feat(bookmarks): sort & group saved messages by room

The Saved Messages panel showed bookmarks in one fixed order (newest
save first) with no way to reorganize. Add a Newest / Oldest / By-room
segmented sort control to the panel toolbar. In "By room" mode the list
renders collapsible per-room sections, with groups ordered by their most
recently saved message so active rooms float to the top. The chosen sort
persists across panel opens via a localStorage-backed atom.

Ordering and grouping are pure functions in utils/bookmarks.ts
(sortBookmarks, groupBookmarksByRoom) with deterministic eventId
tie-breaks, covered by bookmarks.test.ts (9 tests). No change to the
bookmark data model, account-data schema, useBookmarks, or how bookmarks
are created; search still feeds the sorter/grouper unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

LOTUS_FEATURES.md

@@ -727,6 +727,8 @@ Redacted events display "This message has been deleted" along with the redaction
 - Bookmarks are stored in `io.lotus.bookmarks` account data, syncing across all devices
 - Maximum of 500 bookmarked entries
 - `BookmarksPanel.tsx` is a sidebar panel accessible from the navigation rail
+- Live-renders edits/redactions, text search, jump-to-message, and remove
+- **Sort & group**: a Newest / Oldest / By-room segmented control sorts the list; "By room" renders collapsible per-room sections (groups ordered by most-recent save). The chosen sort persists across panel opens (`cinny_bookmarks_sort_v1`). Ordering/grouping logic is pure and unit-tested in `src/app/utils/bookmarks.ts` (`bookmarks.test.ts`).
 - Hook: `src/app/hooks/useBookmarks.ts`
 
 ### Message Scheduling

src/app/features/bookmarks/BookmarksPanel.tsx

@@ -1,5 +1,7 @@
 import React, { ChangeEvent, ReactNode, useCallback, useEffect, useState } from 'react';
 import { Room } from 'matrix-js-sdk';
+import { useAtom } from 'jotai';
+import { atomWithStorage, createJSONStorage } from 'jotai/utils';
 import {
   Avatar,
   Box,
@@ -16,6 +18,11 @@ import {
 } from 'folds';
 import classNames from 'classnames';
 import { useBookmarks, Bookmark } from '../../hooks/useBookmarks';
+import {
+  BookmarkSort,
+  sortBookmarks,
+  groupBookmarksByRoom,
+} from '../../utils/bookmarks';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { useRoomEvent } from '../../hooks/useRoomEvent';
 import { MessageDeletedContent } from '../../components/message/content/FallbackContent';
@@ -41,6 +48,43 @@ function formatTimeAgo(ts: number): string {
   return new Date(ts).toLocaleDateString();
 }
 
+// Remember the last-chosen sort across panel opens (the panel unmounts on close).
+const bookmarkSortAtom = atomWithStorage<BookmarkSort>(
+  'cinny_bookmarks_sort_v1',
+  'newest',
+  createJSONStorage(() => localStorage),
+);
+
+const SORT_OPTIONS: { value: BookmarkSort; label: string }[] = [
+  { value: 'newest', label: 'Newest' },
+  { value: 'oldest', label: 'Oldest' },
+  { value: 'room', label: 'By room' },
+];
+
+// Segmented sort button — mirrors MediaGallery's tab styling for house consistency.
+function SortButton({
+  label,
+  active,
+  onClick,
+}: {
+  label: string;
+  active: boolean;
+  onClick: () => void;
+}) {
+  return (
+    <Button
+      size="300"
+      variant={active ? 'Primary' : 'Secondary'}
+      fill={active ? 'Solid' : 'Soft'}
+      radii="300"
+      aria-pressed={active}
+      onClick={onClick}
+    >
+      <Text size="B300">{label}</Text>
+    </Button>
+  );
+}
+
 type BookmarkItemProps = {
   bookmark: Bookmark;
   onJump: (roomId: string, eventId: string) => void;
@@ -147,6 +191,56 @@ function LiveBookmarkItem({ room, bookmark, onJump, onRemove }: LiveBookmarkItem
   return <BookmarkItem bookmark={bookmark} onJump={onJump} onRemove={onRemove} preview={preview} />;
 }
 
