import fileSize from "filesize";
import { lastIndexOf } from "lodash";

/**
 * 格式化为b
 * @param num 需要格式化的数字
 * @module File
 */
function fileSizeBits(num: number) {
  return fileSize(num, { bits: true });
}

/**
 * 格式化为几位小数
 * @param num 数字
 * @param round 保留几位小数
 * @module File
 */
function fileSizeRound(num: number, round: number = 2) {
  return fileSize(num, {
    round: 2,
  });
}

/**
 * 根据url获取文件名称
 * 本意是获取分隔符的最后一项内容
 * @param url 文件url
 * @param signal 文件分隔符
 * @module File
 */
function getFileNameByUrl(url: string, signal: string = "\\") {
  const idx = lastIndexOf(url, signal) || 0;
  const result = url.slice(0, idx + 1);

  return decodeURIComponent(result);
}

/**
 * file转为base64
 * @param {*} file file对象
 * @returns {Promise}
 * @module File
 */
function fileToDataURL(file: File) {
  const freader = new FileReader();
  freader.readAsDataURL(file);
  return new Promise((resolve, reject) => {
    freader.onload = function (e) {
      resolve(e.target?.result);
    };
    freader.onerror = function (e) {
      reject(e);
    };
  });
}

export {
  /**
   *  filesize(500);                        // "500 B"
   *  filesize(500, {bits: true});          // "4 Kb"
   *  filesize(265318, {base: 10});         // "265.32 kB"
   *  filesize(265318);                     // "259.1 KB"
   *  filesize(265318, {round: 0});         // "259 KB"
   *  filesize(265318, {output: "array"});  // [259.1, "KB"]
   *  filesize(265318, {output: "object"}); // {value: 259.1, symbol: "KB", exponent: 1}
   *  filesize(1, {symbols: {B: "Б"}});     // "1 Б"
   *  filesize(1024);                       // "1 KB"
   *  filesize(1024, {exponent: 0});        // "1024 B"
   *  filesize(1024, {output: "exponent"}); // 1
   *  filesize(265318, {standard: "iec"});  // "259.1 KiB"
   *  filesize(265318, {standard: "iec", fullform: true}); // "259.1 kibibytes"
   *  filesize(12, {fullform: true, fullforms: ["байтов"]});  // "12 байтов"
   *  filesize(265318, {separator: ","});   // "259,1 KB"
   *  filesize(265318, {locale: "de"});   // "259,1 KB"
   */
  fileSize,
  fileSizeBits,
  fileSizeRound,
  getFileNameByUrl,
  fileToDataURL,
};