class MessageEntity { final String ownerId; final String content; final DateTime createdAt; const MessageEntity({ required this.ownerId, required this.content, required this.createdAt, }); static MessageEntity fromDocument(Map doc) { return MessageEntity( ownerId: (doc['sender_id'] ?? doc['owner_id']) as String, content: doc['content'] as String, createdAt: DateTime.parse(doc['created_at'] as String), ); } Map toDocument() { return { 'owner_id': ownerId, 'content': content, 'created_at': createdAt.toIso8601String(), }; } @override String toString() { return '''MessageEntity{ ownerId: $ownerId, content: $content, createdAt: $createdAt }'''; } }