// TRACES: UR-034 | DR-038 | UT-207
import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
import { createRotationTimer } from "./heroRotation";

describe("hero banner rotation timer", () => {
  beforeEach(() => vi.useFakeTimers());
  afterEach(() => vi.useRealTimers());

  it("advances once per interval while running", () => {
    const onElapse = vi.fn();
    const timer = createRotationTimer(6000, onElapse);
    timer.restart();

    vi.advanceTimersByTime(6000);
    expect(onElapse).toHaveBeenCalledTimes(1);
    vi.advanceTimersByTime(6000);
    expect(onElapse).toHaveBeenCalledTimes(2);

    timer.stop();
  });

  it("does nothing until started", () => {
    const onElapse = vi.fn();
    createRotationTimer(6000, onElapse);
    vi.advanceTimersByTime(60_000);
    expect(onElapse).not.toHaveBeenCalled();
  });

  // The bug: a manual swipe/click left the interval running, so the banner
  // rotated again almost immediately instead of waiting a full interval.
  it("restarts the countdown from now, not from the last auto-advance", () => {
    const onElapse = vi.fn();
    const timer = createRotationTimer(6000, onElapse);
    timer.restart();

    // 5.5s in the user swipes — the timer must restart from that moment.
    vi.advanceTimersByTime(5500);
    timer.restart();

    // The remaining 500ms of the old countdown must NOT fire.
    vi.advanceTimersByTime(500);
    expect(onElapse).not.toHaveBeenCalled();

    // A full interval after the swipe, it advances.
    vi.advanceTimersByTime(5500);
    expect(onElapse).toHaveBeenCalledTimes(1);

    timer.stop();
  });

  it("does not stack timers when restarted repeatedly", () => {
    const onElapse = vi.fn();
    const timer = createRotationTimer(1000, onElapse);
    timer.restart();
    timer.restart();
    timer.restart();

    vi.advanceTimersByTime(1000);
    expect(onElapse).toHaveBeenCalledTimes(1);

    timer.stop();
  });

  it("stops firing after stop()", () => {
    const onElapse = vi.fn();
    const timer = createRotationTimer(1000, onElapse);
    timer.restart();
    timer.stop();

    vi.advanceTimersByTime(10_000);
    expect(onElapse).not.toHaveBeenCalled();
  });

  it("reports whether it is running", () => {
    const timer = createRotationTimer(1000, () => {});
    expect(timer.isRunning()).toBe(false);
    timer.restart();
    expect(timer.isRunning()).toBe(true);
    timer.stop();
    expect(timer.isRunning()).toBe(false);
  });
});