Merge pull request #324 from simonorzel26/feat/refactor-timeline

feat(web): timeline refactor and horizontal + vertical scrolling

11 files changed, 1217 insertions, 0 deletions

diff --git a/apps/web/src/components/editor/timeline/timeline-action-handlers.tsx b/apps/web/src/components/editor/timeline/timeline-action-handlers.tsx
new file mode 100644
index 00000000..0e7323d3
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-action-handlers.tsx
@@ -0,0 +1,178 @@
+import { useMemo } from "react";
+import { toast } from "sonner";
+import { useTimelineStore } from "@/stores/timeline-store";
+import { usePlaybackStore } from "@/stores/playback-store";
+
+export function useTimelineActionHandlers() {
+	const {
+		tracks,
+		addElementToTrack,
+		removeElementFromTrack,
+		selectedElements,
+		clearSelectedElements,
+		splitElement,
+		splitAndKeepLeft,
+		splitAndKeepRight,
+		separateAudio,
+	} = useTimelineStore();
+	const { currentTime } = usePlaybackStore();
+
+	// Create optimized lookup maps for O(1) access instead of O(n) find operations
+	const trackMap = useMemo(() => {
+		const map = new Map();
+		tracks.forEach((track) => {
+			map.set(track.id, track);
+			// Also create element lookup for this track
+			const elementMap = new Map();
+			track.elements.forEach((element) => {
+				elementMap.set(element.id, element);
+			});
+			map.set(`${track.id}_elements`, elementMap);
+		});
+		return map;
+	}, [tracks]);
+
+	// Helper function for O(1) track/element lookup
+	const findTrackAndElement = (trackId: string, elementId: string) => {
+		const track = trackMap.get(trackId);
+		const elementMap = trackMap.get(`${trackId}_elements`);
+		const element = elementMap?.get(elementId);
+		return { track, element };
+	};
+
+	// Action handlers for toolbar
+	const handleSplitSelected = () => {
+		if (selectedElements.length === 0) {
+			toast.error("No elements selected");
+			return;
+		}
+		let splitCount = 0;
+		selectedElements.forEach(({ trackId, elementId }) => {
+			const { track, element } = findTrackAndElement(trackId, elementId);
+			if (element && track) {
+				const effectiveStart = element.startTime;
+				const effectiveEnd =
+					element.startTime +
+					(element.duration - element.trimStart - element.trimEnd);
+
+				if (currentTime > effectiveStart && currentTime < effectiveEnd) {
+					const newElementId = splitElement(trackId, elementId, currentTime);
+					if (newElementId) splitCount++;
+				}
+			}
+		});
+		if (splitCount === 0) {
+			toast.error("Playhead must be within selected elements to split");
+		}
+	};
+
+	const handleDuplicateSelected = () => {
+		if (selectedElements.length === 0) {
+			toast.error("No elements selected");
+			return;
+		}
+		const canDuplicate = selectedElements.length === 1;
+		if (!canDuplicate) return;
+
+		selectedElements.forEach(({ trackId, elementId }) => {
+			const { element } = findTrackAndElement(trackId, elementId);
+
+			if (element) {
+				const newStartTime =
+					element.startTime +
+					(element.duration - element.trimStart - element.trimEnd) +
+					0.1;
+
+				// Create element without id (will be generated by store)
+				const { id, ...elementWithoutId } = element;
+
+				addElementToTrack(trackId, {
+					...elementWithoutId,
+					startTime: newStartTime,
+				});
+
+				// We can't predict the new id, so just clear selection for now
+				// TODO: addElementToTrack could return the new element id
+			}
+		});
+
+		clearSelectedElements();
+	};
+
+	const handleFreezeSelected = () => {
+		toast.info("Freeze frame functionality coming soon!");
+	};
+
+	const handleSplitAndKeepLeft = () => {
+		if (selectedElements.length !== 1) {
+			toast.error("Select exactly one element");
+			return;
+		}
+		const { trackId, elementId } = selectedElements[0];
+		const { element } = findTrackAndElement(trackId, elementId);
+		if (!element) return;
+		const effectiveStart = element.startTime;
+		const effectiveEnd =
+			element.startTime +
+			(element.duration - element.trimStart - element.trimEnd);
+		if (currentTime <= effectiveStart || currentTime >= effectiveEnd) {
+			toast.error("Playhead must be within selected element");
+			return;
+		}
+		splitAndKeepLeft(trackId, elementId, currentTime);
+	};
+
+	const handleSplitAndKeepRight = () => {
+		if (selectedElements.length !== 1) {
+			toast.error("Select exactly one element");
+			return;
+		}
+		const { trackId, elementId } = selectedElements[0];
+		const { element } = findTrackAndElement(trackId, elementId);
+		if (!element) return;
+		const effectiveStart = element.startTime;
+		const effectiveEnd =
+			element.startTime +
+			(element.duration - element.trimStart - element.trimEnd);
+		if (currentTime <= effectiveStart || currentTime >= effectiveEnd) {
+			toast.error("Playhead must be within selected element");
+			return;
+		}
