import "core-js/modules/es.array.push.js";
import { isEmpty } from "./../helpers/mixed.mjs";
const ESCAPED_HTML_CHARS = {
  ' ': '\x20',
  '&': '&',
  '&lt;': '<',
  '&gt;': '>'
};
const regEscapedChars = new RegExp(Object.keys(ESCAPED_HTML_CHARS).map(key => `(${key})`).join('|'), 'gi');

/**
 * Verifies if node is an HTMLTable element.
 *
 * @param {Node} element Node to verify if it's an HTMLTable.
 * @returns {boolean}
 */
function isHTMLTable(element) {
  return (element && element.nodeName || '') === 'TABLE';
}

/**
 * Converts Handsontable into HTMLTableElement.
 *
 * @param {Core} instance The Handsontable instance.
 * @returns {string} OuterHTML of the HTMLTableElement.
 */
export function instanceToHTML(instance) {
  const hasColumnHeaders = instance.hasColHeaders();
  const hasRowHeaders = instance.hasRowHeaders();
  const coords = [hasColumnHeaders ? -1 : 0, hasRowHeaders ? -1 : 0, instance.countRows() - 1, instance.countCols() - 1];
  const data = instance.getData(...coords);
  const countRows = data.length;
  const countCols = countRows > 0 ? data[0].length : 0;
  const TABLE = ['<table>', '</table>'];
  const THEAD = hasColumnHeaders ? ['<thead>', '</thead>'] : [];
  const TBODY = ['<tbody>', '</tbody>'];
  const rowModifier = hasRowHeaders ? 1 : 0;
  const columnModifier = hasColumnHeaders ? 1 : 0;
  for (let row = 0; row < countRows; row += 1) {
    const isColumnHeadersRow = hasColumnHeaders && row === 0;
    const CELLS = [];
    for (let column = 0; column < countCols; column += 1) {
      const isRowHeadersColumn = !isColumnHeadersRow && hasRowHeaders && column === 0;
      let cell = '';
      if (isColumnHeadersRow) {
        cell = `<th>${instance.getColHeader(column - rowModifier)}</th>`;
      } else if (isRowHeadersColumn) {
        cell = `<th>${instance.getRowHeader(row - columnModifier)}</th>`;
      } else {
        const cellData = data[row][column];
        const {
          hidden,
          rowspan,
          colspan
        } = instance.getCellMeta(row - columnModifier, column - rowModifier);
        if (!hidden) {
          const attrs = [];
          if (rowspan) {
            attrs.push(`rowspan="${rowspan}"`);
          }
          if (colspan) {
            attrs.push(`colspan="${colspan}"`);
          }
          if (isEmpty(cellData)) {
            cell = `<td ${attrs.join(' ')}></td>`;
          } else {
            const value = cellData.toString().replace('<', '&lt;').replace('>', '&gt;').replace(/(<br(\s*|\/)>(\r\n|\n)?|\r\n|\n)/g, '<br>\r\n').replace(/\x20/gi, '&nbsp;').replace(/\t/gi, '&#9;');
            cell = `<td ${attrs.join(' ')}>${value}</td>`;
          }
        }
      }
      CELLS.push(cell);
    }
    const TR = ['<tr>', ...CELLS, '</tr>'].join('');
    if (isColumnHeadersRow) {
      THEAD.splice(1, 0, TR);
    } else {
      TBODY.splice(-1, 0, TR);
    }
  }
  TABLE.splice(1, 0, THEAD.join(''), TBODY.join(''));
  return TABLE.join('');
}

/**
 * Converts 2D array into HTMLTableElement.
 *
 * @param {Array} input Input array which will be converted to HTMLTable.
 * @returns {string} OuterHTML of the HTMLTableElement.
 */
// eslint-disable-next-line no-restricted-globals
export function _dataToHTML(input) {
  const inputLen = input.length;
  const result = ['<table>'];
  for (let row = 0; row < inputLen; row += 1) {
    const rowData = input[row];
    const columnsLen = rowData.length;
    const columnsResult = [];
    if (row === 0) {
      result.push('<tbody>');
    }
    for (let column = 0; column < columnsLen; column += 1) {
      const cellData = rowData[column];
      const parsedCellData = isEmpty(cellData) ? '' : cellData.toString().replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/(<br(\s*|\/)>(\r\n|\n)?|\r\n|\n)/g, '<br>\r\n').replace(/\x20{2,}/gi, substring => {
        // The way how Excel serializes data with at least two spaces.
        return `<span style="mso-spacerun: yes">${'&nbsp;'.repeat(substring.length - 1)} </span>`;
      }).replace(/\t/gi, '&#9;');
      columnsResult.push(`<td>${parsedCellData}</td>`);
    }
    result.push('<tr>', ...columnsResult, '</tr>');
    if (row + 1 === inputLen) {
      result.push('</tbody>');
    }
  }
  result.push('</table>');
  return result.join('');
}

