import { saveAs } from 'file-saver';
import { SSF, utils, write } from 'xlsx';
import type { WorkBook, WorkSheet, BookType } from 'xlsx';

interface ICell {
  v: Date | number | boolean | string;
  t: string;
  z: string;
}

class Workbook implements WorkBook {
  SheetNames: string[] = [];

  Sheets: { [sheet: string]: WorkSheet } = {};
}

function generateArray(table) {
  const out: any[] = [];
  const rows = table.querySelectorAll('tr');
  const ranges: any[] = [];
  for (let R = 0; R < rows.length; ++R) {
    const outRow: any[] = [];
    const row = rows[R];
    const columns = row.querySelectorAll('td');
    for (let C = 0; C < columns.length; ++C) {
      const cell = columns[C];
      let colspan = cell.getAttribute('colspan');
      let rowspan = cell.getAttribute('rowspan');
      let cellValue = cell.innerText;
      if (cellValue !== '' && cellValue == +cellValue) cellValue = +cellValue;

      //Skip ranges
      ranges.forEach(function (range) {
        if (
          R >= range.s.r &&
          R <= range.e.r &&
          outRow.length >= range.s.c &&
          outRow.length <= range.e.c
        ) {
          for (let i = 0; i <= range.e.c - range.s.c; ++i) outRow.push(null);
        }
      });

      //Handle Row Span
      if (rowspan || colspan) {
        rowspan = rowspan || 1;
        colspan = colspan || 1;
        ranges.push({
          s: {
            r: R,
            c: outRow.length,
          },
          e: {
            r: R + rowspan - 1,
            c: outRow.length + colspan - 1,
          },
        });
      }

      //Handle Value
      outRow.push(cellValue !== '' ? cellValue : null);

      //Handle Colspan
      if (colspan) for (let k = 0; k < colspan - 1; ++k) outRow.push(null);
    }
    out.push(outRow);
  }
  return [out, ranges];
}

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

function sheetFromArrayOfArrays(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: ICell = {
        v: data[R][C],
        t: '',
        z: '',
      };
      if (cell.v == null) continue;
      const cellRef = 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 = SSF._table[14];
        cell.v = datenum(cell.v);
      } else cell.t = 's';

      ws[cellRef] = cell;
    }
  }
  if (range.s.c < 10000000) ws['!ref'] = utils.encode_range(range);
  return ws;
}

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;
}

export function exportTableToExcel(id) {
  const theTable = document.getElementById(id);
  const oo = generateArray(theTable);
  const ranges = oo[1];

  /* original data */
  const data = oo[0];
  const wsName = 'SheetJS';

  const wb = new Workbook(),
    ws = sheetFromArrayOfArrays(data);

  /* add ranges to worksheet */
  // ws['!cols'] = ['apple', 'banan'];
  ws['!merges'] = ranges;

  /* add worksheet to workbook */
  wb.SheetNames.push(wsName);
  wb.Sheets[wsName] = ws;

  const wbout = write(wb, {
    bookType: 'xlsx',
    bookSST: false,
    type: 'binary',
  });

  saveAs(
    new Blob([s2ab(wbout)], {
      type: 'application/octet-stream',
    }),
    'test.xlsx',
  );
}

export function exportJson2Excel({
  multiHeader = [] as string[][],
  header = [] as string[],
  data = [] as any[],
  filename = 'excel-list',
  merges = [] as any[],
  autoWidth = true,
  bookType = 'xlsx' as BookType,
} = {}) {
  /* original data */
  filename = filename || 'excel-list';
  data = [...data];
  data.unshift(header);

  for (let i = multiHeader.length - 1; i > -1; i--) {
    data.unshift(multiHeader[i]);
  }

  const wsName = 'SheetJS';
  const wb = new Workbook(),
    ws = sheetFromArrayOfArrays(data);
  if (merges.length > 0) {
    if (!ws['!merges']) ws['!merges'] = [];
    merges.forEach((item) => {
      ws['!merges'].push(utils.decode_range(item));
    });
  }

  if (autoWidth) {
    /*设置worksheet每列的最大宽度*/
    const colWidth = data.map((row) =>
      row.map((val) => {
        /*先判断是否为null/undefined*/
        if (val == null) {
          return {
            wch: 10,
          };
        } else if (val.toString().charCodeAt(0) > 255) {
          /*再判断是否为中文*/
          return {
            wch: val.toString().length * 2,
          };
        } else {
          return {
            wch: val.toString().length,
          };
        }
      }),
    );
    /*以第一行为初始值*/
    const result = colWidth[0];
    for (let i = 1; i < colWidth.length; i++) {
      for (let j = 0; j < colWidth[i].length; j++) {
        if (result[j]['wch'] < colWidth[i][j]['wch']) {
          result[j]['wch'] = colWidth[i][j]['wch'];
        }
      }
    }
    ws['!cols'] = result;
  }

  /* add worksheet to workbook */
  wb.SheetNames.push(wsName);
  wb.Sheets[wsName] = ws;

  const wbout = write(wb, {
    bookType,
    bookSST: false,
    type: 'binary',
  });
  saveAs(
    new Blob([s2ab(wbout)], {
      type: 'application/octet-stream',
    }),
    `${filename}.${bookType}`,
  );
}