// @vitest-environment happy-dom
import { beforeEach, afterEach, describe, expect, it, vi } from "vitest";

vi.mock("./api.js", () => ({ listDir: vi.fn() }));

import { attachDirAutocomplete, type DirAutocompleteHandle } from "./dirAutocomplete.js";
import { listDir } from "./api.js";

const listDirMock = vi.mocked(listDir);

let input: HTMLInputElement;
let nextField: HTMLInputElement;
let docKeydown: ReturnType<typeof vi.fn>;
let ac: DirAutocompleteHandle | undefined;

function popup(): HTMLUListElement {
  return document.querySelector(".dir-ac") as HTMLUListElement;
}

function items(): HTMLElement[] {
  return [...popup().querySelectorAll<HTMLElement>(".dir-ac-item")];
}

async function type(value: string): Promise<void> {
  input.focus();
  input.value = value;
  input.dispatchEvent(new Event("input", { bubbles: true }));
  await vi.advanceTimersByTimeAsync(100); // past the fetch debounce
}

/** Dispatch a cancelable, bubbling keydown on the input; report whether the
 * default browser behaviour (focus move, form submit) was suppressed. */
function press(key: string): { defaultPrevented: boolean } {
  const evt = new KeyboardEvent("keydown", { key, bubbles: true, cancelable: true });
  input.dispatchEvent(evt);
  return { defaultPrevented: evt.defaultPrevented };
}

beforeEach(() => {
  vi.useFakeTimers();
  document.body.replaceChildren();
  input = document.createElement("input");
  nextField = document.createElement("input");
  document.body.append(input, nextField);
  docKeydown = vi.fn();
  document.addEventListener("keydown", docKeydown);
  listDirMock.mockReset().mockResolvedValue({ path: "/tmp", entries: ["proj-a", "proj-b", "other"], truncated: false });
});

afterEach(() => {
  ac?.destroy();
  document.removeEventListener("keydown", docKeydown);
  vi.useRealTimers();
});

describe("dirAutocomplete dismissal", () => {
  it("Escape closes the popup, keeps the typed value and does not propagate", async () => {
    ac = attachDirAutocomplete(input);
    await type("/tmp/pro");
    expect(popup().hidden).toBe(false);

    const { defaultPrevented } = press("Escape");

    expect(defaultPrevented).toBe(true);
    expect(popup().hidden).toBe(true);
    expect(input.value).toBe("/tmp/pro");
    expect(document.activeElement).toBe(input);
    expect(docKeydown).not.toHaveBeenCalled(); // a draft pane's Escape handler must not fire
  });

  it("blur dismisses the popup", async () => {
    ac = attachDirAutocomplete(input);
    await type("/tmp/pro");
    expect(popup().hidden).toBe(false);

    input.blur();
    await vi.advanceTimersByTimeAsync(150);

    expect(popup().hidden).toBe(true);
  });

  it("does not reopen on refocus until the operator types again", async () => {
    ac = attachDirAutocomplete(input);
    await type("/tmp/pro");
    input.blur();
    await vi.advanceTimersByTimeAsync(150);

    input.focus();
    await vi.advanceTimersByTimeAsync(150);
    expect(popup().hidden).toBe(true);

    await type("/tmp/ot");
    expect(popup().hidden).toBe(false);
  });
});

describe("dirAutocomplete keyboard model", () => {
  it("Tab commits the highlighted entry and lets focus move to the next field", async () => {
    ac = attachDirAutocomplete(input);
    await type("/tmp/pro"); // highlight defaults to the first match: proj-a

    nextField.focus();
    const { defaultPrevented } = press("Tab");

    expect(input.value).toBe("/tmp/proj-a/");
    expect(defaultPrevented).toBe(false); // native tab navigation proceeds
    expect(document.activeElement).toBe(nextField); // focus was not yanked back
  });

  it("Tab with nothing highlighted just moves on", async () => {
    ac = attachDirAutocomplete(input);
    await type("/tmp/nope-matches-nothing");
    expect(popup().hidden).toBe(true);

    const { defaultPrevented } = press("Tab");

    expect(defaultPrevented).toBe(false);
    expect(input.value).toBe("/tmp/nope-matches-nothing");
  });

  it("arrows move the highlight and Enter commits it without submitting", async () => {
    ac = attachDirAutocomplete(input);
    await type("/tmp/");

    press("ArrowDown");
    expect(items()[1].classList.contains("is-active")).toBe(true);

    const enter = press("Enter");
    expect(enter.defaultPrevented).toBe(true); // no form submit
    expect(input.value).toBe("/tmp/proj-b/");
  });
});

describe("dirAutocomplete opening", () => {
  it("still opens on focus when not previously dismissed", async () => {
    ac = attachDirAutocomplete(input);
    input.focus();
    await vi.advanceTimersByTimeAsync(50);

    expect(popup().hidden).toBe(false);
    expect(listDirMock).toHaveBeenCalled();
  });
});