feat: filter to ephemeral streams and particles

js/src/features/particles/particle-list-view.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useMemo, useRef } from "react";
+import { useEffect, useMemo, useRef, useState } from "react";
 import { useNavigate } from "react-router-dom";
 import beepSound from "../../../assets/sound.wav";
 import {
@@ -28,6 +28,8 @@ import { Progress } from "@/components/ui/progress";
 import { Small } from "@/components/ui/typography";
 import type { Particle, StreamProperties } from "@/api/types";
 import { useAutoplayStore } from "@/stores/autoplay-store";
+import { where, Timestamp } from "firebase/firestore";
+import { RECENCY_WINDOW_HOURS } from "@/lib/constants";
 
 function getParticleTypeIcon(particle: Particle): LucideIcon {
   switch (particle.type) {
@@ -257,7 +259,23 @@ export function ParticleListView({ path }: ParticleListViewProps) {
   const user = useAuthStore((s) => s.user);
   const visibilityScopes = useVisibilityScopes(user?.email, networkId);
 
-  const { children, isLoading } = useLiveParticleChildren(path, "last_child_created_at", "desc", visibilityScopes);
+  const [recencyCutoff, setRecencyCutoff] = useState(() => {
+    const d = new Date();
+    d.setHours(d.getHours() - RECENCY_WINDOW_HOURS);
+    return Timestamp.fromDate(d);
+  });
+
+  // Refresh the cutoff every hour so streams don't vanish/appear stale
+  useEffect(() => {
+    const interval = setInterval(() => {
+      const d = new Date();
+      d.setHours(d.getHours() - RECENCY_WINDOW_HOURS);
+      setRecencyCutoff(Timestamp.fromDate(d));
+    }, 60 * 60 * 1000);
+    return () => clearInterval(interval);
+  }, []);
+
+  const { children, isLoading } = useLiveParticleChildren(path, "last_child_created_at", "desc", visibilityScopes, undefined, undefined, where("last_child_created_at", ">=", recencyCutoff));
   const navigate = useNavigate();
 
   const streams = useMemo(

js/src/hooks/use-particle.ts

@@ -12,6 +12,7 @@ import {
   toFirestoreChildrenPath,
 } from "@/lib/particle-path";
 import { useQuery } from "@tanstack/react-query";
+import { QueryFieldFilterConstraint } from "firebase/firestore";
 
 interface UseLiveParticleResult {
   particle: Particle | null;
@@ -62,6 +63,7 @@ export function useLiveParticleChildren(
   visibilityScopes?: string[],
   onAdded?: (child: Particle) => void,
   onRemoved?: (child: Particle, updatedChildren: Particle[]) => void,
+  whereFilter?: QueryFieldFilterConstraint
 ): UseLiveParticleChildrenResult {
   const [children, setChildren] = useState<Particle[]>([]);
   const [isLoading, setIsLoading] = useState(true);
@@ -89,9 +91,11 @@ export function useLiveParticleChildren(
       orderDirection,
       onAdded,
       onRemoved,
+      whereFilter,
     );
 
     return unsubscribe;
+    // FIX: do we need to listen to more deps? Would that cause side effects that break behavior
   }, [collectionPath]);
 
   return { children, isLoading, error };

js/src/hooks/use-stream-playback.ts

@@ -1,9 +1,11 @@
-import { useCallback, useEffect, useEffectEvent, useMemo, useReducer, useRef } from "react";
+import { useCallback, useEffect, useEffectEvent, useMemo, useReducer, useRef, useState } from "react";
 import { useAuthStore } from "@/stores/auth-store";
 import type { Particle } from "@/api/types";
 import { useLiveParticleChildren } from "@/hooks/use-particle";
 import { toFirestoreDocPath, type ParticlePath } from "@/lib/particle-path";
 import { updateStreamPlaybackMarker } from "@/lib/firestore-particles";
+import { where, Timestamp } from "firebase/firestore";
+import { RECENCY_WINDOW_HOURS } from "@/lib/constants";
 
 // --- Playback reducer (ID-based) ---
 
@@ -112,8 +114,15 @@ export function useStreamPlayback(
     });
   });
 
+  const [recencyCutoff] = useState(() => {
+    const d = new Date();
+    d.setHours(d.getHours() - RECENCY_WINDOW_HOURS);
+    return Timestamp.fromDate(d);
+  });
+
   const { children } = useLiveParticleChildren(
     path, "created_at", "asc", undefined, onParticleAdded, onParticleRemoved,
+    where("created_at", ">=", recencyCutoff),
   );
 
   // Derive current index and particle from ID

js/src/lib/constants.ts

@@ -0,0 +1,2 @@
+/** How far back to look when filtering particles by recency. */
+export const RECENCY_WINDOW_HOURS = 24;

js/src/lib/firestore-particles.ts

@@ -16,6 +16,7 @@ import {
   type QueryDocumentSnapshot,
   type SnapshotOptions,
   type Unsubscribe,
+  QueryFieldFilterConstraint,
 } from "firebase/firestore";
 import { firestoreDb } from "@/firebase";
 import { isContainerType, ParticleSchema } from "@/api/types";
@@ -134,6 +135,7 @@ export function subscribeToParticleChildren(
   orderDirection: "asc" | "desc" = "desc",
   onAdded?: (child: Particle) => void,
   onRemoved?: (child: Particle, updatedChildren: Particle[]) => void,
+  whereFilter?: QueryFieldFilterConstraint,
 ): Unsubscribe {
   let q = query(typedCollection(collectionPath), orderBy(orderByField, orderDirection));
   if (visibilityScopes.length > 0) {
@@ -142,6 +144,9 @@ export function subscribeToParticleChildren(
       where("visible_to", "array-contains-any", visibilityScopes),
     );
   }
+  if (whereFilter) {
+    q = query(q, whereFilter);
+  }
   return onSnapshot(
     q,
     (snap) => {