const { data: overview } = useQuery<OverviewData>({
  queryKey: ["overview-data"],
  queryFn: fetchOverviewData,
  refetchInterval: 5000, // 每 5 秒刷新
});

interface SystemSettings {
  // 货币显示偏好
  currencyDisplay: "USD" | "CNY" | "EUR" | "JPY" | "GBP" | "HKD" | "TWD" | "KRW" | "SGD";
  
  // 全局视图开关
  allowGlobalUsageView: boolean; // 允许非管理员查看聚合数据
  
  // 时区配置
  timezone: string; // 例如 "Asia/Shanghai"
  
  // 模型统计计费源
  billingModelSource: "original" | "redirected";
}

# Redis 配置（用于会话追踪）
REDIS_URL=redis://localhost:6379

# 数据库连接
DATABASE_URL=postgresql://user:pass@localhost:5432/claude_code_hub

# 时区回退（当数据库设置无效时使用）
TZ=Asia/Shanghai

GET /api/leaderboard?period=daily&scope=user

interface OverviewData {
  concurrentSessions: number;        // 活跃会话数
  todayRequests: number;             // 今日请求数
  todayCost: number;                 // 今日成本（USD）
  avgResponseTime: number;           // 平均响应时间（毫秒）
  todayErrorRate: number;            // 错误率（百分比）
  yesterdaySamePeriodRequests: number;  // 昨日同时段请求数
  yesterdaySamePeriodCost: number;      // 昨日同时段成本
  yesterdaySamePeriodAvgResponseTime: number; // 昨日同时段平均响应时间
  recentMinuteRequests: number;      // 最近一分钟请求数（RPM）
}

interface ActivityStreamEntry {
  id: string;
  user: string;           // 用户名
  model: string;          // 使用的模型
  provider: string;       // 供应商名称
  latency: number;        // 响应延迟（毫秒）
  status: number;         // HTTP 状态码
  cost: number;           // 请求成本
  startTime: number;      // 开始时间戳
}

interface LeaderboardEntry {
  userId: number;
  userName: string;
  totalRequests: number;
  totalCost: number;
  totalTokens: number;
}

interface ProviderLeaderboardEntry {
  providerId: number;
  providerName: string;
  totalRequests: number;
  totalCost: number;
  totalTokens: number;
  successRate: number;
  avgTtfbMs: number;
  avgTokensPerSecond: number;
}

const timezone = await resolveSystemTimezone();
// 回退链：数据库设置 -> 环境变量 TZ -> UTC

sql`(${messageRequest.createdAt} AT TIME ZONE ${timezone})::date = 
    (CURRENT_TIMESTAMP AT TIME ZONE ${timezone})::date`

WITH time_series AS (
  SELECT generate_series(
    DATE_TRUNC('hour', TIMEZONE('Asia/Shanghai', NOW())),
    DATE_TRUNC('hour', TIMEZONE('Asia/Shanghai', NOW())) + INTERVAL '23 hours',
    '1 hour'::interval
  ) AS hour
),
stats AS (
  SELECT 
    DATE_TRUNC('hour', createdAt AT TIME ZONE 'Asia/Shanghai') AS hour,
    count(*) AS api_calls,
    COALESCE(sum(costUsd), 0) AS total_cost
  FROM message_request
  WHERE createdAt AT TIME ZONE 'Asia/Shanghai' >= DATE_TRUNC('day', TIMEZONE('Asia/Shanghai', NOW()))
  GROUP BY DATE_TRUNC('hour', createdAt AT TIME ZONE 'Asia/Shanghai')
)
SELECT 
  time_series.hour,
  COALESCE(stats.api_calls, 0) AS api_calls,
  COALESCE(stats.total_cost, 0) AS total_cost
FROM time_series
LEFT JOIN stats ON time_series.hour = stats.hour
ORDER BY time_series.hour

const [
  overviewResult,
  activityStreamResult,
  userRankingsResult,
] = await Promise.allSettled([
  getOverviewData(),
  findRecentActivityStream(20),
  findDailyLeaderboard(),
]);

// 提取数据，失败时返回 null
const overviewData =
  overviewResult.status === "fulfilled" && overviewResult.value.ok
    ? overviewResult.value.data
    : null;

static async getProviderSessionCount(providerId: number): Promise<number> {
  const redis = getRedisClient();
  if (!redis || redis.status !== "ready") return 0;  // 故障开放
  
  try {
    // ... 查询逻辑
  } catch (error) {
    logger.error("Failed to get provider session count", { error });
    return 0;  // 故障开放
  }
}