release: prepare v0.9.7

frontend/src/hooks/useAlertToasts.ts

@@ -0,0 +1,97 @@
+/**
+ * useAlertToasts — watches for new high-severity news items and surfaces toast notifications.
+ *
+ * Monitors the `news` data key for articles with risk_score >= 8.
+ * Maintains a seen-set to avoid duplicate toasts. Auto-dismisses after 5 seconds.
+ */
+import { useState, useEffect, useRef, useCallback } from 'react';
+import { useDataKey } from './useDataStore';
+import type { NewsArticle } from '@/types/dashboard';
+
+export interface ToastItem {
+  id: string;
+  title: string;
+  source: string;
+  risk_score: number;
+  lat: number;
+  lng: number;
+  timestamp: number; // when the toast was created
+}
+
+const TOAST_THRESHOLD = 8; // minimum risk_score to trigger a toast
+const MAX_VISIBLE = 3;
+const AUTO_DISMISS_MS = 5_000;
+
+export function useAlertToasts() {
+  const news = useDataKey('news') as NewsArticle[] | undefined;
+  const seenKeys = useRef(new Set<string>());
+  const [toasts, setToasts] = useState<ToastItem[]>([]);
+  const timersRef = useRef<Map<string, ReturnType<typeof setTimeout>>>(new Map());
+
+  // Auto-dismiss scheduled toasts
+  const scheduleDismiss = useCallback((id: string) => {
+    const timer = setTimeout(() => {
+      setToasts((prev) => prev.filter((t) => t.id !== id));
+      timersRef.current.delete(id);
+    }, AUTO_DISMISS_MS);
+    timersRef.current.set(id, timer);
+  }, []);
+
+  const dismiss = useCallback((id: string) => {
+    setToasts((prev) => prev.filter((t) => t.id !== id));
+    const timer = timersRef.current.get(id);
+    if (timer) {
+      clearTimeout(timer);
+      timersRef.current.delete(id);
+    }
+  }, []);
+
+  // Watch for new high-severity articles
+  useEffect(() => {
+    if (!news || !Array.isArray(news)) return;
+
+    const newToasts: ToastItem[] = [];
+
+    for (const article of news) {
+      if ((article.risk_score || 0) < TOAST_THRESHOLD) continue;
+
+      const key = `${article.title}|${article.source}`;
+      if (seenKeys.current.has(key)) continue;
+      seenKeys.current.add(key);
+
+      newToasts.push({
+        id: key,
+        title: article.title,
+        source: article.source,
+        risk_score: article.risk_score,
+        lat: article.lat || article.coords?.[0] || 0,
+        lng: article.lng || article.coords?.[1] || 0,
+        timestamp: Date.now(),
+      });
+    }
+
+    if (newToasts.length > 0) {
+      setToasts((prev) => {
+        // Merge new toasts, keep only MAX_VISIBLE most recent
+        const merged = [...newToasts, ...prev].slice(0, MAX_VISIBLE);
+        return merged;
+      });
+
+      // Schedule auto-dismiss for each new toast
+      for (const t of newToasts) {
+        scheduleDismiss(t.id);
+      }
+    }
+  }, [news, scheduleDismiss]);
+
+  // Cleanup timers on unmount
+  useEffect(() => {
+    return () => {
+      for (const timer of timersRef.current.values()) {
+        clearTimeout(timer);
+      }
+    };
+  }, []);
+
+  return { toasts, dismiss };
+}