retrieves time from NTP and calculate ms between now and a given time in the next 24 hours

Software/src/devboard/utils/ntp_time.cpp

@@ -0,0 +1,64 @@
+#include "ntp_time.h"
+#include "../../include.h"
+#include "time.h"
+
+const unsigned long millisInADay = 24 * 60 * 60 * 1000;  // 24 hours in milliseconds
+
+unsigned long long getNtpTimeInMillis() {
+  configTzTime(time_zone, ntpServer1, ntpServer2);
+  struct tm timeinfo;
+
+  // Wait for time to be set
+  for (int i = 0; i < 5; i++) {
+    if (getLocalTime(&timeinfo)) {
+      logging.println("Time retrieved from NTP Server");
+      break;
+    }
+    delay(1000);
+    logging.println("Waiting for NTP time...");
+  }
+
+  if (!getLocalTime(&timeinfo)) {
+    logging.println("Failed to obtain time");
+    return 0;
+  }
+
+  // Convert to milliseconds
+  time_t epochTime = mktime(&timeinfo);
+  return static_cast<unsigned long long>(epochTime) * 1000;
+}
+
+// Function to calculate the difference in milliseconds to the next target time
+unsigned long long millisToNextTargetTime(unsigned long long currentMillis, int targetTime) {
+  int hour = targetTime / 100;
+  int minute = targetTime % 100;
+
+  time_t currentTime = currentMillis / 1000;  // Convert milliseconds to seconds
+  struct tm* timeinfo = localtime(&currentTime);
+
+  // Set timeinfo to the target time on the next day
+  timeinfo->tm_hour = hour;
+  timeinfo->tm_min = minute;
+  timeinfo->tm_sec = 0;
+
+  // Increment day if the current time is past the target time
+  if (mktime(timeinfo) <= currentTime) {
+    timeinfo->tm_mday += 1;
+  }
+  time_t nextTargetTime = mktime(timeinfo);
+  unsigned long long nextTargetMillis = static_cast<unsigned long long>(nextTargetTime) * 1000;
+  return nextTargetMillis - currentMillis;
+}
+
+unsigned long long getTimeOffsetfromNowUntil(int targetTime) {
+  logging.println("Getting time offset from now until " + String(targetTime));
+  unsigned long long timeinMillis = getNtpTimeInMillis();
+  if (timeinMillis != 0) {
+    logging.println("Time in millis: " + String(timeinMillis));
+    unsigned long long timeOffsetUntilTargetTime = millisInADay - (millisToNextTargetTime(timeinMillis, targetTime));
+    logging.println("Time offset until target time: " + String(timeOffsetUntilTargetTime));
+    return timeOffsetUntilTargetTime;
+  } else
+
+    return 0;
+}

Software/src/devboard/utils/ntp_time.h

@@ -0,0 +1,14 @@
+#ifndef __NTPTIME_H__
+#define __NTPTIME_H__
+
+extern const char* ntpServer1;
+extern const char* ntpServer2;
+extern const char* time_zone;
+
+void init_mqtt(void);
+void mqtt_loop(void);
+unsigned long long getNtpTimeInMillis();
+unsigned long long millisToNextTargetTime(unsigned long long currentMillis, int targetTime);
+unsigned long long getTimeOffsetfromNowUntil(int targetTime);
+
+#endif