enum MessageType { text, image, audio }
enum MessageSender { user, ai }

class Message {
  final String id;
  final String text;
  final MessageSender sender;
  final MessageType type;
  final DateTime timestamp;
  final String? imageUrl;
  final bool isLocked;

  const Message({
    required this.id,
    required this.text,
    required this.sender,
    required this.type,
    required this.timestamp,
    this.imageUrl,
    this.isLocked = false,
  });
}