perf(studio): stabilize virtualized beat gestures

packages/studio/src/player/components/BeatStrip.test.tsx

@@ -0,0 +1,307 @@
+// @vitest-environment happy-dom
+
+import React, { act } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import type { TimelineElement } from "../store/playerStore";
+import { usePlayerStore } from "../store/playerStore";
+import { BeatStrip } from "./BeatStrip";
+
+(globalThis as unknown as { IS_REACT_ACT_ENVIRONMENT: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+const roots: Root[] = [];
+const requestSeek = vi.fn();
+const commitBeatEdits = usePlayerStore.getState().commitBeatEdits;
+const commitBeatEditsSpy = vi.fn((...args: Parameters<typeof commitBeatEdits>) =>
+  commitBeatEdits(...args),
+);
+const MUSIC_ELEMENT: TimelineElement = {
+  id: "background-music",
+  label: "Music",
+  tag: "audio",
+  src: "music.mp3",
+  start: 0,
+  duration: 10,
+  track: 0,
+  timelineRole: "music",
+};
+const BEAT_ANALYSIS = {
+  beatTimes: [1, 3],
+  beatStrengths: [0.5, 0.8],
+  bpm: 120,
+  bpmConfidence: "high" as const,
+  channelData: null,
+  sampleRate: 48_000,
+  peak: 1,
+};
+
+function pointerEvent(type: string, init: PointerEventInit): Event {
+  if (typeof PointerEvent === "function") return new PointerEvent(type, init);
+  const event = new MouseEvent(type, init);
+  Object.defineProperty(event, "pointerId", { value: init.pointerId ?? 0 });
+  return event;
+}
+
+function mountBeatStrip(renderTimeRange?: { start: number; end: number }) {
+  const viewport = document.createElement("div");
+  viewport.dataset.timelineScrollViewport = "";
+  Object.defineProperties(viewport, {
+    clientWidth: { configurable: true, value: 500 },
+    clientHeight: { configurable: true, value: 300 },
+    scrollWidth: { configurable: true, value: 2_000 },
+    scrollHeight: { configurable: true, value: 2_000 },
+  });
+  viewport.getBoundingClientRect = () =>
+    ({ left: 0, right: 1_000, top: 0, bottom: 500, width: 1_000, height: 500 }) as DOMRect;
+  Object.assign(viewport, {
+    setPointerCapture: vi.fn(),
+    hasPointerCapture: vi.fn(() => true),
+    releasePointerCapture: vi.fn(),
+  });
+  document.body.appendChild(viewport);
+  const root = createRoot(viewport);
+  roots.push(root);
+  act(() => {
+    root.render(
+      <BeatStrip
+        beatTimes={[1, 3]}
+        beatStrengths={[0.5, 0.8]}
+        pps={100}
+        renderTimeRange={renderTimeRange}
+      />,
+    );
+  });
+  return { root, viewport };
+}
+
+function firstBeat(): HTMLDivElement {
+  const beat = document.querySelector<HTMLDivElement>(
+    '[title="Drag to move · double-click to delete"]',
+  );
+  if (!beat) throw new Error("Expected a beat handle");
+  return beat;
+}
+
+function startBeatDrag(clientX = 100, pointerId = 1): void {
+  act(() => {
+    firstBeat().dispatchEvent(
+      pointerEvent("pointerdown", { bubbles: true, button: 0, clientX, clientY: 100, pointerId }),
+    );
+  });
+  expect(usePlayerStore.getState().beatDragging).toBe(true);
+}
+
+function releaseBeatDrag(clientX = 140, pointerId = 1): void {
+  act(() => {
+    window.dispatchEvent(
+      pointerEvent("pointerup", { bubbles: true, clientX, clientY: 100, pointerId }),
+    );
+  });
+}
+
+function expectCancelledBeatDrag(): void {
+  expect(commitBeatEditsSpy).not.toHaveBeenCalled();
+  expect(usePlayerStore.getState().beatDragging).toBe(false);
+}
+
+function expectCommittedBeatAt(time: number): void {
+  expect(commitBeatEditsSpy).toHaveBeenCalledExactlyOnceWith(expect.anything(), "move beat");
+  expect(usePlayerStore.getState().beatEdits?.added[0]?.time).toBe(time);
+}
+
+beforeEach(() => {
+  commitBeatEditsSpy.mockClear();
+  requestSeek.mockReset();
+  usePlayerStore.setState({
+    timelineSessionEpoch: 1,
+    timelineProjectId: "project-a",
+    beatDragging: false,
+    requestSeek,
+    elements: [MUSIC_ELEMENT],
+    beatAnalysis: BEAT_ANALYSIS,
+    beatEdits: null,
+    commitBeatEdits: commitBeatEditsSpy,
+  });
+});
+
+afterEach(() => {
+  act(() => window.dispatchEvent(new Event("blur")));
+  for (const root of roots.splice(0)) act(() => root.unmount());
+  document.body.innerHTML = "";
+  vi.unstubAllGlobals();
+});
+
+describe("BeatStrip gesture ownership", () => {
+  it("commits once after its source row unmounts", () => {
+    const { root } = mountBeatStrip();
+    startBeatDrag();
+    act(() => root.render(null));
+    expect(usePlayerStore.getState().beatDragging).toBe(true);
+
+    act(() => {
+      window.dispatchEvent(
