/**
 * File Utils
 *
 * 文件处理工具函数
 */

/**
 * 格式化文件大小
 */
export function formatFileSize(bytes: number): string {
  if (bytes === 0) return '0 B';

  const k = 1024;
  const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));

  return `${(bytes / Math.pow(k, i)).toFixed(2)} ${sizes[i]}`;
}

/**
 * 获取文件扩展名
 */
export function getFileExtension(filename: string): string {
  const lastDot = filename.lastIndexOf('.');
  if (lastDot === -1) return '';
  return filename.slice(lastDot + 1).toLowerCase();
}

/**
 * 判断是否是图片文件
 */
export function isImageFile(filename: string): boolean {
  const imageExtensions = ['jpg', 'jpeg', 'png', 'gif', 'bmp', 'webp', 'svg'];
  const ext = getFileExtension(filename);
  return imageExtensions.includes(ext);
}