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

/**
 * Testes de caminhos-base da chegada à home (complemento de CinematicHome.test.tsx): como o navegador chegou
 * (nova, volta/avança, sem a API de navegação), o destino do fragmento (existe, não existe, ficou velho), as teclas
 * e gestos que cancelam a chegada, o clique em âncora antes e depois do layout pronto, o hashchange e a limpeza.
 */

let layoutReady: () => void = () => {};

function Home() {
  layoutReady = useHomeFragmentNavigation();
  return (
    <>
      <a href="/#about">Sobre</a>
      <section id="about" aria-label="Sobre">
        <button type="button">Ler</button>
      </section>
      <section id="contact" aria-label="Contato" />
    </>
  );
}

const about = () => screen.getByRole("region", { name: "Sobre" });
const contact = () => screen.getByRole("region", { name: "Contato" });
const ready = () => act(() => layoutReady());
/** O jsdom não tem performance.getEntriesByType (é o caso "navegador sem a API"); aqui ela passa a existir. */
function navigationEntries(type?: string) {
  Object.defineProperty(performance, "getEntriesByType", {
    configurable: true,
    writable: true,
    value: jest.fn().mockReturnValue(type ? [{ type }] : []),
  });
}
let scrollTo: jest.SpyInstance;

beforeEach(() => {
  resetHomeArrivalState();
  window.history.replaceState(null, "", "/");
  window.history.scrollRestoration = "auto";
  scrollTo = jest.spyOn(window, "scrollTo").mockImplementation(() => {});
});

afterEach(() => {
  jest.restoreAllMocks();
  Reflect.deleteProperty(performance, "getEntriesByType");
  window.history.replaceState(null, "", "/");
  window.history.scrollRestoration = "auto";
});

describe("useHomeFragmentNavigation: como o navegador chegou", () => {
  it("path: a fresh arrival -> scroll restoration is manual until the layout is ready, then automatic again", () => {
    navigationEntries("navigate");
    render(<Home />);
    expect(window.history.scrollRestoration).toBe("manual");

    ready();

    expect(window.history.scrollRestoration).toBe("auto");
  });

  it("path: back/forward traversal with a fragment in the URL -> the browser keeps its own position: no manual mode, no scroll, no focus", () => {
    navigationEntries("back_forward");
    window.history.replaceState(null, "", "/#contact");
    render(<Home />);
    expect(window.history.scrollRestoration).toBe("auto");

    ready();

    expect(scrollTo).not.toHaveBeenCalled();
    expect(contact()).not.toHaveFocus();
  });

  it("path: no navigation entry in the timeline -> treated as a fresh arrival", () => {
    navigationEntries();
    render(<Home />);
    expect(window.history.scrollRestoration).toBe("manual");

    ready();

    expect(scrollTo).toHaveBeenCalledWith({
      top: 0,
      left: 0,
      behavior: "instant",
    });
  });

  it("path: a browser without getEntriesByType (the jsdom default) -> treated as a fresh arrival", () => {
    expect(performance.getEntriesByType).toBeUndefined();
    render(<Home />);
    expect(window.history.scrollRestoration).toBe("manual");
  });
});

describe("useHomeFragmentNavigation: o destino do fragmento", () => {
  /** Mede o destino e devolve o elemento (capturado antes de getComputedStyle ser trocado). */
  function measure(top: number, padding: string, margin: string) {
    Object.defineProperty(window, "scrollY", {
      configurable: true,
      value: 100,
    });
    const target = about();
    target.getBoundingClientRect = () => ({ top }) as DOMRect;
    jest.spyOn(window, "getComputedStyle").mockImplementation(
      (element) =>
        ({
          scrollPaddingTop: element === document.documentElement ? padding : "",
          scrollMarginTop: element === target ? margin : "",
        }) as unknown as CSSStyleDeclaration,
    );
    return target;
  }

  afterEach(() => {
    Reflect.deleteProperty(window, "scrollY");
  });

  it("path: fragment that exists -> waits for the layout, then focuses it and scrolls under the fixed header and its own margin", () => {
    window.history.replaceState(null, "", "/#about");
    render(<Home />);
    const target = measure(500, "80px", "10px");
    expect(scrollTo).not.toHaveBeenCalled();
    expect(target).not.toHaveFocus();

    ready();

    expect(target).toHaveFocus();
    expect(scrollTo).toHaveBeenCalledWith({
      top: 100 + 500 - 80 - 10,
      left: 0,
      behavior: "instant",
    });
  });

  it("path: no readable header offset or margin -> both count as zero", () => {
    window.history.replaceState(null, "", "/#about");
    render(<Home />);
    measure(500, "", "");

    ready();

    expect(scrollTo).toHaveBeenLastCalledWith({
      top: 600,
      left: 0,
      behavior: "instant",
    });
  });

  it("path: a target far above the current position -> never scrolls to a negative position", () => {
    window.history.replaceState(null, "", "/#about");
    render(<Home />);
    measure(-900, "80px", "0px");

    ready();

    expect(scrollTo).toHaveBeenLastCalledWith({
      top: 0,
      left: 0,
      behavior: "instant",
    });
  });