+		splitAndKeepRight(trackId, elementId, currentTime);
+	};
+
+	const handleSeparateAudio = () => {
+		if (selectedElements.length !== 1) {
+			toast.error("Select exactly one media element to separate audio");
+			return;
+		}
+		const { trackId, elementId } = selectedElements[0];
+		const { track } = findTrackAndElement(trackId, elementId);
+		if (!track || track.type !== "media") {
+			toast.error("Select a media element to separate audio");
+			return;
+		}
+		separateAudio(trackId, elementId);
+	};
+
+	const handleDeleteSelected = () => {
+		if (selectedElements.length === 0) {
+			toast.error("No elements selected");
+			return;
+		}
+		selectedElements.forEach(({ trackId, elementId }) => {
+			removeElementFromTrack(trackId, elementId);
+		});
+		clearSelectedElements();
+	};
+
+	return {
+		handleSplitSelected,
+		handleDuplicateSelected,
+		handleFreezeSelected,
+		handleSplitAndKeepLeft,
+		handleSplitAndKeepRight,
+		handleSeparateAudio,
+		handleDeleteSelected,
+	};
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-content-click.tsx b/apps/web/src/components/editor/timeline/timeline-content-click.tsx
new file mode 100644
index 00000000..7f4676c7
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-content-click.tsx
@@ -0,0 +1,118 @@
+import { useCallback } from "react";
+import { useProjectStore } from "@/stores/project-store";
+import {
+	TIMELINE_CONSTANTS,
+	snapTimeToFrame,
+} from "@/constants/timeline-constants";
+
+export interface TimelineContentClickProps {
+	duration: number;
+	zoomLevel: number;
+	seek: (time: number) => void;
+	rulerScrollRef: React.RefObject<HTMLDivElement>;
+	tracksScrollRef: React.RefObject<HTMLDivElement>;
+	clearSelectedElements: () => void;
+	isSelecting: boolean;
+	justFinishedSelecting: boolean;
+	playheadRef: React.RefObject<HTMLDivElement>;
+}
+
+export function useTimelineContentClick({
+	duration,
+	zoomLevel,
+	seek,
+	rulerScrollRef,
+	tracksScrollRef,
+	clearSelectedElements,
+	isSelecting,
+	justFinishedSelecting,
+	playheadRef,
+}: TimelineContentClickProps) {
+	const { activeProject } = useProjectStore();
+
+	// Timeline content click to seek handler
+	const handleTimelineContentClick = useCallback(
+		(e: React.MouseEvent) => {
+			// Don't seek if this was a selection box operation
+			if (isSelecting || justFinishedSelecting) {
+				return;
+			}
+
+			// Don't seek if clicking on timeline elements, but still deselect
+			if ((e.target as HTMLElement).closest(".timeline-element")) {
+				return;
+			}
+
+			// Don't seek if clicking on playhead
+			if (playheadRef.current?.contains(e.target as Node)) {
+				return;
+			}
+
+			// Don't seek if clicking on track labels
+			if ((e.target as HTMLElement).closest("[data-track-labels]")) {
+				clearSelectedElements();
+				return;
+			}
+
+			// Clear selected elements when clicking empty timeline area
+			clearSelectedElements();
+
+			// Determine if we're clicking in ruler or tracks area
+			const isRulerClick = (e.target as HTMLElement).closest(
+				"[data-ruler-area]",
+			);
+
+			let mouseX: number;
+			let scrollLeft = 0;
+
+			if (isRulerClick) {
+				// Calculate based on ruler position
+				const rulerContent = rulerScrollRef.current?.querySelector(
+					"[data-radix-scroll-area-viewport]",
+				) as HTMLElement;
+				if (!rulerContent) return;
+				const rect = rulerContent.getBoundingClientRect();
+				mouseX = e.clientX - rect.left;
+				scrollLeft = rulerContent.scrollLeft;
+			} else {
+				// Calculate based on tracks content position
+				const tracksContent = tracksScrollRef.current?.querySelector(
+					"[data-radix-scroll-area-viewport]",
+				) as HTMLElement;
+				if (!tracksContent) return;
+				const rect = tracksContent.getBoundingClientRect();
+				mouseX = e.clientX - rect.left;
+				scrollLeft = tracksContent.scrollLeft;
+			}
+
+			const rawTime = Math.max(
+				0,
+				Math.min(
+					duration,
+					(mouseX + scrollLeft) /
+						(TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel),
+				),
+			);
+
+			// Use frame snapping for timeline clicking
+			const projectFps = activeProject?.fps || 30;
+			const time = snapTimeToFrame(rawTime, projectFps);
+
+			seek(time);
+		},
+		[
+			duration,
+			zoomLevel,
+			seek,
+			rulerScrollRef,
+			tracksScrollRef,
+			clearSelectedElements,
+			isSelecting,
+			justFinishedSelecting,
+			playheadRef,
+			activeProject?.fps,
+		],
+	);
+
+	return { handleTimelineContentClick };
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-content.tsx b/apps/web/src/components/editor/timeline/timeline-content.tsx
new file mode 100644
index 00000000..0229c418
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-content.tsx
@@ -0,0 +1,127 @@
+import { SelectionBox } from "../selection-box";
+import { TimelinePlayhead } from "./timeline-playhead";
+import { SnapIndicator } from "../snap-indicator";
