const ROOM_NAME_SANITIZER = /[^\w.-]+/g;
const STORED_FILENAME_SANITIZER = /[^\w.-]+/g;

export function sanitizeAttachmentRoomName(roomName: string): string {
  const sanitizedRoomName = roomName.trim().replace(ROOM_NAME_SANITIZER, '_');

  return sanitizedRoomName || 'room';
}

export function resolveAttachmentStoredFilename(attachmentId: string, filename: string): string {
  const sanitizedAttachmentId = attachmentId.trim().replace(STORED_FILENAME_SANITIZER, '_') || 'attachment';
  const basename = filename.trim().split(/[\\/]/)
    .pop() ?? '';
  const extensionIndex = basename.lastIndexOf('.');

  if (extensionIndex <= 0 || extensionIndex === basename.length - 1) {
    return sanitizedAttachmentId;
  }

  const sanitizedExtension = basename.slice(extensionIndex)
    .replace(STORED_FILENAME_SANITIZER, '_')
    .toLowerCase();

  return sanitizedExtension === '.'
    ? sanitizedAttachmentId
    : `${sanitizedAttachmentId}${sanitizedExtension}`;
}

export function resolveAttachmentStorageBucket(mime: string): 'video' | 'audio' | 'image' | 'files' {
  if (mime.startsWith('video/')) {
    return 'video';
  }

  if (mime.startsWith('audio/')) {
    return 'audio';
  }

  if (mime.startsWith('image/')) {
    return 'image';
  }

  return 'files';
}