+type RoomGroupHeaderProps = {
+  roomId: string;
+  roomName: string;
+  count: number;
+  collapsed: boolean;
+  onToggle: () => void;
+};
+
+// Collapsible section header for the "By room" grouping. Uses the live room name
+// / avatar when the room is joined, falling back to the stored snapshot name.
+function RoomGroupHeader({ roomId, roomName, count, collapsed, onToggle }: RoomGroupHeaderProps) {
+  const mx = useMatrixClient();
+  const useAuthentication = useMediaAuthentication();
+  const room = mx.getRoom(roomId) ?? undefined;
+  const displayRoomName = room?.name ?? roomName;
+  const avatarUrl = room
+    ? (getRoomAvatarUrl(mx, room, 96, useAuthentication) ?? undefined)
+    : undefined;
+
+  return (
+    <Button
+      variant="Secondary"
+      fill="None"
+      size="300"
+      radii="300"
+      onClick={onToggle}
+      aria-expanded={!collapsed}
+      style={{ justifyContent: 'flex-start', padding: config.space.S200 }}
+    >
+      <Box grow="Yes" alignItems="Center" gap="200" style={{ minWidth: 0 }}>
+        <Icon size="100" src={collapsed ? Icons.ChevronRight : Icons.ChevronBottom} />
+        <Avatar size="200" radii="300">
+          <RoomAvatar
+            roomId={roomId}
+            src={avatarUrl}
+            alt={displayRoomName}
+            renderFallback={() => <Text size="H6">{nameInitials(displayRoomName)}</Text>}
+          />
+        </Avatar>
+        <Text size="T200" truncate style={{ flexGrow: 1, fontWeight: config.fontWeight.W600 }}>
+          {displayRoomName}
+        </Text>
+        <Text size="T200" priority="300" style={{ flexShrink: 0 }}>
+          {count}
+        </Text>
+      </Box>
+    </Button>
+  );
+}
+
 type BookmarksPanelProps = {
   onClose: () => void;
 };
@@ -156,6 +250,18 @@ export function BookmarksPanel({ onClose }: BookmarksPanelProps) {
   const { bookmarks, removeBookmark } = useBookmarks();
   const { navigateRoom } = useRoomNavigate();
   const [filter, setFilter] = useState('');
+  const [sort, setSort] = useAtom(bookmarkSortAtom);
+  // roomIds whose group section is collapsed (only relevant in "By room" mode).
+  const [collapsed, setCollapsed] = useState<Set<string>>(new Set());
+
+  const toggleGroup = useCallback((roomId: string) => {
+    setCollapsed((prev) => {
+      const next = new Set(prev);
+      if (next.has(roomId)) next.delete(roomId);
+      else next.add(roomId);
+      return next;
+    });
+  }, []);
 
   // Escape closes the panel (parity with the app's other overlays/drawers).
   useEffect(() => {
@@ -191,6 +297,35 @@ export function BookmarksPanel({ onClose }: BookmarksPanelProps) {
             bk.roomName.toLowerCase().includes(query),
         );
 
+  // Live render when the room is joined (useRoomEvent needs a non-null Room);
+  // otherwise fall back to the stored snapshot for rooms we've left. Shared by
+  // both the flat (newest/oldest) and grouped (by room) render paths.
+  const renderItem = useCallback(
+    (bk: Bookmark) => {
+      const room = mx.getRoom(bk.roomId);
+      return room ? (
+        <LiveBookmarkItem
+          key={bk.eventId}
+          room={room}
+          bookmark={bk}
+          onJump={handleJump}
+          onRemove={removeBookmark}
+        />
+      ) : (
+        <BookmarkItem
+          key={bk.eventId}
+          bookmark={bk}
+          onJump={handleJump}
+          onRemove={removeBookmark}
+        />
+      );
+    },
+    [mx, handleJump, removeBookmark],
+  );
+
+  const sortedItems = sort === 'room' ? filtered : sortBookmarks(filtered, sort);
+  const groups = sort === 'room' ? groupBookmarksByRoom(filtered) : [];
+
   return (
     <Box
       className={classNames(css.BookmarksPanel, ContainerColor({ variant: 'Background' }))}
@@ -237,11 +372,23 @@ export function BookmarksPanel({ onClose }: BookmarksPanelProps) {
           }
         />
         {bookmarks.length > 0 && (
-          <Text size="T200" priority="300">
-            {filtered.length === bookmarks.length
-              ? `${bookmarks.length} saved message${bookmarks.length !== 1 ? 's' : ''}`
-              : `${filtered.length} of ${bookmarks.length} messages`}
-          </Text>
+          <Box alignItems="Center" justifyContent="SpaceBetween" gap="200">
+            <Text size="T200" priority="300">
+              {filtered.length === bookmarks.length
+                ? `${bookmarks.length} saved message${bookmarks.length !== 1 ? 's' : ''}`
+                : `${filtered.length} of ${bookmarks.length} messages`}
+            </Text>
+            <Box as="div" role="group" aria-label="Sort saved messages" gap="100" shrink="No">
+              {SORT_OPTIONS.map((opt) => (
+                <SortButton
+                  key={opt.value}
+                  label={opt.label}
+                  active={sort === opt.value}
+                  onClick={() => setSort(opt.value)}
+                />
+              ))}
+            </Box>
+          </Box>
         )}
       </Box>
 
