From f35aa384e5d5a02ac3878d34961c369334459d3b Mon Sep 17 00:00:00 2001
From: Ajay Bura <32841439+ajbura@users.noreply.github.com>
Date: Mon, 3 Nov 2025 15:29:51 +0530
Subject: [PATCH] thread view - WIP

---
 src/app/features/room/Room.tsx                | 18 ++++-
 src/app/features/room/RoomTimeline.tsx        |  5 ++
 .../features/room/thread-view/ThreadView.tsx  | 79 +++++++++++++++++++
 src/app/features/room/thread-view/index.tsx   |  1 +
 .../features/room/thread-view/styles.css.ts   | 21 +++++
 .../room/threads-menu/ThreadsTimeline.tsx     | 23 ++++--
 src/app/utils/room.ts                         |  1 +
 7 files changed, 137 insertions(+), 11 deletions(-)
 create mode 100644 src/app/features/room/thread-view/ThreadView.tsx
 create mode 100644 src/app/features/room/thread-view/index.tsx
 create mode 100644 src/app/features/room/thread-view/styles.css.ts

diff --git a/src/app/features/room/Room.tsx b/src/app/features/room/Room.tsx
index 24878d5e..47549fc7 100644
--- a/src/app/features/room/Room.tsx
+++ b/src/app/features/room/Room.tsx
@@ -13,6 +13,8 @@ import { useKeyDown } from '../../hooks/useKeyDown';
 import { markAsRead } from '../../utils/notifications';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { useRoomMembers } from '../../hooks/useRoomMembers';
+import { ThreadView } from './thread-view';
+import { useActiveThread } from '../../state/hooks/roomToActiveThread';
 
 export function Room() {
   const { eventId } = useParams();
@@ -25,6 +27,8 @@ export function Room() {
   const powerLevels = usePowerLevels(room);
   const members = useRoomMembers(mx, room.roomId);
 
+  const threadId = useActiveThread(room.roomId);
+
   useKeyDown(
     window,
     useCallback(
@@ -41,11 +45,19 @@ export function Room() {
     <PowerLevelsContextProvider value={powerLevels}>
       <Box grow="Yes">
         <RoomView room={room} eventId={eventId} />
-        {screenSize === ScreenSize.Desktop && isDrawer && (
+        {threadId ? (
           <>
-            <Line variant="Background" direction="Vertical" size="300" />
-            <MembersDrawer key={room.roomId} room={room} members={members} />
+            <Line variant="Surface" direction="Vertical" size="300" />
+            <ThreadView threadId={threadId} />
           </>
+        ) : (
+          screenSize === ScreenSize.Desktop &&
+          isDrawer && (
+            <>
+              <Line variant="Background" direction="Vertical" size="300" />
+              <MembersDrawer key={room.roomId} room={room} members={members} />
+            </>
+          )
         )}
       </Box>
     </PowerLevelsContextProvider>
diff --git a/src/app/features/room/RoomTimeline.tsx b/src/app/features/room/RoomTimeline.tsx
index 44696b0a..5ca2fc8e 100644
--- a/src/app/features/room/RoomTimeline.tsx
+++ b/src/app/features/room/RoomTimeline.tsx
@@ -138,6 +138,7 @@ import {
   getTimelinesEventsCount,
   timelineToEventsCount,
 } from './utils';
+import { useThreadSelector } from '../../state/hooks/roomToActiveThread';
 
 const TimelineFloat = as<'div', css.TimelineFloatVariants>(
   ({ position, className, ...props }, ref) => (
@@ -429,6 +430,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
   const spoilerClickHandler = useSpoilerClickHandler();
   const openUserRoomProfile = useOpenUserRoomProfile();
   const space = useSpaceOptionally();
+  const handleThreadClick = useThreadSelector(room.roomId);
 
   const imagePackRooms: Room[] = useImagePackRooms(room.roomId, roomToParents);
 
