import { describe, expect, it, vi } from 'vitest';

import { lazyWithPreload, preloadAll } from './lazyWithPreload';

describe('lazyWithPreload', () => {
  it('deduplicates preload calls until cleared', async () => {
    const Component = () => null;
    const factory = vi.fn(async () => ({
      default: Component,
    }));

    const LazyComponent = lazyWithPreload(factory);

    const [first, second] = await Promise.all([
      LazyComponent.preload(),
      LazyComponent.preload(),
    ]);

    expect(first.default).toBe(Component);
    expect(second.default).toBe(Component);
    expect(factory).toHaveBeenCalledTimes(1);
    expect(LazyComponent.read()?.default).toBe(Component);

    LazyComponent.clearPreload();
    await LazyComponent.preload();

    expect(factory).toHaveBeenCalledTimes(2);
  });

  it('supports batch preloading and settled failure collection', async () => {
    const ok = {
      preload: vi.fn(async () => 'ok'),
    };

    const bad = {
      preload: vi.fn(async () => {
        throw new Error('nope');
      }),
    };

    const result = await preloadAll([ok, bad], { settle: true });

    expect(ok.preload).toHaveBeenCalledTimes(1);
    expect(bad.preload).toHaveBeenCalledTimes(1);
    expect(result).toHaveLength(2);
    expect((result[0] as PromiseSettledResult<unknown>).status).toBe('fulfilled');
    expect((result[1] as PromiseSettledResult<unknown>).status).toBe('rejected');
  });
});