@@ -265,27 +412,23 @@ export function BookmarksPanel({ onClose }: BookmarksPanelProps) {
             </Box>
           ) : (
             <Box className={css.BookmarksContent} direction="Column" gap="200">
-              {filtered.map((bk) => {
-                // Live render when the room is joined (useRoomEvent needs a non-null Room);
-                // otherwise fall back to the stored snapshot for rooms we've left.
-                const room = mx.getRoom(bk.roomId);
-                return room ? (
-                  <LiveBookmarkItem
-                    key={bk.eventId}
-                    room={room}
-                    bookmark={bk}
-                    onJump={handleJump}
-                    onRemove={removeBookmark}
-                  />
-                ) : (
-                  <BookmarkItem
-                    key={bk.eventId}
-                    bookmark={bk}
-                    onJump={handleJump}
-                    onRemove={removeBookmark}
-                  />
-                );
-              })}
+              {sort === 'room'
+                ? groups.map((group) => {
+                    const isCollapsed = collapsed.has(group.roomId);
+                    return (
+                      <Box key={group.roomId} direction="Column" gap="200">
+                        <RoomGroupHeader
+                          roomId={group.roomId}
+                          roomName={group.roomName}
+                          count={group.items.length}
+                          collapsed={isCollapsed}
+                          onToggle={() => toggleGroup(group.roomId)}
+                        />
+                        {!isCollapsed && group.items.map((bk) => renderItem(bk))}
+                      </Box>
+                    );
+                  })
+                : sortedItems.map((bk) => renderItem(bk))}
             </Box>
           )}
         </Scroll>

src/app/utils/bookmarks.test.ts

@@ -0,0 +1,104 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { sortBookmarks, groupBookmarksByRoom } from './bookmarks';
+import { Bookmark } from '../hooks/useBookmarks';
+
+const bk = (eventId: string, roomId: string, savedAt: number, roomName = roomId): Bookmark => ({
+  eventId,
+  roomId,
+  savedAt,
+  roomName,
+  previewText: eventId,
+});
+
+test('sortBookmarks newest orders by savedAt descending', () => {
+  const input = [bk('a', 'r1', 100), bk('b', 'r1', 300), bk('c', 'r1', 200)];
+  const out = sortBookmarks(input, 'newest');
+  assert.deepEqual(
+    out.map((b) => b.eventId),
+    ['b', 'c', 'a'],
+  );
+});
+
+test('sortBookmarks oldest orders by savedAt ascending', () => {
+  const input = [bk('a', 'r1', 100), bk('b', 'r1', 300), bk('c', 'r1', 200)];
+  const out = sortBookmarks(input, 'oldest');
+  assert.deepEqual(
+    out.map((b) => b.eventId),
+    ['a', 'c', 'b'],
+  );
+});
+
+test('sortBookmarks room falls back to newest for a flat list', () => {
+  const input = [bk('a', 'r1', 100), bk('b', 'r2', 300)];
+  const out = sortBookmarks(input, 'room');
+  assert.deepEqual(
+    out.map((b) => b.eventId),
+    ['b', 'a'],
+  );
+});
+
+test('sortBookmarks breaks savedAt ties deterministically by eventId', () => {
+  const input = [bk('z', 'r1', 100), bk('a', 'r1', 100), bk('m', 'r1', 100)];
+  const newest = sortBookmarks(input, 'newest');
+  const oldest = sortBookmarks(input, 'oldest');
+  // Equal timestamps → ascending eventId in both directions.
+  assert.deepEqual(
+    newest.map((b) => b.eventId),
+    ['a', 'm', 'z'],
+  );
+  assert.deepEqual(
+    oldest.map((b) => b.eventId),
+    ['a', 'm', 'z'],
+  );
+});
+
+test('sortBookmarks does not mutate its input', () => {
+  const input = [bk('a', 'r1', 100), bk('b', 'r1', 300)];
+  const before = input.map((b) => b.eventId);
+  sortBookmarks(input, 'oldest');
+  assert.deepEqual(
+    input.map((b) => b.eventId),
+    before,
+  );
+});
+
+test('groupBookmarksByRoom buckets by room, newest-first within a group', () => {
+  const input = [
+    bk('a', 'r1', 100),
+    bk('b', 'r2', 500),
+    bk('c', 'r1', 300),
+    bk('d', 'r2', 200),
+  ];
+  const groups = groupBookmarksByRoom(input);
+  assert.equal(groups.length, 2);
+  const r1 = groups.find((g) => g.roomId === 'r1')!;
+  const r2 = groups.find((g) => g.roomId === 'r2')!;
+  assert.deepEqual(
+    r1.items.map((b) => b.eventId),
+    ['c', 'a'],
+  );
+  assert.deepEqual(
+    r2.items.map((b) => b.eventId),
+    ['b', 'd'],
+  );
+});
+
+test('groupBookmarksByRoom orders groups by most-recent save (active rooms first)', () => {
+  const input = [bk('a', 'r1', 100), bk('c', 'r1', 300), bk('b', 'r2', 500)];
+  // r2's newest is 500, r1's newest is 300 → r2 first.
+  const groups = groupBookmarksByRoom(input);
+  assert.deepEqual(
+    groups.map((g) => g.roomId),
+    ['r2', 'r1'],
+  );
+});
+
+test('groupBookmarksByRoom carries the stored room name', () => {
+  const groups = groupBookmarksByRoom([bk('a', 'r1', 100, 'General')]);
+  assert.equal(groups[0].roomName, 'General');
+});
+
+test('groupBookmarksByRoom returns empty for empty input', () => {
+  assert.deepEqual(groupBookmarksByRoom([]), []);
+});

