function normalizeClientIp(rawIp) {
  const ip = String(rawIp || '').trim();
  if (!ip) return '';
  if (ip.startsWith('::ffff:')) return ip.slice(7);
  return ip === '::1' ? '127.0.0.1' : ip;
}

function detectDeviceTypeFromUserAgent(userAgent = '') {
  const mobilePattern = /(Mobile|Android|iPhone|iPad|iPod|Windows Phone|HarmonyOS|Mobi)/i;
  return mobilePattern.test(String(userAgent || '')) ? 'mobile' : 'desktop';
}

function inferPlatformFromUserAgent(userAgent = '') {
  const value = String(userAgent || '');
  if (!value) return '未知平台';
  if (/windows/i.test(value)) return 'Windows';
  if (/macintosh|mac os x/i.test(value)) return 'macOS';
  if (/android/i.test(value)) return 'Android';
  if (/iphone|ipad|ios/i.test(value)) return 'iOS';
  if (/linux/i.test(value)) return 'Linux';
  return '未知平台';
}

function normalizeClientType(value = '') {
  const normalized = String(value || '').trim().toLowerCase();
  return ['web', 'desktop', 'mobile', 'api'].includes(normalized) ? normalized : '';
}

function resolveClientType(clientType, userAgent = '') {
  const normalized = normalizeClientType(clientType);
  if (normalized) return normalized;

  const userAgentValue = String(userAgent || '').toLowerCase();
  if (
    userAgentValue.includes('tauri')
    || userAgentValue.includes('electron')
    || userAgentValue.includes('wanwan-cloud-desktop')
    || userAgentValue.includes('玩玩云')
  ) {
    return 'desktop';
  }
  return detectDeviceTypeFromUserAgent(userAgentValue) === 'mobile' ? 'mobile' : 'web';
}

function sanitizeDeviceText(value, maxLength = 120) {
  return typeof value === 'string' ? value.trim().slice(0, maxLength) : '';
}

function buildDeviceName({ clientType, deviceName, platform }) {
  const preferred = sanitizeDeviceText(deviceName, 120);
  if (preferred) return preferred;

  const platformText = sanitizeDeviceText(platform, 80) || '未知平台';
  if (clientType === 'desktop') return `桌面客户端 · ${platformText}`;
  if (clientType === 'mobile') return `移动端浏览器 · ${platformText}`;
  if (clientType === 'api') return `API 客户端 · ${platformText}`;
  return `网页端浏览器 · ${platformText}`;
}

module.exports = {
  buildDeviceName,
  detectDeviceTypeFromUserAgent,
  inferPlatformFromUserAgent,
  normalizeClientIp,
  normalizeClientType,
  resolveClientType,
  sanitizeDeviceText
};