#include <RTClib.h>
#include <LiquidCrystal.h>

RTC_DS1307 rtc;
//                  rs e d4 d5 d6 d7
LiquidCrystal lcd(12, 10, 6, 5, 4, 3);

#define KEY_MINUS 2
#define KEY_SET 7
#define KEY_PLUS 8
int param = 0; //  номер параметра який міняємо або 0

unsigned long timeKEY=1;
#define intervalKEY 100 // інтервал опитування кнопок
int blink=0;
unsigned long timeBlink;
#define intervalBlink 100

DateTime now;

void setup() { 
  /*
  Serial.begin(9600);
  if ( rtc.begin() ) {
    Serial.println("Timer is present!");
  }
  else Serial.println("Timer not found!");
  */
  rtc.begin();
  lcd.begin(16, 2);
  //lcd.print("Hi!");

  //delay(1000);
  lcd.clear();
  pinMode(KEY_PLUS, INPUT_PULLUP);
  pinMode(KEY_MINUS, INPUT_PULLUP);
  pinMode(KEY_SET, INPUT_PULLUP);

  //DateTime tm = DateTime( 2021, 03, 22, 17, 40, 0 );
  //rtc.adjust( tm );
  //rtc.adjust( DateTime( 2021, 04, 29, 17, 40, 15 ) );
}

void print0( int data, int num ) {
  if ( param == num ) { // моргаючий параметр
    if (blink == 1) {
      lcd.print("  ");
      if (param == 6) lcd.print("  ");
    } 
    else {
      if (data < 10) {
        lcd.print( "0" );  
      }
      lcd.print( data );
    }
  }  
  else {
    if (data < 10) {
      lcd.print( "0" );  
    }
    lcd.print( data );
  }
}

void plus(){
  int h = now.hour();
  int m = now.minute();
  int s = now.second();
  int d = now.day();
  int month = now.month();
  int y = now.year();
  switch (param) {
    case 1: // години
      h = h+1;
      if (h > 23) h = 0;
      break;
    case 2:
      m = m+1;
      if (m > 59) m = 0;
      break;
    case 3:
      s = s + 1;
      if (s > 59) s = 0;
      break;
    case 4:
      d = d + 1;
      break;
    case 5:
      month = month + 1;
      if (month > 12) month = 0;
      break;
    case 6:
      y = y + 1;
      break;
  }
  if (param > 0) rtc.adjust( DateTime( y, month, d, h, m, s ) );
}

void minus(){
  int h = now.hour();
  int m = now.minute();
  int s = now.second();
  int d = now.day();
  int month = now.month();
  int y = now.year();
  switch (param) {
    case 1: // години
      h = h-1;
      if (h < 0) h = 23;
      break;
    case 2:
      m = m-1;
      if (m < 0) m = 59;
      break;
    case 3:
      s = s - 1;
      if (s < 0) s = 59;
      break;
    case 4:
      d = d - 1;
      if (d < 1) d = 1;
      break;
    case 5:
      month = month - 1;
      if (month < 1) month = 1;
      break;
    case 6:
      y = y - 1;
      break;
  }
  if (param > 0) rtc.adjust( DateTime( y, month, d, h, m, s ) );
}


void loop() {
  now = rtc.now();
/*
  Serial.print("Current time: ");
  Serial.print(now.year(), DEC);
  Serial.print('/');
  Serial.print(now.month(), DEC);
  Serial.print('/');
  Serial.print(now.day(), DEC);
  Serial.print("  ");
  Serial.print(now.hour(), DEC);
  Serial.print(':');
  Serial.print(now.minute(), DEC);
  Serial.print(':');
  Serial.print(now.second(), DEC);
  Serial.println();
*/

  //lcd.clear();

  lcd.setCursor(4, 0);
  print0( now.hour(), 1 );

  if ( now.second() % 2 == 1 ) {
    lcd.print( ":" );
  }
  else {
    lcd.print( " " );
  }

  print0( now.minute(), 2 );

  if ( now.second() % 2 == 1 ) {
    lcd.print( ":" );
  }
  else {
    lcd.print( " " );
  }

  print0( now.second(), 3 );

  lcd.setCursor(3, 1);
  print0( now.day(), 4 );
  lcd.print( "/" );
  print0( now.month(), 5 );
  lcd.print( "/" );
  print0( now.year(), 6 );

  if ( timeKEY > 0 && millis() > timeKEY) {
    timeKEY = millis() + intervalKEY;
    if ( digitalRead(KEY_SET) == 0 ) {
      param++;
      if (param > 6) {
        param = 0;
      }  
    }
    if ( digitalRead(KEY_MINUS) == 0 ) {
      minus();
    }
    if ( digitalRead(KEY_PLUS) == 0 ) {
      plus();
    }
  }   

  if ( millis() > timeBlink ) {
    timeBlink = millis() + intervalBlink;
    if (blink == 0) blink = 1;
    else blink = 0;
  }
  
}