import { noop } from "../_util/noop";

export interface ProgressInfo {
  /**
   * 文件总大小
   */
  total: number;

  /**
   * 已上传部分大小
   */
  loaded: number;

  /**
   * 百分比
   */
  percent: number;
}

export interface UploadEventContext {
  /**
   * 进度事件
   */
  event: ProgressEvent;

  /**
   * XHR 对象
   */
  xhr: XMLHttpRequest;

  /**
   * 当前文件
   */
  file: File;
}

export interface UploadOption {
  action: string;
  file: File;
  filename: string;
  data?: object;
  headers?: object;
  withCredentials?: boolean;
  method?: string;
  send?: (file: File, formData: FormData) => BodyInit;
  onProgress?: (progress: ProgressInfo, context: UploadEventContext) => void;
  onSuccess?: (result: object | string, context: UploadEventContext) => void;
  onError?: (error: Error, context: UploadEventContext) => void;
}

export function upload({
  action,
  file,
  filename,
  data = {},
  headers = {},
  method = "POST",
  withCredentials = false,
  send = (_, data) => data,
  onProgress = noop,
  onSuccess = noop,
  onError = noop,
}: UploadOption) {
  const formData = new FormData();

  const xhr = new XMLHttpRequest();

  xhr.onload = event => {
    if (!(xhr.status >= 200 && xhr.status < 300)) {
      const error = new Error(`${xhr.status} ${xhr.statusText}`);
      onError(error, { event, xhr, file });
      return;
    }

    const text = xhr.responseText || xhr.response;
    let result;
    try {
      result = JSON.parse(text);
    } catch (err) {
      result = text;
    }
    onSuccess(result, { event, xhr, file });
  };

  xhr.onerror = event =>
    onError(new Error("Http Request Error"), { event, xhr, file });

  if (onProgress && xhr.upload) {
    xhr.upload.onprogress = event => {
      if (event.lengthComputable && event.total) {
        onProgress(
          {
            total: event.total,
            loaded: event.loaded,
            percent: (event.loaded / event.total) * 100,
          },
          { event, xhr, file }
        );
      }
    };
  }

  Object.keys(data).forEach(key => {
    formData.append(key, data[key]);
  });

  formData.append(filename, file);

  xhr.open(method, action, true);

  xhr.withCredentials = withCredentials;

  Object.keys(headers).forEach(key => {
    xhr.setRequestHeader(key, headers[key]);
  });

  xhr.send(send(file, formData));

  return xhr;
}