/**
 * Request组件, modern版, 支持IE9+,chrome,FF
 * @authors yutent (yutent@doui.cc)
 * @date    2016-11-27 13:08:40
 *
 */

'use strict'
import 'promise/index'
import Format from './lib/format'

var _request = function(url, protocol) {
    this.transport = true
    protocol = (protocol + '').trim().toUpperCase()
    this.xhr = Xhr()
    this.defer = Promise.defer()
    this.opt = {
      url: (url + '').trim(),
      type: protocol || 'GET',
      form: '',
      data: {},
      headers: {},
      timeoutID: 0,
      uuid: Math.random()
        .toString(16)
        .substr(2)
    }
  },
  _requestp = _request.prototype,
  toS = Object.prototype.toString,
  win = window,
  doc = win.document,
  encode = encodeURIComponent,
  decode = decodeURIComponent,
  noop = function(e, res) {
    this.defer.resolve(res)
  }

// -----------------------------

// 本地协议判断正则
var rlocalProtocol = /^(?:about|app|app-storage|.+-extension|file|res|widget):$/
var isLocal = false
try {
  isLocal = rlocalProtocol.test(location.ptyperotocol)
} catch (e) {}

var rheaders = /^(.*?):[ \t]*([^\r\n]*)\r?$/gm

// ----------------- 一些兼容性预处理 --------------------

win.Xhr = function() {
  return new XMLHttpRequest()
}
var supportCors = 'withCredentials' in Xhr()

// ---------------------------------------------------------
// -------------------- request 模块开始 --------------------
// ---------------------------------------------------------

var requestConvert = {
  text: function(val) {
    return val
  },
  xml: function(val, xml) {
    return xml !== undefined ? xml : Format.parseXML(val)
  },
  html: function(val) {
    return Format.parseHTML(val)
  },
  json: function(val) {
    return JSON.parse(val)
  },
  script: function(val) {
    return Format.parseJS(val)
  },
  jsonp: function(name) {
    var json = request.cache[name]
    delete request.cache[name]
    return json
  }
}
var requestExtend = {
  formData: function() {
    if (this.opt.form) {
      var data = Format.parseForm(this.opt.form)
      Format.merge(this.opt.data, data)
    }

    var form = new FormData()
    for (var i in this.opt.data) {
      var el = this.opt.data[i]
      if (Array.isArray(el)) {
        el.forEach(function(it) {
          form.append(i + '[]', it)
        })
      } else {
        form.append(i, this.opt.data[i])
      }
    }
    return form
  },
  jsonp: function(jsonpcallback) {
    win[jsonpcallback] = function(val) {
      delete win[jsonpcallback]
      request.cache[jsonpcallback] = val
    }
  },
  dispatch: function(self) {
    if (!this.transport) return this.defer.reject('Request pending...')

    var _this = this,
      result = {
        response: {
          url: this.opt.url,
          headers: { 'content-type': '' }
        },
        request: {
          url: this.opt.url,
          headers: _this.opt.headers
        },
        status: self === null ? 504 : 200,
        statusText: self === null ? 'Connected timeout' : 'ok',
        text: '',
        body: '',
        error: null
      }

    //状态为4,既已成功, 则清除超时
    clearTimeout(_this.opt.timeoutID)

    if (typeof this.transport === 'object' && this.opt.type === 'JSONP') {
      //移除script
      // this.transport.parentNode.removeChild(this.transport);

      //超时返回
      if (self !== null) {
        var exec =
          !this.transport.readyState ||
          this.transport.readyState === 'loaded' ||
          this.transport.readyState === 'complete'

        if (exec) {
          result.body = requestConvert.jsonp(this.opt.data.callback)
          result.text = JSON.stringify(result.body)
        }
      }

      this.callback(result.error, result)
    } else {
      //成功的回调
      var isSucc = self
          ? (self.status >= 200 && self.status < 300) || self.status === 304
          : false,
        headers = (self && self.getAllResponseHeaders().split('\n')) || []

