/* @vitest-environment jsdom */

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

import type { CanvasLayer } from './ImageCanvasEditorTypes';
import { createProjectCoverSnapshotBlob } from './ImageCanvasProjectCoverSnapshotRenderer';

function layer(overrides: Partial<CanvasLayer> = {}): CanvasLayer {
  return {
    id: 'layer-offscreen',
    resourceId: 'resource-offscreen',
    title: '离屏图层',
    src: '/generated/offscreen.webp',
    x: 10_000,
    y: 10_000,
    width: 320,
    height: 240,
    originalWidth: 320,
    originalHeight: 240,
    zIndex: 1,
    sourceType: 'generated',
    ...overrides,
  };
}

describe('ImageCanvasProjectCoverSnapshotRenderer', () => {
  afterEach(() => {
    vi.restoreAllMocks();
  });

  it('exports the canvas background when every drawable layer is outside the cover frame', async () => {
    const fillRect = vi.fn();
    const drawImage = vi.fn();
    vi.spyOn(HTMLCanvasElement.prototype, 'getContext').mockReturnValue({
      fillRect,
      drawImage,
      fillStyle: '',
    } as unknown as CanvasRenderingContext2D);
    vi.spyOn(HTMLCanvasElement.prototype, 'toBlob').mockImplementation(
      (callback) => callback(new Blob(['cover'], { type: 'image/webp' })),
    );

    const blob = await createProjectCoverSnapshotBlob({
      layers: [layer()],
      viewport: { x: 0, y: 0, scale: 1 },
      viewportSize: { width: 1280, height: 960 },
      backgroundColor: '#f8fafc',
    });

    expect(blob?.type).toBe('image/webp');
    expect(fillRect).toHaveBeenCalledWith(0, 0, 320, 240);
    expect(drawImage).not.toHaveBeenCalled();
  });
});