import { Message } from "element-ui";

const file = {
  /** 下载文件
   * @param data {blob} 文件流
   * @param filename {String} 文件名称
   */
  downloadFileByBlob: (data, filename) => {
    if (!data) {
      return false;
    }
    if (!!window.ActiveXObject || "ActiveXObject" in window) {
      window.navigator.msSaveOrOpenBlob(new Blob([data]), filename);
    } else {
      const url = window.URL.createObjectURL(new Blob([data]));
      const link = document.createElement("a");
      link.style.display = "none";
      link.href = url;
      link.setAttribute("download", filename);
      document.body.appendChild(link);
      link.click();
      document.body.removeChild(link);
    }
  },

  /** 下载文件
   * @param url {String} 文件下载地址
   * @param filename {String} 文件名称
   */
  downloadFileByUrl: (url, filename) => {
    if (!!window.ActiveXObject || "ActiveXObject" in window) {
      window.navigator.msSaveOrOpenBlob(url, filename);
    } else {
      const link = document.createElement("a");
      link.style.display = "none";
      link.href = url;
      link.setAttribute("download", filename);
      document.body.appendChild(link);
      link.click();
      document.body.removeChild(link);
    }
  },

  dealBase64ToBlob(base64Url) {
    // 截取base64的数据内容（去掉前面的描述信息，类似这样的一段：data:image/png;base64,）并解码为2进制数据
    let bstr = atob(base64Url.split(",")[1]);
    // 获取解码后的二进制数据的长度，用于后面创建二进制数据容器
    let olength = bstr.length;
    // 创建一个Uint8Array类型的数组以存放二进制数据
    var u8arr = new Uint8Array(olength);
    // 将二进制数据存入Uint8Array类型的数组中
    while (olength--) {
      u8arr[olength] = bstr.charCodeAt(olength);
    }
    // 创建blob对象
    let blob = new Blob([u8arr]);
    return blob;
  },

  // 获取文件扩展名
  getFileExtension: (fileName) => {
    const fileNameSplited = fileName.split(".");
    return fileNameSplited[fileNameSplited.length - 1].toLowerCase();
  },
  getFileName: (fileName) => {
    return filename.substring(0, filename.lastIndexOf("."));
  },
};

export default file;