Method writeCharacteristic

app/src/IO/Drivers/BluetoothLE.cpp:595–630

* @brief Writes to a UUID-resolved characteristic for split read/write devices. */

 * @brief Writes to a UUID-resolved characteristic for split read/write devices.
 */
qint64 IO::Drivers::BluetoothLE::writeCharacteristic(const QString& uuid, const QByteArray& data)
{
  const QBluetoothUuid target = bleUuidFromString(uuid);
  if (target.isNull()) {
    qWarning() << "BLE writeCharacteristic: invalid UUID" << uuid;
    return 0;
  }

  QLowEnergyService* service = m_service;
  if (!service) {
    for (auto* inst : std::as_const(s_instances))
      if (inst != this && inst->m_deviceIndex == m_deviceIndex && inst->m_service) {
        service = inst->m_service;
        break;
      }
  }

  if (!service) {
    qWarning() << "BLE writeCharacteristic: no active service for the selected device";
    return 0;
  }

  const auto characteristic = service->characteristic(target);
  if (!characteristic.isValid()) {
    qWarning() << "BLE writeCharacteristic: characteristic" << uuid << "not found in service";
    return 0;
  }

  const auto props = characteristic.properties();
  const auto mode  = (props & QLowEnergyCharacteristic::WriteNoResponse)
                     ? QLowEnergyService::WriteWithoutResponse
                     : QLowEnergyService::WriteWithResponse;

  service->writeCharacteristic(characteristic, data, mode);
  return data.length();
}

/**
 * @brief Opens a connection to a Bluetooth LE device.