import { afterEach, beforeEach, describe, expect, it, vi } from "vite-plus/test"; import { observeVisibleAnimation } from "./visibleAnimation"; let page = Object.assign(new EventTarget(), { visibilityState: "visible" });let motion = Object.assign(new EventTarget(), { matches: false });let observers: TestIntersectionObserver[] = [];let cleanups: Array<() => void> = []; class TestIntersectionObserver {  constructor(private readonly callback: IntersectionObserverCallback) {    observers.push(this);  }   observe = vi.fn();  unobserve = vi.fn();  disconnect = vi.fn();   report(target: Element, isIntersecting: boolean) {    this.callback(      [{ target, isIntersecting } as IntersectionObserverEntry],      this as unknown as IntersectionObserver,    );  }} function animationElement() {  const properties = new Map<string, string>();  const element = {    style: { setProperty: (name: string, value: string) => properties.set(name, value) },  } as unknown as HTMLElement;  return {    element,    state: () => properties.get("--visible-animation-state"),    willChange: () => properties.get("--visible-animation-will-change"),  };} function attach(element: HTMLElement) {  const cleanup = observeVisibleAnimation(element);  if (cleanup) cleanups.push(cleanup);  return cleanup;} beforeEach(() => {  page = Object.assign(new EventTarget(), { visibilityState: "visible" });  motion = Object.assign(new EventTarget(), { matches: false });  observers = [];  cleanups = [];  vi.stubGlobal("document", page);  vi.stubGlobal("window", { matchMedia: () => motion });  vi.stubGlobal("IntersectionObserver", TestIntersectionObserver);}); afterEach(() => {  for (const cleanup of cleanups) cleanup();  vi.unstubAllGlobals();  vi.restoreAllMocks();}); describe("observeVisibleAnimation", () => {  it("runs only intersecting animations in a visible document with motion enabled", () => {    const first = animationElement();    const second = animationElement();    attach(first.element);    attach(second.element);    expect(first.state()).toBe("paused");     const observer = observers[0]!;    observer.report(first.element, true);    expect(first.state()).toBe("running");    expect(second.state()).toBe("paused");     page.visibilityState = "hidden";    page.dispatchEvent(new Event("visibilitychange"));    observer.report(second.element, true);    expect(first.state()).toBe("paused");    expect(first.willChange()).toBe("auto");    expect(second.state()).toBe("paused");     page.visibilityState = "visible";    page.dispatchEvent(new Event("visibilitychange"));    expect(first.state()).toBe("running");    expect(second.state()).toBe("running");     observer.report(first.element, false);    motion.matches = true;    motion.dispatchEvent(new Event("change"));    expect(first.state()).toBe("paused");    expect(second.state()).toBe("paused");     motion.matches = false;    motion.dispatchEvent(new Event("change"));    expect(first.state()).toBe("paused");    expect(second.state()).toBe("running");  });   it.each(["hidden", "reduced motion"])("starts paused with %s already active", (condition) => {    page.visibilityState = condition === "hidden" ? "hidden" : "visible";    motion.matches = condition === "reduced motion";    const animation = animationElement();    attach(animation.element);    observers[0]!.report(animation.element, true);    expect(animation.state()).toBe("paused");     page.visibilityState = "visible";    motion.matches = false;    page.dispatchEvent(new Event("visibilitychange"));    expect(animation.state()).toBe("running");  });   it("shares observers, releases the final ref, and ignores late callbacks after remount", () => {    const addVisibility = vi.spyOn(page, "addEventListener");    const removeVisibility = vi.spyOn(page, "removeEventListener");    const addMotion = vi.spyOn(motion, "addEventListener");    const removeMotion = vi.spyOn(motion, "removeEventListener");    const first = animationElement();    const second = animationElement();    const detachFirst = attach(first.element);    const detachSecond = attach(second.element);    expect(observers).toHaveLength(1);    expect(addVisibility).toHaveBeenCalledTimes(1);    expect(addMotion).toHaveBeenCalledTimes(1);     const previousObserver = observers[0]!;    detachFirst?.();    previousObserver.report(first.element, true);    expect(first.state()).toBe("paused");    expect(previousObserver.unobserve).toHaveBeenCalledWith(first.element);    expect(previousObserver.disconnect).not.toHaveBeenCalled();     detachSecond?.();    expect(previousObserver.disconnect).toHaveBeenCalledTimes(1);    expect(removeVisibility).toHaveBeenCalledTimes(1);    expect(removeMotion).toHaveBeenCalledTimes(1);     attach(second.element);    expect(observers).toHaveLength(2);    detachSecond?.();    previousObserver.report(second.element, true);    expect(second.state()).toBe("paused");    observers[1]!.report(second.element, true);    expect(second.state()).toBe("running");  });   it("keeps unknown visibility static when IntersectionObserver is unavailable", () => {    vi.stubGlobal("IntersectionObserver", undefined);    const animation = animationElement();    attach(animation.element);    expect(animation.state()).toBe("paused");    expect(animation.willChange()).toBe("auto");    expect(observers).toHaveLength(0);  });});