE' | 'TRACE' | 'CONNECT',
    url: string,
    data: Object | string = '',
    header: HttpHeader = {},
    dataType?: 'json' | '其他',
  ): Promise<T> {
    const token = getSign()
    const language = 'zh-Hans'
    let authHeader = {}
    if (token != null) {
      authHeader = {
        Authorization: `Bearer ${token}`,
        '.AspNetCore.Culture': `c=${language}|uic=${language}`,
        Accept: 'application/json',
      } as Record<string, any>
    }

    const config: HttpRequestConfig = {
      method,
      url: this.config.baseUrl + url,
      data,
      header: { ...header, ...this.config.header, ...authHeader },
      dataType: dataType || this.config.dataType,
    }
    return new Promise((resolve, reject) => {
      const entity: RequestJob = { config, resolve, reject, response: null }
      this.queue.push(entity)
      this.next()
    })
  }

  head<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('HEAD', url, data, header, dataType)
  }

  options<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('OPTIONS', url, data, header, dataType)
  }

  get<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('GET', url, data, header, dataType)
  }

  post<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('POST', url, data, header, dataType)
  }

  put<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('PUT', url, data, header, dataType)
  }

  ['delete']<T>(
    url: string,
    data?: Object | string,
    header?: HttpHeader,
    dataType?: 'json' | '其他',
  ) {
    return this.request<T>('DELETE', url, data, header, dataType)
  }
  trace<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('TRACE', url, data, header, dataType)
  }

  connect<T>(url: string, data?: Object | string, header?: HttpHeader, dataType?: 'json' | '其他') {
    return this.request<T>('CONNECT', url, data, header, dataType)
  }

  setRequestInterceptor(interceptor: (config: HttpRequestConfig) => boolean) {
    this.requestInterceptor = interceptor
    return this
  }

  setResponseInterceptor(
    interceptor: (config: HttpRequestConfig, response: HttpResponse) => Promise<any>,
  ) {
    this.responseInterceptor = interceptor
    return this
  }

  clean(): void {
    this.queue = []
  }
}

export default EventRequest