+        pointerEvent("pointermove", {
+          bubbles: true,
+          clientX: 140,
+          clientY: 100,
+          pointerId: 1,
+        }),
+      );
+      window.dispatchEvent(
+        pointerEvent("pointerup", {
+          bubbles: true,
+          clientX: 140,
+          clientY: 100,
+          pointerId: 1,
+        }),
+      );
+      window.dispatchEvent(
+        pointerEvent("pointerup", {
+          bubbles: true,
+          clientX: 160,
+          clientY: 100,
+          pointerId: 1,
+        }),
+      );
+    });
+
+    expectCommittedBeatAt(1.4);
+    expect(usePlayerStore.getState().beatDragging).toBe(false);
+  });
+
+  it("includes viewport scrolling in the final beat time", () => {
+    const { viewport } = mountBeatStrip();
+    startBeatDrag(100);
+    viewport.scrollLeft = 50;
+
+    releaseBeatDrag(110);
+    expectCommittedBeatAt(1.6);
+  });
+
+  it("cancels without mutation on pointer cancel, Escape, and project switch", () => {
+    mountBeatStrip();
+    startBeatDrag();
+    act(() => {
+      window.dispatchEvent(pointerEvent("pointercancel", { pointerId: 1 }));
+      window.dispatchEvent(pointerEvent("pointerup", { clientX: 140, clientY: 100, pointerId: 1 }));
+    });
+
+    startBeatDrag();
+    act(() => window.dispatchEvent(new KeyboardEvent("keydown", { key: "Escape" })));
+
+    startBeatDrag();
+    act(() => usePlayerStore.getState().beginTimelineSession("project-b"));
+    releaseBeatDrag();
+    expectCancelledBeatDrag();
+  });
+
+  it("cancels without mutation when the captured music source disappears", () => {
+    mountBeatStrip();
+    startBeatDrag();
+    act(() => usePlayerStore.setState({ elements: [] }));
+    releaseBeatDrag();
+    expectCancelledBeatDrag();
+  });
+
+  it("cancels when the captured beat disappears during the gesture", () => {
+    mountBeatStrip();
+    startBeatDrag();
+    act(() => {
+      usePlayerStore.setState({
+        beatAnalysis: { ...BEAT_ANALYSIS, beatTimes: [3], beatStrengths: [0.8] },
+      });
+    });
+    releaseBeatDrag();
+    expectCancelledBeatDrag();
+  });
+
+  it("releases the actor when the owning timeline viewport unmounts", async () => {
+    const { viewport } = mountBeatStrip();
+    startBeatDrag();
+
+    await act(async () => {
+      viewport.remove();
+      await Promise.resolve();
+    });
+    releaseBeatDrag();
+    expectCancelledBeatDrag();
+  });
+
+  it("ignores unrelated pointers and keeps the active beat rendered outside the time window", () => {
+    const { root } = mountBeatStrip();
+    startBeatDrag();
+    act(() => {
+      window.dispatchEvent(
+        pointerEvent("pointermove", {
+          bubbles: true,
+          clientX: 150,
+          clientY: 100,
+          pointerId: 2,
+        }),
+      );
+      window.dispatchEvent(
+        pointerEvent("pointerup", {
+          bubbles: true,
+          clientX: 150,
+          clientY: 100,
+          pointerId: 2,
+        }),
+      );
+      root.render(
+        <BeatStrip
+          beatTimes={[1, 3]}
+          beatStrengths={[0.5, 0.8]}
+          pps={100}
+          renderTimeRange={{ start: 2.5, end: 3.5 }}
+        />,
+      );
+    });
+
+    expect(
+      document.querySelectorAll('[title="Drag to move · double-click to delete"]'),
+    ).toHaveLength(2);
+    expect(commitBeatEditsSpy).not.toHaveBeenCalled();
+
+    act(() => {
+      window.dispatchEvent(
+        pointerEvent("pointerup", {
+          bubbles: true,
+          clientX: 150,
+          clientY: 100,
+          pointerId: 1,
+        }),
+      );
+    });
+    expect(commitBeatEditsSpy).toHaveBeenCalledOnce();
+  });
+
+  it("does not autoscroll or mutate below the drag threshold", () => {
+    const requestAnimationFrame = vi.fn(() => 1);
+    vi.stubGlobal("requestAnimationFrame", requestAnimationFrame);
+    vi.stubGlobal("cancelAnimationFrame", vi.fn());
+    mountBeatStrip();
+    startBeatDrag(990);
+
+    act(() => {
+      window.dispatchEvent(
+        pointerEvent("pointermove", {
+          bubbles: true,
+          clientX: 991,
+          clientY: 100,
+          pointerId: 1,
+        }),
+      );
+      window.dispatchEvent(
+        pointerEvent("pointerup", {
+          bubbles: true,
+          clientX: 991,
+          clientY: 100,
+          pointerId: 1,
+        }),
+      );
+    });
+
+    expect(requestAnimationFrame).not.toHaveBeenCalled();
+    expect(commitBeatEditsSpy).not.toHaveBeenCalled();
+  });
+});