import { mkdtempSync, writeFileSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import { describe, expect, it } from 'vitest';
import { inspectVrm } from '../src/models/vrm-inspector';

const dir = mkdtempSync(join(tmpdir(), 'opendance-vrm-'));

/** 构造合法 GLB：magic + version + length + JSON chunk */
function buildGlb(json: unknown): Buffer {
  const jsonBuf = Buffer.from(JSON.stringify(json), 'utf8');
  const pad = (4 - (jsonBuf.length % 4)) % 4;
  const padded = Buffer.concat([jsonBuf, Buffer.alloc(pad, 0x20)]);
  const header = Buffer.alloc(12);
  header.write('glTF', 0, 'ascii');
  header.writeUInt32LE(2, 4);
  header.writeUInt32LE(12 + 8 + padded.length, 8);
  const chunkHeader = Buffer.alloc(8);
  chunkHeader.writeUInt32LE(padded.length, 0);
  chunkHeader.writeUInt32LE(0x4e4f534a, 4);
  return Buffer.concat([header, chunkHeader, padded]);
}

function write(name: string, content: Buffer): string {
  const path = join(dir, name);
  writeFileSync(path, content);
  return path;
}

describe('VRM 版本识别', () => {
  it('识别 VRM 1.0（VRMC_vrm 扩展）', async () => {
    const path = write('v1.vrm', buildGlb({ extensions: { VRMC_vrm: { specVersion: '1.0' } } }));
    const result = await inspectVrm(path);
    expect(result.isGlb).toBe(true);
    expect(result.vrmVersion).toBe('1.0');
  });

  it('识别 VRM 0.x（VRM 扩展）', async () => {
    const path = write('v0.vrm', buildGlb({ extensions: { VRM: { specVersion: '0.0', exporterVersion: '0.79' } } }));
    const result = await inspectVrm(path);
    expect(result.vrmVersion).toBe('0.0');
  });

  it('VRM 扩展缺失时版本为 null（普通 GLB）', async () => {
    const path = write('plain.glb', buildGlb({ asset: { version: '2.0' }, meshes: [] }));
    const result = await inspectVrm(path);
    expect(result.isGlb).toBe(true);
    expect(result.vrmVersion).toBeNull();
    expect(result.generator).toBeNull();
  });

  it('文本 glTF 不按 GLB 处理', async () => {
    const path = write('scene.gltf', Buffer.from('{"asset":{"version":"2.0"}}', 'utf8'));
    const result = await inspectVrm(path);
    expect(result.isGlb).toBe(false);
    expect(result.vrmVersion).toBeNull();
  });

  it('文件过小时报错', async () => {
    const path = write('tiny.glb', Buffer.from('glTF', 'ascii'));
    await expect(inspectVrm(path)).rejects.toThrow(/过小/);
  });

  it('首 chunk 非 JSON 时报错', async () => {
    const header = Buffer.alloc(12);
    header.write('glTF', 0, 'ascii');
    header.writeUInt32LE(2, 4);
    header.writeUInt32LE(32, 8);
    const chunk = Buffer.alloc(8);
    chunk.writeUInt32LE(4, 0);
    chunk.writeUInt32LE(0x004e4942, 4); // 'BIN\0'
    await expect(inspectVrm(write('bin-first.glb', Buffer.concat([header, chunk, Buffer.alloc(4)])))).rejects.toThrow(
      /JSON/,
    );
  });
});