feat(desktop): sync themes per community

desktop/src/app/App.tsx

@@ -18,6 +18,7 @@ import {
 } from "@/app/communityViewTransition";
 import { deriveShellRoute } from "@/app/AppShell.helpers";
 import { ThemeGrainientBackground } from "@/app/ThemeGrainientBackground";
+import { CommunityThemeController } from "@/shared/theme/CommunityThemeController";
 import { useReloadShortcut } from "@/app/useReloadShortcut";
 import { KnownAgentPubkeysProvider } from "@/features/agents/useKnownAgentPubkeys";
 import { useAppOnboardingState } from "@/features/onboarding/hooks";
@@ -546,6 +547,7 @@ function CommunityApp({
   if (appContent === null && (!transaction || isEnteringCurtain)) {
     appContent = communityApplied ? (
       <CommunityQueryProvider key={communityKey}>
+        <CommunityThemeController />
         <AppReady
           isCommunitySwitch={isCommunitySwitch}
           key={communityKey}

desktop/src/features/settings/lib/appearanceScopeCopy.test.mjs

@@ -0,0 +1,19 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { appearanceCommunityLabel } from "./appearanceScopeCopy.ts";
+
+test("labels the active community by name", () => {
+  assert.equal(appearanceCommunityLabel("Block Builders"), "Block Builders");
+});
+
+test("trims surrounding whitespace from the community name", () => {
+  assert.equal(appearanceCommunityLabel("  Buzz HQ  "), "Buzz HQ");
+});
+
+test("falls back to a generic label when no community is active", () => {
+  assert.equal(appearanceCommunityLabel(null), "this community");
+  assert.equal(appearanceCommunityLabel(undefined), "this community");
+  assert.equal(appearanceCommunityLabel(""), "this community");
+  assert.equal(appearanceCommunityLabel("   "), "this community");
+});

desktop/src/features/settings/lib/appearanceScopeCopy.ts

@@ -0,0 +1,20 @@
+/**
+ * Copy helper for the Appearance settings panel's per-community scoping.
+ *
+ * Theme, mode, and accent are saved per community (see
+ * `shared/theme/CommunityThemeController`), so the panel badges the community
+ * being customized. Kept as a pure function so the copy is unit-testable
+ * without rendering the settings tree.
+ */
+
+/**
+ * Display label for the community whose appearance is being edited.
+ * Falls back to a generic phrase when no community is active or the
+ * stored name is blank.
+ */
+export function appearanceCommunityLabel(
+  communityName: string | null | undefined,
+): string {
+  const trimmed = communityName?.trim();
+  return trimmed ? trimmed : "this community";
+}

desktop/src/features/settings/ui/SettingsPanels.tsx

@@ -37,7 +37,10 @@ import {
   type ThreadViewMode,
 } from "@/features/channels/lib/threadViewModePreference";
 import { cn } from "@/shared/lib/cn";
+import { useCommunities } from "@/features/communities/useCommunities";
+import { Badge } from "@/shared/ui/badge";
 import { Button } from "@/shared/ui/button";
+import { SectionHeader } from "@/shared/ui/PageHeader";
 import {
   DropdownMenu,
   DropdownMenuContent,
@@ -68,6 +71,7 @@ import {
   useThemePreviewVars,
   withAccentPreviewVars,
 } from "@/shared/theme/useThemePreviewVars";
+import { appearanceCommunityLabel } from "../lib/appearanceScopeCopy";
 import { ChannelTemplatesSettingsCard } from "./ChannelTemplatesSettingsCard";
 import { HarnessesSettingsPanel } from "./HarnessesSettingsPanel";
 import { ExperimentalFeaturesCard } from "./ExperimentalFeaturesCard";
@@ -420,6 +424,13 @@ function ThemeSettingsCard() {
     setFollowSystem,
   } = useTheme();
 