/**
 * Converts HTMLTable or string into Handsontable configuration object.
 *
 * @param {Element|string} element Node element which should contain `<table>...</table>`.
 * @param {Document} [rootDocument] The document window owner.
 * @returns {object} Return configuration object. Contains keys as DefaultSettings.
 */
// eslint-disable-next-line no-restricted-globals
export function htmlToGridSettings(element) {
  let rootDocument = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : document;
  const settingsObj = {};
  const fragment = rootDocument.createDocumentFragment();
  const tempElem = rootDocument.createElement('div');
  fragment.appendChild(tempElem);
  let checkElement = element;
  if (typeof checkElement === 'string') {
    const escapedAdjacentHTML = checkElement.replace(/<td\b[^>]*?>([\s\S]*?)<\/\s*td>/g, cellFragment => {
      const openingTag = cellFragment.match(/<td\b[^>]*?>/g)[0];
      const cellValue = cellFragment.substring(openingTag.length, cellFragment.lastIndexOf('<')).replace(/(<(?!br)([^>]+)>)/gi, '');
      const closingTag = '</td>';
      return `${openingTag}${cellValue}${closingTag}`;
    });
    tempElem.insertAdjacentHTML('afterbegin', `${escapedAdjacentHTML}`);
    checkElement = tempElem.querySelector('table');
  }
  if (!checkElement || !isHTMLTable(checkElement)) {
    return;
  }
  const generator = tempElem.querySelector('meta[name$="enerator"]');
  const hasRowHeaders = checkElement.querySelector('tbody th') !== null;
  const trElement = checkElement.querySelector('tr');
  const countCols = !trElement ? 0 : Array.from(trElement.cells).reduce((cols, cell) => cols + cell.colSpan, 0) - (hasRowHeaders ? 1 : 0);
  const fixedRowsBottom = checkElement.tFoot && Array.from(checkElement.tFoot.rows) || [];
  const fixedRowsTop = [];
  let hasColHeaders = false;
  let thRowsLen = 0;
  let countRows = 0;
  if (checkElement.tHead) {
    const thRows = Array.from(checkElement.tHead.rows).filter(tr => {
      const isDataRow = tr.querySelector('td') !== null;
      if (isDataRow) {
        fixedRowsTop.push(tr);
      }
      return !isDataRow;
    });
    thRowsLen = thRows.length;
    hasColHeaders = thRowsLen > 0;
    if (thRowsLen > 1) {
      settingsObj.nestedHeaders = Array.from(thRows).reduce((rows, row) => {
        const headersRow = Array.from(row.cells).reduce((headers, header, currentIndex) => {
          if (hasRowHeaders && currentIndex === 0) {
            return headers;
          }
          const {
            colSpan: colspan,
            innerHTML
          } = header;
          const nextHeader = colspan > 1 ? {
            label: innerHTML,
            colspan
          } : innerHTML;
          headers.push(nextHeader);
          return headers;
        }, []);
        rows.push(headersRow);
        return rows;
      }, []);
    } else if (hasColHeaders) {
      settingsObj.colHeaders = Array.from(thRows[0].children).reduce((headers, header, index) => {
        if (hasRowHeaders && index === 0) {
          return headers;
        }
        headers.push(header.innerHTML);
        return headers;
      }, []);
    }
  }
  if (fixedRowsTop.length) {
    settingsObj.fixedRowsTop = fixedRowsTop.length;
  }
  if (fixedRowsBottom.length) {
    settingsObj.fixedRowsBottom = fixedRowsBottom.length;
  }
  const dataRows = [...fixedRowsTop, ...Array.from(checkElement.tBodies).reduce((sections, section) => {
    sections.push(...Array.from(section.rows));
    return sections;
  }, []), ...fixedRowsBottom];
  countRows = dataRows.length;
  const dataArr = new Array(countRows);
  for (let r = 0; r < countRows; r++) {
    dataArr[r] = new Array(countCols);
  }
  const mergeCells = [];
  const rowHeaders = [];
  for (let row = 0; row < countRows; row++) {
    const tr = dataRows[row];
    const cells = Array.from(tr.cells);
    const cellsLen = cells.length;
    for (let cellId = 0; cellId < cellsLen; cellId++) {
      const cell = cells[cellId];
      const {
        nodeName,
        innerHTML,
        rowSpan: rowspan,
        colSpan: colspan
      } = cell;
      const col = dataArr[row].findIndex(value => value === void 0);
      if (nodeName === 'TD') {
        if (rowspan > 1 || colspan > 1) {
          for (let rstart = row; rstart < row + rowspan; rstart++) {
            if (rstart < countRows) {
              for (let cstart = col; cstart < col + colspan; cstart++) {
                dataArr[rstart][cstart] = null;
              }
            }
          }
          const styleAttr = cell.getAttribute('style');
          const ignoreMerge = styleAttr && styleAttr.includes('mso-ignore:colspan');
          if (!ignoreMerge) {
            mergeCells.push({
              col,
              row,
              rowspan,
              colspan
            });
          }
        }
        let cellValue = '';
        if (generator && /excel/gi.test(generator.content)) {
          cellValue = innerHTML.replace(/[\r\n][\x20]{0,2}/g, '\x20').replace(/<br(\s*|\/)>[\r\n]?[\x20]{0,3}/gim, '\r\n');
        } else {
          cellValue = innerHTML.replace(/<br(\s*|\/)>[\r\n]?/gim, '\r\n');
        }
        dataArr[row][col] = cellValue.replace(regEscapedChars, match => ESCAPED_HTML_CHARS[match]);
      } else {
        rowHeaders.push(innerHTML);
      }
    }
  }
  if (mergeCells.length) {
    settingsObj.mergeCells = mergeCells;
  }
  if (rowHeaders.length) {
    settingsObj.rowHeaders = rowHeaders;
  }
  if (dataArr.length) {
    settingsObj.data = dataArr;
  }
  return settingsObj;
}