import React, { useState, useMemo } from 'react';
import './Table.css';

/**
 * Aurora Admin Table（React）
 * 对齐 table.json 契约：
 *  - feature: sortable / selectable / batch-actions（含全选）
 *  - state:   hover / selected / loading / empty
 *  - 表头/行高48px、分割线 #E8ECF1、悬停 #F5F7FA、选中 #F0F5FF、单元格左右16px、数字右对齐、操作列右对齐
 *
 * columns: [{ key, title, align?:'left'|'right', sortable?, width?, fixed?, type?:'action' }]
 * 受控选择：selectedKeys={keys} onSelectionChange={setKeys}
 * 操作列：renderAction={(row, index) => <Buttons/>}
 */
function sortData(data, key, order) {
  if (!key) return data;
  const dir = order === 'asc' ? 1 : -1;
  return [...data].sort((a, b) => {
    const av = a[key], bv = b[key];
    if (typeof av === 'number' && typeof bv === 'number') return (av - bv) * dir;
    return String(av).localeCompare(String(bv), 'zh') * dir;
  });
}

export default function Table({
  columns = [],
  data = [],
  rowKey = 'id',
  selectable = false,
  selectedKeys = [],
  loading = false,
  emptyText = '暂无数据',
  onSelectionChange,
  onSortChange,
  renderAction
}) {
  const [sortKey, setSortKey] = useState(null);
  const [sortOrder, setSortOrder] = useState(null);   // asc | desc | null

  const sortedData = useMemo(
    () => sortData(data, sortKey, sortOrder),
    [data, sortKey, sortOrder]
  );

  const allSelected = data.length > 0 && selectedKeys.length === data.length;
  const someSelected = selectedKeys.length > 0 && selectedKeys.length < data.length;

  const isSelected = (id) => selectedKeys.includes(id);
  const emitSelection = (next) => onSelectionChange && onSelectionChange(next);

  const toggleRow = (id) => {
    const next = isSelected(id) ? selectedKeys.filter((x) => x !== id) : [...selectedKeys, id];
    emitSelection(next);
  };
  const toggleAll = () => {
    const next = allSelected ? [] : data.map((r) => r[rowKey]);
    emitSelection(next);
  };
  const onSort = (col) => {
    if (!col.sortable) return;
    let k = sortKey, o = sortOrder;
    if (k !== col.key) { k = col.key; o = 'asc'; }
    else { o = o === 'asc' ? 'desc' : o === 'desc' ? null : 'asc'; if (o === null) k = null; }
    setSortKey(k); setSortOrder(o);
    onSortChange && onSortChange({ key: k, order: o });
  };

  const colCount = columns.length + (selectable ? 1 : 0);

  return (
    <div className="aa-table">
      <table>
        <thead>
          <tr>
            {selectable && (
              <th className="col-selection" style={{ width: 48 }}>
                <input
                  type="checkbox" className="checkbox"
                  checked={allSelected} ref={(el) => el && (el.indeterminate = someSelected)}
                  onChange={toggleAll}
                />
              </th>
            )}
            {columns.map((col) => (
              <th
                key={col.key || col.title}
                className={[
                  col.align === 'right' ? 'align-right' : '',
                  col.sortable ? 'sortable' : '',
                  col.fixed ? 'col-fixed' : ''
                ].filter(Boolean).join(' ')}
                style={col.width ? { width: col.width } : null}
                onClick={() => onSort(col)}
              >
                {col.title}
                {col.sortable && (
                  <span className={`sort-ind${sortKey === col.key ? ' active' : ''}`}>
                    {sortKey === col.key ? (sortOrder === 'asc' ? '↑' : sortOrder === 'desc' ? '↓' : '↕') : '↕'}
                  </span>
                )}
              </th>
            ))}
          </tr>
        </thead>
        <tbody>
          {sortedData.length === 0 ? (
            <tr><td className="empty" colSpan={colCount}>{emptyText}</td></tr>
          ) : (
            sortedData.map((row, index) => (
              <tr key={row[rowKey]} className={isSelected(row[rowKey]) ? 'is-selected' : ''}>
                {selectable && (
                  <td className="col-selection">
                    <input
                      type="checkbox" className="checkbox"
                      checked={isSelected(row[rowKey])} onChange={() => toggleRow(row[rowKey])}
                    />
                  </td>
                )}
                {columns.map((col) => (
                  <td
                    key={col.key || col.title}
                    className={[
                      col.align === 'right' ? 'align-right' : '',
                      col.fixed ? 'col-fixed' : '',
                      col.type === 'action' ? 'col-action' : ''
                    ].filter(Boolean).join(' ')}
                  >
                    {col.type === 'action' && renderAction ? renderAction(row, index) : row[col.key]}
                  </td>
                ))}
              </tr>
            ))
          )}
        </tbody>
      </table>
      {loading && (
        <div className="loading-mask"><span className="spinner" /></div>
      )}
    </div>
  );
}

/*
用法示例：
import Table from './Table';

const columns = [
  { key: 'name', title: '客户名称' },
  { key: 'amount', title: '合同金额', align: 'right', sortable: true },
  { type: 'action', title: '操作' }
];
<Table
  columns={columns}
  data={rows}
  selectable
  selectedKeys={keys}
  onSelectionChange={setKeys}
  renderAction={(row) => (<>
    <button className="link-btn" onClick={() => edit(row)}>编辑</button>
    <button className="link-btn danger" onClick={() => del(row)}>删除</button>
  </>)}
/>
*/