feat: Add carousel functionality with scrolling and image handling in RoomTimeline

src/app/features/room/RoomTimeline.css.ts

@@ -1,5 +1,6 @@
+import { style } from '@vanilla-extract/css';
 import { RecipeVariants, recipe } from '@vanilla-extract/recipes';
-import { DefaultReset, config } from 'folds';
+import { DefaultReset, color, config, toRem } from 'folds';
 
 export const TimelineFloat = recipe({
   base: [
@@ -28,3 +29,81 @@ export const TimelineFloat = recipe({
 });
 
 export type TimelineFloatVariants = RecipeVariants<typeof TimelineFloat>;
+
+export const CarouselScroller = style([
+  DefaultReset,
+  {
+    display: 'flex',
+    gap: config.space.S200,
+    overflowX: 'auto',
+    overflowY: 'hidden',
+    paddingBottom: config.space.S100,
+    width: '100%',
+    cursor: 'grab',
+    userSelect: 'none',
+  },
+]);
+
+export const CarouselScrollerDragging = style([
+  DefaultReset,
+  {
+    cursor: 'grabbing',
+  },
+]);
+
+export const CarouselItem = style([
+  DefaultReset,
+  {
+    flex: '0 0 auto',
+    maxWidth: '100%',
+  },
+]);
+
+export const CarouselEdgeGradient = recipe({
+  base: [
+    DefaultReset,
+    {
+      position: 'absolute',
+      top: 0,
+      height: '100%',
+      width: toRem(16),
+      pointerEvents: 'none',
+      zIndex: 1,
+    },
+  ],
+  variants: {
+    position: {
+      Left: {
+        left: 0,
+        background: `linear-gradient(to right, ${color.Surface.Container}, rgba(116, 116, 116, 0))`,
+      },
+      Right: {
+        right: 0,
+        background: `linear-gradient(to left, ${color.Surface.Container}, rgba(116, 116, 116, 0))`,
+      },
+    },
+  },
+});
+
+export const CarouselScrollBtn = recipe({
+  base: [
+    DefaultReset,
+    {
+      position: 'absolute',
+      top: '50%',
+      zIndex: 2,
+    },
+  ],
+  variants: {
+    position: {
+      Left: {
+        left: 0,
+        transform: 'translate(-25%, -50%)',
+      },
+      Right: {
+        right: 0,
+        transform: 'translate(25%, -50%)',
+      },
+    },
+  },
+});

src/app/features/room/RoomTimeline.tsx

@@ -19,6 +19,7 @@ import {
   IContent,
   MatrixClient,
   MatrixEvent,
+  MsgType,
   Room,
   RoomEvent,
   RoomEventHandlerMap,
@@ -35,6 +36,7 @@ import {
   Chip,
   ContainerColor,
   Icon,
+  IconButton,
   Icons,
   Line,
   Scroll,
@@ -62,6 +64,7 @@ import {
   Time,
   MessageNotDecryptedContent,
   RedactedContent,
+  MImage,
   MSticker,
   ImageContent,
   EventContent,
@@ -135,6 +138,12 @@ import {
   useRoomWideEmbedFilters,
   combineEmbedFilters,
 } from '../../hooks/useRoomEmbedFilters';
+import {
+  IImageContent,
+  PAARROT_CAROUSEL_INDEX_PROPERTY_NAME,
+  PAARROT_CAROUSEL_TOTAL_PROPERTY_NAME,
+  PAARROT_CAROUSEL_UUID_PROPERTY_NAME,
+} from '../../../types/matrix/common';
 
 /** Information about a call member event for grouping */
 interface CallEventInfo {
@@ -147,6 +156,39 @@ interface CallEventInfo {
   mEvent: MatrixEvent;
 }
 
