export class Ajax {

  public data: object
  public fail: Function
  public method: string = 'GET'
  public success: Function
  public URL: string
  public xhr: XMLHttpRequest

  constructor(properties: object) {
    this.setProperties(properties)
    this.xhr = new XMLHttpRequest()
    return this
  }

  public setProperties(properties: object): Ajax {
    for (let key in properties) {
      this[key] = properties[key]
    }
    return this
  }

  public send(): Ajax {
    let onStateChange: Function = (): void => {
      if (this.xhr.readyState === XMLHttpRequest.DONE) {
        let data : object
        if (this.xhr.responseText) {
          data = JSON.parse(this.xhr.responseText)
        }
        if (this.xhr.status === 200) {
          this.success(data, this.xhr)
        } else {
          this.fail(data, this.xhr)
        }
      }
      this.xhr.open(this.method, this.URL, true)
      if (this.method === 'POST') {
        this.xhr.setRequestHeader('Content-Type', 'application/jsoncharset=UTF-8')
      }
      if (typeof this.data !== 'undefined') {
        this.xhr.send(JSON.stringify(this.data))
      } else {
        this.xhr.send()
      }
    }
    this.xhr.onreadystatechange = onStateChange.bind(this)
    return this
  }

}