refactor: thinner hooks

1 files changed, 47 insertions, 592 deletions

diff --git a/apps/web/src/preview/hooks/use-transform-handles.ts b/apps/web/src/preview/hooks/use-transform-handles.ts
index 030e026c..f4b7e306 100644
--- a/apps/web/src/preview/hooks/use-transform-handles.ts
+++ b/apps/web/src/preview/hooks/use-transform-handles.ts
@@ -1,629 +1,84 @@
-import { useCallback, useEffect, useRef, useState } from "react";
+import { useEffect, useReducer, useRef } from "react";
 import { usePreviewViewport } from "@/preview/components/preview-viewport";
 import type { OnSnapLinesChange } from "@/preview/hooks/use-preview-interaction";
 import { useEditor } from "@/editor/use-editor";
 import { useShiftKey } from "@/hooks/use-shift-key";
-import {
-	getVisibleElementsWithBounds,
-	type ElementWithBounds,
-} from "@/preview/element-bounds";
-import {
-	MIN_SCALE,
-	SNAP_THRESHOLD_SCREEN_PIXELS,
-	snapRotation,
-	snapScale,
-	snapScaleAxes,
-	type ScaleEdgePreference,
-	type SnapLine,
-} from "@/preview/preview-snap";
-import { isVisualElement } from "@/timeline/element-utils";
-import {
-	getElementLocalTime,
-	hasKeyframesForPath,
-	resolveTransformAtTime,
-	setChannel,
-} from "@/animation";
-import type { Transform } from "@/rendering";
-import type { ElementAnimations } from "@/animation/types";
 import { registerCanceller } from "@/editor/cancel-interaction";
-
-type Corner = "top-left" | "top-right" | "bottom-left" | "bottom-right";
-type Edge = "right" | "left" | "bottom";
-type HandleType = Corner | Edge | "rotation";
-
-function getPreferredEdge({ edge }: { edge: Edge }): ScaleEdgePreference {
-	return edge === "right"
-		? { right: true }
-		: edge === "left"
-			? { left: true }
-			: { bottom: true };
-}
-
-interface ScaleState {
-	trackId: string;
-	elementId: string;
-	initialTransform: Transform;
-	initialDistance: number;
-	initialBoundsCx: number;
-	initialBoundsCy: number;
-	baseWidth: number;
-	baseHeight: number;
-	shouldClearScaleAnimation: boolean;
-	animationsWithoutScale: ElementAnimations | undefined;
-}
-
-interface RotationState {
-	trackId: string;
-	elementId: string;
-	initialTransform: Transform;
-	initialAngle: number;
-	initialBoundsCx: number;
-	initialBoundsCy: number;
-}
-
-interface EdgeScaleState {
-	trackId: string;
-	elementId: string;
-	initialTransform: Transform;
-	initialBoundsCx: number;
-	initialBoundsCy: number;
-	baseWidth: number;
-	baseHeight: number;
-	edge: Edge;
-	rotationRad: number;
-	shouldClearScaleAnimation: boolean;
-	animationsWithoutScale: ElementAnimations | undefined;
-}
-
-function clampScaleNonZero(scale: number): number {
-	if (Math.abs(scale) < MIN_SCALE) {
-		return scale < 0 ? -MIN_SCALE : MIN_SCALE;
-	}
-	return scale;
-}
-
-function getCornerDistance({
-	bounds,
-	corner,
-}: {
-	bounds: {
-		cx: number;
-		cy: number;
-		width: number;
-		height: number;
-		rotation: number;
-	};
-	corner: Corner;
-}): number {
-	const halfWidth = bounds.width / 2;
-	const halfHeight = bounds.height / 2;
-	const angleRad = (bounds.rotation * Math.PI) / 180;
-	const cos = Math.cos(angleRad);
-	const sin = Math.sin(angleRad);
-
-	const localX =
-		corner === "top-left" || corner === "bottom-left" ? -halfWidth : halfWidth;
-	const localY =
-		corner === "top-left" || corner === "top-right" ? -halfHeight : halfHeight;
-
-	const rotatedX = localX * cos - localY * sin;
-	const rotatedY = localX * sin + localY * cos;
-	return Math.sqrt(rotatedX * rotatedX + rotatedY * rotatedY) || 1;
-}
+import {
+	TransformHandleController,
+	type TransformHandleDeps,
+} from "@/preview/controllers/transform-handle-controller";
 
