// +----------------------------------------------------------------------
// | CRMEB [ CRMEB赋能开发者，助力企业发展 ]
// +----------------------------------------------------------------------
// | Copyright (c) 2016~2022 https://www.crmeb.com All rights reserved.
// +----------------------------------------------------------------------
// | Licensed CRMEB并不是自由软件，未经许可不能去掉CRMEB相关版权
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// | Author: CRMEB Team <admin@crmeb.com>
// +----------------------------------------------------------------------

import { saveAs } from 'file-saver';
import XLSX from 'xlsx';

function datenum(v, date1904) {
  if (date1904) v += 1462;
  let epoch = Date.parse(v);
  return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);
}

function data2ws(data) {
  const ws = {};
  const range = { s: { c: 10000000, r: 10000000 }, e: { c: 0, r: 0 } };
  for (let R = 0; R !== data.length; ++R) {
    for (let C = 0; C !== data[R].length; ++C) {
      if (range.s.r > R) range.s.r = R;
      if (range.s.c > C) range.s.c = C;
      if (range.e.r < R) range.e.r = R;
      if (range.e.c < C) range.e.c = C;
      const cell = { v: data[R][C] };
      if (cell.v == null) continue;
      const cellRef = XLSX.utils.encode_cell({ c: C, r: R });

      if (typeof cell.v === 'number') cell.t = 'n';
      else if (typeof cell.v === 'boolean') cell.t = 'b';
      else if (cell.v instanceof Date) {
        cell.t = 'n';
        cell.z = XLSX.SSF._table[14];
        cell.v = datenum(cell.v);
      } else cell.t = 's';

      ws[cellRef] = cell;
    }
  }
  if (range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range);
  return ws;
}
function Workbook() {
  if (!(this instanceof Workbook)) return new Workbook();
  this.SheetNames = [];
  this.Sheets = {};
}

function s2ab(s) {
  const buf = new ArrayBuffer(s.length);
  const view = new Uint8Array(buf);
  for (let i = 0; i !== s.length; ++i) view[i] = s.charCodeAt(i) & 0xff;
  return buf;
}

/*
 * th => 表头
 * data => 数据
 * fileName => 文件名
 * fileType => 文件类型
 * sheetName => sheet页名
 */
export default function toExcel({ th, data, fileName, fileType, sheetName }) {
  data.unshift(th);
  let wb = new Workbook();
  let ws = data2ws(data);
  sheetName = sheetName || 'sheet1';
  wb.SheetNames.push(sheetName);
  wb.Sheets[sheetName] = ws;
  fileType = fileType || 'xlsx';
  let wbout = XLSX.write(wb, { bookType: fileType, bookSST: false, type: 'binary' });
  fileName = fileName || '列表';
  saveAs(new Blob([s2ab(wbout)], { type: 'application/octet-stream' }), `${fileName}.${fileType}`);
}