1 files changed, 190 insertions, 0 deletions
diff --git a/apps/web/src/timeline/controllers/__tests__/drag-drop-controller-transition.test.ts b/apps/web/src/timeline/controllers/__tests__/drag-drop-controller-transition.test.ts
new file mode 100644
index 00000000..b24f9ad9
--- /dev/null
+++ b/apps/web/src/timeline/controllers/__tests__/drag-drop-controller-transition.test.ts
@@ -0,0 +1,190 @@
+import { describe, expect, mock, test } from "bun:test";
+import type { DragEvent } from "react";
+import type { SceneTracks, VideoElement, VideoTrack } from "@/timeline";
+import {
+	DragDropController,
+	type DragDropConfig,
+	type DragDropConfigRef,
+} from "@/timeline/controllers/drag-drop-controller";
+import { TimelineDragSource } from "@/timeline/drag-source";
+import { mediaTime, TICKS_PER_SECOND, ZERO_MEDIA_TIME } from "@/wasm";
+
+function buildVideo({
+	id,
+	start,
+}: {
+	id: string;
+	start: number;
+}): VideoElement {
+	return {
+		id,
+		type: "video",
+		name: id,
+		mediaId: `media-${id}`,
+		startTime: mediaTime({ ticks: start }),
+		duration: mediaTime({ ticks: TICKS_PER_SECOND }),
+		trimStart: ZERO_MEDIA_TIME,
+		trimEnd: ZERO_MEDIA_TIME,
+		params: { opacity: id === "incoming" ? 0.8 : 1 },
+	};
+}
+
+function buildTracks(): SceneTracks {
+	const main: VideoTrack = {
+		id: "visual",
+		type: "video",
+		name: "Visual",
+		elements: [
+			buildVideo({ id: "outgoing", start: 0 }),
+			buildVideo({ id: "incoming", start: TICKS_PER_SECOND }),
+		],
+		muted: false,
+		hidden: false,
+	};
+	return { overlay: [], main, audio: [] };
+}
+
+function buildDataTransfer(): DataTransfer {
+	return {
+		types: [],
+		files: [],
+		dropEffect: "none",
+		effectAllowed: "none",
+		setData: mock(() => {}),
+	} as unknown as DataTransfer;
+}
+
+function buildDragEvent({
+	clientX,
+	dataTransfer,
+}: {
+	clientX: number;
+	dataTransfer: DataTransfer;
+}): DragEvent {
+	return {
+		clientX,
+		clientY: 10,
+		dataTransfer,
+		preventDefault: mock(() => {}),
+	} as unknown as DragEvent;
+}
+
+function setup() {
+	const dragSource = new TimelineDragSource();
+	const updateElements = mock<DragDropConfig["updateElements"]>(() => {});
+	const insertElement = mock<DragDropConfig["insertElement"]>(() => {});
+	const executeCommand = mock<DragDropConfig["executeCommand"]>(() => {});
+	const tracksElement = {
+		scrollLeft: 0,
+		scrollTop: 0,
+		getBoundingClientRect: () => ({ left: 0, top: 0 }),
+	} as unknown as HTMLDivElement;
+	const config: DragDropConfig = {
+		zoomLevel: 1,
+		getContainerEl: () => tracksElement,
+		getHeaderEl: () => null,
+		getTracksScrollEl: () => tracksElement,
+		getActiveProjectFps: () => null,
+		getActiveProjectId: () => null,
+		getSceneTracks: buildTracks,
+		getCurrentPlayheadTime: () => ZERO_MEDIA_TIME,
+		getMediaAssets: () => [],
+		dragSource,
+		addMediaAsset: () => Promise.resolve(null),
+		executeCommand,
+		insertElement,
+		updateElements,
+		addClipEffect: mock(() => {}),
+	};
+	const configRef: DragDropConfigRef = { current: config };
+	return {
+		controller: new DragDropController({ configRef }),
+		dragSource,
+		updateElements,
+		insertElement,
+		executeCommand,
+	};
+}
+
+function beginTransitionDrag(
+	dragSource: TimelineDragSource,
+	dataTransfer: DataTransfer,
+) {
+	dragSource.begin({
+		dataTransfer,
+		dragData: {
+			type: "transition",
+			id: "push-left",
+			name: "Slide left",
+			transitionKind: "push-left",
+			inDuration: 0.45,
+			outDuration: 0,
+		},
+	});
+}
+
+describe("DragDropController transition drops", () => {
+	test("hovers and applies a transition only to the incoming clip", () => {
+		const {
+			controller,
+			dragSource,
+			updateElements,
+			insertElement,
+			executeCommand,
+		} = setup();
+		const dataTransfer = buildDataTransfer();
+		beginTransitionDrag(dragSource, dataTransfer);
+
+		controller.onDragOver(buildDragEvent({ clientX: 50, dataTransfer }));
+
+		expect(dataTransfer.dropEffect).toBe("copy");
+		expect(controller.dropTarget?.targetCut).toEqual({
+			trackId: "visual",
+			outgoingElementId: "outgoing",
+			incomingElementId: "incoming",
+			time: mediaTime({ ticks: TICKS_PER_SECOND }),
+		});
+
+		controller.onDrop(buildDragEvent({ clientX: 50, dataTransfer }));
+
+		expect(updateElements).toHaveBeenCalledTimes(1);
+		expect(updateElements).toHaveBeenCalledWith({
+			updates: [
+				{
+					trackId: "visual",
+					elementId: "incoming",
+					patch: {
+						params: {
+							opacity: 0.8,
+							"transition.kind": "push-left",
+							"transition.inDuration": 0.45,
+							"transition.outDuration": 0,
+						},
+					},
+				},
+			],
+		});
+		expect(insertElement).not.toHaveBeenCalled();
+		expect(executeCommand).not.toHaveBeenCalled();
+	});
+
+	test("does nothing when the transition has no cut target", () => {
+		const {
+			controller,
+			dragSource,
+			updateElements,
+			insertElement,
+			executeCommand,
+		} = setup();
+		const dataTransfer = buildDataTransfer();
+		beginTransitionDrag(dragSource, dataTransfer);
+
+		controller.onDragOver(buildDragEvent({ clientX: 80, dataTransfer }));
+		expect(controller.dropTarget).toBeNull();
+		controller.onDrop(buildDragEvent({ clientX: 80, dataTransfer }));
+
+		expect(updateElements).not.toHaveBeenCalled();
+		expect(insertElement).not.toHaveBeenCalled();
+		expect(executeCommand).not.toHaveBeenCalled();
+	});
+});