import { useEffect, useState } from 'react';
import { Server, Users, Gamepad2, Activity, Wifi, WifiOff } from 'lucide-react';
import { apiService, wsClient, type ServerStats } from '../api';

export default function Dashboard() {
  const [stats, setStats] = useState<ServerStats | null>(null);
  const [health, setHealth] = useState<any>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState('');

  useEffect(() => {
    loadData();
    const off = wsClient.on('status', (data: any) => {
      setStats(prev => prev ? {
        ...prev,
        node: { ...prev.node, rooms: data.rooms, players: data.players },
        cluster: data.nodes || prev.cluster,
      } : prev);
    });
    return () => off();
  }, []);

  async function loadData() {
    try {
      setLoading(true);
      const [statsData, healthData] = await Promise.all([
        apiService.getStats(),
        apiService.getHealth(),
      ]);
      setStats(statsData);
      setHealth(healthData);
      setError('');
    } catch (err: any) {
      setError('无法连接到服务器: ' + (err.message || '未知错误'));
    } finally {
      setLoading(false);
    }
  }

  if (loading) {
    return (
      <div className="flex items-center justify-center h-64">
        <div className="animate-spin w-8 h-8 border-2 border-mc-green border-t-transparent rounded-full" />
      </div>
    );
  }

  if (error) {
    return (
      <div className="card border-red-500/30">
        <div className="flex items-center gap-3 text-red-400">
          <WifiOff className="w-6 h-6" />
          <div>
            <h3 className="font-bold">连接失败</h3>
            <p className="text-sm mt-1">{error}</p>
          </div>
        </div>
        <button onClick={loadData} className="btn-primary mt-4">重试</button>
      </div>
    );
  }

  const statCards = [
    {
      label: '在线房间',
      value: stats?.node.rooms || 0,
      max: stats?.node.maxRooms || 100,
      icon: Gamepad2,
      color: 'text-green-400',
      bg: 'bg-green-400/10',
    },
    {
      label: '在线玩家',
      value: stats?.node.players || 0,
      icon: Users,
      color: 'text-blue-400',
      bg: 'bg-blue-400/10',
    },
    {
      label: '集群节点',
      value: stats?.cluster?.onlineNodes || 1,
      max: stats?.cluster?.totalNodes || 1,
      icon: Server,
      color: 'text-purple-400',
      bg: 'bg-purple-400/10',
    },
    {
      label: '服务状态',
      value: health?.status === 'ok' ? '正常' : '异常',
      icon: Activity,
      color: health?.status === 'ok' ? 'text-green-400' : 'text-red-400',
      bg: health?.status === 'ok' ? 'bg-green-400/10' : 'bg-red-400/10',
    },
  ];

  return (
    <div>
      <div className="flex items-center justify-between mb-8">
        <div>
          <h2 className="text-2xl font-bold">仪表盘</h2>
          <p className="text-gray-400 text-sm mt-1">FunMC 服务器运行状态总览</p>
        </div>
        <div className="flex items-center gap-2 text-sm">
          <Wifi className="w-4 h-4 text-green-400" />
          <span className="text-gray-400">节点: {stats?.node.name || 'N/A'}</span>
        </div>
      </div>

      {/* Stats Cards */}
      <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-6 mb-8">
        {statCards.map((card, i) => {
          const Icon = card.icon;
          return (
            <div key={i} className="card hover:border-mc-accent/60 transition-colors">
              <div className="flex items-center justify-between">
                <div>
                  <p className="text-gray-400 text-sm">{card.label}</p>
                  <p className={`text-3xl font-bold mt-2 ${card.color}`}>
                    {card.value}
                    {card.max !== undefined && (
                      <span className="text-sm text-gray-500 font-normal">/{card.max}</span>
                    )}
                  </p>
                </div>
                <div className={`w-12 h-12 rounded-xl ${card.bg} flex items-center justify-center`}>
                  <Icon className={`w-6 h-6 ${card.color}`} />
                </div>
              </div>
            </div>
          );
        })}
      </div>

      {/* Server Info */}
      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
        <div className="card">
          <h3 className="text-lg font-bold mb-4 flex items-center gap-2">
            <Server className="w-5 h-5 text-mc-green" />
            服务器信息
          </h3>
          <div className="space-y-3">
            <InfoRow label="节点ID" value={health?.nodeId || 'N/A'} />
            <InfoRow label="节点名称" value={health?.nodeName || 'N/A'} />
            <InfoRow label="运行模式" value={health?.isMaster ? '主节点' : '工作节点'} />
            <InfoRow label="运行时间" value={formatUptime(health?.uptime || 0)} />
            <InfoRow label="最大房间数" value={String(stats?.node.maxRooms || 0)} />
          </div>
        </div>

        {stats?.cluster && (
          <div className="card">
            <h3 className="text-lg font-bold mb-4 flex items-center gap-2">
              <Activity className="w-5 h-5 text-purple-400" />
              集群状态
            </h3>
            <div className="space-y-3">
              <InfoRow label="总节点数" value={String(stats.cluster.totalNodes)} />
              <InfoRow label="在线节点" value={String(stats.cluster.onlineNodes)} />
              <InfoRow label="总房间数" value={String(stats.cluster.totalRooms)} />
              <InfoRow label="总玩家数" value={String(stats.cluster.totalPlayers)} />
            </div>
          </div>
        )}
      </div>

      {/* Quick Guide */}
      <div className="card mt-6">
        <h3 className="text-lg font-bold mb-4">快速入门</h3>
        <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
          <StepCard
            step={1}
            title="创建房间"
            desc="在「创建房间」页面填写房间信息，启动你的Minecraft服务器"
          />
          <StepCard
            step={2}
            title="分享房间号"
            desc="将生成的房间号发给你的好友，他们可以通过房间号连接"
          />
          <StepCard
            step={3}
            title="开始游戏"
            desc="好友使用FunMC客户端连接到中继服务器，即可一起畅玩"
          />
        </div>
      </div>
    </div>
  );
}

function InfoRow({ label, value }: { label: string; value: string }) {
  return (
    <div className="flex items-center justify-between py-2 border-b border-mc-accent/10">
      <span className="text-gray-400 text-sm">{label}</span>
      <span className="text-white font-medium text-sm">{value}</span>
    </div>
  );
}

function StepCard({ step, title, desc }: { step: number; title: string; desc: string }) {
  return (
    <div className="bg-mc-dark/50 rounded-lg p-4 border border-mc-accent/10">
      <div className="w-8 h-8 rounded-full bg-mc-green/20 text-mc-green font-bold flex items-center justify-center text-sm mb-3">
        {step}
      </div>
      <h4 className="font-bold text-sm mb-1">{title}</h4>
      <p className="text-gray-400 text-xs">{desc}</p>
    </div>
  );
}

function formatUptime(seconds: number): string {
  const h = Math.floor(seconds / 3600);
  const m = Math.floor((seconds % 3600) / 60);
  const s = Math.floor(seconds % 60);
  if (h > 0) return `${h}时${m}分${s}秒`;
  if (m > 0) return `${m}分${s}秒`;
  return `${s}秒`;
}