+import { TimelineRuler } from "./timeline-ruler";
+import { TimelineTracksArea } from "./timeline-tracks-area";
+import type { TimelineTrack } from "@/types/timeline";
+import type { SnapPoint } from "@/hooks/use-timeline-snapping";
+
+export interface TimelineContentProps {
+	dynamicTimelineWidth: number;
+	tracks: TimelineTrack[];
+	duration: number;
+	zoomLevel: number;
+	currentTime: number;
+	seek: (time: number) => void;
+	rulerRef: React.RefObject<HTMLDivElement>;
+	rulerScrollRef: React.RefObject<HTMLDivElement>;
+	tracksScrollRef: React.RefObject<HTMLDivElement>;
+	playheadRef: React.RefObject<HTMLDivElement>;
+	trackLabelsRef: React.RefObject<HTMLDivElement>;
+	timelineRef: React.RefObject<HTMLDivElement>;
+	handleSelectionMouseDown: (e: React.MouseEvent) => void;
+	handleTimelineContentClick: (e: React.MouseEvent) => void;
+	handleSnapPointChange: (snapPoint: SnapPoint | null) => void;
+	clearSelectedElements: () => void;
+	selectionBox: {
+		startPos: { x: number; y: number } | null;
+		currentPos: { x: number; y: number } | null;
+		isActive: boolean;
+	} | null;
+	tracksContainerRef: React.RefObject<HTMLDivElement>;
+	currentSnapPoint: SnapPoint | null;
+	showSnapIndicator: boolean;
+}
+
+export function TimelineContent({
+	dynamicTimelineWidth,
+	tracks,
+	duration,
+	zoomLevel,
+	currentTime,
+	seek,
+	rulerRef,
+	rulerScrollRef,
+	tracksScrollRef,
+	playheadRef,
+	trackLabelsRef,
+	timelineRef,
+	handleSelectionMouseDown,
+	handleTimelineContentClick,
+	handleSnapPointChange,
+	clearSelectedElements,
+	selectionBox,
+	tracksContainerRef,
+	currentSnapPoint,
+	showSnapIndicator,
+}: TimelineContentProps) {
+	return (
+		<div
+			className="relative min-w-max min-h-max"
+			style={{ minWidth: `${dynamicTimelineWidth}px` }}
+		>
+			<div
+				className={`h-full grid grid-cols-[192px_1fr] ${tracks.length > 0 ? `grid-rows-[20px_repeat(${tracks.length},minmax(0,max-content))]` : "grid-rows-[20px_1fr]"}`}
+			>
+				{/* Top-Left Corner (Empty space above track labels) */}
+				<div className="sticky top-0 left-0 border-inset bg-card/[0.99]"></div>
+
+				{/* Top Row (Sticky Ruler Header) */}
+				<TimelineRuler
+					duration={duration}
+					zoomLevel={zoomLevel}
+					currentTime={currentTime}
+					seek={seek}
+					rulerRef={rulerRef}
+					rulerScrollRef={rulerScrollRef}
+					tracksScrollRef={tracksScrollRef}
+					playheadRef={playheadRef}
+					handleSelectionMouseDown={handleSelectionMouseDown}
+					handleTimelineContentClick={handleTimelineContentClick}
+				/>
+
+				{/* Track Rows */}
+				<TimelineTracksArea
+					tracks={tracks}
+					zoomLevel={zoomLevel}
+					handleSnapPointChange={handleSnapPointChange}
+					clearSelectedElements={clearSelectedElements}
+				/>
+			</div>
+
+			{/* Overlay Components - positioned absolutely relative to the timeline container */}
+			<SelectionBox
+				startPos={selectionBox?.startPos || null}
+				currentPos={selectionBox?.currentPos || null}
+				containerRef={tracksContainerRef}
+				isActive={selectionBox?.isActive || false}
+			/>
+
+			<TimelinePlayhead
+				currentTime={currentTime}
+				duration={duration}
+				zoomLevel={zoomLevel}
+				tracks={tracks}
+				seek={seek}
+				rulerRef={rulerRef}
+				rulerScrollRef={rulerScrollRef}
+				tracksScrollRef={tracksScrollRef}
+				trackLabelsRef={trackLabelsRef}
+				timelineRef={timelineRef}
+				playheadRef={playheadRef}
+				isSnappingToPlayhead={
+					showSnapIndicator && currentSnapPoint?.type === "playhead"
+				}
+			/>
+
+			<SnapIndicator
+				snapPoint={currentSnapPoint}
+				zoomLevel={zoomLevel}
+				tracks={tracks}
+				timelineRef={timelineRef}
+				trackLabelsRef={trackLabelsRef}
+				isVisible={showSnapIndicator}
+			/>
+		</div>
+	);
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-drag-handlers.tsx b/apps/web/src/components/editor/timeline/timeline-drag-handlers.tsx
new file mode 100644
index 00000000..60cd7122
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-drag-handlers.tsx
@@ -0,0 +1,144 @@
+import { useState, useRef } from "react";
+import { toast } from "sonner";
+import { useTimelineStore } from "@/stores/timeline-store";
+import { useMediaStore } from "@/stores/media-store";
+import { useProjectStore } from "@/stores/project-store";
+import { processMediaFiles } from "@/lib/media-processing";
+import type { DragData } from "@/types/timeline";
+
+export interface TimelineDragHandlersProps {
+	isDragOver: boolean;
+	setIsDragOver: (isDragOver: boolean) => void;
+	isProcessing: boolean;
+	setIsProcessing: (isProcessing: boolean) => void;
+	progress: number;
+	setProgress: (progress: number) => void;
+}
+
+export function useTimelineDragHandlers({
+	isDragOver,
+	setIsDragOver,
+	isProcessing,
+	setIsProcessing,
+	progress,
+	setProgress,
+}: TimelineDragHandlersProps) {
+	const { mediaItems, addMediaItem } = useMediaStore();
