import { render, screen } from "@testing-library/react";
import userEvent from "@testing-library/user-event";
import { useState } from "react";
import { describe, expect, it, vi } from "vitest";
import { Button } from "@/components/ui/Button";
import { TextField } from "@/components/ui/Field";
import { Modal } from "@/components/ui/Modal";
import { SlideOver } from "@/components/ui/SlideOver";

function ModalHarness({ onClose = () => {} }: { onClose?: () => void }) {
  const [first, setFirst] = useState("");
  const [second, setSecond] = useState("");
  return (
    <Modal
      open
      onClose={onClose}
      title="Testdialog"
      footer={
        <Button onClick={() => {}}>Speichern</Button>
      }
    >
      <TextField label="Erstes Feld" value={first} onChange={setFirst} />
      <TextField label="Zweites Feld" value={second} onChange={setSecond} />
    </Modal>
  );
}

describe("Modal focus management", () => {
  it("names the dialog from its visible heading", () => {
    render(<ModalHarness />);
    expect(screen.getByRole("dialog", { name: "Testdialog" })).toBeInTheDocument();
  });

  it("moves focus into the dialog on open", () => {
    render(<ModalHarness />);
    // Not the page behind it: without this, the first Tab would start from
    // the top of the document.
    expect(document.body.contains(document.activeElement)).toBe(true);
    expect(screen.getByRole("dialog").contains(document.activeElement)).toBe(true);
  });

  it("keeps Tab inside the dialog and wraps at the end", async () => {
    render(<ModalHarness />);
    const dialog = screen.getByRole("dialog");
    for (let i = 0; i < 8; i++) {
      await userEvent.tab();
      expect(dialog.contains(document.activeElement)).toBe(true);
    }
  });

  it("wraps backwards on Shift+Tab", async () => {
    render(<ModalHarness />);
    const dialog = screen.getByRole("dialog");
    for (let i = 0; i < 8; i++) {
      await userEvent.tab({ shift: true });
      expect(dialog.contains(document.activeElement)).toBe(true);
    }
  });

  it("closes on Escape", async () => {
    const onClose = vi.fn();
    render(<ModalHarness onClose={onClose} />);
    await userEvent.keyboard("{Escape}");
    expect(onClose).toHaveBeenCalled();
  });

  it("returns focus to the element that opened it", async () => {
    function Toggle() {
      const [open, setOpen] = useState(false);
      return (
        <>
          <button onClick={() => setOpen(true)}>Öffnen</button>
          <Modal open={open} onClose={() => setOpen(false)} title="Testdialog">
            <p>Inhalt</p>
          </Modal>
        </>
      );
    }
    render(<Toggle />);
    const trigger = screen.getByRole("button", { name: "Öffnen" });
    await userEvent.click(trigger);
    expect(screen.getByRole("dialog")).toBeInTheDocument();
    await userEvent.keyboard("{Escape}");
    expect(trigger).toHaveFocus();
  });
});

describe("SlideOver", () => {
  it("marks a closed panel inert", () => {
    // It stays mounted for the slide transition, so without `inert` its
    // fields stay in the tab order behind the page — aria-hidden does not
    // remove them.
    //
    // Asserted on the attribute rather than by tabbing: jsdom does not
    // implement inert at all ("inert" in HTMLElement.prototype === false),
    // so a focus-based assertion here would be testing jsdom, not this
    // component. Browsers enforce it.
    const { container } = render(
      <SlideOver open={false} onClose={() => {}} title="Geschlossen">
        <button>Im Panel</button>
      </SlideOver>
    );
    expect(container.firstElementChild).toHaveAttribute("inert");
  });

  it("is not inert while open", () => {
    const { container } = render(
      <SlideOver open onClose={() => {}} title="Offen">
        <button>Im Panel</button>
      </SlideOver>
    );
    expect(container.firstElementChild).not.toHaveAttribute("inert");
  });

  it("traps focus once open", async () => {
    render(
      <>
        <button>Dahinter</button>
        <SlideOver open onClose={() => {}} title="Offen" footer={<Button>Speichern</Button>}>
          <button>Im Panel</button>
        </SlideOver>
      </>
    );
    const dialog = screen.getByRole("dialog", { name: "Offen" });
    for (let i = 0; i < 6; i++) {
      await userEvent.tab();
      expect(dialog.contains(document.activeElement)).toBe(true);
    }
  });
});
