(1) Fix debug output.

(2) Use UpDown-Argument for calculation of next tiem step.

library/src/calculate_price.cpp

@@ -97,6 +97,7 @@ void CALCULATE_LIBRARY_API free_tariff(parking_tariff_t *tariff) {
 // UpDown 1 -> up; 0 -> down
 int CALCULATE_LIBRARY_API compute_next_timestep(parking_tariff_t *tariff, int currentTimeMinutes, int UpDown)
 {
+    qCritical() << "   compute_next_timestep()  currentTimeMinutes: " << currentTimeMinutes;
     Configuration const *cfg = tariff;
 
     // compute payment method id (e.g. Linear=3, Steps=4)
@@ -157,21 +158,23 @@ int CALCULATE_LIBRARY_API compute_next_timestep(parking_tariff_t *tariff, int cu
         // value is an offset from the start time and cannot be used as a
         // QDateTime.
 
-        qCritical() << "compute_next_timestep() currentTimeMinutes:" << currentTimeMinutes;
-
+        qCritical() << "compute_next_timestep() up/down (1=up, 0=down):" << UpDown;
 
         // get minimal and maximal parking times
         int const minParkingTime = Utilities::getMinimalParkingTime(cfg, paymentMethodId);
         int const maxParkingTime = Utilities::getMaximalParkingTime(cfg, paymentMethodId);
 
-        qCritical() << "    compute_next_timestep() maxParkingTime:" << paymentMethodId;
-        qCritical() << "    compute_next_timestep() minParkingTime:" << paymentMethodId;
+        qCritical() << "        compute_next_timestep() maxParkingTime:" << maxParkingTime;
+        qCritical() << "        compute_next_timestep() minParkingTime:" << minParkingTime;
 
         // use the first (i.e. main duration step contained in the tariff json-file)
         int firstDurationStep = Utilities::getFirstDurationStep(cfg, paymentMethodId);
-        qCritical() << " compute_next_timestep() firstDurationStep:" << paymentMethodId;
+        firstDurationStep = ((UpDown == 1) ? firstDurationStep : -firstDurationStep);
+
+        qCritical() << "     compute_next_timestep() firstDurationStep:" << firstDurationStep;
 
         int nextTimeStep = currentTimeMinutes + firstDurationStep;
+
         if (currentTimeMinutes >= minParkingTime && nextTimeStep <= maxParkingTime) {
             qCritical() << "          compute_next_timestep() nextTimeStep:" << nextTimeStep;
             return nextTimeStep;

library/src/utilities.cpp

@@ -387,7 +387,15 @@ uint32_t Utilities::getMinimalParkingPrice(Configuration const *cfg, PaymentMeth
 }
 
 uint32_t Utilities::getFirstDurationStep(Configuration const *cfg, PaymentMethod methodId) {
-    int popId = cfg->PaymentOption.find(methodId)->second.pop_id;
-    int punId = cfg->PaymentRate.find(popId)->second.pra_payment_unit_id;
-    return cfg->Duration.find(punId)->second.pun_id;
+
+    int const popId = cfg->PaymentOption.find(methodId)->second.pop_id;
+    int const punId = cfg->PaymentRate.find(popId)->second.pra_payment_unit_id;
+    uint32_t const firstDurationStep= cfg->Duration.find(punId)->second.pun_duration;
+
+    qCritical() << "getFirstDurationStep() payment-method-id:" << (int)methodId;
+    qCritical() << "getFirstDurationStep()            pop-id:" << popId;
+    qCritical() << "getFirstDurationStep()            pun-id:" << punId;
+    qCritical() << "getFirstDurationStep()        first-step:" << firstDurationStep;
+
+    return firstDurationStep;
 }