+interface CarouselEventMetadata {
+  uuid: string;
+  index: number;
+  total: number;
+  content: IImageContent;
+}
+
+interface CarouselRenderableEvent {
+  mEvent: MatrixEvent;
+  mEventId: string;
+  item: number;
+  content: IImageContent;
+  index: number;
+}
+
+const getCarouselEventMetadata = (mEvent: MatrixEvent): CarouselEventMetadata | undefined => {
+  if (mEvent.getType() !== MessageEvent.RoomMessage || mEvent.isRedacted()) {
+    return undefined;
+  }
+
+  const content = mEvent.getContent() as IImageContent;
+  const uuid = content[PAARROT_CAROUSEL_UUID_PROPERTY_NAME];
+  const index = content[PAARROT_CAROUSEL_INDEX_PROPERTY_NAME];
+  const total = content[PAARROT_CAROUSEL_TOTAL_PROPERTY_NAME];
+
+  if (content.msgtype !== MsgType.Image) return undefined;
+  if (typeof uuid !== 'string') return undefined;
+  if (typeof index !== 'number' || !Number.isInteger(index) || index < 0) return undefined;
+  if (typeof total !== 'number' || !Number.isInteger(total) || total < 1) return undefined;
+
+  return { uuid, index, total, content };
+};
+
 const TimelineFloat = as<'div', css.TimelineFloatVariants>(
   ({ position, className, ...props }, ref) => (
     <Box
@@ -170,6 +212,81 @@ const TimelineDivider = as<'div', { variant?: ContainerColor | 'Inherit' }>(
   )
 );
 
+type CarouselScrollerProps = {
+  children: React.ReactNode;
+};
+
+function CarouselScroller({ children }: CarouselScrollerProps) {
+  const {
+    scrollRef,
+    isDragging,
+    canScrollBack,
+    canScrollForward,
+    scrollBack,
+    scrollForward,
+    scrollProps,
+  } = useInertialHorizontalScroll();
+
+  return (
+    <Box style={{ position: 'relative' }}>
+      <Box
+        ref={scrollRef}
+        className={classNames(css.CarouselScroller, isDragging && css.CarouselScrollerDragging)}
+        {...scrollProps}
+      >
+        {children}
+      </Box>
+
+      {canScrollBack && (
+        <>
+          <div className={css.CarouselEdgeGradient({ position: 'Left' })} />
+          <IconButton
+            className={css.CarouselScrollBtn({ position: 'Left' })}
+            variant="Secondary"
+            radii="Pill"
+            size="300"
+            outlined
+            onClick={scrollBack}
+          >
+            <Icon size="300" src={Icons.ArrowLeft} />
+          </IconButton>
+        </>
+      )}
+
+      {canScrollForward && (
+        <>
+          <div className={css.CarouselEdgeGradient({ position: 'Right' })} />
+          <IconButton
+            className={css.CarouselScrollBtn({ position: 'Right' })}
+            variant="Primary"
+            radii="Pill"
+            size="300"
+            outlined
+            onClick={scrollForward}
+          >
+            <Icon size="300" src={Icons.ArrowRight} />
+          </IconButton>
+        </>
+      )}
+    </Box>
+  );
+}
+
+const getCarouselItemWidth = (content: IImageContent): string => {
+  const width = content.info?.w;
+  const height = content.info?.h;
+
+  if (!width || !height || height <= 0) {
+    return 'min(24rem, 72vw)';
+  }
+
+  const aspectRatio = width / height;
+  const baseHeightRem = 22;
+  const computedWidthRem = Math.max(11, Math.min(24, baseHeightRem * aspectRatio));
+
+  return `min(${computedWidthRem}rem, 72vw)`;
+};
+
 export const getLiveTimeline = (room: Room): EventTimeline =>
   room.getUnfilteredTimelineSet().getLiveTimeline();
 
@@ -1753,6 +1870,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
   let isPrevRendered = false;
   let newDivider = false;
   let dayDivider = false;
+  const groupedCarouselEventIds = new Set<string>();
 
   // Clear pending call events at the start of each render
   pendingCallEventsRef.current = [];
@@ -1874,6 +1992,110 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
     );
   };
 
