import { h } from '@ui-arch/frame';
import type { RowModel } from '@ui-arch/table-core';
import { button } from './button.js';
import type { TableColumn } from './types.js';

/*** 单元格转义：含逗号 / 引号 / 换行时整体加引号，内部引号翻倍 ***/
function cell(v: unknown): string {
  const s = v == null ? '' : String(v);
  return /[",\r\n]/.test(s) ? `"${s.replace(/"/g, '""')}"` : s;
}

/*** 导出 CSV：前置 BOM + CRLF 换行，Excel 打开中文不乱码 ***/
export function downloadCsv(name: string, header: string[], rows: unknown[][]): void {
  const text = '\ufeff' + [header, ...rows].map((r) => r.map(cell).join(',')).join('\r\n') + '\r\n';
  const url = URL.createObjectURL(new Blob([text], { type: 'text/csv;charset=utf-8' }));
  const a = h('a', { href: url, download: name }) as HTMLAnchorElement;
  document.body.appendChild(a); // 挂进文档再点击：Safari 对游离锚点不触发下载
  a.click();
  a.remove(); // 立即摘除，不留残留节点
  URL.revokeObjectURL(url);
}

/*** 导出按钮：取筛选 + 排序后的全量行（不分页），列序与表头一致、单元格走 format；列可由读取器惰性给出，跟随列显隐 ***/
export function exportButton<T>(
  table: { getAllRows(): RowModel<T>; getCellValue(row: T, key: string): unknown },
  columns: TableColumn<T>[] | (() => TableColumn<T>[]),
  name: string,
): HTMLElement {
  const run = (): void => {
    const cols = typeof columns === 'function' ? columns() : columns; // 点导出时才取列：隐藏列变化后导出跟着变
    const rows = table.getAllRows().rows;
    const header = cols.map((c) => String(c.header ?? c.key));
    const body = rows.map((row) => cols.map((c) => {
      const raw = table.getCellValue(row, c.key);
      return c.format ? c.format(raw, row) : raw; // 与单元格显示同源，导出内容与看到的一致
    }));
    downloadCsv(name, header, body);
  };
  return button({ label: '导出 CSV', variant: 'ghost', onClick: run });
}