// @vitest-environment jsdom
//
// The undo container chains calls made in one tick: a `reset` not yet committed is what the next
// call builds on. A `rebase` read the mirror ref, which only follows a commit, so it rebased the
// value from BEFORE the reset and wrote that back — the playlist page, remounted under StrictMode
// over a cached list, re-ran its seeding effect (reset, then rebase) and painted an empty list.
import { describe, expect, it } from "vitest";
import { act, renderHook } from "@testing-library/react";
import { useUndoable } from "./useUndoable";

describe("useUndoable", () => {
  it("rebases the value a reset in the same tick installed, not the one before it", () => {
    const { result } = renderHook(() => useUndoable<number[]>([]));
    act(() => {
      result.current.reset([1, 2]);
      result.current.rebase((xs) => xs.map((x) => x * 10));
    });
    expect(result.current.value).toEqual([10, 20]);
  });

  it("keeps the undo history through a rebase", () => {
    const { result } = renderHook(() => useUndoable<number[]>([1]));
    act(() => result.current.set([1, 2]));
    act(() => result.current.rebase((xs) => xs.map((x) => x + 1)));
    expect(result.current.value).toEqual([2, 3]);
    act(() => result.current.undo());
    expect(result.current.value).toEqual([2]);
  });

  it("undoes to a rebased snapshot when the undo comes in the same tick as the rebase", () => {
    const { result } = renderHook(() => useUndoable<number[]>([1, 2]));
    act(() => result.current.set([2, 1]));
    act(() => {
      result.current.rebase((xs) => xs.filter((x) => x !== 2)); // a row removed
      result.current.undo();
    });
    expect(result.current.value).toEqual([1]);
    expect(result.current.canRedo).toBe(true);
  });
});