+  // Per-community scoping labels only earn their place when the user is
+  // actually in more than one community; with a single community there is
+  // nothing to disambiguate.
+  const { activeCommunity, communities } = useCommunities();
+  const showCommunityScope = communities.length > 1;
+  const communityLabel = appearanceCommunityLabel(activeCommunity?.name);
+
   // Buzz themes pin a neutral accent (GitHub black in light, white in dark),
   // so the accent picker is hidden while a Buzz theme is active. `themeName` is
   // the effective theme, so this also covers System mode resolving to Buzz.
@@ -520,6 +531,34 @@ function ThemeSettingsCard() {
         description="Choose a theme for Buzz."
       />
 
+      {/* Mode, theme, and accent are saved per community
+          (CommunityThemeController restores them on switch). When the user is
+          in multiple communities, a subheader with an inline badge names the
+          community being edited; with one community there is nothing to
+          disambiguate, so no scoping labels are shown. */}
+      {showCommunityScope ? (
+        <SectionHeader
+          className="mb-4"
+          title={
+            <span className="flex min-w-0 items-center gap-2">
+              Theme{" "}
+              <span className="font-normal text-muted-foreground">
+                (per community)
+              </span>
+              {activeCommunity ? (
+                <Badge
+                  className="max-w-56 shrink-0 font-medium normal-case tracking-normal"
+                  data-testid="appearance-community-badge"
+                  variant="outline"
+                >
+                  <span className="truncate">{communityLabel}</span>
+                </Badge>
+              ) : null}
+            </span>
+          }
+        />
+      ) : null}
+
       {/* Mode selector: System / Light / Dark */}
       <div className="mb-4 flex gap-2">
         {(
@@ -675,6 +714,11 @@ const THREAD_VIEW_MODE_OPTIONS: {
  */
 function ThreadLayoutSetting() {
   const threadViewMode = useThreadViewMode();
+  // The "(all communities)" qualifier contrasts with the per-community theme
+  // controls above; it's only meaningful when the user has multiple
+  // communities.
+  const { communities } = useCommunities();
+  const showCommunityScope = communities.length > 1;
   const activeOption =
     THREAD_VIEW_MODE_OPTIONS.find(
       (option) => option.value === threadViewMode,
@@ -684,7 +728,15 @@ function ThreadLayoutSetting() {
     <SettingsOptionGroup className="mt-8">
       <SettingsOptionRow>
         <div className="min-w-0">
-          <p className="text-sm font-medium">Thread layout</p>
+          <p className="text-sm font-medium">
+            Thread layout
+            {showCommunityScope ? (
+              <span className="font-normal text-muted-foreground">
+                {" "}
+                (all communities)
+              </span>
+            ) : null}
+          </p>
           <p className="text-sm font-normal text-muted-foreground">
             {activeOption.description}
           </p>

desktop/src/shared/constants/kinds.ts

@@ -46,6 +46,7 @@ export const KIND_CHANNEL_SECTIONS = 30078;
 export const KIND_CHANNEL_MUTES = 30078;
 export const KIND_CHANNEL_STARS = 30078;
 export const KIND_CHANNEL_SORT = 30078;
+export const KIND_COMMUNITY_THEME = 30078;
 // NIP-33 persona/team/managed-agent projection events (d-tag keyed). Published
 // backend-side as secrets-stripped snapshots; the inbound sync hook subscribes
 // to all three to patch local records. Mirror of buzz-core's KIND_PERSONA etc.