+  const renderImageCarouselMessage = (
+    carouselEvents: CarouselRenderableEvent[],
+    mEventId: string,
+    mEvent: MatrixEvent,
+    item: number,
+    timelineSet: EventTimelineSet,
+    collapse: boolean
+  ): React.ReactNode => {
+    const reactionRelations = getEventReactions(timelineSet, mEventId);
+    const reactions = reactionRelations && reactionRelations.getSortedAnnotationsByKey();
+    const hasReactions = reactions && reactions.length > 0;
+    const { replyEventId, threadRootId } = mEvent;
+    const highlighted = focusItem?.index === item && focusItem.highlight;
+    const senderId = mEvent.getSender() ?? '';
+
+    const orderedCarouselEvents = [...carouselEvents].sort((a, b) => a.index - b.index);
+
+    return (
+      <Message
+        key={`carousel-${mEventId}`}
+        data-message-item={item}
+        data-message-id={mEventId}
+        room={room}
+        mEvent={mEvent}
+        messageSpacing={messageSpacing}
+        messageLayout={messageLayout}
+        collapse={collapse}
+        highlight={highlighted}
+        edit={editId === mEventId}
+        canDelete={canRedact || mEvent.getSender() === mx.getUserId()}
+        canSendReaction={canSendReaction}
+        canPinEvent={canPinEvent}
+        imagePackRooms={imagePackRooms}
+        relations={hasReactions ? reactionRelations : undefined}
+        onUserClick={handleUserClick}
+        onUsernameClick={handleUsernameClick}
+        onReplyClick={handleReplyClick}
+        onReactionToggle={handleReactionToggle}
+        onEditId={handleEdit}
+        reply={
+          replyEventId && (
+            <Reply
+              room={room}
+              timelineSet={timelineSet}
+              replyEventId={replyEventId}
+              threadRootId={threadRootId}
+              onClick={handleOpenReply}
+              onOpenThread={handleOpenThread}
+              getMemberPowerTag={getMemberPowerTag}
+              accessibleTagColors={accessiblePowerTagColors}
+              legacyUsernameColor={legacyUsernameColor || direct}
+            />
+          )
+        }
+        reactions={
+          reactionRelations && (
+            <Reactions
+              style={{ marginTop: config.space.S200 }}
+              room={room}
+              relations={reactionRelations}
+              mEventId={mEventId}
+              canSendReaction={canSendReaction}
+              onReactionToggle={handleReactionToggle}
+            />
+          )
+        }
+        hideReadReceipts={hideActivity}
+        showDeveloperTools={showDeveloperTools}
+        memberPowerTag={getMemberPowerTag(senderId)}
+        accessibleTagColors={accessiblePowerTagColors}
+        legacyUsernameColor={legacyUsernameColor || direct}
+        hour24Clock={hour24Clock}
+        dateFormatString={dateFormatString}
+      >
+        {mEvent.isRedacted() ? (
+          <RedactedContent reason={mEvent.getUnsigned().redacted_because?.content.reason} />
+        ) : (
+          <CarouselScroller>
+            {orderedCarouselEvents.map((carouselEvent) => (
+              <Box
+                key={carouselEvent.mEventId}
+                className={css.CarouselItem}
+                style={{ width: getCarouselItemWidth(carouselEvent.content) }}
+              >
+                <MImage
+                  content={carouselEvent.content}
+                  renderImageContent={(props) => (
+                    <ImageContent
+                      {...props}
+                      autoPlay={mediaAutoLoad}
+                      renderImage={(p) => <Image {...p} loading="lazy" />}
+                      renderViewer={(p) => <ImageViewer {...p} />}
+                    />
+                  )}
+                  outlined={messageLayout === MessageLayout.Bubble}
+                />
+              </Box>
+            ))}
+          </CarouselScroller>
+        )}
+      </Message>
+    );
+  };
+
   const eventRenderer = (item: number, index: number, allItems: number[]) => {
     const [eventTimeline, baseIndex] = getTimelineAndBaseIndex(timeline.linkedTimelines, item);
     if (!eventTimeline) return null;
@@ -1898,6 +2120,12 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
       dayDivider = prevEvent ? !inSameDay(prevEvent.getTs(), mEvent.getTs()) : false;
     }
 
+    if (groupedCarouselEventIds.has(mEventId)) {
+      prevEvent = mEvent;
+      isPrevRendered = true;
+      return null;
+    }
+
     const collapsed =
       isPrevRendered &&
       !dayDivider &&
@@ -1907,17 +2135,71 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
       prevEvent.getType() === mEvent.getType() &&
       minuteDifference(prevEvent.getTs(), mEvent.getTs()) < 2;
 
