Function applyPublisherTopics

app/src/API/Handlers/MqttHandler.cpp:305–339

* @brief Applies topic + mode + frequency fields to the publisher; returns error on failure. */

 * @brief Applies topic + mode + frequency fields to the publisher; returns error on failure.
 */
[[nodiscard]] static std::optional<QString> applyPublisherTopics(MQTT::Publisher& p,
                                                                 const QJsonObject& params)
{
  if (params.contains(QStringLiteral("topicBase")))
    p.setTopicBase(params.value(QStringLiteral("topicBase")).toString());

  if (params.contains(QStringLiteral("notificationTopic")))
    p.setNotificationTopic(params.value(QStringLiteral("notificationTopic")).toString());

  if (params.contains(QStringLiteral("publishNotifications")))
    p.setPublishNotifications(params.value(QStringLiteral("publishNotifications")).toBool());

  if (params.contains(QStringLiteral("mode"))) {
    const int mode = params.value(QStringLiteral("mode")).toInt(-1);
    if (!indexInRange(mode, p.modes().size()))
      return QStringLiteral("mode index out of range (got %1, valid 0..%2)")
        .arg(mode)
        .arg(p.modes().size() - 1);

    p.setMode(mode);
  }

  if (params.contains(QStringLiteral("publishFrequency"))) {
    const int hz = params.value(QStringLiteral("publishFrequency")).toInt(-1);
    if (hz < MQTT::Publisher::kMinPublishHz || hz > MQTT::Publisher::kMaxPublishHz)
      return QStringLiteral("publishFrequency must be in [%1, %2] (got %3)")
        .arg(MQTT::Publisher::kMinPublishHz)
        .arg(MQTT::Publisher::kMaxPublishHz)
        .arg(hz);

    p.setPublishFrequency(hz);
  }

  return std::nullopt;
}

/**
 * @brief Applies session + TLS fields to the publisher; returns error on failure.