desktop/src/shared/theme/CommunityThemeController.tsx

@@ -0,0 +1,202 @@
+import { useCallback, useEffect, useLayoutEffect, useRef } from "react";
+import { useCommunities } from "@/features/communities/useCommunities";
+import { relayClient } from "@/shared/api/relayClient";
+import { useIdentityQuery } from "@/shared/api/hooks";
+import {
+  DEFAULT_COMMUNITY_THEME,
+  cacheAndApplyCommunityTheme,
+  clearCommunityThemeOutbox,
+  communityThemeApplyExpectation,
+  communityThemePersistenceAction,
+  hasMigratedCommunityTheme,
+  markCommunityThemeMigrated,
+  readCommunityThemeOutbox,
+  readCommunityThemePreference,
+  sameCommunityThemePreference,
+  writeCommunityThemeOutbox,
+  writeCommunityThemePreference,
+  type CommunityThemePreference,
+} from "./communityThemePreference";
+import {
+  CommunityThemeSyncManager,
+  shouldSeedCommunityTheme,
+  type RemoteCommunityTheme,
+} from "./communityThemeSync";
+import { useTheme } from "./ThemeProvider";
+
+export function CommunityThemeController() {
+  const { activeCommunity } = useCommunities();
+  const identity = useIdentityQuery();
+  const theme = useTheme();
+  const pubkey = identity.data?.pubkey;
+  const relayUrl = activeCommunity?.relayUrl;
+  const managerRef = useRef<CommunityThemeSyncManager | null>(null);
+  const scopeRef = useRef("");
+  const expectedAppliedRef = useRef<CommunityThemePreference | null>(null);
+  const scopedPreferenceRef = useRef<CommunityThemePreference | null>(null);
+  const lastRemoteRef = useRef({ createdAt: 0, eventId: "" });
+  const initialPreferenceRef = useRef<CommunityThemePreference>({
+    version: 1,
+    theme: theme.selectedThemeName as CommunityThemePreference["theme"],
+    accent: theme.accentColor,
+    followSystem: theme.followSystem,
+  });
+
+  const currentPreferenceRef = useRef<CommunityThemePreference>({
+    version: 1,
+    theme: theme.selectedThemeName as CommunityThemePreference["theme"],
+    accent: theme.accentColor,
+    followSystem: theme.followSystem,
+  });
+  currentPreferenceRef.current = {
+    version: 1,
+    theme: theme.selectedThemeName as CommunityThemePreference["theme"],
+    accent: theme.accentColor,
+    followSystem: theme.followSystem,
+  };
+
+  const applyPreference = useCallback(
+    (preference: CommunityThemePreference) => {
+      expectedAppliedRef.current = communityThemeApplyExpectation(
+        preference,
+        currentPreferenceRef.current,
+      );
+      theme.applyAppearance(preference);
+    },
+    [theme.applyAppearance],
+  );
+
+  useLayoutEffect(() => {
+    if (!pubkey || !relayUrl) return;
+    const local = readCommunityThemePreference(pubkey, relayUrl);
+    const dirty = readCommunityThemeOutbox(pubkey, relayUrl);
+    // Preserve the user's existing global appearance the first time this
+    // feature sees their current community. Later missing/malformed target
+    // records use the stable default so the previous community never leaks.
+    const fallback = hasMigratedCommunityTheme(pubkey)
+      ? DEFAULT_COMMUNITY_THEME
+      : initialPreferenceRef.current;
+    const scopedPreference = dirty ?? local ?? fallback;
+    scopedPreferenceRef.current = scopedPreference;
+    applyPreference(scopedPreference);
+  }, [pubkey, relayUrl, applyPreference]);
+
+  useEffect(() => {
+    if (!pubkey || !relayUrl) return;
+    const scope = `${pubkey}:${relayUrl}`;
+    scopeRef.current = scope;
+    lastRemoteRef.current = { createdAt: 0, eventId: "" };
+    const manager = new CommunityThemeSyncManager(pubkey, (acknowledged) => {
+      clearCommunityThemeOutbox(pubkey, relayUrl, acknowledged);
+    });
+    managerRef.current = manager;
+    const durablePending = readCommunityThemeOutbox(pubkey, relayUrl);
+    if (durablePending) manager.publish(durablePending);