-    const rawEventJSX = reactionOrEditEvent(mEvent)
+    const getEventByItem = (
-      ? null
+      timelineItem: number
-      : renderMatrixEvent(
+    ): { event: MatrixEvent; eventId: string } | undefined => {
-          mEvent.getType(),
+      const [tm, bIndex] = getTimelineAndBaseIndex(timeline.linkedTimelines, timelineItem);
-          typeof mEvent.getStateKey() === 'string',
+      if (!tm) return undefined;
-          mEventId,
+
-          mEvent,
+      const event = getTimelineEvent(tm, getTimelineRelativeIndex(timelineItem, bIndex));
-          item,
+      const nextEventId = event?.getId();
-          timelineSet,
+      if (!event || !nextEventId) return undefined;
-          collapsed
+
-        );
+      return { event, eventId: nextEventId };
+    };
+
+    const carouselMetadata = getCarouselEventMetadata(mEvent);
+    const carouselEvents: CarouselRenderableEvent[] = [];
+    if (carouselMetadata && eventSender) {
+      carouselEvents.push({
+        mEvent,
+        mEventId,
+        item,
+        content: carouselMetadata.content,
+        index: carouselMetadata.index,
+      });
+
+      for (let nextIndex = index + 1; nextIndex < allItems.length; nextIndex += 1) {
+        const nextEvt = getEventByItem(allItems[nextIndex]);
+        if (!nextEvt) break;
+
+        const nextSender = nextEvt.event.getSender();
+        const nextMeta = getCarouselEventMetadata(nextEvt.event);
+
+        if (!nextMeta || nextSender !== eventSender || nextMeta.uuid !== carouselMetadata.uuid) {
+          break;
+        }
+
+        groupedCarouselEventIds.add(nextEvt.eventId);
+        carouselEvents.push({
+          mEvent: nextEvt.event,
+          mEventId: nextEvt.eventId,
+          item: allItems[nextIndex],
+          content: nextMeta.content,
+          index: nextMeta.index,
+        });
+
+        if (carouselEvents.length >= carouselMetadata.total) {
+          break;
+        }
+      }
+    }
+
+    let rawEventJSX: React.ReactNode = null;
+    if (!reactionOrEditEvent(mEvent)) {
+      rawEventJSX =
+        carouselEvents.length > 1
+          ? renderImageCarouselMessage(carouselEvents, mEventId, mEvent, item, timelineSet, collapsed)
+          : renderMatrixEvent(
+              mEvent.getType(),
+              typeof mEvent.getStateKey() === 'string',
+              mEventId,
+              mEvent,
+              item,
+              timelineSet,
+              collapsed
+            );
+    }
 
     // Check if this is a call event that should be grouped
     const isCallEventPending = rawEventJSX === ('CALL_EVENT_PENDING' as unknown as React.ReactNode);

src/types/matrix/common.ts

@@ -4,6 +4,9 @@ import { MsgType } from 'matrix-js-sdk';
 export const MATRIX_BLUR_HASH_PROPERTY_NAME = 'xyz.amorgan.blurhash';
 export const MATRIX_SPOILER_PROPERTY_NAME = 'page.codeberg.everypizza.msc4193.spoiler';
 export const MATRIX_SPOILER_REASON_PROPERTY_NAME = 'page.codeberg.everypizza.msc4193.spoiler.reason';
+export const PAARROT_CAROUSEL_UUID_PROPERTY_NAME = 'com.paarrot.carousel_uuid';
+export const PAARROT_CAROUSEL_INDEX_PROPERTY_NAME = 'com.paarrot.carousel_index';
+export const PAARROT_CAROUSEL_TOTAL_PROPERTY_NAME = 'com.paarrot.carousel_total';
 
 export type IImageInfo = {
   w?: number;
@@ -51,6 +54,9 @@ export type IImageContent = {
   file?: IEncryptedFile;
   [MATRIX_SPOILER_PROPERTY_NAME]?: boolean;
   [MATRIX_SPOILER_REASON_PROPERTY_NAME]?: string;
+  [PAARROT_CAROUSEL_UUID_PROPERTY_NAME]?: string;
+  [PAARROT_CAROUSEL_INDEX_PROPERTY_NAME]?: number;
+  [PAARROT_CAROUSEL_TOTAL_PROPERTY_NAME]?: number;
 };
 
 export type IVideoContent = {