fix(search): apply the date range to server results client-side

from_ts/to_ts are not Matrix filter fields; the server dropped them, so
the range only worked for the local encrypted-room search. Stop sending
them and post-filter server results by origin_server_ts with the same
inclusive predicate. Unit-tested; docs corrected.

Fixes #13

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

LOTUS_FEATURES.md

@@ -742,7 +742,7 @@ never leaves it.
 
 ### Message Search Date Range
 
-- The search panel accepts `from_ts` and `to_ts` values (epoch milliseconds) passed to the search API
+- The search panel accepts `from_ts` and `to_ts` values (epoch milliseconds); server results are filtered client-side by `origin_server_ts` (they are not Matrix filter fields), matching the local encrypted-room search
 - A chip shows the active date range with an **×** button to clear it
 
 ### Encrypted Search Cache (P4-8, opt-in)

src/app/features/message-search/MessageSearch.tsx

@@ -36,6 +36,7 @@ import { mDirectAtom } from '../../state/mDirectList';
 import { getStateEvent } from '../../utils/room';
 import { StateEvent } from '../../../types/matrix/room';
 import {
+  filterGroupsByDateRange,
   filterGroupsByMsgType,
   filterGroupsByPinned,
   MessageSearchParams,
@@ -316,12 +317,21 @@ export function MessageSearch({
     getNextPageParam: (lastPage) => lastPage.nextToken,
   });
 
-  // Shared client-side post-filter (msgtype + pinned) applied to BOTH the
-  // server results and the local/encrypted-cache results, so the filter chips
-  // narrow the whole UI consistently rather than only the server section.
+  // Shared client-side post-filter (date range + msgtype + pinned) applied to
+  // BOTH the server results and the local/encrypted-cache results, so the
+  // filter chips narrow the whole UI consistently rather than only the
+  // server section. The date range must be enforced here because the Matrix
+  // search API has no timestamp filter fields (see useMessageSearch.ts); the
+  // local/encrypted path already filters in-range before this runs, so this
+  // is a no-op there and only actually trims the server section.
   const applyResultFilters = useCallback(
     (allGroups: ResultGroup[]): ResultGroup[] => {
-      const byMsgType = filterGroupsByMsgType(allGroups, msgTypeFilters);
+      const inDateRange = filterGroupsByDateRange(
+        allGroups,
+        msgSearchParams.fromTs,
+        msgSearchParams.toTs,
+      );
+      const byMsgType = filterGroupsByMsgType(inDateRange, msgTypeFilters);
       if (!pinnedOnly) return byMsgType;
       // Build a per-room pinned-event lookup. Heavy Matrix reads stay here
       // (where `mx` is available); the pure helper only consumes the predicate.
@@ -343,7 +353,7 @@ export function MessageSearch({
       };
       return filterGroupsByPinned(byMsgType, pinnedOnly, isPinned);
     },
-    [msgTypeFilters, pinnedOnly, mx],
+    [msgSearchParams.fromTs, msgSearchParams.toTs, msgTypeFilters, pinnedOnly, mx],
   );
 
   const groups = useMemo(() => {

src/app/features/message-search/useMessageSearch.test.ts

@@ -1,6 +1,11 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
-import { filterGroupsByMsgType, filterGroupsByPinned, ResultGroup } from './useMessageSearch';
+import {
+  filterGroupsByDateRange,
+  filterGroupsByMsgType,
+  filterGroupsByPinned,
+  ResultGroup,
+} from './useMessageSearch';
 
 // Minimal ResultGroup/ResultItem fixtures — only the fields the filters read
 // (event.content.msgtype, event.event_id, group.roomId).
@@ -9,6 +14,11 @@ const item = (msgtype: string | undefined, eventId: string) => ({
   event: { event_id: eventId, content: msgtype === undefined ? {} : { msgtype } },
   context: {},
 });
+const tsItem = (eventId: string, ts: number) => ({
+  rank: 1,
+  event: { event_id: eventId, origin_server_ts: ts, content: {} },
+  context: {},
+});
 const mkGroups = (
   ...groups: { roomId: string; items: ReturnType<typeof item>[] }[]
 ): ResultGroup[] => groups as unknown as ResultGroup[];
@@ -48,6 +58,33 @@ test('filterGroupsByMsgType: ignores items with a non-string msgtype', () => {
   assert.equal(out[0].items[0].event.event_id, '$2');
 });
 