 export function useTransformHandles({
 	onSnapLinesChange,
 }: {
 	onSnapLinesChange?: OnSnapLinesChange;
 }) {
+	const viewport = usePreviewViewport();
 	const editor = useEditor();
 	const isShiftHeldRef = useShiftKey();
-	const viewport = usePreviewViewport();
-	const [activeHandle, setActiveHandle] = useState<HandleType | null>(null);
-	const scaleStateRef = useRef<ScaleState | null>(null);
-	const rotationStateRef = useRef<RotationState | null>(null);
-	const edgeScaleStateRef = useRef<EdgeScaleState | null>(null);
-	const captureRef = useRef<{ element: HTMLElement; pointerId: number } | null>(
-		null,
-	);
-
 	const selectedElements = useEditor((e) => e.selection.getSelectedElements());
 	const tracks = useEditor(
 		(e) => e.timeline.getPreviewTracks() ?? e.scenes.getActiveScene().tracks,
 	);
 	const currentTime = useEditor((e) => e.playback.getCurrentTime());
-	const currentTimeRef = useRef(currentTime);
-	currentTimeRef.current = currentTime;
 	const mediaAssets = useEditor((e) => e.media.getAssets());
 	const canvasSize = useEditor(
 		(e) => e.project.getActive().settings.canvasSize,
 	);
-
-	const elementsWithBounds = getVisibleElementsWithBounds({
-		tracks,
-		currentTime,
-		canvasSize,
-		mediaAssets,
-	});
-
-	const selectedWithBounds: ElementWithBounds | null =
-		selectedElements.length === 1
-			? (elementsWithBounds.find(
-					(entry) =>
-						entry.trackId === selectedElements[0].trackId &&
-						entry.elementId === selectedElements[0].elementId,
-				) ?? null)
-			: null;
-
-	const hasVisualSelection =
-		selectedWithBounds !== null && isVisualElement(selectedWithBounds.element);
-
-	const clearActiveHandleState = useCallback(() => {
-		scaleStateRef.current = null;
-		rotationStateRef.current = null;
-		edgeScaleStateRef.current = null;
-		setActiveHandle(null);
-		onSnapLinesChange?.([]);
-	}, [onSnapLinesChange]);
-
-	const releaseCapturedPointer = useCallback(() => {
-		const capture = captureRef.current;
-		if (!capture) return;
-
-		if (capture.element.hasPointerCapture(capture.pointerId)) {
-			capture.element.releasePointerCapture(capture.pointerId);
-		}
-
-		captureRef.current = null;
-	}, []);
-
-	useEffect(() => {
-		if (!activeHandle) return;
-
-		return registerCanceller({
-			fn: () => {
-				editor.timeline.discardPreview();
-				clearActiveHandleState();
-				releaseCapturedPointer();
-			},
-		});
-	}, [
-		activeHandle,
-		clearActiveHandleState,
-		editor.timeline,
-		releaseCapturedPointer,
-	]);
-
-	const handleCornerPointerDown = useCallback(
-		({ event, corner }: { event: React.PointerEvent; corner: Corner }) => {
-			if (!selectedWithBounds) return;
-			event.stopPropagation();
-
-			const { bounds, trackId, elementId, element } = selectedWithBounds;
-			if (!isVisualElement(element)) return;
-
-			const localTime = getElementLocalTime({
-				timelineTime: currentTimeRef.current,
-				elementStartTime: element.startTime,
-				elementDuration: element.duration,
-			});
-			const resolvedTransform = resolveTransformAtTime({
-				baseTransform: element.transform,
-				animations: element.animations,
-				localTime,
-			});
-
-			const initialDistance = getCornerDistance({ bounds, corner });
-			const baseWidth = bounds.width / resolvedTransform.scaleX;
-			const baseHeight = bounds.height / resolvedTransform.scaleY;
-			const shouldClearScaleAnimation =
-				hasKeyframesForPath({
-					animations: element.animations,
-					propertyPath: "transform.scaleX",
-				}) ||
-				hasKeyframesForPath({
-					animations: element.animations,
-					propertyPath: "transform.scaleY",
-				});
-			const animationsWithoutScale = shouldClearScaleAnimation
-				? setChannel({
-						animations: setChannel({
-							animations: element.animations,
-							propertyPath: "transform.scaleX",
-							channel: undefined,
-						}),
-						propertyPath: "transform.scaleY",
-						channel: undefined,
-					})
-				: element.animations;
-
-			scaleStateRef.current = {
-				trackId,
-				elementId,
-				initialTransform: resolvedTransform,
-				initialDistance,
-				initialBoundsCx: bounds.cx,
-				initialBoundsCy: bounds.cy,
-				baseWidth,
-				baseHeight,
-				shouldClearScaleAnimation,
-				animationsWithoutScale,
-			};
-			setActiveHandle(corner);
