#include <WiFi.h>
#include <WifiUDP.h>
#include <String.h>
#include <Wire.h>

#include <NTPClient.h>
#include <Time.h>
#include <TimeLib.h>
#include <Timezone.h>
#include <U8g2lib.h>

#include <Wire.h>

U8G2_SSD1306_128X32_UNIVISION_F_HW_I2C u8g2(U8G2_R0); 

// Define NTP properties
#define NTP_OFFSET   60 * 60      // In seconds
#define NTP_INTERVAL 60 * 1000    // In miliseconds
#define NTP_ADDRESS  "ca.pool.ntp.org"  // change this to whatever pool is closest (see ntp.org)

// Set up the NTP UDP client
WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, NTP_ADDRESS, NTP_OFFSET, NTP_INTERVAL);


const char* ssid = "Wokwi-GUEST";   // insert your own ssid 
const char* password = "";              // and password


String date;
String t;
const char * days[] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"} ;
const char * months[] = {"Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec"} ;
const char * ampm[] = {"AM", "PM"} ;
 
void setup () 
{
  Serial.begin(115200); // most ESP-01's use 115200 but this could vary
  timeClient.begin();   // Start the NTP UDP client
  u8g2.begin();

  // Connect to wifi
  Serial.println("");
  Serial.print("Connecting to ");
  Serial.print(ssid);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) 
  {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to WiFi at ");
  Serial.print(WiFi.localIP());
  Serial.println("");
 
  delay(1000);
}

void loop() 
{
  if (WiFi.status() == WL_CONNECTED) //Check WiFi connection status
  {   
    date = "";  // clear the variables
    t = "";
    
    // update the NTP client and get the UNIX UTC timestamp 
    timeClient.update();
    unsigned long epochTime =  timeClient.getEpochTime();

    // convert received time stamp to time_t object
    time_t local, utc;
    utc = epochTime;

    // Then convert the UTC UNIX timestamp to local time
    TimeChangeRule usEDT = {"EDT", Second, Sun, Mar, 2, -300};  //UTC - 5 hours - change this as needed
    TimeChangeRule usEST = {"EST", First, Sun, Nov, 2, -360};   //UTC - 6 hours - change this as needed
    Timezone usEastern(usEDT, usEST);
    local = usEastern.toLocal(utc);

    // now format the Time variables into strings with proper names for month, day etc
    date += days[weekday(local)-1];
    date += ", ";
    date += months[month(local)-1];
    date += " ";
    date += day(local)+1;
    date += ", ";
    date += year(local);

    // format the time to 12-hour format with AM/PM and no seconds
    t += hourFormat12(local-1)-1;
    t += ":";
    if(minute(local) < 10)  // add a zero if minute is under 10
      t += "0";
    t += minute(local);
    t += " ";
    if (ampm[isPM(local)] == "PM"){
      t += "AM";
    }
    if (ampm[isPM(local)] == "AM"){
      t += "PM";
    }

    
   

    // Display the date and time
  
    Serial.println(t);

    // print the date and time on the OLED


   u8g2.clearBuffer();          // clear the internal memory
   u8g2.setFont(u8g2_font_logisoso24_tr);  // choose a suitable font at https://github.com/olikraus/u8g2/wiki/fntlistall
   u8g2.setCursor(10, 29);
   u8g2.print(t);
   u8g2.sendBuffer(); 
    
 
  }
  else // attempt to connect to wifi again if disconnected
  {

  }
    
  delay(10000);    //Send a request to update every 10 sec (= 10,000 ms)
}