import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import { renderHook } from '@testing-library/react';
import { useReducedMotion } from '../../hooks/useReducedMotion';

type Listener = (e: { matches: boolean }) => void;

function createMatchMediaMock(initialMatches: boolean) {
  const listeners = new Set<Listener>();
  const mql = {
    matches: initialMatches,
    media: '',
    addEventListener: vi.fn((_evt: string, cb: Listener) => {
      listeners.add(cb);
    }),
    removeEventListener: vi.fn((_evt: string, cb: Listener) => {
      listeners.delete(cb);
    }),
    addListener: vi.fn((cb: Listener) => listeners.add(cb)),
    removeListener: vi.fn((cb: Listener) => listeners.delete(cb)),
    dispatchEvent: vi.fn(),
    onchange: null,
  };
  return { mql };
}

describe('useReducedMotion', () => {
  let originalMatchMedia: typeof window.matchMedia | undefined;

  beforeEach(() => {
    originalMatchMedia = window.matchMedia;
  });

  afterEach(() => {
    if (originalMatchMedia) {
      window.matchMedia = originalMatchMedia;
    } else {
      // @ts-expect-error cleanup
      delete window.matchMedia;
    }
    vi.restoreAllMocks();
  });

  it('returns false when matchMedia reports no match', () => {
    const { mql } = createMatchMediaMock(false);
    window.matchMedia = vi.fn().mockReturnValue(mql) as unknown as typeof window.matchMedia;

    const { result } = renderHook(() => useReducedMotion());
    expect(result.current).toBe(false);
  });

  it('returns true when matchMedia reports a match', () => {
    const { mql } = createMatchMediaMock(true);
    window.matchMedia = vi.fn().mockReturnValue(mql) as unknown as typeof window.matchMedia;

    const { result } = renderHook(() => useReducedMotion());
    expect(result.current).toBe(true);
  });
});