初始化2

bj_power_dashboard/src/hooks/useDashboardData.ts

@@ -0,0 +1,49 @@
+import { useEffect, useRef, useState } from 'react';
+import { DashboardDataService } from '../services/dashboardService';
+import type { DashboardData } from '../types';
+
+export type DataMode = 'sse' | 'polling' | 'init';
+
+interface UseDashboardResult {
+  data: DashboardData | null;
+  mode: DataMode;
+  error: string | null;
+  retry: () => void;
+}
+
+/**
+ * 订阅看板数据。SSE 优先，失败自动降级为 HTTP 轮询；
+ * 数据加载失败时暴露 error 与 retry，供 UI 展示重试/错误状态。
+ */
+export function useDashboardData(): UseDashboardResult {
+  const [data, setData] = useState<DashboardData | null>(null);
+  const [mode, setMode] = useState<DataMode>('init');
+  const [error, setError] = useState<string | null>(null);
+  const serviceRef = useRef<DashboardDataService | null>(null);
+
+  useEffect(() => {
+    const svc = new DashboardDataService();
+    serviceRef.current = svc;
+    const offChange = svc.onChange((d) => {
+      setData(d);
+      if (d) setError(null);
+    });
+    const offMode = svc.onModeChange((m) => setMode(m));
+    const offError = svc.onError((msg) => setError(msg));
+    svc.start();
+    return () => {
+      offChange();
+      offMode();
+      offError();
+      svc.stop();
+      serviceRef.current = null;
+    };
+  }, []);
+
+  const retry = () => {
+    setError(null);
+    serviceRef.current?.retry();
+  };
+
+  return { data, mode, error, retry };
+}