import { addClass, hasClass, query, queryAll } from '@/utils/frontend/dom';

// 表头分组
export default function useGroupingHeaders(tableWrapper: HTMLElement, cellGrid: number[][], fixedColumnsLeft = 0) {
  const generateGroupHeaders = () => {
    const heighten = ($th: Element, count: number) => {
      addClass($th, 'real-th');
      const $relative = query($th, '.relative') as HTMLElement;
      $relative.style.height = `${count * 26 - 1}px`;
      $relative.style.lineHeight = `${count * 26}px`;
    };

    const grouping = ($thead: HTMLElement, rowNums: number, colNums: number) => {
      const $trList = Array.from(queryAll($thead, 'tr'));
      if ($trList.length <= 1) return;
      const $thList = [] as Element[][];
      $trList.forEach($tr => {
        const $rowThList = Array.from(queryAll($tr, 'th'));
        // 去掉左上角的 th
        $rowThList.shift();
        $thList.push($rowThList);
      });
      // 二维数组，记录每个 th 是否已被它正下方的 th 覆盖，初始化为 false 代表没有被覆盖
      const coveredGrid = new Array(rowNums).fill(null).map(() => new Array(colNums).fill(false));
      for (let i = rowNums - 1; i >= 0; i--) {
        for (let j = 0; j < colNums; j++) {
          const $th = $thList[i][j];
          if (!$th) return;
          // coveredGrid[i][j] 为 true 说明这个单元格被它下面的单元格覆盖了，不用再考虑了
          if (coveredGrid[i][j] || hasClass($th, 'hiddenHeader')) continue;
          coveredGrid[i][j] = true;
          // 将当前单元格上面的拥有相同 id 的单元格（这些单元格属于同一个合并单元格）标记为已覆盖：coveredGrid[k][j] = true
          let k;
          for (k = i - 1; k >= 0; k--) {
            if (cellGrid[k][j] !== cellGrid[i][j]) break;
            coveredGrid[k][j] = true;
          }
          // 从当前单元格开始往上数，有几个单元格属于同一个合并单元格
          const count = i - k;
          if (count > 1) {
            heighten($th, count);
          }
        }
      }
    };
    // handsontable clone top 部分
    const $thead = query(tableWrapper, '.ht_clone_top .wtHolder .htCore thead') as HTMLElement;
    grouping($thead, cellGrid.length, cellGrid[0].length);

    // handsontable clone top left corner 部分
    const $topLeftHead = query(tableWrapper, '.ht_clone_top_left_corner .wtHolder .htCore thead') as HTMLElement;
    grouping($topLeftHead, cellGrid.length, fixedColumnsLeft);

    // 设置左上角的单元格合并为一个单元格
    const $topLeftLastTr = Array.from(queryAll($topLeftHead, 'tr')).pop() as HTMLElement;
    const $topLeftLastTh = query($topLeftLastTr, 'th') as HTMLElement;
    heighten($topLeftLastTh, cellGrid.length);
  };
  return {
    generateGroupHeaders,
  };
}