import { act, render } from "@testing-library/react";
import FilmGrain from "./FilmGrain";

/**
 * Testes de caminhos-base de FilmGrain (complemento de CinematicEffects.test.tsx): cada condição do retângulo
 * de uma tela de projeto (altura, fim acima do topo da janela, início abaixo da janela), várias telas, quadros
 * agrupados e a limpeza ao desmontar.
 */

const INNER_HEIGHT = 800;

function addScreen(
  className: string,
  rect: { top: number; bottom: number; height: number },
) {
  const element = document.createElement("div");
  element.className = className;
  element.getBoundingClientRect = () => rect as DOMRect;
  document.body.append(element);
  return element;
}

beforeEach(() => {
  jest.useFakeTimers();
  Object.defineProperty(window, "innerHeight", {
    configurable: true,
    value: INNER_HEIGHT,
  });
});

afterEach(() => {
  jest.useRealTimers();
  jest.restoreAllMocks();
  document.body.innerHTML = "";
});

function renderGrain() {
  const view = render(<FilmGrain />);
  return { ...view, grain: view.container.firstElementChild as HTMLElement };
}

describe("FilmGrain: is a project screen in view?", () => {
  it("path: a visible screen -> the grain steps aside", () => {
    addScreen("ds-phone", { top: 100, bottom: 700, height: 600 });

    const { grain } = renderGrain();

    expect(grain).toHaveAttribute("data-over-projects");
  });

  it.each([
    ["has no height (hidden by CSS)", { top: 100, bottom: 100, height: 0 }],
    ["ended exactly at the top edge", { top: -600, bottom: 0, height: 600 }],
    ["ended above the window", { top: -900, bottom: -300, height: 600 }],
    [
      "starts exactly at the bottom edge",
      { top: INNER_HEIGHT, bottom: 1400, height: 600 },
    ],
    ["starts below the window", { top: 2000, bottom: 2600, height: 600 }],
  ])("path: a screen that %s -> does not count", (_label, rect) => {
    addScreen("ds-bframe", rect);

    const { grain } = renderGrain();

    expect(grain).not.toHaveAttribute("data-over-projects");
  });

  it("path: just inside the window by one pixel at either edge -> counts", () => {
    addScreen("ds-frame", { top: -599, bottom: 1, height: 600 });
    const top = renderGrain();
    expect(top.grain).toHaveAttribute("data-over-projects");
    top.unmount();
    document.body.innerHTML = "";

    addScreen("ds-frame", { top: INNER_HEIGHT - 1, bottom: 1400, height: 600 });
    const bottom = renderGrain();
    expect(bottom.grain).toHaveAttribute("data-over-projects");
  });

  it("path: one screen off the window and another in view -> counts (any is enough)", () => {
    addScreen("ds-reel", { top: 5000, bottom: 5600, height: 600 });
    addScreen("ds-phone", { top: 100, bottom: 700, height: 600 });

    const { grain } = renderGrain();

    expect(grain).toHaveAttribute("data-over-projects");
  });

  it("path: no project screen on the page -> the grain stays", () => {
    const { grain } = renderGrain();

    expect(grain).not.toHaveAttribute("data-over-projects");
  });
});

describe("FilmGrain: frames and cleanup", () => {
  it("path: many scroll events inside one frame -> the page is measured once", () => {
    const screenEl = addScreen("ds-reel", {
      top: 5000,
      bottom: 5600,
      height: 600,
    });
    const measure = jest.spyOn(screenEl, "getBoundingClientRect");
    renderGrain();
    measure.mockClear();

    act(() => {
      window.dispatchEvent(new Event("scroll"));
      window.dispatchEvent(new Event("scroll"));
      window.dispatchEvent(new Event("resize"));
      jest.advanceTimersByTime(40);
    });

    expect(measure).toHaveBeenCalledTimes(1);
  });

  it("path: unmount -> listeners removed and no measurement afterwards", () => {
    const screenEl = addScreen("ds-reel", {
      top: 5000,
      bottom: 5600,
      height: 600,
    });
    const measure = jest.spyOn(screenEl, "getBoundingClientRect");
    const { unmount } = renderGrain();
    act(() => {
      window.dispatchEvent(new Event("scroll"));
    });

    unmount();
    measure.mockClear();
    act(() => {
      window.dispatchEvent(new Event("scroll"));
      window.dispatchEvent(new Event("resize"));
      jest.advanceTimersByTime(100);
    });

    expect(measure).not.toHaveBeenCalled();
  });
});