src/app/utils/bookmarks.ts

@@ -0,0 +1,59 @@
+import { Bookmark } from '../hooks/useBookmarks';
+
+export type BookmarkSort = 'newest' | 'oldest' | 'room';
+
+export type BookmarkRoomGroup = {
+  roomId: string;
+  roomName: string;
+  items: Bookmark[];
+};
+
+// Deterministic newest-first comparator: most recently saved first, ties broken
+// by eventId so the order is stable regardless of input order (keeps tests and
+// re-renders from shuffling equal-timestamp entries).
+const byNewest = (a: Bookmark, b: Bookmark): number =>
+  b.savedAt - a.savedAt || (a.eventId < b.eventId ? -1 : a.eventId > b.eventId ? 1 : 0);
+
+/**
+ * Return a new array of bookmarks ordered per the selected sort. `room` has no
+ * flat ordering of its own (grouping is a render concern) and falls back to
+ * newest-first so callers can still render a sensible flat list if they want.
+ */
+export function sortBookmarks(bookmarks: Bookmark[], sort: BookmarkSort): Bookmark[] {
+  const copy = [...bookmarks];
+  if (sort === 'oldest') {
+    // Oldest-first is the reverse ordering; keep the same eventId tie-break shape.
+    return copy.sort(
+      (a, b) => a.savedAt - b.savedAt || (a.eventId < b.eventId ? -1 : a.eventId > b.eventId ? 1 : 0),
+    );
+  }
+  return copy.sort(byNewest);
+}
+
+/**
+ * Bucket bookmarks by room. Items within a group are newest-first; groups are
+ * ordered by each group's most-recently-saved bookmark (active rooms float up),
+ * with the room's stored name (the panel overrides with the live name when the
+ * room is joined). Deterministic tie-breaks keep the output stable.
+ */
+export function groupBookmarksByRoom(bookmarks: Bookmark[]): BookmarkRoomGroup[] {
+  const groups = new Map<string, BookmarkRoomGroup>();
+  bookmarks.forEach((bk) => {
+    const existing = groups.get(bk.roomId);
+    if (existing) {
+      existing.items.push(bk);
+    } else {
+      groups.set(bk.roomId, { roomId: bk.roomId, roomName: bk.roomName, items: [bk] });
+    }
+  });
+
+  const result = [...groups.values()];
+  result.forEach((group) => group.items.sort(byNewest));
+  // Order groups by their newest item's savedAt (desc); tie-break by roomId.
+  result.sort((a, b) => {
+    const diff = b.items[0].savedAt - a.items[0].savedAt;
+    if (diff !== 0) return diff;
+    return a.roomId < b.roomId ? -1 : a.roomId > b.roomId ? 1 : 0;
+  });
+  return result;
+}