-			const captureTarget = event.currentTarget as HTMLElement;
-			captureTarget.setPointerCapture(event.pointerId);
-			captureRef.current = {
-				element: captureTarget,
-				pointerId: event.pointerId,
-			};
+	const deps: TransformHandleDeps = {
+		viewport,
+		input: {
+			isShiftHeld: () => isShiftHeldRef.current,
 		},
-		[selectedWithBounds],
-	);
-
-	const handleRotationPointerDown = useCallback(
-		({ event }: { event: React.PointerEvent }) => {
-			if (!selectedWithBounds) return;
-			event.stopPropagation();
-
-			const { bounds, trackId, elementId, element } = selectedWithBounds;
-			if (!isVisualElement(element)) return;
-
-			const localTime = getElementLocalTime({
-				timelineTime: currentTimeRef.current,
-				elementStartTime: element.startTime,
-				elementDuration: element.duration,
-			});
-			const resolvedTransform = resolveTransformAtTime({
-				baseTransform: element.transform,
-				animations: element.animations,
-				localTime,
-			});
-
-			const position = viewport.screenToCanvas({
-				clientX: event.clientX,
-				clientY: event.clientY,
-			});
-			if (!position) return;
-			const deltaX = position.x - bounds.cx;
-			const deltaY = position.y - bounds.cy;
-			const initialAngle = (Math.atan2(deltaY, deltaX) * 180) / Math.PI;
-
-			rotationStateRef.current = {
-				trackId,
-				elementId,
-				initialTransform: resolvedTransform,
-				initialAngle,
-				initialBoundsCx: bounds.cx,
-				initialBoundsCy: bounds.cy,
-			};
-			setActiveHandle("rotation");
-			const captureTarget = event.currentTarget as HTMLElement;
-			captureTarget.setPointerCapture(event.pointerId);
-			captureRef.current = {
-				element: captureTarget,
-				pointerId: event.pointerId,
-			};
+		scene: {
+			getSelectedElements: () => selectedElements,
+			getTracks: () => tracks,
+			getCurrentTime: () => currentTime,
+			getMediaAssets: () => mediaAssets,
+			getCanvasSize: () => canvasSize,
 		},
-		[selectedWithBounds, viewport],
-	);
-
-	const handleEdgePointerDown = useCallback(
-		({ event, edge }: { event: React.PointerEvent; edge: Edge }) => {
-			if (!selectedWithBounds) return;
-			event.stopPropagation();
-
-			const { bounds, trackId, elementId, element } = selectedWithBounds;
-			if (!isVisualElement(element)) return;
-
-			const localTime = getElementLocalTime({
-				timelineTime: currentTimeRef.current,
-				elementStartTime: element.startTime,
-				elementDuration: element.duration,
-			});
-			const resolvedTransform = resolveTransformAtTime({
-				baseTransform: element.transform,
-				animations: element.animations,
-				localTime,
-			});
-
-			const baseWidth = bounds.width / resolvedTransform.scaleX;
-			const baseHeight = bounds.height / resolvedTransform.scaleY;
-			const rotationRad = (bounds.rotation * Math.PI) / 180;
-
-			const propertyPath =
-				edge === "right" || edge === "left"
-					? "transform.scaleX"
-					: "transform.scaleY";
-			const shouldClearScaleAnimation = hasKeyframesForPath({
-				animations: element.animations,
-				propertyPath,
-			});
-			const animationsWithoutScale = shouldClearScaleAnimation
-				? setChannel({
-						animations: element.animations,
-						propertyPath,
-						channel: undefined,
-					})
-				: element.animations;
-
-			edgeScaleStateRef.current = {
-				trackId,
-				elementId,
-				initialTransform: resolvedTransform,
-				initialBoundsCx: bounds.cx,
-				initialBoundsCy: bounds.cy,
-				baseWidth,
-				baseHeight,
-				edge,
-				rotationRad,
-				shouldClearScaleAnimation,
-				animationsWithoutScale,
-			};
-			setActiveHandle(edge);
-			const captureTarget = event.currentTarget as HTMLElement;
-			captureTarget.setPointerCapture(event.pointerId);
-			captureRef.current = {
-				element: captureTarget,
-				pointerId: event.pointerId,
-			};
+		timeline: {
+			previewElements: (updates) =>
+				editor.timeline.previewElements({ updates }),
+			commitPreview: () => editor.timeline.commitPreview(),
+			discardPreview: () => editor.timeline.discardPreview(),
 		},
-		[selectedWithBounds],
-	);
-
-	const handlePointerMove = useCallback(
-		({ event }: { event: React.PointerEvent }) => {
-			if (
-				!scaleStateRef.current &&
-				!rotationStateRef.current &&
-				!edgeScaleStateRef.current
-			)
-				return;
-