+	const { activeProject } = useProjectStore();
+	const dragCounterRef = useRef(0);
+
+	const handleDragEnter = (e: React.DragEvent) => {
+		// When something is dragged over the timeline, show overlay
+		e.preventDefault();
+		// Don't show overlay for timeline elements - they're handled by tracks
+		if (e.dataTransfer.types.includes("application/x-timeline-element")) {
+			return;
+		}
+		dragCounterRef.current += 1;
+		if (!isDragOver) {
+			setIsDragOver(true);
+		}
+	};
+
+	const handleDragOver = (e: React.DragEvent) => {
+		e.preventDefault();
+	};
+
+	const handleDragLeave = (e: React.DragEvent) => {
+		e.preventDefault();
+
+		// Don't update state for timeline elements - they're handled by tracks
+		if (e.dataTransfer.types.includes("application/x-timeline-element")) {
+			return;
+		}
+
+		dragCounterRef.current -= 1;
+		if (dragCounterRef.current === 0) {
+			setIsDragOver(false);
+		}
+	};
+
+	const handleDrop = async (e: React.DragEvent) => {
+		// When media is dropped, add it as a new track/element
+		e.preventDefault();
+		setIsDragOver(false);
+		dragCounterRef.current = 0;
+
+		// Ignore timeline element drags - they're handled by track-specific handlers
+		const hasTimelineElement = e.dataTransfer.types.includes(
+			"application/x-timeline-element",
+		);
+		if (hasTimelineElement) {
+			return;
+		}
+
+		const itemData = e.dataTransfer.getData("application/x-media-item");
+		if (itemData) {
+			try {
+				const dragData: DragData = JSON.parse(itemData);
+
+				if (dragData.type === "text") {
+					// Always create new text track to avoid overlaps
+					useTimelineStore.getState().addTextToNewTrack(dragData);
+				} else {
+					// Handle media items
+					const mediaItem = mediaItems.find(
+						(item: any) => item.id === dragData.id,
+					);
+					if (!mediaItem) {
+						toast.error("Media item not found");
+						return;
+					}
+
+					useTimelineStore.getState().addMediaToNewTrack(mediaItem);
+				}
+			} catch (error) {
+				console.error("Error parsing dropped item data:", error);
+				toast.error("Failed to add item to timeline");
+			}
+		} else if (e.dataTransfer.files?.length > 0) {
+			// Handle file drops by creating new tracks
+			if (!activeProject) {
+				toast.error("No active project");
+				return;
+			}
+
+			setIsProcessing(true);
+			setProgress(0);
+			try {
+				const processedItems = await processMediaFiles(
+					e.dataTransfer.files,
+					(p) => setProgress(p),
+				);
+				for (const processedItem of processedItems) {
+					await addMediaItem(activeProject.id, processedItem);
+					const currentMediaItems = useMediaStore.getState().mediaItems;
+					const addedItem = currentMediaItems.find(
+						(item) =>
+							item.name === processedItem.name &&
+							item.url === processedItem.url,
+					);
+					if (addedItem) {
+						useTimelineStore.getState().addMediaToNewTrack(addedItem);
+					}
+				}
+			} catch (error) {
+				// Show error if file processing fails
+				console.error("Error processing external files:", error);
+				toast.error("Failed to process dropped files");
+			} finally {
+				setIsProcessing(false);
+				setProgress(0);
+			}
+		}
+	};
+
+	const dragProps = {
+		onDragEnter: handleDragEnter,
+		onDragOver: handleDragOver,
+		onDragLeave: handleDragLeave,
+		onDrop: handleDrop,
+	};
+
+	return { dragProps };
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-playhead.tsx b/apps/web/src/components/editor/timeline/timeline-playhead.tsx
new file mode 100644
index 00000000..5e531e9c
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-playhead.tsx
@@ -0,0 +1,122 @@
+"use client";
+
+import { useRef } from "react";
+import { TimelineTrack } from "@/types/timeline";
+import {
+	TIMELINE_CONSTANTS,
+	getTotalTracksHeight,
+} from "@/constants/timeline-constants";
+import { useTimelinePlayhead } from "@/hooks/use-timeline-playhead";
+
+interface TimelinePlayheadProps {
+	currentTime: number;
+	duration: number;
+	zoomLevel: number;
+	tracks: TimelineTrack[];
+	seek: (time: number) => void;
+	rulerRef: React.RefObject<HTMLDivElement>;
+	rulerScrollRef: React.RefObject<HTMLDivElement>;
+	tracksScrollRef: React.RefObject<HTMLDivElement>;
+	trackLabelsRef?: React.RefObject<HTMLDivElement>;
+	timelineRef: React.RefObject<HTMLDivElement>;
+	playheadRef?: React.RefObject<HTMLDivElement>;
+	isSnappingToPlayhead?: boolean;
+}
+
+export function TimelinePlayhead({
+	currentTime,
+	duration,
+	zoomLevel,
+	tracks,
+	seek,
+	rulerRef,
+	rulerScrollRef,
+	tracksScrollRef,
+	trackLabelsRef,
+	timelineRef,
+	playheadRef: externalPlayheadRef,
+	isSnappingToPlayhead = false,
+}: TimelinePlayheadProps) {
+	const internalPlayheadRef = useRef<HTMLDivElement>(null);
+	const playheadRef = externalPlayheadRef || internalPlayheadRef;
+	const { playheadPosition, handlePlayheadMouseDown } = useTimelinePlayhead({