      //处理返回的Header
      headers.forEach(function(it, i) {
        it = it.trim()
        if (it) {
          it = it.split(':')
          result.response.headers[it.shift().toLowerCase()] = it
            .join(':')
            .trim()
        }
      })

      if (isSucc) {
        result.status = self.status
        if (result.status === 204) {
          result.statusText = 'no content'
        } else if (result.status === 304) {
          result.statusText = 'not modified'
        }
      } else {
        result.status = self === null ? 504 : self.status || 500
        result.statusText =
          self === null
            ? 'Connected timeout'
            : self.statusText || 'Internal Server Error'
        result.error = Format.merge(new Error(result.statusText), {
          status: result.status
        })
      }

      try {
        //处理返回的数据
        var dataType = result.response.headers['content-type'].match(
          /json|xml|script|html/i
        ) || ['text']

        dataType = dataType[0].toLowerCase()
        result.text = (self && (self.responseText || self.responseXML)) || ''
        result.body = requestConvert[dataType](
          result.text,
          self && self.responseXML
        )
      } catch (err) {
        result.error = err
        result.statusText = 'parse error'
      }

      _this.callback(result.error, result)
    }
    delete _this.defer
    delete _this.transport
    delete _this.opt
    delete _this.xhr
  }
}

// 设置表单类型, 支持2种, form/json
_requestp.type = function(t) {
  if (this.opt.formType === 'form-data') return this

  this.opt.formType = t || 'form'
  if (t === 'form' || this.opt.type === 'GET')
    this.set('content-type', 'application/x-www-form-urlencoded; charset=UTF-8')
  else this.set('content-type', 'application/json; charset=UTF-8')

  return this
}

//设置头信息
_requestp.set = function(k, val) {
  if (!this.transport) return

  if (typeof k === 'object') {
    for (var i in k) {
      i = i.toLowerCase()
      this.opt.headers[i] = k[i]
    }
  } else if (typeof k === 'string') {
    if (arguments.length < 2) throw new Error('2 arguments required')

    // 全转小写,避免重复写入
    k = k.toLowerCase()

    if (val === undefined) delete this.opt.headers[k]
    else this.opt.headers[k] = val
  } else {
    throw new Error(
      'arguments must be string/object, but [' + typeof k + '] given'
    )
  }
  return this
}

//设置请求参数
_requestp.send = function(k, val) {
  if (!this.transport) return

  // 1. send方法可以多次调用, 但必须保证格式一致
  // 2. 2次圴提交纯字符串也会抛出异常
  if (typeof k === 'object') {
    if (this.opt.data && typeof this.opt.data === 'string')
      throw new Error('param can not be string and object at the same time')
    if (!this.opt.data) this.opt.data = {}

    Format.merge(this.opt.data, k)
  } else {
    if (typeof k === 'string') {
      if (arguments.length === 1) {
        if (this.opt.data) throw new Error('invalid param in function send')

        this.opt.data = k
      } else {
        if (this.opt.data && typeof this.opt.data === 'string')
          throw new Error('param can not be string and object at the same time')

        if (!this.opt.data) this.opt.data = {}

        this.opt.data[k] = val
      }
    } else {
      throw new Error(
        'argument of send must be string/object, but [' + typeof k + '] given'
      )
    }
  }

  return this
}

//该方法用于 form-data类型的post请求的参数设置
_requestp.field = function(k, val) {
  if (!this.transport) return this

  // 此类型优先级最高
  this.opt.formType = 'form-data'
  this.opt.type = 'POST'
  if (!this.opt.data || (this.opt.data && typeof this.opt.data !== 'object'))
    this.opt.data = {}

  if (arguments.length === 1 && typeof k === 'object') {
    Format.merge(this.opt.data, k)
  } else if (arguments.length === 2) {
    this.opt.data[k] = val
  } else {
    throw new TypeError(
      'argument must be an object, but ' + typeof k + ' given'
    )
  }
  return this
}

//设置缓存
_requestp.cache = function(t) {
  if (!this.transport) return

  if (this.opt.type === 'GET') this.opt.cache = !!t

  return this
}

//取消网络请求
_requestp.abort = function() {
  delete this.transport
  if (!this.opt.form) this.xhr.abort()

  return this
}

//超时设置, 单位毫秒
_requestp.timeout = function(time) {
  if (typeof time !== 'number' || time < 1) return this

  this.opt.timeout = time
  return this
}

_requestp.form = function(form) {
  if (typeof form === 'object' && form.nodeName === 'FORM') {
    this.opt.type = 'POST'
    this.opt.form = form
  }

  return this
}

var originAnchor = doc.createElement('a')
originAnchor.href = location.href
_requestp.end = function(callback) {
  var _this = this
  // 回调已执行, 或已取消, 则直接返回, 防止重复执行
  if (!this.transport) return this

  if (!this.opt.url) throw new Error('Invalid  request url')

  Format.merge(this, requestExtend)

  this.callback = callback || noop.bind(this)

