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

let mockPathname = "/";
jest.mock("next/navigation", () => ({ usePathname: () => mockPathname }));

// o grão vem por import dinâmico (pacote próprio): aqui ele vira um marcador, e o contador diz se o pacote foi pedido
const mockLoaded = jest.fn();
jest.mock("./FilmGrain", () => {
  mockLoaded();
  return {
    __esModule: true,
    default: function MockGrain() {
      return <div data-testid="grain" />;
    },
  };
});

/** O import dinâmico do grão resolve em microtarefas. */
const loaded = () =>
  act(async () => {
    for (let i = 0; i < 5; i++) await Promise.resolve();
  });

const original = window.matchMedia;

function mockMedia(active: string[] = []) {
  window.matchMedia = jest.fn().mockImplementation((query: string) => ({
    matches: active.includes(query),
    media: query,
    addEventListener() {},
    removeEventListener() {},
  }));
}

beforeEach(() => {
  mockPathname = "/";
  mockMedia();
});

afterEach(() => {
  window.matchMedia = original;
});

/*
 * Os três primeiros testes vêm antes de qualquer um que carregue o grão: o módulo, depois de pedido uma vez, fica
 * no registro do Jest, então "o pacote nunca foi pedido" só vale enquanto ninguém o pediu.
 */
describe("CinematicOverlays: where the grain package is never requested", () => {
  it("does not request the grain on a touch screen (nothing invisible left measuring the page); the progress bar stays", async () => {
    mockMedia(["(pointer: coarse)"]);
    const { container } = render(<CinematicOverlays />);
    await loaded();

    expect(mockLoaded).not.toHaveBeenCalled();
    expect(screen.queryByTestId("grain")).toBeNull();
    // a barra de progresso é CSS puro: continua
    expect(container.querySelector(".ds-scroll-bar")).toBeInTheDocument();
  });

  it("does not request the grain for users who prefer reduced motion", async () => {
    mockMedia(["(prefers-reduced-motion: reduce)"]);
    render(<CinematicOverlays />);
    await loaded();

    expect(mockLoaded).not.toHaveBeenCalled();
    expect(screen.queryByTestId("grain")).toBeNull();
  });

  it("shows nothing, and requests nothing, on the other pages", async () => {
    mockPathname = "/cases";
    const { container } = render(<CinematicOverlays />);
    await loaded();

    expect(mockLoaded).not.toHaveBeenCalled();
    expect(screen.queryByTestId("grain")).toBeNull();
    expect(container).toBeEmptyDOMElement();
  });
});

describe("CinematicOverlays: with a mouse", () => {
  it("shows the scroll progress at once and the film grain as soon as its package arrives", async () => {
    const { container } = render(<CinematicOverlays />);

    // a barra vem no HTML; o grão só depois do import
    expect(container.querySelector(".ds-scroll-bar")).toBeInTheDocument();
    expect(screen.queryByTestId("grain")).toBeNull();

    await loaded();
    expect(screen.getByTestId("grain")).toBeInTheDocument();
    expect(mockLoaded).toHaveBeenCalled();
  });

  it("does not mount the grain if the page unmounts while its package loads", async () => {
    const { unmount } = render(<CinematicOverlays />);
    unmount();

    await loaded();

    expect(screen.queryByTestId("grain")).toBeNull();
  });
});