use-presence-toasts.ts

use-presence-toasts.tsapps/web/src/hooks/use-presence-toasts.tsraw ← hooks2,365 B← Back to the app
1"use client";
2 
3/**
4 * usePresenceToasts (TASK-0093, spec R5) — the join/leave TOASTS for a
5 * page's presence (the live region is the a11y channel; the toasts are the
6 * visual one). Controlled by the `presenceToastsEnabled` setting (ON by
7 * default) in the ui store.
8 *
9 *  - Join: "{name} joined" (a peer newly present — a `presence` frame for
10 *    a userId not in the prior roster).
11 *  - Leave: "{name} left" (a `presence-leave`, or a peer dropped from the
12 *    roster — the 90 s prune surfaces as their frame not re-asserting;
13 *    we key on the store roster diff, so the prune toast fires too).
14 *  - Edit START/STOP are NOT toasted (the live region covers them; toasts
15 *    for every start/stop would be noisy — the spec says toasts are
16 *    join/leave).
17 *
18 * Deterministic (no timers — toasts auto-dismiss on their own duration).
19 * Call once per page (the page view, next to `usePresenceAnnouncer`).
20 */
21import { useEffect, useRef } from "react";
22import { toast, useUiStore } from "@/stores/ui-store";
23import { useBlockPatchStore } from "@/stores/block-patch-store";
24import type { Presence } from "@/lib/types";
25 
26const EMPTY_PRESENCE: Record<string, Presence> = {};
27 
28export function usePresenceToasts(pageId: string | null, selfUserId?: string | null): void {
29  const enabled = useUiStore((s) => s.presenceToastsEnabled);
30  const prevRef = useRef<Map<string, string> | null>(null);
31 
32  useEffect(() => {
33    if (pageId === null || !enabled) {
34      prevRef.current = null;
35      return;
36    }
37    const feed = (state: { presence: Record<string, Record<string, Presence>> }): void => {
38      const roster = Object.values(state.presence[pageId] ?? EMPTY_PRESENCE);
39      const now = new Map<string, string>();
40      for (const p of roster) if (p.userId !== selfUserId) now.set(p.userId, p.name);
41      const prev = prevRef.current;
42      if (prev !== null) {
43        for (const [userId, name] of now) {
44          if (!prev.has(userId)) toast("info", `${name} joined`);
45        }
46        for (const [userId, name] of prev) {
47          if (!now.has(userId)) toast("info", `${name} left`);
48        }
49      }
50      prevRef.current = now;
51    };
52    feed(useBlockPatchStore.getState());
53    const off = useBlockPatchStore.subscribe(feed);
54    return () => {
55      off();
56      prevRef.current = null;
57    };
58  }, [pageId, enabled, selfUserId]);
59}
60