+		currentTime,
+		duration,
+		zoomLevel,
+		seek,
+		rulerRef,
+		rulerScrollRef,
+		tracksScrollRef,
+		playheadRef,
+	});
+
+	// Use timeline container height minus a few pixels for breathing room
+	const timelineContainerHeight = timelineRef.current?.offsetHeight || 400;
+	const totalHeight = timelineContainerHeight - 8; // 8px padding from edges
+
+	// Get dynamic track labels width, fallback to 192px (ml-48) if no tracks or no ref
+	const trackLabelsWidth = 192; // Fixed width from grid layout
+	const leftPosition =
+		playheadPosition * TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel;
+
+	return (
+		<>
+			{/* Playhead line container */}
+			<div
+				ref={playheadRef}
+				className="absolute pointer-events-auto z-[95]"
+				style={{
+					left: `${trackLabelsWidth + leftPosition}px`,
+					top: 0,
+					bottom: 0,
+					width: "2px", // Slightly wider for better click target
+				}}
+				onMouseDown={handlePlayheadMouseDown}
+			>
+				{/* The playhead line spanning full height */}
+				<div
+					className={`absolute left-0 w-0.5 cursor-col-resize h-full ${isSnappingToPlayhead ? "bg-primary" : "bg-foreground"}`}
+				/>
+			</div>
+
+			{/* Playhead dot indicator - separate container with highest z-index */}
+			<div
+				className="absolute pointer-events-none z-[100]"
+				style={{
+					left: `${trackLabelsWidth + leftPosition}px`,
+					top: 0,
+					bottom: 0,
+				}}
+			>
+				<div
+					className={`sticky top-1 left-1 -translate-x-[40%] transform w-3 h-3 rounded-full shadow-sm ${isSnappingToPlayhead ? "bg-primary border-primary" : "bg-foreground border-foreground"}`}
+				/>
+			</div>
+		</>
+	);
+}
+
+// Also export a hook for getting ruler handlers
+export function useTimelinePlayheadRuler({
+	currentTime,
+	duration,
+	zoomLevel,
+	seek,
+	rulerRef,
+	rulerScrollRef,
+	tracksScrollRef,
+	playheadRef,
+}: Omit<TimelinePlayheadProps, "tracks" | "trackLabelsRef" | "timelineRef">) {
+	const { handleRulerMouseDown, isDraggingRuler } = useTimelinePlayhead({
+		currentTime,
+		duration,
+		zoomLevel,
+		seek,
+		rulerRef,
+		rulerScrollRef,
+		tracksScrollRef,
+		playheadRef,
+	});
+
+	return { handleRulerMouseDown, isDraggingRuler };
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-ruler.tsx b/apps/web/src/components/editor/timeline/timeline-ruler.tsx
new file mode 100644
index 00000000..fbe5ae1f
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-ruler.tsx
@@ -0,0 +1,127 @@
+import { useMemo } from "react";
+import { TIMELINE_CONSTANTS } from "@/constants/timeline-constants";
+import { useTimelinePlayheadRuler } from "./timeline-playhead";
+
+export interface TimelineRulerProps {
+	duration: number;
+	zoomLevel: number;
+	currentTime: number;
+	seek: (time: number) => void;
+	rulerRef: React.RefObject<HTMLDivElement>;
+	rulerScrollRef: React.RefObject<HTMLDivElement>;
+	tracksScrollRef: React.RefObject<HTMLDivElement>;
+	playheadRef: React.RefObject<HTMLDivElement>;
+	handleSelectionMouseDown: (e: React.MouseEvent) => void;
+	handleTimelineContentClick: (e: React.MouseEvent) => void;
+}
+
+export function TimelineRuler({
+	duration,
+	zoomLevel,
+	currentTime,
+	seek,
+	rulerRef,
+	rulerScrollRef,
+	tracksScrollRef,
+	playheadRef,
+	handleSelectionMouseDown,
+	handleTimelineContentClick,
+}: TimelineRulerProps) {
+	// Timeline playhead ruler handlers
+	const { handleRulerMouseDown } = useTimelinePlayheadRuler({
+		currentTime,
+		duration,
+		zoomLevel,
+		seek,
+		rulerRef,
+		rulerScrollRef,
+		tracksScrollRef,
+		playheadRef,
+	});
+
+	// Memoize the expensive ruler markers calculation
+	const rulerMarkers = useMemo(() => {
+		// Calculate appropriate time interval based on zoom level
+		const getTimeInterval = (zoom: number) => {
+			const pixelsPerSecond = TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoom;
+			if (pixelsPerSecond >= 200) return 0.1; // Every 0.1s when very zoomed in
+			if (pixelsPerSecond >= 100) return 0.5; // Every 0.5s when zoomed in
+			if (pixelsPerSecond >= 50) return 1; // Every 1s at normal zoom
+			if (pixelsPerSecond >= 25) return 2; // Every 2s when zoomed out
+			if (pixelsPerSecond >= 12) return 5; // Every 5s when more zoomed out
+			if (pixelsPerSecond >= 6) return 10; // Every 10s when very zoomed out
+			return 30; // Every 30s when extremely zoomed out
+		};
+
+		const formatTime = (seconds: number, interval: number) => {
+			const hours = Math.floor(seconds / 3600);
+			const minutes = Math.floor((seconds % 3600) / 60);
+			const secs = seconds % 60;
+
+			if (hours > 0) {
+				return `${hours}:${minutes.toString().padStart(2, "0")}:${Math.floor(secs).toString().padStart(2, "0")}`;
+			} else if (minutes > 0) {
+				return `${minutes}:${Math.floor(secs).toString().padStart(2, "0")}`;
+			} else if (interval >= 1) {
+				return `${Math.floor(secs)}s`;
+			} else {
