1 files changed, 243 insertions, 0 deletions
diff --git a/apps/web/src/hooks/timeline/use-selection-box.ts b/apps/web/src/hooks/timeline/use-selection-box.ts
new file mode 100644
index 00000000..702abad9
--- /dev/null
+++ b/apps/web/src/hooks/timeline/use-selection-box.ts
@@ -0,0 +1,243 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+import { TIMELINE_CONSTANTS } from "@/constants/timeline-constants";
+import { getCumulativeHeightBefore, getTrackHeight } from "@/lib/timeline";
+import { useEditor } from "../use-editor";
+
+interface UseSelectionBoxProps {
+	containerRef: React.RefObject<HTMLElement>;
+	onSelectionComplete: (
+		elements: { trackId: string; elementId: string }[],
+	) => void;
+	isEnabled?: boolean;
+	tracksScrollRef: React.RefObject<HTMLDivElement>;
+	zoomLevel: number;
+}
+
+interface SelectionBoxState {
+	startPos: { x: number; y: number };
+	currentPos: { x: number; y: number };
+	isActive: boolean;
+}
+
+interface SelectionRectangle {
+	left: number;
+	top: number;
+	right: number;
+	bottom: number;
+}
+
+function getNormalizedRectangle({
+	startPos,
+	endPos,
+}: {
+	startPos: { x: number; y: number };
+	endPos: { x: number; y: number };
+}): SelectionRectangle {
+	return {
+		left: Math.min(startPos.x, endPos.x),
+		top: Math.min(startPos.y, endPos.y),
+		right: Math.max(startPos.x, endPos.x),
+		bottom: Math.max(startPos.y, endPos.y),
+	};
+}
+
+function getSelectionRectangleInContent({
+	container,
+	scrollContainer,
+	startPos,
+	endPos,
+}: {
+	container: HTMLElement;
+	scrollContainer: HTMLDivElement | null;
+	startPos: { x: number; y: number };
+	endPos: { x: number; y: number };
+}): SelectionRectangle {
+	const containerRect = container.getBoundingClientRect();
+	const scrollLeft = scrollContainer?.scrollLeft ?? 0;
+	const scrollTop = scrollContainer?.scrollTop ?? 0;
+
+	const adjustedStart = {
+		x: startPos.x - containerRect.left + scrollLeft,
+		y: startPos.y - containerRect.top + scrollTop,
+	};
+	const adjustedEnd = {
+		x: endPos.x - containerRect.left + scrollLeft,
+		y: endPos.y - containerRect.top + scrollTop,
+	};
+
+	return getNormalizedRectangle({
+		startPos: adjustedStart,
+		endPos: adjustedEnd,
+	});
+}
+
+function isRectangleIntersecting({
+	elementRectangle,
+	selectionRectangle,
+}: {
+	elementRectangle: SelectionRectangle;
+	selectionRectangle: SelectionRectangle;
+}): boolean {
+	return !(
+		elementRectangle.right < selectionRectangle.left ||
+		elementRectangle.left > selectionRectangle.right ||
+		elementRectangle.bottom < selectionRectangle.top ||
+		elementRectangle.top > selectionRectangle.bottom
+	);
+}
+
+export function useSelectionBox({
+	containerRef,
+	onSelectionComplete,
+	isEnabled = true,
+	tracksScrollRef,
+	zoomLevel,
+}: UseSelectionBoxProps) {
+	const editor = useEditor();
+	const tracks = editor.timeline.getTracks();
+	const [selectionBox, setSelectionBox] = useState<SelectionBoxState | null>(
+		null,
+	);
+	const justFinishedSelectingRef = useRef(false);
+
+	const handleMouseDown = useCallback(
+		({ clientX, clientY }: React.MouseEvent) => {
+			if (!isEnabled) return;
+
+			setSelectionBox({
+				startPos: { x: clientX, y: clientY },
+				currentPos: { x: clientX, y: clientY },
+				isActive: false,
+			});
+		},
+		[isEnabled],
+	);
+
+	const selectElementsInBox = useCallback(
+		({
+			startPos,
+			endPos,
+		}: {
+			startPos: { x: number; y: number };
+			endPos: { x: number; y: number };