+test('filterGroupsByDateRange: no bounds returns groups unchanged', () => {
+  const groups = mkGroups({ roomId: '!r1', items: [tsItem('$1', 100)] });
+  assert.equal(filterGroupsByDateRange(groups, undefined, undefined), groups);
+});
+
+test('filterGroupsByDateRange: keeps only items within an inclusive range', () => {
+  const groups = mkGroups({
+    roomId: '!r1',
+    items: [tsItem('$1', 50), tsItem('$2', 100), tsItem('$3', 150), tsItem('$4', 200)],
+  });
+  const out = filterGroupsByDateRange(groups, 100, 150);
+  assert.deepEqual(
+    out[0].items.map((i) => i.event.event_id),
+    ['$2', '$3'],
+  );
+});
+
+test('filterGroupsByDateRange: drops groups left empty and supports one-sided bounds', () => {
+  const groups = mkGroups(
+    { roomId: '!r1', items: [tsItem('$1', 50)] },
+    { roomId: '!r2', items: [tsItem('$2', 500)] },
+  );
+  const out = filterGroupsByDateRange(groups, 100, undefined);
+  assert.equal(out.length, 1);
+  assert.equal(out[0].roomId, '!r2');
+});
+
 test('filterGroupsByPinned: disabled returns groups unchanged', () => {
   const groups = mkGroups({ roomId: '!r1', items: [item('m.text', '$1')] });
   assert.equal(

src/app/features/message-search/useMessageSearch.ts

@@ -71,6 +71,31 @@ export const filterGroupsByPinned = (
     .filter((group) => group.items.length > 0);
 };
 
+/** Inclusive-range predicate, mirrored from `inRange` in useLocalMessageSearch.ts. */
+export const inTsRange = (ts: number, fromTs?: number, toTs?: number): boolean =>
+  (fromTs === undefined || ts >= fromTs) && (toTs === undefined || ts <= toTs);
+
+/**
+ * Filter result groups to items whose `origin_server_ts` falls within
+ * [fromTs, toTs] (inclusive, either bound optional). The Matrix search API
+ * has no timestamp filter fields, so server results must be post-filtered
+ * here — the same predicate the local/encrypted search already applies.
+ * Now-empty groups are dropped.
+ */
+export const filterGroupsByDateRange = (
+  groups: ResultGroup[],
+  fromTs?: number,
+  toTs?: number,
+): ResultGroup[] => {
+  if (fromTs === undefined && toTs === undefined) return groups;
+  return groups
+    .map((group) => ({
+      ...group,
+      items: group.items.filter((item) => inTsRange(item.event.origin_server_ts, fromTs, toTs)),
+    }))
+    .filter((group) => group.items.length > 0);
+};
+
 const groupSearchResult = (results: ISearchResult[]): ResultGroup[] => {
   const groups: ResultGroup[] = [];
 
@@ -119,7 +144,9 @@ export type MessageSearchParams = {
 };
 export const useMessageSearch = (params: MessageSearchParams) => {
   const mx = useMatrixClient();
-  const { term, order, rooms, senders, fromTs, toTs, containsUrl } = params;
+  // fromTs/toTs are intentionally not sent to the server (see comment below) —
+  // callers post-filter results with filterGroupsByDateRange instead.
+  const { term, order, rooms, senders, containsUrl } = params;
 
   const searchMessages = useCallback(
     async (nextBatch?: string) => {
@@ -142,9 +169,10 @@ export const useMessageSearch = (params: MessageSearchParams) => {
               limit,
               rooms,
               senders,
-              // from_ts / to_ts and contains_url are valid Matrix spec fields not yet in SDK types
-              ...(fromTs !== undefined && { from_ts: fromTs }),
-              ...(toTs !== undefined && { to_ts: toTs }),
+              // `RoomEventFilter` has no timestamp bounds — from_ts/to_ts are not
+              // Matrix filter fields and the homeserver silently drops them, so the
+              // date range is instead enforced client-side (see filterGroupsByDateRange).
+              // contains_url is a valid spec field not yet in SDK types.
               ...(containsUrl !== undefined && { contains_url: containsUrl }),
               // eslint-disable-next-line @typescript-eslint/no-explicit-any
             } as any,
@@ -161,7 +189,7 @@ export const useMessageSearch = (params: MessageSearchParams) => {
       });
       return parseSearchResult(r);
     },
-    [mx, term, order, rooms, senders, fromTs, toTs, containsUrl],
+    [mx, term, order, rooms, senders, containsUrl],
   );
 
   return searchMessages;