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

const hostApi = vi.hoisted(() => ({
  fetch: vi.fn(),
  fetchBytes: vi.fn(),
}));

vi.mock('@/lib/host-api', () => ({
  hostApiFetch: hostApi.fetch,
  hostApiFetchBytes: hostApi.fetchBytes,
}));

describe('coding attachment Host facade', () => {
  beforeEach(() => vi.clearAllMocks());

  it('uploads raw image bytes only when invoked and returns the attachment reference', async () => {
    const attachment = { attachmentId: 'attachment-1', mime: 'image/png', byteLength: 4 };
    hostApi.fetch.mockResolvedValueOnce(attachment);
    const { uploadCodingAttachment } = await import('@/lib/coding-attachments');
    const file = new File([new Uint8Array([1, 2, 3, 4])], 'pixel.png', { type: 'image/png' });

    await expect(uploadCodingAttachment(file)).resolves.toEqual(attachment);
    expect(hostApi.fetch).toHaveBeenCalledOnce();
    const [path, init] = hostApi.fetch.mock.calls[0] as [string, RequestInit];
    expect(path).toBe('/api/coding/attachments');
    expect(init).toMatchObject({ method: 'POST', headers: { 'Content-Type': 'image/png' } });
    expect(Array.from(new Uint8Array(init.body as ArrayBuffer))).toEqual([1, 2, 3, 4]);
  });

  it('loads an authenticated binary preview without constructing a data URL', async () => {
    hostApi.fetchBytes.mockResolvedValueOnce({
      bytes: new Uint8Array([5, 6, 7]),
      contentType: 'image/webp',
    });
    const { loadCodingAttachmentPreview } = await import('@/lib/coding-attachments');

    await expect(loadCodingAttachmentPreview('attachment/a')).resolves.toEqual({
      bytes: new Uint8Array([5, 6, 7]),
      mime: 'image/webp',
    });
    expect(hostApi.fetchBytes).toHaveBeenCalledWith(
      '/api/coding/attachments/attachment%2Fa/content',
    );
  });
});