+				return `${secs.toFixed(1)}s`;
+			}
+		};
+
+		const interval = getTimeInterval(zoomLevel);
+		const markerCount = Math.ceil(duration / interval) + 1;
+		const markers = [];
+
+		for (let i = 0; i < markerCount; i++) {
+			const time = i * interval;
+			if (time > duration) break;
+
+			const isMainMarker =
+				time % (interval >= 1 ? Math.max(1, interval) : 1) === 0;
+			const leftPosition =
+				time * TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel;
+
+			markers.push(
+				<div
+					key={i}
+					className={`absolute top-0 bottom-0 z-[99] ${
+						isMainMarker
+							? "border-l border-muted-foreground/40"
+							: "border-l border-muted-foreground/20"
+					}`}
+					style={{ left: `${leftPosition}px` }}
+				>
+					<span
+						className={`absolute top-1 left-1 text-[0.6rem] z-[99] ${
+							isMainMarker
+								? "text-muted-foreground font-medium"
+								: "text-muted-foreground/70"
+						}`}
+					>
+						{formatTime(time, interval)}
+					</span>
+				</div>,
+			);
+		}
+
+		return markers;
+	}, [duration, zoomLevel]); // Only recalculate when duration or zoomLevel changes
+
+	return (
+		<div
+			className="sticky top-0 bg-card/[0.99] border-b border-muted/30 z-[99]"
+			onMouseDown={handleSelectionMouseDown}
+			onClick={handleTimelineContentClick}
+			data-ruler-area
+		>
+			<div
+				ref={rulerRef}
+				className="relative h-5 select-none cursor-default pb-1 z-[99]"
+				onMouseDown={handleRulerMouseDown}
+			>
+				{rulerMarkers}
+			</div>
+		</div>
+	);
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-scroll-sync.tsx b/apps/web/src/components/editor/timeline/timeline-scroll-sync.tsx
new file mode 100644
index 00000000..6537d909
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-scroll-sync.tsx
@@ -0,0 +1,61 @@
+import { useEffect, useRef } from "react";
+
+export interface TimelineScrollSyncProps {
+	rulerScrollRef: React.RefObject<HTMLDivElement>;
+	tracksScrollRef: React.RefObject<HTMLDivElement>;
+}
+
+export function useTimelineScrollSync({
+	rulerScrollRef,
+	tracksScrollRef,
+}: TimelineScrollSyncProps) {
+	const isUpdatingRef = useRef(false);
+	const lastSyncRef = useRef(0);
+
+	// --- Horizontal scroll synchronization between ruler and tracks ---
+	useEffect(() => {
+		const rulerViewport = rulerScrollRef.current?.querySelector(
+			"[data-radix-scroll-area-viewport]",
+		) as HTMLElement;
+		const tracksViewport = tracksScrollRef.current?.querySelector(
+			"[data-radix-scroll-area-viewport]",
+		) as HTMLElement;
+
+		if (!rulerViewport || !tracksViewport) return;
+
+		// Throttled scroll handlers for better performance
+		const handleRulerScroll = () => {
+			const now = Date.now();
+			if (isUpdatingRef.current || now - lastSyncRef.current < 16) return; // 60fps throttling
+			lastSyncRef.current = now;
+
+			isUpdatingRef.current = true;
+			tracksViewport.scrollLeft = rulerViewport.scrollLeft;
+			isUpdatingRef.current = false;
+		};
+
+		const handleTracksScroll = () => {
+			const now = Date.now();
+			if (isUpdatingRef.current || now - lastSyncRef.current < 16) return; // 60fps throttling
+			lastSyncRef.current = now;
+
+			isUpdatingRef.current = true;
+			rulerViewport.scrollLeft = tracksViewport.scrollLeft;
+			isUpdatingRef.current = false;
+		};
+
+		rulerViewport.addEventListener("scroll", handleRulerScroll, {
+			passive: true,
+		});
+		tracksViewport.addEventListener("scroll", handleTracksScroll, {
+			passive: true,
+		});
+
+		return () => {
+			rulerViewport.removeEventListener("scroll", handleRulerScroll);
+			tracksViewport.removeEventListener("scroll", handleTracksScroll);
+		};
+	}, [rulerScrollRef, tracksScrollRef]);
+
+	return null;
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-toolbar.tsx b/apps/web/src/components/editor/timeline/timeline-toolbar.tsx
new file mode 100644
index 00000000..da8b6107
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-toolbar.tsx
@@ -0,0 +1,201 @@
+import { Button } from "../../ui/button";
+import {
+	Scissors,
+	ArrowLeftToLine,
+	ArrowRightToLine,
+	Trash2,
+	Snowflake,
+	Copy,
+	SplitSquareHorizontal,
+	Pause,
+	Play,
+	Lock,
+	LockOpen,
+} from "lucide-react";
+import {
+	Tooltip,
+	TooltipContent,
+	TooltipTrigger,
+	TooltipProvider,
+} from "../../ui/tooltip";
+import { useTimelineStore } from "@/stores/timeline-store";
+import { usePlaybackStore } from "@/stores/playback-store";
+import { TIMELINE_CONSTANTS } from "@/constants/timeline-constants";
+
+export interface TimelineToolbarProps {
+	handleSplitSelected: () => void;
+	handleSplitAndKeepLeft: () => void;
+	handleSplitAndKeepRight: () => void;
+	handleSeparateAudio: () => void;
+	handleDuplicateSelected: () => void;
+	handleFreezeSelected: () => void;
+	handleDeleteSelected: () => void;
+}
+
+export function TimelineToolbar({
+	handleSplitSelected,
+	handleSplitAndKeepLeft,
