use virtual segments in event review timeline

web/src/components/timeline/EventReviewTimeline.tsx

@@ -1,9 +1,17 @@
-import { useEffect, useCallback, useMemo, useRef, RefObject } from "react";
-import EventSegment from "./EventSegment";
+import React, {
+  useEffect,
+  useMemo,
+  useRef,
+  RefObject,
+  useCallback,
+} from "react";
 import { useTimelineUtils } from "@/hooks/use-timeline-utils";
 import { ReviewSegment, ReviewSeverity } from "@/types/review";
 import ReviewTimeline from "./ReviewTimeline";
-import scrollIntoView from "scroll-into-view-if-needed";
+import {
+  VirtualizedEventSegments,
+  VirtualizedEventSegmentsRef,
+} from "./VirtualizedEventSegments";
 
 export type EventReviewTimelineProps = {
   segmentDuration: number;
@@ -56,6 +64,7 @@ export function EventReviewTimeline({
 }: EventReviewTimelineProps) {
   const internalTimelineRef = useRef<HTMLDivElement>(null);
   const selectedTimelineRef = timelineRef || internalTimelineRef;
+  const virtualizedSegmentsRef = useRef<VirtualizedEventSegmentsRef>(null);
 
   const timelineDuration = useMemo(
     () => timelineStart - timelineEnd,
@@ -73,79 +82,27 @@ export function EventReviewTimeline({
     [timelineStart, alignStartDateToTimeline],
   );
 
-  // Generate segments for the timeline
-  const generateSegments = useCallback(() => {
+  // Generate segment times for the timeline
+  const segmentTimes = useMemo(() => {
     const segmentCount = Math.ceil(timelineDuration / segmentDuration);
-
-    return Array.from({ length: segmentCount }, (_, index) => {
-      const segmentTime = timelineStartAligned - index * segmentDuration;
-
-      return (
-        <EventSegment
-          key={segmentTime + severityType}
-          events={events}
-          segmentDuration={segmentDuration}
-          segmentTime={segmentTime}
-          timestampSpread={timestampSpread}
-          showMinimap={showMinimap}
-          minimapStartTime={minimapStartTime}
-          minimapEndTime={minimapEndTime}
-          severityType={severityType}
-          contentRef={contentRef}
-          setHandlebarTime={setHandlebarTime}
-          dense={dense}
-        />
-      );
-    });
-    // we know that these deps are correct
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [
-    segmentDuration,
-    timestampSpread,
-    timelineStart,
-    timelineDuration,
-    showMinimap,
-    minimapStartTime,
-    minimapEndTime,
-    events,
-  ]);
-
-  const segments = useMemo(
-    () => generateSegments(),
-    // we know that these deps are correct
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-    [
-      segmentDuration,
-      timestampSpread,
-      timelineStart,
-      timelineDuration,
-      showMinimap,
-      minimapStartTime,
-      minimapEndTime,
-      events,
-    ],
+    return Array.from(
+      { length: segmentCount },
+      (_, index) => timelineStartAligned - index * segmentDuration,
     );
+  }, [timelineDuration, segmentDuration, timelineStartAligned]);
 
   useEffect(() => {
     if (
-      selectedTimelineRef.current &&
-      segments &&
       visibleTimestamps &&
-      visibleTimestamps?.length > 0 &&
-      !showMinimap
+      visibleTimestamps.length > 0 &&
+      !showMinimap &&
+      virtualizedSegmentsRef.current
     ) {
       const alignedVisibleTimestamps = visibleTimestamps.map(
         alignStartDateToTimeline,
       );
-      const element = selectedTimelineRef.current?.querySelector(
-        `[data-segment-id="${Math.max(...alignedVisibleTimestamps)}"]`,
-      );
-      if (element) {
-        scrollIntoView(element, {
-          scrollMode: "if-needed",
-          behavior: "smooth",
-        });
-      }
+
+      scrollToSegment(Math.max(...alignedVisibleTimestamps), true);
     }
     // don't scroll when segments update from unreviewed -> reviewed
     // we know that these deps are correct
@@ -155,8 +112,18 @@ export function EventReviewTimeline({
     showMinimap,
     alignStartDateToTimeline,
     visibleTimestamps,
+    segmentDuration,
   ]);
 
+  const scrollToSegment = useCallback(
+    (segmentTime: number, ifNeeded?: boolean) => {
+      if (virtualizedSegmentsRef.current) {
+        virtualizedSegmentsRef.current.scrollToSegment(segmentTime, ifNeeded);
+      }
+    },
+    [],
+  );
+
   return (
     <ReviewTimeline
       timelineRef={selectedTimelineRef}
@@ -174,8 +141,25 @@ export function EventReviewTimeline({
       setExportStartTime={setExportStartTime}
       setExportEndTime={setExportEndTime}
       dense={dense}
+      segments={segmentTimes}
+      scrollToSegment={scrollToSegment}
     >
-      {segments}
+      <VirtualizedEventSegments
+        ref={virtualizedSegmentsRef}
+        timelineRef={selectedTimelineRef}
+        segments={segmentTimes}
+        events={events}
+        segmentDuration={segmentDuration}
+        timestampSpread={timestampSpread}
+        showMinimap={showMinimap}
+        minimapStartTime={minimapStartTime}
+        minimapEndTime={minimapEndTime}
+        severityType={severityType}
+        contentRef={contentRef}
+        setHandlebarTime={setHandlebarTime}
+        dense={dense}
+        alignStartDateToTimeline={alignStartDateToTimeline}
+      />
     </ReviewTimeline>
   );
 }

web/src/components/timeline/ReviewTimeline.tsx

@@ -30,7 +30,9 @@ export type ReviewTimelineProps = {
   setExportEndTime?: React.Dispatch<React.SetStateAction<number>>;
   timelineCollapsed?: boolean;
   dense: boolean;
-  children: ReactNode[];
+  segments: number[];
+  scrollToSegment: (segmentTime: number, ifNeeded?: boolean) => void;
+  children: ReactNode;
 };
 
 export function ReviewTimeline({
@@ -51,6 +53,8 @@ export function ReviewTimeline({
   setExportEndTime,
   timelineCollapsed = false,
   dense,
+  segments,
+  scrollToSegment,
   children,
 }: ReviewTimelineProps) {
   const [isDraggingHandlebar, setIsDraggingHandlebar] = useState(false);
@@ -116,7 +120,8 @@ export function ReviewTimeline({
     setIsDragging: setIsDraggingHandlebar,
     draggableElementTimeRef: handlebarTimeRef,
     dense,
-    timelineSegments: children,
+    segments,
+    scrollToSegment,
   });
 
   const {
@@ -140,7 +145,8 @@ export function ReviewTimeline({
     draggableElementTimeRef: exportStartTimeRef,
     setDraggableElementPosition: setExportStartPosition,
     dense,
-    timelineSegments: children,
+    segments,
+    scrollToSegment,
   });
 
   const {
@@ -164,7 +170,8 @@ export function ReviewTimeline({
     draggableElementTimeRef: exportEndTimeRef,
     setDraggableElementPosition: setExportEndPosition,
     dense,
-    timelineSegments: children,
+    segments,
+    scrollToSegment,
   });
 
   const handleHandlebar = useCallback(
@@ -327,7 +334,7 @@ export function ReviewTimeline({
         <div className="pointer-events-none absolute inset-x-0 bottom-0 z-20 h-[30px] w-full bg-gradient-to-t from-secondary to-transparent"></div>
         {children}
       </div>
-      {children.length > 0 && (
+      {children && (
         <>
           {showHandlebar && (
             <div