-			const position = viewport.screenToCanvas({
-				clientX: event.clientX,
-				clientY: event.clientY,
-			});
-			if (!position) return;
-
-			if (
-				scaleStateRef.current &&
-				activeHandle &&
-				activeHandle !== "rotation"
-			) {
-				const {
-					trackId,
-					elementId,
-					initialTransform,
-					initialDistance,
-					initialBoundsCx,
-					initialBoundsCy,
-					baseWidth,
-					baseHeight,
-					shouldClearScaleAnimation,
-					animationsWithoutScale,
-				} = scaleStateRef.current;
-
-				const deltaX = position.x - initialBoundsCx;
-				const deltaY = position.y - initialBoundsCy;
-				const currentDistance =
-					Math.sqrt(deltaX * deltaX + deltaY * deltaY) || 1;
-				const scaleFactor = currentDistance / initialDistance;
-
-				// Use actual element dimensions (base * current scale) so snap
-				// computes the correct edges when scaleX ≠ scaleY
-				const effectiveWidth = baseWidth * initialTransform.scaleX;
-				const effectiveHeight = baseHeight * initialTransform.scaleY;
-
-				const snapThreshold = viewport.screenPixelsToLogicalThreshold({
-					screenPixels: SNAP_THRESHOLD_SCREEN_PIXELS,
-				});
-				const { snappedScale: snappedFactor, activeLines } =
-					isShiftHeldRef.current
-						? { snappedScale: scaleFactor, activeLines: [] as SnapLine[] }
-						: snapScale({
-								proposedScale: scaleFactor,
-								position: initialTransform.position,
-								baseWidth: effectiveWidth,
-								baseHeight: effectiveHeight,
-								rotation: initialTransform.rotate,
-								canvasSize,
-								snapThreshold,
-							});
-
-				onSnapLinesChange?.(activeLines);
-
-				editor.timeline.previewElements({
-					updates: [
-						{
-							trackId,
-							elementId,
-							updates: {
-								transform: {
-									...initialTransform,
-									scaleX: clampScaleNonZero(
-										initialTransform.scaleX * snappedFactor,
-									),
-									scaleY: clampScaleNonZero(
-										initialTransform.scaleY * snappedFactor,
-									),
-								},
-								...(shouldClearScaleAnimation && {
-									animations: animationsWithoutScale,
-								}),
-							},
-						},
-					],
-				});
-				return;
-			}
-
-			if (
-				edgeScaleStateRef.current &&
-				(activeHandle === "right" ||
-					activeHandle === "left" ||
-					activeHandle === "bottom")
-			) {
-				const {
-					trackId,
-					elementId,
-					initialTransform,
-					initialBoundsCx,
-					initialBoundsCy,
-					baseWidth,
-					baseHeight,
-					edge,
-					rotationRad,
-					shouldClearScaleAnimation,
-					animationsWithoutScale,
-				} = edgeScaleStateRef.current;
-
-				const deltaX = position.x - initialBoundsCx;
-				const deltaY = position.y - initialBoundsCy;
-				const xProjection =
-					deltaX * Math.cos(rotationRad) + deltaY * Math.sin(rotationRad);
-				const yProjection =
-					-deltaX * Math.sin(rotationRad) + deltaY * Math.cos(rotationRad);
-				const projection =
-					edge === "right"
-						? xProjection
-						: edge === "left"
-							? -xProjection
-							: yProjection;
-
-				const baseAxisHalf =
-					edge === "right" || edge === "left" ? baseWidth / 2 : baseHeight / 2;
-				const proposedScale = clampScaleNonZero(projection / baseAxisHalf);
-
-				const proposedScaleX =
-					edge === "right" || edge === "left"
-						? proposedScale
-						: initialTransform.scaleX;
-				const proposedScaleY =
-					edge === "bottom" ? proposedScale : initialTransform.scaleY;
-
-				const snapThreshold = viewport.screenPixelsToLogicalThreshold({
-					screenPixels: SNAP_THRESHOLD_SCREEN_PIXELS,
-				});
-				const { x: xSnap, y: ySnap } = isShiftHeldRef.current
-					? {
-							x: {
-								snappedScale: proposedScaleX,
-								snapDistance: Infinity,
-								activeLines: [] as SnapLine[],
-							},
-							y: {
-								snappedScale: proposedScaleY,
-								snapDistance: Infinity,
-								activeLines: [] as SnapLine[],
-							},
-						}
-					: snapScaleAxes({
-							proposedScaleX,
-							proposedScaleY,
-							position: initialTransform.position,
-							baseWidth,
-							baseHeight,
-							rotation: initialTransform.rotate,
-							canvasSize,
-							snapThreshold,
-							preferredEdges: getPreferredEdge({ edge }),
-						});
+		preview: {
+			onSnapLinesChange,
+		},
+	};
 