+
+    const applyRemote = (remote: RemoteCommunityTheme) => {
+      if (scopeRef.current !== scope) return;
+      const dirty = readCommunityThemeOutbox(pubkey, relayUrl);
+      if (dirty) {
+        manager.publish(dirty);
+        return;
+      }
+      const last = lastRemoteRef.current;
+      if (
+        remote.createdAt < last.createdAt ||
+        (remote.createdAt === last.createdAt && remote.eventId <= last.eventId)
+      ) {
+        return;
+      }
+      lastRemoteRef.current = {
+        createdAt: remote.createdAt,
+        eventId: remote.eventId,
+      };
+      scopedPreferenceRef.current = remote.preference;
+      manager.cancelPendingPublish();
+      cacheAndApplyCommunityTheme(
+        pubkey,
+        relayUrl,
+        remote.preference,
+        applyPreference,
+      );
+    };
+
+    void manager.fetchRemote().then((result) => {
+      if (scopeRef.current !== scope) return;
+      if (result.status === "valid") {
+        applyRemote(result.remote);
+        markCommunityThemeMigrated(pubkey);
+      } else if (shouldSeedCommunityTheme(result)) {
+        const local =
+          readCommunityThemeOutbox(pubkey, relayUrl) ??
+          readCommunityThemePreference(pubkey, relayUrl) ??
+          scopedPreferenceRef.current ??
+          DEFAULT_COMMUNITY_THEME;
+        writeCommunityThemePreference(pubkey, relayUrl, local);
+        writeCommunityThemeOutbox(pubkey, relayUrl, local);
+        markCommunityThemeMigrated(pubkey);
+        manager.publish(local);
+      }
+      // Invalid/future or unavailable records use the already-applied local
+      // fallback without publishing over relay state we cannot safely read.
+    });
+
+    let unsubscribe: (() => Promise<void>) | null = null;
+    void manager.subscribe(applyRemote).then((dispose) => {
+      if (scopeRef.current !== scope) void dispose();
+      else unsubscribe = dispose;
+    });
+    const unsubscribeReconnect = relayClient.subscribeToReconnects(() => {
+      void manager.fetchRemote().then((result) => {
+        if (result.status === "valid") {
+          applyRemote(result.remote);
+          return;
+        }
+        if (result.status !== "absent") return;
+        const pending = readCommunityThemeOutbox(pubkey, relayUrl);
+        if (pending) manager.publish(pending);
+      });
+    });
+
+    return () => {
+      if (scopeRef.current === scope) scopeRef.current = "";
+      manager.destroy();
+      if (managerRef.current === manager) managerRef.current = null;
+      unsubscribeReconnect();
+      if (unsubscribe) void unsubscribe();
+    };
+  }, [pubkey, relayUrl, applyPreference]);
+
+  useEffect(() => {
+    if (!pubkey || !relayUrl) return;
+    const preference: CommunityThemePreference = {
+      version: 1,
+      theme: theme.selectedThemeName as CommunityThemePreference["theme"],
+      accent: theme.accentColor,
+      followSystem: theme.followSystem,
+    };
+    const persistenceAction = communityThemePersistenceAction(
+      expectedAppliedRef.current,
+      preference,
+    );
+    if (persistenceAction === "defer") return;
+    if (persistenceAction === "acknowledge") {
+      expectedAppliedRef.current = null;
+      return;
+    }
+    const stored = readCommunityThemePreference(pubkey, relayUrl);
+    if (stored && sameCommunityThemePreference(stored, preference)) return;
+    scopedPreferenceRef.current = preference;
+    if (!writeCommunityThemePreference(pubkey, relayUrl, preference)) return;
+    if (!writeCommunityThemeOutbox(pubkey, relayUrl, preference)) return;
+    managerRef.current?.publish(preference);
+  }, [
+    pubkey,
+    relayUrl,
+    theme.selectedThemeName,
+    theme.accentColor,
+    theme.followSystem,
+  ]);
+
+  return null;
+}