/**
 * https://stackoverflow.com/a/58651649
 *
 * Utility function that mocks the `IntersectionObserver` API. Necessary for components that rely
 * on it, otherwise the tests will crash. Recommended to execute inside `beforeEach`.
 * @param intersectionObserverMock - Parameter that is sent to the `Object.defineProperty`
 * overwrite method. `jest.fn()` mock functions can be passed here if the goal is to not only
 * mock the intersection observer, but its methods.
 */
function setupIntersectionObserverMock({
  root = null,
  rootMargin = '',
  thresholds = [],
  disconnect = () => null,
  observe = () => null,
  takeRecords = () => [],
  unobserve = () => null,
} = {}): void {
  class MockIntersectionObserver implements IntersectionObserver {
    readonly root: Element | null = root;

    readonly rootMargin: string = rootMargin;

    readonly thresholds: ReadonlyArray < number > = thresholds;

    disconnect: () => void = disconnect;

    observe: (target: Element) => void = observe;

    takeRecords: () => IntersectionObserverEntry[] = takeRecords;

    unobserve: (target: Element) => void = unobserve;
  }

  Object.defineProperty(
    window,
    'IntersectionObserver', {
      writable: true,
      configurable: true,
      value: MockIntersectionObserver,
    },
  );

  Object.defineProperty(
    globalThis,
    'IntersectionObserver', {
      writable: true,
      configurable: true,
      value: MockIntersectionObserver,
    },
  );
}

export default setupIntersectionObserverMock;