  it("path: fragment of an element that does not exist -> nothing is focused or scrolled, and nothing throws", () => {
    window.history.replaceState(null, "", "/#nao-existe");
    render(<Home />);

    expect(() => ready()).not.toThrow();

    expect(scrollTo).not.toHaveBeenCalled();
    expect(document.body).toHaveFocus();
  });

  it("path: the URL changed without a hashchange event before the layout was ready -> the old fragment is not applied", () => {
    window.history.replaceState(null, "", "/#about");
    render(<Home />);
    window.history.replaceState(null, "", "/#contact");

    ready();

    expect(about()).not.toHaveFocus();
    expect(scrollTo).not.toHaveBeenCalled();
  });
});

describe("useHomeFragmentNavigation: o visitante assume a rolagem", () => {
  it.each([
    "ArrowUp",
    "ArrowDown",
    "PageUp",
    "PageDown",
    "Home",
    "End",
    " ",
    "Tab",
  ])(
    "path: the %j key -> the pending arrival is dropped and the browser takes back its scroll restoration",
    (key) => {
      window.history.replaceState(null, "", "/#about");
      render(<Home />);
      expect(window.history.scrollRestoration).toBe("manual");

      fireEvent.keyDown(window, { key });
      expect(window.history.scrollRestoration).toBe("auto");
      ready();

      expect(about()).not.toHaveFocus();
      expect(scrollTo).not.toHaveBeenCalled();
    },
  );

  it.each(["a", "Enter", "Escape", "Shift"])(
    "path: the %j key (not a scroll key) -> the pending arrival still happens",
    (key) => {
      window.history.replaceState(null, "", "/#about");
      render(<Home />);

      fireEvent.keyDown(window, { key });
      ready();

      expect(about()).toHaveFocus();
      expect(scrollTo).toHaveBeenCalledTimes(1);
    },
  );

  it.each([
    ["touchmove", () => fireEvent.touchMove(window)],
    ["pointerdown", () => fireEvent.pointerDown(window)],
    ["wheel", () => fireEvent.wheel(window, { deltaY: 40 })],
  ])("path: %s -> the pending arrival is dropped", (_gesture, gesture) => {
    window.history.replaceState(null, "", "/#about");
    render(<Home />);

    gesture();
    ready();

    expect(about()).not.toHaveFocus();
    expect(scrollTo).not.toHaveBeenCalled();
  });
});

describe("useHomeFragmentNavigation: cliques e hashchange", () => {
  it("path: click on an anchor before the layout is ready -> the destination gets the focus now and the scroll waits for the layout", () => {
    render(<Home />);
    fireEvent.click(screen.getByRole("link", { name: "Sobre" }));
    // o jsdom não segue a âncora sozinho: o navegador deixaria a URL já no fragmento
    window.history.replaceState(null, "", "/#about");
    expect(about()).toHaveFocus();
    expect(scrollTo).not.toHaveBeenCalled();

    ready();

    // a âncora vira a chegada pendente (não a rolagem ao topo)
    expect(scrollTo).toHaveBeenCalledTimes(1);
  });

  it("path: click on an anchor after the layout is ready -> the focus moves, no arrival scroll is left pending", () => {
    render(<Home />);
    ready();
    scrollTo.mockClear();

    fireEvent.click(screen.getByRole("link", { name: "Sobre" }));
    ready();

    expect(about()).toHaveFocus();
    expect(scrollTo).not.toHaveBeenCalled();
  });

  it("path: hashchange to an element that exists, after the layout is ready -> it gets the focus", () => {
    render(<Home />);
    ready();

    act(() => {
      window.history.replaceState(null, "", "/#contact");
      window.dispatchEvent(new HashChangeEvent("hashchange"));
    });

    expect(contact()).toHaveFocus();
  });

  it("path: hashchange to an element that does not exist -> nothing happens", () => {
    render(<Home />);
    ready();

    act(() => {
      window.history.replaceState(null, "", "/#nao-existe");
      window.dispatchEvent(new HashChangeEvent("hashchange"));
    });

    expect(document.body).toHaveFocus();
  });

  it("path: hashchange before the layout is ready -> no focus yet (the arrival is not resolved early)", () => {
    render(<Home />);

    act(() => {
      window.history.replaceState(null, "", "/#contact");
      window.dispatchEvent(new HashChangeEvent("hashchange"));
    });

    expect(contact()).not.toHaveFocus();
  });
});

describe("useHomeFragmentNavigation: desmontagem", () => {
  it("path: unmount -> scroll restoration goes back to auto and the listeners are gone", () => {
    window.history.replaceState(null, "", "/#about");
    const view = render(<Home />);
    expect(window.history.scrollRestoration).toBe("manual");

    view.unmount();
    expect(window.history.scrollRestoration).toBe("auto");

    window.history.scrollRestoration = "manual";
    fireEvent.wheel(window, { deltaY: 40 });
    expect(window.history.scrollRestoration).toBe("manual");
  });

  it("path: the ready callback called after unmount -> nothing to resolve, no error, restoration stays automatic", () => {
    const view = render(<Home />);
    view.unmount();

    expect(() => act(() => layoutReady())).not.toThrow();

    expect(window.history.scrollRestoration).toBe("auto");
    expect(scrollTo).not.toHaveBeenCalled();
  });
});