#include <WiFi.h>
#include "time.h"
#include "sntp.h"

const char* ssid       = "Wokwi-GUEST";
const char* password   = "";

const char* ntpServer1 = "pool.ntp.org";
const char* ntpServer2 = "time.nist.gov";
//const long  gmtOffset_sec = 3600;
//const int   daylightOffset_sec = 3600;

const char* time_zone = "WIB-7"; // TimeZone rule for Europe/Rome including daylight adjustment rules (optional)

void printLocalTime()
{
  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) {
    Serial.println("No time available (yet)");
    return;
  }
  Serial.println(&timeinfo, "%A, %B %d %Y %H:%M:%S");
}

// Callback function (get's called when time adjusts via NTP)
void timeavailable(struct timeval *t)
{
  Serial.println("Got time adjustment from NTP!");
  printLocalTime();
}

void setup()
{
  Serial.begin(115200);

  // set notification call-back function
  sntp_set_time_sync_notification_cb( timeavailable );

  /**
     NTP server address could be aquired via DHCP,

     NOTE: This call should be made BEFORE esp32 aquires IP address via DHCP,
     otherwise SNTP option 42 would be rejected by default.
     NOTE: configTime() function call if made AFTER DHCP-client run
     will OVERRIDE aquired NTP server address
  */
  sntp_servermode_dhcp(1);    // (optional)

  /**
     This will set configured ntp servers and constant TimeZone/daylightOffset
     should be OK if your time zone does not need to adjust daylightOffset twice a year,
     in such a case time adjustment won't be handled automagicaly.
  */
  //configTime(gmtOffset_sec, daylightOffset_sec, ntpServer1, ntpServer2);

  /**
     A more convenient approach to handle TimeZones with daylightOffset
     would be to specify a environmnet variable with TimeZone definition including daylight adjustmnet rules.
     A list of rules for your zone could be obtained from https://github.com/esp8266/Arduino/blob/master/cores/esp8266/TZ.h
  */
  configTzTime(time_zone, ntpServer1, ntpServer2);

  //connect to WiFi
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" CONNECTED");

}

void loop()
{
  delay(5000);
  printLocalTime();     // it will take some time to sync time :)
}