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;
  // Tool invocations attached to this message. Each entry matches the shape
  // persisted by the backend (`function`, `arguments`, `result`, `status`) so
  // the UI can render the same chips whether they arrive live over SSE or
  // from a reload.
  final List<Map<String, dynamic>>? toolCalls;

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

  factory Message.fromJson(Map<String, dynamic> json) {
    final rawCalls = json['tool_calls'];
    List<Map<String, dynamic>>? parsedCalls;
    if (rawCalls is List) {
      parsedCalls = [
        for (final tc in rawCalls)
          if (tc is Map<String, dynamic>) tc,
      ];
      if (parsedCalls.isEmpty) parsedCalls = null;
    }
    return 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>?,
      toolCalls: parsedCalls,
    );
  }

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