+	handleSplitAndKeepRight,
+	handleSeparateAudio,
+	handleDuplicateSelected,
+	handleFreezeSelected,
+	handleDeleteSelected,
+}: TimelineToolbarProps) {
+	const {
+		tracks,
+		addTrack,
+		addElementToTrack,
+		snappingEnabled,
+		toggleSnapping,
+	} = useTimelineStore();
+	const { currentTime, duration, isPlaying, toggle } = usePlaybackStore();
+
+	return (
+		<div className="border-b flex items-center justify-between px-2 py-1 bg-card z-90">
+			<div className="flex items-center gap-1 w-full">
+				<TooltipProvider delayDuration={500}>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button
+								variant="text"
+								size="icon"
+								onClick={toggle}
+								className="mr-2"
+							>
+								{isPlaying ? (
+									<Pause className="h-4 w-4" />
+								) : (
+									<Play className="h-4 w-4" />
+								)}
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>
+							{isPlaying ? "Pause (Space)" : "Play (Space)"}
+						</TooltipContent>
+					</Tooltip>
+					<div className="w-px h-6 bg-border mx-1" />
+					<div
+						className="text-xs text-muted-foreground font-mono px-2"
+						style={{ minWidth: "18ch", textAlign: "center" }}
+					>
+						{currentTime.toFixed(1)}s / {duration.toFixed(1)}s
+					</div>
+					{tracks.length === 0 && (
+						<>
+							<div className="w-px h-6 bg-border mx-1" />
+							<Tooltip>
+								<TooltipTrigger asChild>
+									<Button
+										variant="outline"
+										size="sm"
+										onClick={() => {
+											const trackId = addTrack("media");
+											addElementToTrack(trackId, {
+												type: "media",
+												mediaId: "test",
+												name: "Test Clip",
+												duration: TIMELINE_CONSTANTS.DEFAULT_TEXT_DURATION,
+												startTime: 0,
+												trimStart: 0,
+												trimEnd: 0,
+											});
+										}}
+										className="text-xs"
+									>
+										Add Test Clip
+									</Button>
+								</TooltipTrigger>
+								<TooltipContent>Add a test clip to try playback</TooltipContent>
+							</Tooltip>
+						</>
+					)}
+					<div className="w-px h-6 bg-border mx-1" />
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button variant="text" size="icon" onClick={handleSplitSelected}>
+								<Scissors className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Split element (Ctrl+S)</TooltipContent>
+					</Tooltip>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button
+								variant="text"
+								size="icon"
+								onClick={handleSplitAndKeepLeft}
+							>
+								<ArrowLeftToLine className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Split and keep left (Ctrl+Q)</TooltipContent>
+					</Tooltip>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button
+								variant="text"
+								size="icon"
+								onClick={handleSplitAndKeepRight}
+							>
+								<ArrowRightToLine className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Split and keep right (Ctrl+W)</TooltipContent>
+					</Tooltip>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button variant="text" size="icon" onClick={handleSeparateAudio}>
+								<SplitSquareHorizontal className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Separate audio (Ctrl+D)</TooltipContent>
+					</Tooltip>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button
+								variant="text"
+								size="icon"
+								onClick={handleDuplicateSelected}
+							>
+								<Copy className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Duplicate element (Ctrl+D)</TooltipContent>
+					</Tooltip>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button variant="text" size="icon" onClick={handleFreezeSelected}>
+								<Snowflake className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Freeze frame (F)</TooltipContent>
+					</Tooltip>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button variant="text" size="icon" onClick={handleDeleteSelected}>
+								<Trash2 className="h-4 w-4" />
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Delete element (Delete)</TooltipContent>
+					</Tooltip>
+				</TooltipProvider>
+			</div>
+			<div className="flex items-center gap-1">
+				<TooltipProvider delayDuration={500}>
+					<Tooltip>
+						<TooltipTrigger asChild>
+							<Button variant="text" size="icon" onClick={toggleSnapping}>
+								{snappingEnabled ? (
+									<Lock className="h-4 w-4" />
+								) : (
+									<LockOpen className="h-4 w-4 text-primary" />
+								)}
+							</Button>
+						</TooltipTrigger>
+						<TooltipContent>Auto snapping</TooltipContent>
+					</Tooltip>
+				</TooltipProvider>
+			</div>
+		</div>
+	);
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-tracks-area.tsx b/apps/web/src/components/editor/timeline/timeline-tracks-area.tsx
new file mode 100644
index 00000000..9242bccd
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-tracks-area.tsx
