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

import {
  isModel3dViewerFormatSupported,
  isModel3dViewerOverSize,
  MODEL3D_VIEWER_MAX_MODEL_BYTES,
  Model3dViewerAbortedError,
  readModel3dViewerSource,
  resolveModel3dViewerFormat,
  resolveModel3dViewerFormatFromBytes,
  resolveModel3dViewerFormatFromMimeType,
} from './loader';

describe('模型格式承诺范围', () => {
  it('只承诺 glb / gltf / fbx', () => {
    for (const format of ['glb', 'gltf', 'fbx']) {
      expect(isModel3dViewerFormatSupported(format)).toBe(true);
    }
    for (const format of [
      'obj',
      'stl',
      'usdz',
      '3mf',
      '',
      null,
      undefined,
      7,
    ]) {
      expect(isModel3dViewerFormatSupported(format)).toBe(false);
    }
  });
});

describe('模型体积上限', () => {
  it('超过 64 MiB 判定为超限', () => {
    expect(isModel3dViewerOverSize(0)).toBe(false);
    expect(isModel3dViewerOverSize(MODEL3D_VIEWER_MAX_MODEL_BYTES)).toBe(false);
    expect(isModel3dViewerOverSize(MODEL3D_VIEWER_MAX_MODEL_BYTES + 1)).toBe(
      true,
    );
  });

  it('非有限值不算超限，由加载流程自行失败', () => {
    expect(isModel3dViewerOverSize(Number.NaN)).toBe(false);
  });
});

const GLB_MAGIC = new Uint8Array([0x67, 0x6c, 0x54, 0x46, 0x02, 0x00, 0x00]);
const FBX_MAGIC = new Uint8Array([
  0x4b, 0x61, 0x79, 0x64, 0x61, 0x72, 0x61, 0x20, 0x46, 0x42, 0x58, 0x20, 0x42,
  0x69, 0x6e, 0x61, 0x72, 0x79, 0x00,
]);

describe('模型格式判定', () => {
  it('声明类型按子串匹配各家拼法', () => {
    expect(resolveModel3dViewerFormatFromMimeType('model/gltf-binary')).toBe(
      'glb',
    );
    expect(resolveModel3dViewerFormatFromMimeType('model/gltf+json')).toBe(
      'gltf',
    );
    expect(
      resolveModel3dViewerFormatFromMimeType('application/x-fbx; charset=x'),
    ).toBe('fbx');
    expect(
      resolveModel3dViewerFormatFromMimeType('application/octet-stream'),
    ).toBeNull();
    expect(resolveModel3dViewerFormatFromMimeType(null)).toBeNull();
  });

  it('字节魔数认出自包含的三种容器', () => {
    expect(resolveModel3dViewerFormatFromBytes(GLB_MAGIC)).toBe('glb');
    expect(resolveModel3dViewerFormatFromBytes(FBX_MAGIC)).toBe('fbx');
    expect(
      resolveModel3dViewerFormatFromBytes(
        new TextEncoder().encode('\n  {"asset":{"version":"2.0"}}'),
      ),
    ).toBe('gltf');
    expect(
      resolveModel3dViewerFormatFromBytes(
        new TextEncoder().encode('\uFEFF{"asset":{}}'),
      ),
    ).toBe('gltf');
    expect(
      resolveModel3dViewerFormatFromBytes(new Uint8Array([0x00, 0x01])),
    ).toBeNull();
  });

  it('顺序是声明 → 魔数 → 地址扩展名', () => {
    // 声明正确时轮不到魔数。
    expect(
      resolveModel3dViewerFormat({
        declaredType: 'model/gltf-binary',
        url: 'https://x/model.fbx',
        bytes: FBX_MAGIC,
      }),
    ).toBe('glb');
    // 声明写歪（provider 给 octet-stream、扩展名也不对）时按魔数纠正。
    expect(
      resolveModel3dViewerFormat({
        declaredType: 'application/octet-stream',
        url: 'https://x/model.obj',
        bytes: GLB_MAGIC,
      }),
    ).toBe('glb');
    // 没声明也没字节时只剩扩展名这条派生线索。
    expect(
      resolveModel3dViewerFormat({ url: 'https://x/model.glb?sig=1' }),
    ).toBe('glb');
    expect(resolveModel3dViewerFormat({ url: 'https://x/model.FBX' })).toBe(
      'fbx',
    );
  });

  it('三条线索都给不出答案时返回 null，交给加载流程报 unsupported-format', () => {
    expect(
      resolveModel3dViewerFormat({
        declaredType: 'application/octet-stream',
        url: 'https://x/model.obj',
        bytes: new Uint8Array([0x00, 0x01]),
      }),
    ).toBeNull();
  });
});

describe('模型下载可中止', () => {
  it('把宿主的 signal 交给 fetch，中止后抛取消错误而不是加载失败', async () => {
    const controller = new AbortController();
    const originalFetch = globalThis.fetch;
    const calls: Array<{ url: string; signal?: AbortSignal | null }> = [];
    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
      calls.push({ url: String(input), signal: init?.signal });
      controller.abort();
      return Promise.reject(new DOMException('aborted', 'AbortError'));
    }) as typeof fetch;

    try {
      await expect(
        readModel3dViewerSource(
          { kind: 'url', url: 'https://x/model.glb' },
          controller.signal,
        ),
      ).rejects.toBeInstanceOf(Model3dViewerAbortedError);
    } finally {
      globalThis.fetch = originalFetch;
    }

    expect(calls).toEqual([
      { url: 'https://x/model.glb', signal: controller.signal },
    ]);
  });
});