int onTime = 1000;
String strbuff;

int digitPins[4] = {13,12,14,27};

void allDigitsOff(){
  digitalWrite(13,0);
  digitalWrite(12,0);
  digitalWrite(14,0);
  digitalWrite(27,0);
}

void allSegmentsOff(){
  digitalWrite(18,0);
  digitalWrite(19,0);
  digitalWrite(5,0);
  digitalWrite(2,0);
  digitalWrite(17,0);
  digitalWrite(4,0);
  digitalWrite(16,0);
}

void drawChar(char buffer, int index){
  int digitPin = digitPins[index];
  allDigitsOff();
  digitalWrite(digitPin,1);
  switch(buffer){
      case '0':
      digitalWrite(18,1);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,1);
      digitalWrite(17,1);
      digitalWrite(4,1);
      digitalWrite(16,0);
    break;
      case '1':
      digitalWrite(18,0);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,0);
      digitalWrite(17,0);
      digitalWrite(4,0);
      digitalWrite(16,0);
    break;
      case '2':
      digitalWrite(18,1);
      digitalWrite(19,1);
      digitalWrite(5,0);
      digitalWrite(2,1);
      digitalWrite(17,1);
      digitalWrite(4,0);
      digitalWrite(16,1);
    break;
      case '3':
      digitalWrite(18,1);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,1);
      digitalWrite(17,0);
      digitalWrite(4,0);
      digitalWrite(16,1);
    break;
      case '4':
      digitalWrite(18,0);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,0);
      digitalWrite(17,0);
      digitalWrite(4,1);
      digitalWrite(16,1);
    break;
      case '5':
      digitalWrite(18,1);
      digitalWrite(19,0);
      digitalWrite(5,1);
      digitalWrite(2,1);
      digitalWrite(17,0);
      digitalWrite(4,1);
      digitalWrite(16,1);
    break;
      case '6':
      digitalWrite(18,1);
      digitalWrite(19,0);
      digitalWrite(5,1);
      digitalWrite(2,1);
      digitalWrite(17,1);
      digitalWrite(4,1);
      digitalWrite(16,1);
    break;
      case '7':
      digitalWrite(18,1);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,0);
      digitalWrite(17,0);
      digitalWrite(4,0);
      digitalWrite(16,0);
    break;
                            case '8':
      digitalWrite(18,1);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,1);
      digitalWrite(17,1);
      digitalWrite(4,1);
      digitalWrite(16,1);
    break;
        case '9':
      digitalWrite(18,1);
      digitalWrite(19,1);
      digitalWrite(5,1);
      digitalWrite(2,1);
      digitalWrite(17,0);
      digitalWrite(4,1);
      digitalWrite(16,1);
    break;

  }
}
void drawStringd(String buffer){
drawChar(buffer[0],3);
delayMicroseconds(onTime);

allSegmentsOff();

drawChar(buffer[1],2);
delayMicroseconds(onTime);

allSegmentsOff();

drawChar(buffer[2],1);
delayMicroseconds(onTime);

allSegmentsOff();

drawChar(buffer[3],0);
delayMicroseconds(onTime);

allSegmentsOff();
}

#define timescale 1000
bool ispm;
unsigned long startmillis = 0;
int startsecs = 0;
int startmins = 0;
int starthrs = 0;
unsigned long secs;
unsigned long mins;
unsigned long hrs;
unsigned long prevsecs;
unsigned long timeout;
bool adjust = 0;
int setLevel = 0;

void setup() {
  // put your setup code here, to run once:
pinMode(18,OUTPUT);
pinMode(19,OUTPUT);
pinMode(5,OUTPUT);
pinMode(2,OUTPUT);
pinMode(17,OUTPUT);
pinMode(4,OUTPUT);
pinMode(16,OUTPUT);

pinMode(15,OUTPUT);

pinMode(13,OUTPUT);
pinMode(12,OUTPUT);
pinMode(14,OUTPUT);
pinMode(27,OUTPUT);
pinMode(1,INPUT_PULLUP);
allDigitsOff();
allSegmentsOff();
}



void loop() {
  if(!adjust){
secs = ((millis() - startmillis) / timescale); 
secs += (startsecs) + (startmins * 60) + (starthrs * 3600);
mins = secs / 60;
hrs = mins / 60;
// Only update display if time has changed and the display is on
if (secs != prevsecs){
prevsecs = secs;
secs %= 60;
mins %= 60;
hrs %= 24;
if (hrs > 12){
  ispm = 1;
  hrs -= 12;
}
else ispm = 0;
if (hrs == 0) hrs = 12;
strbuff = "";
if(hrs < 10) strbuff += "-";
strbuff += String(hrs);
if(mins < 10) strbuff += "0";
strbuff += String(mins);
digitalWrite(15, ((secs % 2) == 0));
}
if(!digitalRead(1)){
  adjust = true;
  setLevel = 0;
  startsecs = 0;
  startmins = 0;
  starthrs = 0;
  digitalWrite(15,1);
  while(!digitalRead(1));
}
}
if(adjust){
  if(setLevel == 0){
    strbuff = "1-" + String(starthrs);
    if(!digitalRead(1)){
      timeout = millis();
      while(!digitalRead(1) && (millis() - 2000) < timeout);
      if(digitalRead(1)){
        starthrs++;
        if(starthrs == 24) starthrs = 0;
      }
      else{
        digitalWrite(15,0);
        setLevel = 1;
        while(!digitalRead(1));
        digitalWrite(15,1);
      }
    }
  }

    if(setLevel == 1){
    strbuff = "2-" + String(startmins);
    if(!digitalRead(1)){
      timeout = millis();
      while(!digitalRead(1) && (millis() - 2000) < timeout);
      if(digitalRead(1)){
        startmins++;
        if(startmins == 60) startmins = 0;
      }
      else{
        digitalWrite(15,0);
        setLevel = 2;
        while(!digitalRead(1));
        digitalWrite(15,1);
      }
    }
  }

      if(setLevel == 2){
    strbuff = "3-" + String(startsecs);
    if(!digitalRead(1)){
      timeout = millis();
      while(!digitalRead(1) && (millis() - 2000) < timeout);
      if(digitalRead(1)){
        startsecs++;
        if(startsecs == 60) startsecs = 0;
      }
      else{
        digitalWrite(15,0);
        adjust = 0;
        startmillis = millis();
        while(!digitalRead(1));
        digitalWrite(15,1);
      }
    }
  }
  }

drawStringd(strbuff);
}