// @vitest-environment jsdom
//
// useUrlMirror: mirror a set of nav params onto the CURRENT history entry (replaceState) whenever they
// change. Backfills the E4 deep-review's deferred coverage — the effect keys on the SERIALIZED updates
// so an inline object literal (new identity every render) only fires when a param actually changes; a
// null value clears a key; and every other param on the URL is preserved.
import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
import { renderHook } from "@testing-library/react";
import { useUrlMirror } from "./useUrlMirror";

const setUrl = (search: string) => window.history.replaceState(null, "", search || "/");
let spy: ReturnType<typeof vi.spyOn>;

beforeEach(() => {
  setUrl("/");
  spy = vi.spyOn(window.history, "replaceState");
});
afterEach(() => spy.mockRestore());

describe("useUrlMirror", () => {
  it("writes the param onto the current entry on mount", () => {
    renderHook(() => useUrlMirror({ pl: "5" }));
    expect(window.location.search).toBe("?pl=5");
    expect(spy).toHaveBeenCalledTimes(1);
  });

  it("does not re-fire when the serialized updates are unchanged (stable dep)", () => {
    const { rerender } = renderHook((p: Record<string, string | null>) => useUrlMirror(p), {
      initialProps: { pl: "5" } as Record<string, string | null>,
    });
    expect(spy).toHaveBeenCalledTimes(1);
    rerender({ pl: "5" }); // new object identity, same serialized value
    expect(spy).toHaveBeenCalledTimes(1);
  });

  it("clears a key when its value turns null", () => {
    const { rerender } = renderHook((p: Record<string, string | null>) => useUrlMirror(p), {
      initialProps: { pl: "5" } as Record<string, string | null>,
    });
    expect(window.location.search).toBe("?pl=5");
    rerender({ pl: null });
    expect(window.location.search).toBe("");
    expect(spy).toHaveBeenCalledTimes(2);
  });

  it("preserves other params already on the URL", () => {
    setUrl("?page=playlists");
    renderHook(() => useUrlMirror({ pl: "5" }));
    expect(window.location.search).toBe("?page=playlists&pl=5");
  });

  it("leaves an unconsumed auth token in the fragment alone", () => {
    // This hook's mount effect is what ran before <App> (and therefore before the auth card) had even
    // loaded, so whatever it writes to the address bar is what the card later reads. It must not eat
    // the #verify=/#reset= token that the emailed link carries.
    window.history.replaceState(null, "", "/?page=playlists#verify=tok123");
    renderHook(() => useUrlMirror({ pl: "5" }));
    expect(window.location.hash).toBe("#verify=tok123");
    expect(window.location.search).toBe("?page=playlists&pl=5");
  });
});