Add flags to handle NTP sync

Author: pennam

src/ArduinoCellular.cpp

@@ -126,21 +126,26 @@ Time ArduinoCellular::getGPSTime(){
     return Time(year, month, day, hour, minute, second);
 }
 
-Time ArduinoCellular::getCellularTime(bool localTime){
+Time ArduinoCellular::getCellularTime(bool localTime, bool forceNTPSync) {
     int year = 1970;
     int month = 1;
     int day = 1;
     int hour = 0;
     int minute = 0;
     int second = 0;
     float tz;
-    if (modem.NTPServerSync() == 0) {
-      if (localTime) {
-        modem.getNetworkTime(&year, &month, &day, &hour, &minute, &second, &tz);
-      } else {
-        modem.getNetworkUTCTime(&year, &month, &day, &hour, &minute, &second, &tz);
-      }
+
+    if ((needNTPSync || forceNTPSync) && (modem.NTPServerSync() != 0)) {
+        return Time(year, month, day, hour, minute, second);
     }
+    needNTPSync = false;
+
+    if (localTime) {
+      modem.getNetworkTime(&year, &month, &day, &hour, &minute, &second, &tz);
+    } else {
+      modem.getNetworkUTCTime(&year, &month, &day, &hour, &minute, &second, &tz);
+    }
+
     return Time(year, month, day, hour, minute, second);
 }
 

src/ArduinoCellular.h

@@ -163,7 +163,7 @@ class ArduinoCellular {
          * @brief Gets the current time from the network.
          * @return The current time.
          */
-        Time getCellularTime(bool localTime = true);
+        Time getCellularTime(bool localTime = true, bool forceNTPSync = false);
 
         /**
          * @brief Gets the current time from the GPS module.
@@ -277,7 +277,6 @@ class ArduinoCellular {
 
     private:
         bool connectToGPRS(const char * apn, const char * gprsUser, const char * gprsPass);
-        
 
         /**
          * @brief Waits for network registration. (Blocking call)
@@ -304,6 +303,8 @@ class ArduinoCellular {
         static unsigned long getTime(); /** Callback for getting the current time as an unix timestamp. */
 
         static constexpr unsigned long waitForNetworkTimeout = 20000L; /**< Maximum wait time for network registration (In milliseconds). */
+
+        bool needNTPSync = true; /**< Flag to indicate if NTP synchronization is needed. */
 };