@@ -961,6 +963,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
     },
     [editor]
   );
+
   const { t } = useTranslation();
 
   const renderMatrixEvent = useMatrixEventRenderer<
@@ -1060,10 +1063,12 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
               <ThreadSelectorContainer>
                 <ThreadSelector
                   room={room}
+                  threadId={mEventId}
                   threadDetail={threadDetail}
                   hour24Clock={hour24Clock}
                   dateFormatString={dateFormatString}
                   outlined={messageLayout === MessageLayout.Bubble}
+                  onClick={handleThreadClick}
                 />
               </ThreadSelectorContainer>
             )}
diff --git a/src/app/features/room/thread-view/ThreadView.tsx b/src/app/features/room/thread-view/ThreadView.tsx
new file mode 100644
index 00000000..6b6f4642
--- /dev/null
+++ b/src/app/features/room/thread-view/ThreadView.tsx
@@ -0,0 +1,79 @@
+import React from 'react';
+import { Box, Icon, IconButton, Icons, Scroll, Text, Tooltip, TooltipProvider } from 'folds';
+import classNames from 'classnames';
+import FocusTrap from 'focus-trap-react';
+import { Page, PageHeader } from '../../../components/page';
+import * as css from './styles.css';
+import { useRoom } from '../../../hooks/useRoom';
+import { useThreadClose } from '../../../state/hooks/roomToActiveThread';
+import { ScreenSize, useScreenSizeContext } from '../../../hooks/useScreenSize';
+
+type ThreadViewProps = {
+  threadId: string;
+};
+export function ThreadView({ threadId }: ThreadViewProps) {
+  const room = useRoom();
+  const screenSize = useScreenSizeContext();
+  const floating = screenSize !== ScreenSize.Desktop;
+
+  const closeThread = useThreadClose(room.roomId);
+
+  const thread = room.getThread(threadId);
+  const events = thread?.events ?? [];
+
+  return (
+    <FocusTrap
+      paused={!floating}
+      focusTrapOptions={{
+        initialFocus: false,
+        clickOutsideDeactivates: true,
+        onDeactivate: floating ? closeThread : undefined,
+      }}
+    >
+      <Page
+        className={classNames(css.ThreadView, {
+          [css.ThreadViewFloating]: floating,
+        })}
+      >
+        <PageHeader>
+          <Box grow="Yes" alignItems="Center" gap="200">
+            <Box grow="Yes">
+              <Text size="H5" truncate>
+                Thread
+              </Text>
+            </Box>
+            <Box shrink="No" alignItems="Center">
+              <TooltipProvider
+                position="Bottom"
+                align="End"
+                offset={4}
+                tooltip={
+                  <Tooltip>
+                    <Text>Close</Text>
+                  </Tooltip>
+                }
+              >
+                {(triggerRef) => (
+                  <IconButton ref={triggerRef} variant="Surface" onClick={closeThread}>
+                    <Icon src={Icons.Cross} />
+                  </IconButton>
+                )}
+              </TooltipProvider>
+            </Box>
+          </Box>
+        </PageHeader>
+        <Box grow="Yes" direction="Column">
+          <Scroll visibility="Hover" hideTrack>
+            <div>
+              {events.map((mEvent) => (
+                <p style={{ padding: `8px 16px` }} key={mEvent.getId()}>
+                  {mEvent.sender?.name}: {mEvent.getContent().body}
+                </p>
+              ))}
+            </div>
+          </Scroll>
+        </Box>
+      </Page>
+    </FocusTrap>
+  );
+}
diff --git a/src/app/features/room/thread-view/index.tsx b/src/app/features/room/thread-view/index.tsx
new file mode 100644
index 00000000..6ba05aab
--- /dev/null
+++ b/src/app/features/room/thread-view/index.tsx
@@ -0,0 +1 @@
+export * from './ThreadView';
diff --git a/src/app/features/room/thread-view/styles.css.ts b/src/app/features/room/thread-view/styles.css.ts
new file mode 100644
index 00000000..fe66d49b
--- /dev/null
+++ b/src/app/features/room/thread-view/styles.css.ts
@@ -0,0 +1,21 @@
+import { style } from '@vanilla-extract/css';
+import { config, toRem } from 'folds';
+
+export const ThreadView = style({
+  width: toRem(456),
+  flexShrink: 0,
+  flexGrow: 0,
+});
+
+export const ThreadViewFloating = style({
+  position: 'absolute',
+  right: 0,
+  top: 0,
+  bottom: 0,
+  zIndex: 1,
+
+  maxWidth: toRem(456),
+  flexShrink: 1,
+  width: '100vw',
+  boxShadow: config.shadow.E400,
+});
diff --git a/src/app/features/room/threads-menu/ThreadsTimeline.tsx b/src/app/features/room/threads-menu/ThreadsTimeline.tsx
index d6cbb62d..0e28f97d 100644
--- a/src/app/features/room/threads-menu/ThreadsTimeline.tsx
+++ b/src/app/features/room/threads-menu/ThreadsTimeline.tsx
@@ -77,7 +77,7 @@ import * as css from './ThreadsMenu.css';
 type ThreadMessageProps = {
   room: Room;
   event: MatrixEvent;
-  renderContent: RenderMatrixEvent<[MatrixEvent, string, GetContentCallback]>;
+  renderContent: RenderMatrixEvent<[string, MatrixEvent, string, GetContentCallback]>;
   onOpen: (roomId: string, eventId: string) => void;
   getMemberPowerTag: GetMemberPowerTag;
   accessibleTagColors: Map<string, string>;
@@ -134,6 +134,10 @@ function ThreadMessage({
 
