import { useEffect, useState, useCallback } from 'react';
import { adminApi } from '../lib/api';
import type { AuditLog } from '../types';
import { showToast } from '../components/Toast';
import { DatePicker } from '../components/DatePicker';
import { Select } from '../components/Select';
import styles from './AuditLogsPage.module.css';

const ACTION_OPTIONS = [
  { label: '全部操作', value: '' },
  { label: '创建团队', value: 'team_create' },
  { label: '更新团队', value: 'team_update' },
  { label: '团队充值', value: 'team_topup' },
  { label: '设置额度池', value: 'team_set_pool' },
  { label: '创建团队管理员', value: 'team_create_admin' },
  { label: '创建用户', value: 'user_create' },
  { label: '更新用户额度', value: 'user_quota_update' },
  { label: '切换用户状态', value: 'user_status_toggle' },
  { label: '更新系统设置', value: 'settings_update' },
  { label: '创建团队成员', value: 'member_create' },
  { label: '更新成员额度', value: 'member_quota_update' },
  { label: '切换成员状态', value: 'member_status_toggle' },
];

function renderChanges(before: Record<string, unknown> | null, after: Record<string, unknown> | null) {
  if (!before && !after) return '-';
  const fields = new Set([...Object.keys(before || {}), ...Object.keys(after || {})]);
  if (fields.size === 0) return '-';

  return (
    <div className={styles.changeDetail}>
      {[...fields].map((field) => {
        const oldVal = before?.[field];
        const newVal = after?.[field];
        if (oldVal === undefined && newVal !== undefined) {
          return (
            <div key={field} className={styles.changeItem}>
              <span className={styles.changeField}>{field}:</span>
              <span className={styles.changeNew}>{String(newVal)}</span>
            </div>
          );
        }
        if (oldVal !== undefined && newVal !== undefined && String(oldVal) !== String(newVal)) {
          return (
            <div key={field} className={styles.changeItem}>
              <span className={styles.changeField}>{field}:</span>
              <span className={styles.changeOld}>{String(oldVal)}</span>
              <span className={styles.changeArrow}>&rarr;</span>
              <span className={styles.changeNew}>{String(newVal)}</span>
            </div>
          );
        }
        if (oldVal === undefined && newVal === undefined) return null;
        // Same value, show as-is for create actions
        if (oldVal === undefined) {
          return (
            <div key={field} className={styles.changeItem}>
              <span className={styles.changeField}>{field}:</span>
              <span className={styles.changeNew}>{String(newVal)}</span>
            </div>
          );
        }
        return null;
      })}
    </div>
  );
}

export function AuditLogsPage() {
  const [logs, setLogs] = useState<AuditLog[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [actionFilter, setActionFilter] = useState('');
  const [operatorSearch, setOperatorSearch] = useState('');
  const [startDate, setStartDate] = useState('');
  const [endDate, setEndDate] = useState('');
  const [loading, setLoading] = useState(true);
  const pageSize = 20;

  const fetchLogs = useCallback(async () => {
    setLoading(true);
    try {
      const { data } = await adminApi.getAuditLogs({
        page, page_size: pageSize,
        action: actionFilter || undefined,
        operator: operatorSearch || undefined,
        start_date: startDate || undefined,
        end_date: endDate || undefined,
      });
      setLogs(data.results);
      setTotal(data.total);
    } catch {
      showToast('加载审计日志失败');
    } finally {
      setLoading(false);
    }
  }, [page, actionFilter, operatorSearch, startDate, endDate]);

  useEffect(() => { fetchLogs(); }, [fetchLogs]);

  const handleSearch = () => {
    setPage(1);
    fetchLogs();
  };

  const totalPages = Math.ceil(total / pageSize);

  return (
    <div className={styles.page}>
      <h1 className={styles.title}>操作日志</h1>

      <div className={styles.filters}>
        <Select
          value={actionFilter}
          onChange={(v) => { setActionFilter(v); setPage(1); }}
          placeholder="全部操作"
          options={ACTION_OPTIONS}
        />
        <input
          type="text"
          className={styles.searchInput}
          placeholder="按操作人搜索..."
          value={operatorSearch}
          onChange={(e) => setOperatorSearch(e.target.value)}
          onKeyDown={(e) => e.key === 'Enter' && handleSearch()}
        />
        <DatePicker value={startDate} onChange={setStartDate} placeholder="开始日期" />
        <span className={styles.dateSep}>~</span>
        <DatePicker value={endDate} onChange={setEndDate} placeholder="结束日期" />
        <button className={styles.searchBtn} onClick={handleSearch}>查询</button>
        <button className={styles.refreshBtn} onClick={fetchLogs}>刷新</button>
      </div>

      <div className={styles.tableWrapper}>
        <table className={styles.table}>
          <thead>
            <tr>
              <th>时间</th>
              <th>操作人</th>
              <th>操作类型</th>
              <th>目标</th>
              <th>变更详情</th>
              <th>IP</th>
            </tr>
          </thead>
          <tbody>
            {loading ? (
              Array.from({ length: 5 }).map((_, i) => (
                <tr key={i}>
                  {Array.from({ length: 6 }).map((_, j) => (
                    <td key={j}><div className={styles.skeletonCell} /></td>
                  ))}
                </tr>
              ))
            ) : logs.length === 0 ? (
              <tr><td colSpan={6} className={styles.empty}>暂无日志记录</td></tr>
            ) : (
              logs.map((log) => (
                <tr key={log.id}>
                  <td className={styles.timeCell}>{new Date(log.created_at).toLocaleString('zh-CN')}</td>
                  <td>{log.operator_name}</td>
                  <td><span className={styles.actionBadge}>{log.action_display}</span></td>
                  <td className={styles.targetCell}>
                    {log.target_name || '-'}
                    {log.target_type && <span style={{ color: '#8b8ea8', fontSize: 11, marginLeft: 4 }}>({log.target_type})</span>}
                  </td>
                  <td>{renderChanges(log.before, log.after)}</td>
                  <td className={styles.ipCell}>{log.ip_address || '-'}</td>
                </tr>
              ))
            )}
          </tbody>
        </table>
      </div>

      {totalPages > 1 && (
        <div className={styles.pagination}>
          <span className={styles.pageInfo}>共 {total} 条</span>
          <div className={styles.pageButtons}>
            <button disabled={page <= 1} onClick={() => setPage(page - 1)}>&lt;</button>
            {Array.from({ length: Math.min(totalPages, 5) }, (_, i) => {
              let p: number;
              if (totalPages <= 5) p = i + 1;
              else if (page <= 3) p = i + 1;
              else if (page >= totalPages - 2) p = totalPages - 4 + i;
              else p = page - 2 + i;
              return (
                <button key={p} className={page === p ? styles.activePage : ''} onClick={() => setPage(p)}>
                  {p}
                </button>
              );
            })}
            <button disabled={page >= totalPages} onClick={() => setPage(page + 1)}>&gt;</button>
          </div>
        </div>
      )}
    </div>
  );
}