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

import { detectWebGLSupport, getWebGLFailureMessage } from './webgl';

describe('webgl detection', () => {
  it('reports unsupported when no context can be created', () => {
    const canvas = {
      getContext: vi.fn(() => null),
    } as unknown as HTMLCanvasElement;

    const result = detectWebGLSupport({ canvas });

    expect(result.supported).toBe(false);
    expect(result.reason).toBe('context-unavailable');
    expect(getWebGLFailureMessage(result)).toContain('WebGL is unavailable');
  });

  it('returns renderer details when a WebGL context is available', () => {
    const context = {
      VERSION: 0x1f02,
      VENDOR: 0x1f00,
      RENDERER: 0x1f01,
      MAX_TEXTURE_SIZE: 0x0d33,
      MAX_VERTEX_UNIFORM_VECTORS: 0x8dfb,
      getExtension: vi.fn(() => null),
      getParameter: vi.fn((parameter: number) => {
        const values: Record<number, string | number> = {
          0x1f02: 'WebGL 2.0 test',
          0x1f00: 'Mechanica GPU Vendor',
          0x1f01: 'Mechanica GPU Renderer',
          0x0d33: 8192,
          0x8dfb: 1024,
        };

        return values[parameter];
      }),
    };

    const canvas = {
      getContext: vi.fn((name: string) => (name === 'webgl2' ? context : null)),
    } as unknown as HTMLCanvasElement;

    const result = detectWebGLSupport({ canvas });

    expect(result.supported).toBe(true);
    expect(result.renderer).toBe('webgl2');
    expect(result.details.version).toBe('WebGL 2.0 test');
    expect(result.details.maxTextureSize).toBe(8192);
  });
});