import { useEffect, useState, useCallback } from 'react';
import { Loader2, RefreshCw, Activity, Database, Wifi } from 'lucide-react';
import { Card, CardContent } from '@shared/components/ui/card';
import { Badge } from '@shared/components/ui/badge';
import type { BadgeIntent } from '@lib/theme/variants';
import { fetchVesselAnalysis, type VesselAnalysisStats } from '@/services/vesselAnalysisApi';

const API_BASE = import.meta.env.VITE_API_URL ?? '/api';

interface PredictionHealth {
  status?: string;
  message?: string;
  snpdb?: boolean;
  kcgdb?: boolean;
  store?: { vessels?: number; points?: number; memory_mb?: number; targets?: number; permitted?: number };
}

interface AnalysisStatus {
  timestamp?: string;
  duration_sec?: number;
  vessel_count?: number;
  upserted?: number;
  error?: string | null;
  status?: string;
}

/**
 * 시스템 상태 대시보드 (관제 모니터 카드).
 *
 * 표시:
 *   1. 우리 백엔드 (kcg-ai-backend) 상태
 *   2. iran 백엔드 + Prediction (분석 사이클)
 *   3. 분석 결과 통계 (현재 시점)
 */
export function SystemStatusPanel() {
  const [stats, setStats] = useState<VesselAnalysisStats | null>(null);
  const [health, setHealth] = useState<PredictionHealth | null>(null);
  const [analysis, setAnalysis] = useState<AnalysisStatus | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState('');

  const load = useCallback(async () => {
    setLoading(true); setError('');
    try {
      const [vaRes, healthRes, statusRes] = await Promise.all([
        fetchVesselAnalysis().catch(() => null),
        fetch(`${API_BASE}/prediction/health`, { credentials: 'include' }).then((r) => r.json()).catch(() => null),
        fetch(`${API_BASE}/prediction/status`, { credentials: 'include' }).then((r) => r.json()).catch(() => null),
      ]);
      if (vaRes) setStats(vaRes.stats);
      if (healthRes) setHealth(healthRes);
      if (statusRes) setAnalysis(statusRes);
    } catch (e: unknown) {
      setError(e instanceof Error ? e.message : 'unknown');
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    load();
    // 30초마다 자동 새로고침
    const timer = setInterval(load, 30000);
    return () => clearInterval(timer);
  }, [load]);

  return (
    <Card>
      <CardContent className="p-4 space-y-3">
        <div className="flex items-center justify-between">
          <div className="text-sm font-bold text-heading flex items-center gap-2">
            <Activity className="w-4 h-4 text-cyan-400" /> 시스템 상태
            <span className="text-[9px] text-hint">(30초 자동 갱신)</span>
          </div>
          <button type="button" onClick={load}
                  className="p-1.5 rounded text-hint hover:text-blue-400 hover:bg-surface-overlay" title="새로고침">
            <RefreshCw className={`w-3.5 h-3.5 ${loading ? 'animate-spin' : ''}`} />
          </button>
        </div>

        {error && <div className="text-xs text-red-400">에러: {error}</div>}

        <div className="grid grid-cols-3 gap-3">
          {/* KCG 백엔드 */}
          <ServiceCard
            icon={<Database className="w-4 h-4" />}
            title="KCG AI Backend"
            status="UP"
            statusIntent="success"
            details={[
              ['포트', ':8080'],
              ['프로파일', 'local'],
              ['DB', 'kcgaidb'],
            ]}
          />

          {/* iran 백엔드 */}
          <ServiceCard
            icon={<Wifi className="w-4 h-4" />}
            title="iran 백엔드 (분석)"
            status={stats ? 'CONNECTED' : 'DISCONNECTED'}
            statusIntent={stats ? 'success' : 'critical'}
            details={[
              ['선박 분석', stats ? `${stats.total.toLocaleString()}건` : '-'],
              ['클러스터', stats ? `${stats.clusterCount}` : '-'],
              ['어구 그룹', stats ? `${stats.gearGroups}` : '-'],
            ]}
          />

          {/* Prediction */}
          <ServiceCard
            icon={<Activity className="w-4 h-4" />}
            title="Prediction Service"
            status={health?.status || 'UNKNOWN'}
            statusIntent={health?.status === 'ok' ? 'success' : 'warning'}
            details={[
              ['SNPDB', health?.snpdb === true ? 'OK' : '-'],
              ['KCGDB', health?.kcgdb === true ? 'OK' : '-'],
              ['최근 분석', analysis?.duration_sec ? `${analysis.duration_sec}초` : '-'],
            ]}
          />
        </div>

        {/* 위험도 분포 */}
        {stats && (
          <div className="grid grid-cols-4 gap-2">
            <RiskBox label="CRITICAL" value={stats.critical} color="text-red-400" />
            <RiskBox label="HIGH" value={stats.high} color="text-orange-400" />
            <RiskBox label="MEDIUM" value={stats.medium} color="text-yellow-400" />
            <RiskBox label="LOW" value={stats.low} color="text-blue-400" />
          </div>
        )}
      </CardContent>
    </Card>
  );
}

function ServiceCard({ icon, title, status, statusIntent, details }: {
  icon: React.ReactNode;
  title: string;
  status: string;
  statusIntent: BadgeIntent;
  details: [string, string][];
}) {
  return (
    <div className="bg-surface-overlay border border-border rounded p-3">
      <div className="flex items-center justify-between mb-2">
        <div className="flex items-center gap-1.5 text-xs text-heading font-medium">
          <span className="text-cyan-400">{icon}</span>
          {title}
        </div>
        <Badge intent={statusIntent} size="xs">
          {status}
        </Badge>
      </div>
      <div className="space-y-0.5">
        {details.map(([k, v]) => (
          <div key={k} className="flex justify-between text-[10px]">
            <span className="text-hint">{k}</span>
            <span className="text-label font-mono">{v}</span>
          </div>
        ))}
      </div>
    </div>
  );
}

function RiskBox({ label, value, color }: { label: string; value: number; color: string }) {
  return (
    <div className="px-3 py-2 rounded border border-border bg-surface-overlay">
      <div className="text-[9px] text-hint">{label}</div>
      <div className={`text-lg font-bold ${color}`}>{value.toLocaleString()}</div>
    </div>
  );
}