@@ -0,0 +1,89 @@
+import { Fragment } from "react";
+import { Plus } from "lucide-react";
+import {
+	ContextMenu,
+	ContextMenuContent,
+	ContextMenuItem,
+	ContextMenuTrigger,
+} from "../../ui/context-menu";
+import { useTimelineStore } from "@/stores/timeline-store";
+import { TimelineTrackContent } from "../timeline-track";
+import { TrackIcon } from "./track-icon";
+import { getTrackHeight } from "@/constants/timeline-constants";
+import type { TimelineTrack } from "@/types/timeline";
+import type { SnapPoint } from "@/hooks/use-timeline-snapping";
+
+export interface TimelineTracksAreaProps {
+	tracks: TimelineTrack[];
+	zoomLevel: number;
+	handleSnapPointChange: (snapPoint: SnapPoint | null) => void;
+	clearSelectedElements: () => void;
+}
+
+export function TimelineTracksArea({
+	tracks,
+	zoomLevel,
+	handleSnapPointChange,
+	clearSelectedElements,
+}: TimelineTracksAreaProps) {
+	const { addTrack, toggleTrackMute } = useTimelineStore();
+
+	return (
+		<>
+			{/* Track Rows */}
+			{tracks.map((track, index) => (
+				<Fragment key={track.id}>
+					{/* Left Column (Sticky Track Labels) */}
+					<div
+						className="sticky left-0 flex items-center border-b border-panel border-inset group bg-card/[0.99] z-[98]"
+						style={{ height: `${getTrackHeight(track.type)}px` }}
+					>
+						<div className="flex items-center gap-2 px-2">
+							<TrackIcon track={track} />
+						</div>
+						{track.muted && (
+							<span className="text-xs text-red-500 font-semibold">Muted</span>
+						)}
+					</div>
+
+					{/* Scrollable Track Content */}
+					<ContextMenu>
+						<ContextMenuTrigger asChild>
+							<div
+								className=" h-full"
+								onClick={(e) => {
+									// If clicking empty area (not on a element), deselect all elements
+									if (!(e.target as HTMLElement).closest(".timeline-element")) {
+										clearSelectedElements();
+									}
+								}}
+							>
+								<TimelineTrackContent
+									track={track}
+									zoomLevel={zoomLevel}
+									onSnapPointChange={handleSnapPointChange}
+								/>
+							</div>
+						</ContextMenuTrigger>
+						<ContextMenuContent>
+							<ContextMenuItem onClick={() => toggleTrackMute(track.id)}>
+								{track.muted ? "Unmute Track" : "Mute Track"}
+							</ContextMenuItem>
+							<ContextMenuItem>Track settings (soon)</ContextMenuItem>
+						</ContextMenuContent>
+					</ContextMenu>
+				</Fragment>
+			))}
+			{/* Add Track Button - spans full width */}
+			<div
+				onClick={() => addTrack("media")}
+				className="col-span-1 sticky left-0 w-full flex items-center border-b border-muted bg-card/[0.99] hover:bg-card/50 transition-colors cursor-pointer z-[89]"
+				style={{ height: `${getTrackHeight("media")}px` }}
+			>
+				<div className="w-full flex  justify-center items-center">
+					<Plus className="w-4 h-4 text-muted-foreground" />
+				</div>
+			</div>
+		</>
+	);
+}
diff --git a/apps/web/src/components/editor/timeline/timeline-wheel-handler.tsx b/apps/web/src/components/editor/timeline/timeline-wheel-handler.tsx
new file mode 100644
index 00000000..8036b96c
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/timeline-wheel-handler.tsx
@@ -0,0 +1,32 @@
+import { useEffect } from "react";
+
+export interface TimelineWheelHandlerProps {
+	timelineRef: React.RefObject<HTMLDivElement>;
+	isInTimeline: boolean;
+	handleWheel: (e: React.WheelEvent) => void;
+}
+
+export function useTimelineWheelHandler({
+	timelineRef,
+	isInTimeline,
+	handleWheel,
+}: TimelineWheelHandlerProps) {
+	useEffect(() => {
+		const timelineContainer = timelineRef.current;
+		if (!timelineContainer || !isInTimeline) return;
+
+		const handleWheelCapture = (e: WheelEvent) => {
+			handleWheel(e as any);
+		};
+
+		timelineContainer.addEventListener("wheel", handleWheelCapture, {
+			passive: false,
+		});
+
+		return () => {
+			timelineContainer.removeEventListener("wheel", handleWheelCapture);
+		};
+	}, [handleWheel, isInTimeline, timelineRef]);
+
+	return null;
+}
diff --git a/apps/web/src/components/editor/timeline/track-icon.tsx b/apps/web/src/components/editor/timeline/track-icon.tsx
new file mode 100644
index 00000000..609c2849
--- /dev/null
+++ b/apps/web/src/components/editor/timeline/track-icon.tsx
@@ -0,0 +1,18 @@
+import { Video, Music, TypeIcon } from "lucide-react";
+import type { TimelineTrack } from "@/types/timeline";
+
+export function TrackIcon({ track }: { track: TimelineTrack }) {
+	return (
+		<>
+			{track.type === "media" && (
+				<Video className="w-4 h-4 flex-shrink-0 text-muted-foreground" />
+			)}
+			{track.type === "text" && (
+				<TypeIcon className="w-4 h-4 flex-shrink-0 text-muted-foreground" />
+			)}
+			{track.type === "audio" && (
+				<Music className="w-4 h-4 flex-shrink-0 text-muted-foreground" />
+			)}
+		</>
+	);
+}