import { useEffect, useState, useCallback } from 'react';
import { Loader2, RefreshCw, Activity } from 'lucide-react';
import { Card, CardContent, CardHeader, CardTitle } from '@shared/components/ui/card';
import { Badge } from '@shared/components/ui/badge';
import { Button } from '@shared/components/ui/button';
import { PageContainer, PageHeader } from '@shared/components/layout';
import { fetchAccessLogs, fetchAccessStats, type AccessLog, type AccessStats } from '@/services/adminApi';
import { formatDateTime } from '@shared/utils/dateFormat';
import { getHttpStatusIntent } from '@shared/constants/httpStatusCodes';

/**
 * 접근 이력 조회 + 메트릭 카드.
 * 권한: admin:access-logs (READ)
 */
export function AccessLogs() {
  const [items, setItems] = useState<AccessLog[]>([]);
  const [stats, setStats] = useState<AccessStats | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');

  const load = useCallback(async () => {
    setLoading(true); setError('');
    try {
      const [logs, st] = await Promise.all([fetchAccessLogs(0, 100), fetchAccessStats()]);
      setItems(logs.content);
      setStats(st);
    } catch (e: unknown) {
      setError(e instanceof Error ? e.message : 'unknown');
    } finally {
      setLoading(false);
    }
  }, []);

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

  return (
    <PageContainer size="lg">
      <PageHeader
        icon={Activity}
        iconColor="text-label"
        title="접근 이력"
        description="AccessLogFilter가 모든 HTTP 요청 비동기 기록"
        actions={
          <Button variant="primary" size="sm" onClick={load} icon={<RefreshCw className="w-3.5 h-3.5" />}>
            새로고침
          </Button>
        }
      />

      {stats && (
        <div className="grid grid-cols-5 gap-3">
          <MetricCard label="전체 요청" value={stats.total} color="text-heading" />
          <MetricCard label="24시간 내" value={stats.last24h} color="text-label" />
          <MetricCard label="4xx (24h)" value={stats.error4xx} color="text-heading" />
          <MetricCard label="5xx (24h)" value={stats.error5xx} color="text-heading" />
          <MetricCard label="평균 응답(ms)" value={Math.round(stats.avgDurationMs)} color="text-heading" />
        </div>
      )}

      {stats && stats.topPaths.length > 0 && (
        <Card>
          <CardHeader className="px-4 pt-3 pb-2"><CardTitle className="text-xs text-label">호출 빈도 Top 10 (24시간)</CardTitle></CardHeader>
          <CardContent className="px-4 pb-4">
            <table className="w-full text-[11px]">
              <thead className="text-hint">
                <tr>
                  <th className="text-left py-1">경로</th>
                  <th className="text-right py-1 w-24">호출수</th>
                  <th className="text-right py-1 w-28">평균(ms)</th>
                </tr>
              </thead>
              <tbody>
                {stats.topPaths.map((p) => (
                  <tr key={p.path} className="border-t border-border">
                    <td className="py-1.5 text-heading font-mono text-[10px]">{p.path}</td>
                    <td className="py-1.5 text-right text-label font-bold">{p.count}</td>
                    <td className="py-1.5 text-right text-muted-foreground">{p.avg_ms}</td>
                  </tr>
                ))}
              </tbody>
            </table>
          </CardContent>
        </Card>
      )}

      {error && <div className="text-xs text-heading">에러: {error}</div>}

      {loading && <div className="flex items-center justify-center py-12 text-muted-foreground"><Loader2 className="w-5 h-5 animate-spin" /></div>}

      {!loading && (
        <Card>
          <CardContent className="p-0 overflow-x-auto">
            <table className="w-full text-xs">
              <thead className="bg-surface-overlay text-hint">
                <tr>
                  <th className="px-3 py-2 text-left">SN</th>
                  <th className="px-3 py-2 text-left">시각</th>
                  <th className="px-3 py-2 text-left">사용자</th>
                  <th className="px-3 py-2 text-left">메서드</th>
                  <th className="px-3 py-2 text-left">경로</th>
                  <th className="px-3 py-2 text-center">상태</th>
                  <th className="px-3 py-2 text-right">시간(ms)</th>
                  <th className="px-3 py-2 text-left">IP</th>
                </tr>
              </thead>
              <tbody>
                {items.length === 0 && <tr><td colSpan={8} className="px-3 py-8 text-center text-hint">접근 로그가 없습니다.</td></tr>}
                {items.map((it) => (
                  <tr key={it.accessSn} className="border-t border-border hover:bg-surface-overlay/50">
                    <td className="px-3 py-2 text-hint font-mono">{it.accessSn}</td>
                    <td className="px-3 py-2 text-muted-foreground text-[10px]">{formatDateTime(it.createdAt)}</td>
                    <td className="px-3 py-2 text-label">{it.userAcnt || '-'}</td>
                    <td className="px-3 py-2 text-heading font-mono">{it.httpMethod}</td>
                    <td className="px-3 py-2 text-heading font-mono text-[10px] max-w-md truncate">{it.requestPath}</td>
                    <td className="px-3 py-2 text-center">
                      <Badge intent={getHttpStatusIntent(it.statusCode)} size="sm">{it.statusCode}</Badge>
                    </td>
                    <td className="px-3 py-2 text-right text-muted-foreground">{it.durationMs}</td>
                    <td className="px-3 py-2 text-muted-foreground text-[10px]">{it.ipAddress || '-'}</td>
                  </tr>
                ))}
              </tbody>
            </table>
          </CardContent>
        </Card>
      )}
    </PageContainer>
  );
}

function MetricCard({ label, value, color }: { label: string; value: number; color: string }) {
  return (
    <Card>
      <CardContent className="p-4">
        <div className="text-[10px] text-hint">{label}</div>
        <div className={`text-2xl font-bold ${color} mt-1`}>{value.toLocaleString()}</div>
      </CardContent>
    </Card>
  );
}
