#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DS3231.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

const byte brightnessPin = 6;
byte i = 0;

byte ledGreen = 3;
byte ledRed = 2;

int LDRInput = A0;
int PSInput = A1;
int valuePS,cp,test;

DS3231 Clock;
byte year, month, date, DoW, hour, minute, second;
bool century = false;
bool h12, pm;
const int delayPeriod = 1000;
unsigned long lastTime; 

void setup() 
{
  lcd.init();
  lcd.clear();
  lcd.display();
  lcd.backlight();

 
  
  pinMode(PSInput, INPUT_PULLUP);
  
  Serial.begin(9600);
  pinMode(ledGreen, OUTPUT);
  pinMode(ledRed, OUTPUT); // set leds as outputs
  pinMode(LDRInput, INPUT);
  pinMode(PSInput, INPUT); // set sensors as inputs
  lcd.init(); 

  
  GetDateTime();

}

void loop() 
{
  //LDR
  int valueLDR=analogRead(LDRInput);
  Serial.println("LDR value is :");
Serial.println(valueLDR);
  if(valueLDR>500) //no light
  {
   lcd.noDisplay();
   lcd.noBacklight();// no display
  }

  else
  {
   lcd.display();
   lcd.backlight(); // otherwise display on
  }
  
  //PS
  int valuePS = analogRead(PSInput);
  Serial.println("PS value is :");
Serial.println(valuePS);

valuePS = analogRead(PSInput);
if (valuePS==8) //if someone on seat
{ test=1;
cp=0; // initialize the timer to 0
while(test==1) {
 
lcd.setCursor(4, 2);
cp++; // increment the counter
lcd.print("Timer :");
lcd.print(cp);
delay(1000);
valuePS = analogRead(PSInput);
if (valuePS >9) { //if the come off seat
test=0; // stop the clock

delay(1000);
}
}
}


 //rtc
  if(millis()- lastTime > delayPeriod)
  { 
  lastTime = millis();

  GetDateTime();
String dt =GetDateTimeString();
Serial.println(dt);

lcd.setCursor(3,0);
lcd.print(dt);
}
}

void GetDateTime() //for RTC, read time as previously set on RTC
{
date = Clock.getDate();
month = Clock.getMonth( century);
year = Clock.getYear();
DoW = Clock.getDoW();
hour = Clock.getHour( h12, pm);
minute = Clock.getMinute();
second = Clock.getSecond();
}


String GetDateTimeString() //for RTC, format time for printing 
{
  String dt = String(date) + "/" + String(month) + "/" + String(year) + " ";
dt += Get2Digits(hour) + ":" + Get2Digits(minute) + ":" + Get2Digits(second);
return dt;
}

String Get2Digits(byte number) // for RTC
{
  return number < 10 ?" " + String(number) : String(number);
}