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

import { createSpawnForm, type SpawnFormHandle } from "./spawnForm.js";

/** Debounce window under test — must equal GITROOT_PROBE_DEBOUNCE_MS in
 * spawnForm.ts (#74). */
const DEBOUNCE_MS = 250;

const PROJECTS = [
  { path: "/home/user/maestro", name: "maestro", last_activity: "2026-08-20T10:00:00Z" },
];

/** Stub the fetches the form makes. Gitroot responses for a given path can be
 * held until `releaseGitRoot(path)` is called, so tests can land answers out
 * of order. */
function stubFetch(opts?: { holdGitRootFor?: string[] }): {
  urls: string[];
  gitRootCalls: string[];
  releaseGitRoot: (path: string) => void;
} {
  const urls: string[] = [];
  const gitRootCalls: string[] = [];
  const releases = new Map<string, () => void>();
  const held = new Map<string, Promise<void>>();
  vi.stubGlobal(
    "fetch",
    vi.fn(async (input: RequestInfo | URL) => {
      const url = String(input);
      urls.push(url);
      if (url.includes("/api/dirs")) {
        return new Response(JSON.stringify({ entries: [] }), { status: 200 });
      }
      if (url.includes("/api/gitroot")) {
        const path = new URL(url, "http://localhost").searchParams.get("path") ?? "";
        gitRootCalls.push(path);
        if (opts?.holdGitRootFor?.includes(path)) {
          let release!: () => void;
          held.set(
            path,
            new Promise<void>((r) => {
              release = r;
            }),
          );
          releases.set(path, release);
        }
        await held.get(path);
        return new Response(JSON.stringify({ root: path }), { status: 200 });
      }
      if (url.includes("/api/names")) {
        return new Response(JSON.stringify({ names: ["amber-fox"] }), { status: 200 });
      }
      if (url.includes("/api/projects")) {
        return new Response(JSON.stringify(PROJECTS), { status: 200 });
      }
      return new Response(
        JSON.stringify({ hostname: "h", version: "0", home_dir: "/home/user", presets: [] }),
        { status: 200 },
      );
    }),
  );
  return {
    urls,
    gitRootCalls,
    releaseGitRoot: (path: string) => releases.get(path)?.(),
  };
}

describe("spawnForm gitroot probe debounce (#74)", () => {
  let handle: SpawnFormHandle | null = null;

  beforeEach(() => {
    vi.useFakeTimers();
  });

  afterEach(() => {
    handle?.destroy();
    handle = null;
    vi.unstubAllGlobals();
    vi.useRealTimers();
  });

  async function mount(opts?: Parameters<typeof stubFetch>[0]) {
    const stub = stubFetch(opts);
    handle = createSpawnForm({ onSuccess() {} });
    document.body.appendChild(handle.el);
    for (let i = 0; i < 40; i++) await Promise.resolve();
    return { form: handle.el, stub };
  }

  const drain = async () => {
    for (let i = 0; i < 40; i++) await Promise.resolve();
  };

  function typeRaw(form: HTMLFormElement, value: string): void {
    const raw = form.querySelector<HTMLInputElement>("input[name=cwd_raw]")!;
    raw.value = value;
    raw.dispatchEvent(new Event("input"));
  }

  it("a keystroke burst fires exactly one probe after the quiet period", async () => {
    const { form, stub } = await mount();

    form.querySelector<HTMLElement>(".project-other")!.click();
    // Burst: every keystroke reschedules; nothing may hit /api/gitroot yet.
    for (let i = 1; i <= "/opt/somewhere".length; i++) {
      typeRaw(form, "/opt/somewhere".slice(0, i));
      await drain();
      expect(stub.gitRootCalls).toEqual([]);
    }

    await vi.advanceTimersByTimeAsync(DEBOUNCE_MS);
    await drain();

    expect(stub.gitRootCalls).toEqual(["/opt/somewhere"]);
    expect(stub.urls.filter((u) => u.includes("/api/gitroot")).length).toBe(1);
  });

  it("a stale probe answer cannot overwrite a newer input", async () => {
    const { form, stub } = await mount({ holdGitRootFor: ["/repo/old"] });

    form.querySelector<HTMLElement>(".project-other")!.click();

    // Probe for the old target, held in flight.
    typeRaw(form, "/repo/old");
    await vi.advanceTimersByTimeAsync(DEBOUNCE_MS);

    // Newer target supersedes it and answers immediately.
    typeRaw(form, "/repo/new");
    await vi.advanceTimersByTimeAsync(DEBOUNCE_MS);
    await drain();

    expect(stub.gitRootCalls).toEqual(["/repo/old", "/repo/new"]);
    expect(form.querySelector<HTMLElement>(".wt-repo")!.textContent).toContain("/repo/new");
    expect(
      form.querySelector<HTMLInputElement>("input[name=worktree_enabled]")!.checked,
    ).toBe(true);

    // The late answer to the old target lands last but must lose.
    stub.releaseGitRoot("/repo/old");
    await drain();

    expect(form.querySelector<HTMLElement>(".wt-repo")!.textContent).toContain("/repo/new");
    expect(
      form.querySelector<HTMLInputElement>("input[name=worktree_enabled]")!.checked,
    ).toBe(true);
  });
});