//sntp_sync_notification.c

#include <WiFi.h>
//#include "time.h"     // 削除
#include <sys/time.h>   // 追加 for struct timeval
#include <sntp.h>       // 追加 for sntp_sync_status

const char* ssid       = "xxxxxx"; // 自宅のWiFi UserID を設定
const char* password   = "xxxxxx"; // 自宅のWiFi Password を設定

const char* ntpServer1 = "ntp.nict.jp";
const char* ntpServer2 = "time.google.com";
const char* ntpServer3 = "ntp.jst.mfeed.ad.jp";
const long  gmtOffset_sec = 9 * 3600;
const int   daylightOffset_sec = 0;
int itimeout = 1000; //Wait WiFi Connection

void printLocalTime() // CPU 内蔵の RTC の時刻表示
{
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){ // CPU 内蔵の RTC の時刻を取得
    Serial.println("Failed to obtain time");
    return;
  }
  Serial.println(&timeinfo, "%A, %B %d %Y %H:%M:%S");// RTC の時刻表示
  //       17:32:27.842 -> Monday, January 08 2024 17:32:27
}

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

void setup()
{
  Serial.begin(115200);
  
  //connect to WiFi
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED ) {
	itimeout--;
	if(itimeout < 1) WIFI_REASON_TDLS_PEER_UNREACHABLE;
	else {
      Serial.print(".");
      delay(500);
    }
  }
  Serial.println(" CONNECTED");
  
  //init and get the time
  sntp_set_time_sync_notification_cb( timeavailable );
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer1, ntpServer2, ntpServer3);// CPU 内蔵の RTC に時刻を設定
  printLocalTime();// 時刻表示

  //disconnect WiFi as it's no longer needed
  WiFi.disconnect(true);// NTP の参照は完了、WiFi 停止
  WiFi.mode(WIFI_OFF);  // WiFi切断
}

void loop()
{
  delay(1000);
  printLocalTime();// 時刻表示
}