import { startFramePulse } from "./FramePulse";

const invalidate = jest.fn();
let stops: Array<() => void> = [];

/** Liga a batida e guarda o desligamento para o afterEach não deixar ouvinte para trás. */
function start(options?: Parameters<typeof startFramePulse>[1]) {
  const stop = startFramePulse(invalidate, options);
  stops.push(stop);
  return stop;
}

beforeEach(() => {
  jest.useFakeTimers();
  invalidate.mockClear();
  stops = [];
});

afterEach(() => {
  for (const stop of stops) stop();
  jest.useRealTimers();
});

const advance = (ms: number) => jest.advanceTimersByTime(ms);

describe("startFramePulse", () => {
  it("asks for frames at about 30 per second, not 60", () => {
    start();
    advance(1000);
    expect(invalidate.mock.calls.length).toBeGreaterThan(20);
    expect(invalidate.mock.calls.length).toBeLessThanOrEqual(34);
  });

  it("asks for the first frame right away", () => {
    start();
    expect(invalidate).toHaveBeenCalledTimes(1);
  });

  it("is a single setInterval, never a second animation-frame loop", () => {
    const frames = jest.spyOn(window, "requestAnimationFrame");
    start();
    expect(jest.getTimerCount()).toBe(1);
    advance(1000);
    expect(frames).not.toHaveBeenCalled();
    frames.mockRestore();
  });

  it("does nothing once it is stopped (the hero is off screen)", () => {
    const stop = start();
    advance(200);
    const running = invalidate.mock.calls.length;
    expect(running).toBeGreaterThan(0);

    stop();
    advance(1000);
    expect(invalidate.mock.calls.length).toBe(running);
    expect(jest.getTimerCount()).toBe(0);
  });

  it("removes its listeners when it stops", () => {
    const stop = start();
    stop();
    invalidate.mockClear();

    window.dispatchEvent(new Event("pointermove"));
    advance(500);
    expect(invalidate).not.toHaveBeenCalled();
    expect(jest.getTimerCount()).toBe(0);
  });

  it("can be stopped twice", () => {
    const stop = start();
    stop();
    expect(() => stop()).not.toThrow();
  });
});

describe("startFramePulse: stops when nobody is looking", () => {
  it("stops drawing, and has no timer left, after 5 s without a cursor or scroll", () => {
    start();
    advance(4000);
    const drawn = invalidate.mock.calls.length;
    expect(drawn).toBeGreaterThan(80); // ainda batendo, ~30 por segundo

    advance(1500); // passou dos 5 s
    const stopped = invalidate.mock.calls.length;
    // parou perto dos 5 s: no máximo 5 s de batidas a ~30 por segundo
    expect(stopped).toBeLessThanOrEqual(5 * 32);

    advance(3000);
    expect(invalidate.mock.calls.length).toBe(stopped);
    expect(jest.getTimerCount()).toBe(0);
  });

  it.each([["pointermove"], ["scroll"], ["wheel"], ["keydown"]])(
    "wakes up again with %s and keeps drawing",
    (type) => {
      start();
      advance(7000);
      const stopped = invalidate.mock.calls.length;

      window.dispatchEvent(new Event(type));
      advance(500);

      expect(invalidate.mock.calls.length).toBeGreaterThan(stopped + 8);
    },
  );

  it("wakes up once, not once per gesture (one timer, however many events arrive)", () => {
    start();
    for (let i = 0; i < 20; i++) window.dispatchEvent(new Event("pointermove"));
    expect(jest.getTimerCount()).toBe(1);
  });

  it("each gesture buys another 5 s: it does not stop while there is movement", () => {
    start();
    for (let i = 0; i < 4; i++) {
      advance(3000);
      window.dispatchEvent(new Event("pointermove"));
    }
    const before = invalidate.mock.calls.length;

    advance(1000);

    expect(invalidate.mock.calls.length).toBeGreaterThan(before + 20);
  });

  it("lets the idle time and the rate be configured", () => {
    start({ idleMs: 1000 });
    advance(1500);
    const stopped = invalidate.mock.calls.length;
    advance(2000);
    expect(invalidate.mock.calls.length).toBe(stopped);

    invalidate.mockClear();
    start({ fps: 10 });
    advance(1000);
    expect(invalidate.mock.calls.length).toBeLessThanOrEqual(11);
    expect(invalidate.mock.calls.length).toBeGreaterThanOrEqual(9);
  });
});