-				const relevantSnap =
-					edge === "right" || edge === "left" ? xSnap : ySnap;
-				onSnapLinesChange?.(relevantSnap.activeLines);
+	const depsRef = useRef<TransformHandleDeps>(deps);
+	depsRef.current = deps;
 
-				editor.timeline.previewElements({
-					updates: [
-						{
-							trackId,
-							elementId,
-							updates: {
-								transform: {
-									...initialTransform,
-									scaleX:
-										edge === "right" || edge === "left"
-											? xSnap.snappedScale
-											: initialTransform.scaleX,
-									scaleY:
-										edge === "bottom"
-											? ySnap.snappedScale
-											: initialTransform.scaleY,
-								},
-								...(shouldClearScaleAnimation && {
-									animations: animationsWithoutScale,
-								}),
-							},
-						},
-					],
-				});
-				return;
-			}
+	const controllerRef = useRef<TransformHandleController | null>(null);
+	if (!controllerRef.current) {
+		controllerRef.current = new TransformHandleController({ depsRef });
+	}
+	const controller = controllerRef.current;
 
-			if (rotationStateRef.current && activeHandle === "rotation") {
-				const {
-					trackId,
-					elementId,
-					initialTransform,
-					initialAngle,
-					initialBoundsCx,
-					initialBoundsCy,
-				} = rotationStateRef.current;
+	const [, rerender] = useReducer((n: number) => n + 1, 0);
+	useEffect(() => controller.subscribe(rerender), [controller]);
 
-				const deltaX = position.x - initialBoundsCx;
-				const deltaY = position.y - initialBoundsCy;
-				const currentAngle = (Math.atan2(deltaY, deltaX) * 180) / Math.PI;
-				let deltaAngle = currentAngle - initialAngle;
-				if (deltaAngle > 180) deltaAngle -= 360;
-				if (deltaAngle < -180) deltaAngle += 360;
-				const newRotate = initialTransform.rotate + deltaAngle;
-				const { snappedRotation } = isShiftHeldRef.current
-					? { snappedRotation: newRotate }
-					: snapRotation({ proposedRotation: newRotate });
+	useEffect(() => {
+		if (!controller.isActive) return;
+		return registerCanceller({ fn: () => controller.cancel() });
+	}, [controller, controller.isActive]);
 
-				editor.timeline.previewElements({
-					updates: [
-						{
-							trackId,
-							elementId,
-							updates: {
-								transform: { ...initialTransform, rotate: snappedRotation },
-							},
-						},
-					],
-				});
-			}
-		},
-		[
-			activeHandle,
-			canvasSize,
-			editor,
-			isShiftHeldRef,
-			onSnapLinesChange,
-			viewport,
-		],
-	);
+	useEffect(() => () => controller.destroy(), [controller]);
 
-	const handlePointerUp = useCallback(() => {
-		if (
-			scaleStateRef.current ||
-			rotationStateRef.current ||
-			edgeScaleStateRef.current
-		) {
-			editor.timeline.commitPreview();
-			clearActiveHandleState();
-		}
-		releaseCapturedPointer();
-	}, [clearActiveHandleState, editor, releaseCapturedPointer]);
+	const selectedWithBounds = controller.selectedWithBounds;
+	const hasVisualSelection = selectedWithBounds !== null;
 
 	return {
 		selectedWithBounds,
 		hasVisualSelection,
-		activeHandle,
-		handleCornerPointerDown,
-		handleEdgePointerDown,
-		handleRotationPointerDown,
-		handlePointerMove,
-		handlePointerUp,
+		activeHandle: controller.activeHandle,
+		handleCornerPointerDown: controller.onCornerPointerDown,
+		handleEdgePointerDown: controller.onEdgePointerDown,
+		handleRotationPointerDown: controller.onRotationPointerDown,
+		handlePointerMove: controller.onPointerMove,
+		handlePointerUp: controller.onPointerUp,
 	};
 }