  // 1. url规范化
  this.opt.url = this.opt.url
    .replace(/#.*$/, '')
    .replace(/^\/\//, location.protocol + '//')

  // 2. 处理跨域
  if (typeof this.opt.crossDomain !== 'boolean') {
    var anchor = doc.createElement('a')
    try {
      anchor.href = this.opt.url
      // IE7及以下浏览器 '1'[0]的结果是 undefined
      // IE7下需要获取绝对路径
      var absUrl = !'1'[0] ? anchor.getAttribute('href', 4) : anchor.href
      anchor.href = absUrl
      anchor.async = true
      this.opt.crossDomain =
        originAnchor.protocol !== anchor.protocol ||
        originAnchor.host !== anchor.host
    } catch (e) {
      this.opt.crossDomain = true
    }
  }

  // 2.1 进一步处理跨域配置
  if (this.opt.type === 'JSONP') {
    //如果没有跨域，自动转回xhr GET
    if (!this.opt.crossDomain) {
      this.opt.type = 'GET'
    } else {
      this.opt.data['callback'] =
        this.opt.data['callback'] || 'jsonp' + request.cid++
      this.jsonp(this.opt.data['callback']) //创建临时处理方法
    }
  }
  // 2.2 如果不是跨域请求，则自动加上一条header信息，用以标识这是ajax请求
  if (!this.opt.crossDomain) {
    this.set('X-Requested-With', 'XMLHttpRequest')
  } else {
    supportCors && (this.xhr.withCredentials = true)
  }

  // 3. data转字符串
  this.opt.param = Format.param(this.opt.data)

  // 4. 设置Content-Type类型, 默认x-www-form-urlencoded
  if (!this.opt.formType) this.type('form')

  // 5.处理GET请求
  this.opt.hasContent = this.opt.type === 'POST' //是否为post请求
  if (!this.opt.hasContent) {
    //GET请求直接把参数拼接到url上
    if (this.opt.param) {
      this.opt.url += (/\?/.test(this.opt.url) ? '&' : '?') + this.opt.param
    }
    //加随机值,避免缓存
    if (this.opt.cache === false)
      this.opt.url +=
        (/\?/.test(this.opt.url) ? '&' : '?') + '_=' + Math.random()
  } else {
    if (this.opt.formType === 'form-data') {
      delete this.opt.headers['content-type']
      this.opt.param = this.formData()
    } else if (this.opt.formType !== 'form') {
      this.opt.param = JSON.stringify(this.opt.data)
    }
  }

  //jsonp
  if (this.opt.type === 'JSONP') {
    this.transport = doc.createElement('script')
    this.transport.onerror = this.transport.onload = function() {
      _this.dispatch(_this.transport)
    }
    this.transport.src = this.opt.url
    doc.head.insertBefore(this.transport, doc.head.firstChild)

    //6. 超时处理
    if (this.opt.timeout && this.opt.timeout > 0) {
      this.opt.timeoutID = setTimeout(function() {
        _this.transport.onerror = _this.transport.onload = null
        _this.dispatch(null)
      }, this.opt.timeout)
    }
  } else {
    this.xhr.onreadystatechange = function(ev) {
      if (_this.opt.timeout && _this.opt.timeout > 0) {
        _this.opt['time' + this.readyState] = ev.timeStamp
        if (this.readyState === 4) {
          _this.opt.isTimeout =
            _this.opt.time4 - _this.opt.time1 > _this.opt.timeout
        }
      }

      if (this.readyState !== 4) {
        return
      }

      _this.dispatch(_this.opt.isTimeout ? null : _this.xhr)
    }

    // 6. 初始化xhr提交
    this.xhr.open(this.opt.type, this.opt.url, true)

    // 7. 设置头信息
    for (var i in this.opt.headers) {
      if (this.opt.headers[i]) this.xhr.setRequestHeader(i, this.opt.headers[i])
    }

    // 8. 发起网络请求
    _this.xhr.send(_this.opt.param)

    //超时处理
    if (this.opt.timeout && this.opt.timeout > 0) {
      this.xhr.timeout = this.opt.timeout
    }
  }
  return this.defer.promise
}

// ---------------------- end ------------------------

if (!win.request) {
  win.request = {
    get: function(url) {
      if (!url) throw new Error('argument url is required')

      return new _request(url, 'GET')
    },
    post: function(url) {
      if (!url) throw new Error('argument url is required')

      return new _request(url, 'POST')
    },
    cache: {},
    cid: 0,
    version: '1.1.0-light'
  }
  Anot.ui.request = request.version
}

export default request