Method processMessage

app/src/API/CommandHandler.cpp:102–148

* @brief Process an incoming message and generate a response */

 * @brief Process an incoming message and generate a response
 */
QByteArray API::CommandHandler::processMessage(const QByteArray& data, const CommandOrigin origin)
{
  QString type;
  QJsonObject json;

  if (!parseMessage(data, type, json)) {
    return CommandResponse::makeError(
             QString(), ErrorCode::InvalidJson, QStringLiteral("Failed to parse JSON message"))
      .toJsonBytes();
  }

  if (type == MessageType::Command) {
    const auto request = CommandRequest::fromJson(json);
    if (!request.isValid()) {
      return CommandResponse::makeError(
               request.id, ErrorCode::InvalidMessageType, QStringLiteral("Missing 'command' field"))
        .toJsonBytes();
    }
    return processCommand(request, origin).toJsonBytes();
  }

  else if (type == MessageType::Batch) {
    const QString batchId    = json.value(QStringLiteral("id")).toString();
    const auto commandsArray = json.value(QStringLiteral("commands")).toArray();

    if (commandsArray.isEmpty()) {
      return CommandResponse::makeError(batchId,
                                        ErrorCode::InvalidMessageType,
                                        QStringLiteral("Empty or invalid 'commands' array"))
        .toJsonBytes();
    }

    if (commandsArray.size() > kMaxBatchCommands) {
      return CommandResponse::makeError(
               batchId, ErrorCode::InvalidParam, QStringLiteral("Batch size exceeds limit"))
        .toJsonBytes();
    }

    const auto batch = BatchRequest::fromJson(json);
    return processBatch(batch, origin).toJsonBytes();
  }

  return CommandResponse::makeError(QString(),
                                    ErrorCode::InvalidMessageType,
                                    QStringLiteral("Unknown message type: %1").arg(type))
    .toJsonBytes();
}

/**
 * @brief Process a single command request; remote-origin device-write commands must clear the