+		}) => {
+			if (!containerRef.current) return;
+
+			const container = containerRef.current;
+			const selectionRectangle = getSelectionRectangleInContent({
+				container,
+				scrollContainer: tracksScrollRef.current,
+				startPos,
+				endPos,
+			});
+			const pixelsPerSecond = TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel;
+			const selectedElements: { trackId: string; elementId: string }[] = [];
+
+			for (const [trackIndex, track] of tracks.entries()) {
+				const trackTop = getCumulativeHeightBefore({
+					tracks,
+					trackIndex,
+				});
+				const trackHeight = getTrackHeight({ type: track.type });
+				const elementTop = trackTop;
+				const elementBottom = trackTop + trackHeight;
+
+				for (const element of track.elements) {
+					const elementLeft = element.startTime * pixelsPerSecond;
+					const elementRight = elementLeft + element.duration * pixelsPerSecond;
+
+					const elementRectangle = {
+						left: elementLeft,
+						top: elementTop,
+						right: elementRight,
+						bottom: elementBottom,
+					};
+
+					const intersects = isRectangleIntersecting({
+						elementRectangle,
+						selectionRectangle,
+					});
+
+					if (intersects) {
+						selectedElements.push({
+							trackId: track.id,
+							elementId: element.id,
+						});
+					}
+				}
+			}
+			onSelectionComplete(selectedElements);
+		},
+		[containerRef, onSelectionComplete, tracks, tracksScrollRef, zoomLevel],
+	);
+
+	useEffect(() => {
+		if (!selectionBox) return;
+
+		const handleMouseMove = ({ clientX, clientY }: MouseEvent) => {
+			const deltaX = Math.abs(clientX - selectionBox.startPos.x);
+			const deltaY = Math.abs(clientY - selectionBox.startPos.y);
+			const shouldActivate = deltaX > 5 || deltaY > 5;
+
+			const newSelectionBox = {
+				...selectionBox,
+				currentPos: { x: clientX, y: clientY },
+				isActive: shouldActivate || selectionBox.isActive,
+			};
+
+			setSelectionBox(newSelectionBox);
+
+			if (newSelectionBox.isActive) {
+				selectElementsInBox({
+					startPos: newSelectionBox.startPos,
+					endPos: newSelectionBox.currentPos,
+				});
+			}
+		};
+
+		const handleMouseUp = () => {
+			if (selectionBox?.isActive) {
+				justFinishedSelectingRef.current = true;
+				requestAnimationFrame(() => {
+					justFinishedSelectingRef.current = false;
+				});
+			}
+			setSelectionBox(null);
+		};
+
+		window.addEventListener("mousemove", handleMouseMove);
+		window.addEventListener("mouseup", handleMouseUp);
+
+		return () => {
+			window.removeEventListener("mousemove", handleMouseMove);
+			window.removeEventListener("mouseup", handleMouseUp);
+		};
+	}, [selectionBox, selectElementsInBox]);
+
+	useEffect(() => {
+		if (!selectionBox) return;
+
+		const previousBodyUserSelect = document.body.style.userSelect;
+		const container = containerRef.current;
+		const previousContainerUserSelect = container?.style.userSelect ?? "";
+
+		document.body.style.userSelect = "none";
+		if (container) container.style.userSelect = "none";
+
+		return () => {
+			document.body.style.userSelect = previousBodyUserSelect;
+			if (container) container.style.userSelect = previousContainerUserSelect;
+		};
+	}, [selectionBox, containerRef]);
+
+	const shouldIgnoreClick = useCallback(() => {
+		return justFinishedSelectingRef.current;
+	}, []);
+
+	return {
+		selectionBox,
+		handleMouseDown,
+		isSelecting: selectionBox?.isActive || false,
+		shouldIgnoreClick,
+	};
+}