enum MessageRole { user, assistant }

class Message {
  final int? id;
  final int conversationId;
  final MessageRole role;
  final String content;
  final String status; // "complete" | "generating"
  final DateTime? createdAt;
  final Map<String, dynamic>? metadata;

  const Message({
    this.id,
    required this.conversationId,
    required this.role,
    required this.content,
    this.status = 'complete',
    this.createdAt,
    this.metadata,
  });

  factory Message.fromJson(Map<String, dynamic> json) => Message(
        id: json['id'] as int?,
        conversationId: json['conversation_id'] as int,
        role: json['role'] == 'user' ? MessageRole.user : MessageRole.assistant,
        content: json['content'] as String,
        status: json['status'] as String? ?? 'complete',
        createdAt: json['created_at'] != null
            ? DateTime.parse(json['created_at'] as String)
            : null,
        metadata: json['metadata'] as Map<String, dynamic>?,
      );

  Message copyWith({String? content, String? status}) => Message(
        id: id,
        conversationId: conversationId,
        role: role,
        content: content ?? this.content,
        status: status ?? this.status,
        createdAt: createdAt,
        metadata: metadata,
      );
}