const UUID_V4_REGEX =
  /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;

function formatUuidV4(bytes: Uint8Array): string {
  bytes[6] = (bytes[6] & 0x0f) | 0x40;
  bytes[8] = (bytes[8] & 0x3f) | 0x80;

  const hex = Array.from(bytes, (value) => value.toString(16).padStart(2, '0'));

  return [
    hex.slice(0, 4).join(''),
    hex.slice(4, 6).join(''),
    hex.slice(6, 8).join(''),
    hex.slice(8, 10).join(''),
    hex.slice(10, 16).join(''),
  ].join('-');
}

/**
 * 生成客户端 turn 标识，兼容非 Secure Context（如局域网 HTTP）。
 * 优先 randomUUID；否则用 getRandomValues 生成 RFC 4122 v4 UUID。
 */
export function createClientTurnId(): string {
  if (typeof globalThis.crypto?.randomUUID === 'function') {
    return globalThis.crypto.randomUUID();
  }

  if (typeof globalThis.crypto?.getRandomValues === 'function') {
    const bytes = new Uint8Array(16);
    globalThis.crypto.getRandomValues(bytes);
    return formatUuidV4(bytes);
  }

  throw new Error('当前浏览器不支持安全随机标识，请升级浏览器或通过 HTTPS 访问');
}

export function isUuidV4(value: string): boolean {
  return UUID_V4_REGEX.test(value);
}