/* eslint-disable */
import { saveAs } from 'file-saver'
import XLSX from 'xlsx'
/* ExcelJS 官方文档：https://gitee.com/mirrors/exceljs#exceljs */
const ExcelJS = require('exceljs');

function generateArray(table) {
  var out = [];
  var rows = table.querySelectorAll('tr');
  var ranges = [];
  for (var R = 0; R < rows.length; ++R) {
    var outRow = [];
    var row = rows[R];
    var columns = row.querySelectorAll('td');
    for (var C = 0; C < columns.length; ++C) {
      var cell = columns[C];
      var colspan = cell.getAttribute('colspan');
      var rowspan = cell.getAttribute('rowspan');
      var 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 (var 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 (var k = 0; k < colspan - 1; ++k) outRow.push(null);
    }
    out.push(outRow);
  }
  return [out, ranges];
};

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

function sheet_from_array_of_arrays(data, opts) {
  var ws = {};
  var range = {
    s: {
      c: 10000000,
      r: 10000000
    },
    e: {
      c: 0,
      r: 0
    }
  };
  for (var R = 0; R != data.length; ++R) {
    for (var 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;
      var cell = {
        v: data[R][C]
      };
      if (cell.v == null) continue;
      var cell_ref = 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[cell_ref] = 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) {
  var buf = new ArrayBuffer(s.length);
  var view = new Uint8Array(buf);
  for (var i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;
  return buf;
}

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

  /* original data */
  var data = oo[0];
  var ws_name = "SheetJS";

  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);

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

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

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

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

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

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

  var ws_name = "SheetJS";
  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);

  if (merges.length > 0) {
    if (!ws['!merges']) ws['!merges'] = [];
    merges.forEach(item => {
      ws['!merges'].push(XLSX.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
        };
      }
      /*再判断是否为中文*/
      else if (val.toString().charCodeAt(0) > 255) {
        return {
          'wch': val.toString().length * 2
        };
      } else {
        return {
          'wch': val.toString().length
        };
      }
    }))
    /*以第一行为初始值*/
    let 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(ws_name);
  wb.Sheets[ws_name] = ws;

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

/* 设置worksheet数据验证 */
function set_excel_data_validation(ws, colCodeList) {
    /* 设置worksheet下拉列表 */
    if (colCodeList && Object.keys(colCodeList).length > 0) {
        Object.keys(colCodeList).forEach((name) => {
            const col = ws.getColumn(name);
            if (col) {
                /* 表头单元格不设置下拉列表，空单元格设置下拉列表 */
                col.eachCell({ includeEmpty: true }, function (cell, rowNumber) {
                    if (rowNumber !== 1) {
                        cell.dataValidation = {
                            type: 'list',
                            allowBlank: true,
                            formulae: [`"${colCodeList[name]}"`]
                        }
                    }
                });
            }
        })
    }
}

/* 设置worksheet数据格式化 */
function set_excel_data_format(ws, colFormat) {
    if (colFormat && Object.keys(colFormat).length > 0) {
        Object.keys(colFormat).forEach((name) => {
            const col = ws.getColumn(name);
            if (col) {
                /* 表头单元格不设置格式化，非空单元格格式化(目前只识别数值格式化) */
                col.eachCell(function (cell, rowNumber) {
                    if (cell.type == ExcelJS.ValueType.Number) {
                        if (rowNumber !== 1) {
                            cell.numFmt = colFormat[name]
                        }
                    }
                });
            }
        })
    }
}

export async function export_data_to_excel({ 
    columns = [], 
    data = [], 
    filename, 
    colCodeList, 
    colFormat,
    bookType = 'xlsx',
    insertRows = 0,
} = {}) {
    const wb = new ExcelJS.Workbook();
    const ws = wb.addWorksheet('Sheet');
    const wsColumns = [];
    /* 设置worksheet每列的模型 */
    columns.forEach((column) => {
        wsColumns.push({
            header: column.label,
            key: column.name,
            width: column.label ? column.label.length * 3 : 10,
        })
    })
    ws.columns = wsColumns;
    /* 设置worksheet行数据 */
    ws.addRows(data);
    /* 插入行 下载导入模板时增添的行数，用于给指定单元格添加下拉列表等数据校验 */
    if (insertRows > 0) {
        ws.duplicateRow(data.length > 0 ? data.length + 1 : 0, insertRows, true);
    }
    set_excel_data_validation(ws, colCodeList);
    set_excel_data_format(ws, colFormat)
    const buffer = await wb.xlsx.writeBuffer();
    saveAs(new Blob([buffer], {
        type: "application/octet-stream"
    }), `${filename}.${bookType}`);
}