   const usernameColor = legacyUsernameColor ? colorMXID(sender) : tagColor;
 
+  const mEventId = event.getId();
+
+  if (!mEventId) return null;
+
   return (
     <ModernLayout
       before={
@@ -179,7 +183,7 @@ function ThreadMessage({
           legacyUsernameColor={legacyUsernameColor}
         />
       )}
-      {renderContent(event.getType(), false, event, displayName, getContent)}
+      {renderContent(event.getType(), false, mEventId, event, displayName, getContent)}
     </ModernLayout>
   );
 }
@@ -238,9 +242,11 @@ export function ThreadsTimeline({ timelines, requestClose }: ThreadsTimelineProp
     [mx, room, linkifyOpts, mentionClickHandler, spoilerClickHandler, useAuthentication]
   );
 
-  const renderMatrixEvent = useMatrixEventRenderer<[MatrixEvent, string, GetContentCallback]>(
+  const renderMatrixEvent = useMatrixEventRenderer<
+    [string, MatrixEvent, string, GetContentCallback]
+  >(
     {
-      [MessageEvent.RoomMessage]: (event, displayName, getContent) => {
+      [MessageEvent.RoomMessage]: (eventId, event, displayName, getContent) => {
         if (event.isRedacted()) {
           return <RedactedContent reason={event.getUnsigned().redacted_because?.content.reason} />;
         }
@@ -265,6 +271,7 @@ export function ThreadsTimeline({ timelines, requestClose }: ThreadsTimelineProp
               <ThreadSelectorContainer>
                 <ThreadSelector
                   room={room}
+                  threadId={eventId}
                   threadDetail={threadDetail}
                   outlined
                   hour24Clock={hour24Clock}
@@ -275,8 +282,7 @@ export function ThreadsTimeline({ timelines, requestClose }: ThreadsTimelineProp
           </>
         );
       },
-      [MessageEvent.RoomMessageEncrypted]: (mEvent, displayName) => {
-        const eventId = mEvent.getId()!;
+      [MessageEvent.RoomMessageEncrypted]: (eventId, mEvent, displayName) => {
         const evtTimeline = room.getTimelineForEvent(eventId);
 
         return (
@@ -333,7 +339,7 @@ export function ThreadsTimeline({ timelines, requestClose }: ThreadsTimelineProp
           </EncryptedContent>
         );
       },
-      [MessageEvent.Sticker]: (event, displayName, getContent) => {
+      [MessageEvent.Sticker]: (eventId, event, displayName, getContent) => {
         if (event.isRedacted()) {
           return <RedactedContent reason={event.getUnsigned().redacted_because?.content.reason} />;
         }
@@ -357,6 +363,7 @@ export function ThreadsTimeline({ timelines, requestClose }: ThreadsTimelineProp
               <ThreadSelectorContainer>
                 <ThreadSelector
                   room={room}
+                  threadId={eventId}
                   threadDetail={threadDetail}
                   outlined
                   hour24Clock={hour24Clock}
@@ -369,7 +376,7 @@ export function ThreadsTimeline({ timelines, requestClose }: ThreadsTimelineProp
       },
     },
     undefined,
-    (event) => {
+    (eventId, event) => {
       if (event.isRedacted()) {
         return <RedactedContent reason={event.getUnsigned().redacted_because?.content.reason} />;
       }
diff --git a/src/app/utils/room.ts b/src/app/utils/room.ts
index e80edb20..f7b8f017 100644
--- a/src/app/utils/room.ts
+++ b/src/app/utils/room.ts
@@ -203,6 +203,7 @@ export const isNotificationEvent = (mEvent: MatrixEvent) => {
 
   if (mEvent.isRedacted()) return false;
   if (mEvent.getRelation()?.rel_type === 'm.replace') return false;
+  if (mEvent.getRelation()?.rel_type === 'm.thread') return false;
 
   return true;
 };