/**
 * Utility functions for the FileUpload component
 */

/**
 * Parse a file size string (e.g. "5MB", "500KB") to bytes.
 * Also accepts raw numbers (returned as-is).
 *
 * @example
 * parseFileSize("5MB")    // 5242880
 * parseFileSize("500KB")  // 512000
 * parseFileSize("1GB")    // 1073741824
 * parseFileSize(1024)     // 1024
 */
export const parseFileSize = (size: string | number): number => {
  if (typeof size === 'number') return size

  const match = size.trim().match(/^(\d+(?:\.\d+)?)\s*(B|KB|MB|GB)$/i)
  if (!match) {
    console.warn(
      `PktFileUpload: Invalid maxFileSize format "${size}". Use format like "5MB", "500KB", or a number in bytes.`,
    )
    return 0
  }

  const value = parseFloat(match[1])
  const unit = match[2].toUpperCase()

  switch (unit) {
    case 'B':
      return value
    case 'KB':
      return value * 1024
    case 'MB':
      return value * 1024 * 1024
    case 'GB':
      return value * 1024 * 1024 * 1024
    default:
      return value
  }
}

/**
 * Format bytes to a human-readable string (e.g. "5 MB", "500 KB").
 *
 * @example
 * formatFileSize(5242880)  // "5 MB"
 * formatFileSize(512000)   // "500 KB"
 * formatFileSize(500)      // "500 B"
 */
export const formatFileSize = (bytes: number): string => {
  if (bytes < 1024) return `${bytes} B`
  if (bytes < 1024 * 1024) return `${Math.round(bytes / 1024)} KB`
  if (bytes < 1024 * 1024 * 1024) return `${Math.round(bytes / (1024 * 1024))} MB`
  return `${Math.round(bytes / (1024 * 1024 * 1024))} GB`
}