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

RTC_DS1307 rtc;

char daysOfTheWeek[7][12] = {"Sun ", "Mon ", "Tue ", "Wed ", "Thu ", "Fri ", "Sat "};

const int rs = 13, en = 12, d4 = 11, d5 = 10, d6 = 9, d7 = 8;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

 int sw = 4;    
 int dt = 3;       
 int clk = 2;
 int cw = 0;

int contrast = 7 ;   
int LDR_sensor = 5;

const float BETA = 3950;

int menu = 0;

void time(){
  lcd.clear();
  DateTime now = rtc.now();
  lcd.setCursor(0,0);
  lcd.print(daysOfTheWeek[now.dayOfTheWeek()]);
  lcd.print(now.year(), DEC);
  lcd.print("/");
  lcd.print(now.month(),DEC);
  lcd.print("/");
  lcd.print(now.day(),DEC);
  lcd.setCursor(0,1);
  lcd.print("Time ");
  lcd.print(now.hour(), DEC);
  lcd.print(":");
  lcd.print(now.minute(), DEC);
  lcd.print(":");
  lcd.print(now.second(), DEC);
  delay(50);
}

void encoder()
{
  if(digitalRead(clk)==0)
  {
    cw++;
    delay(200);
  }

  if(digitalRead(dt)==0)
  {
    cw--;
    delay(200);
  }

  if(digitalRead(sw)==0)
  {
    menu++;
    delay(50);
  }
}

void setup() {
  lcd.begin(16, 2);
  lcd.print("loading...");
  pinMode(clk , INPUT);
  pinMode(dt, INPUT);
  pinMode(sw , INPUT_PULLUP);
  rtc.begin();
  Serial.begin(57600);
  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    while (1) delay(10);
  }
  if (! rtc.isrunning()) {
    Serial.println("RTC is NOT running, let's set the time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
  //rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
  attachInterrupt(digitalPinToInterrupt(clk), encoder, LOW);
  attachInterrupt(digitalPinToInterrupt(dt), encoder, LOW);

}

void loop() {
  if(digitalRead(sw)==0)
  {
    menu++;
    delay(50);
  }

  switch (menu) {
    case 0:
      time();
    break;
    case 1:
      switch(cw)
      {
        case 0:
          lcd.clear();
          lcd.print(">Display time");
          lcd.setCursor(0,1);
          lcd.print(" Room condition");
          delay(50);
          break;
        case 1:
          lcd.clear();
          lcd.print(" Display time");
          lcd.setCursor(0,1);
          lcd.print(">Room condition");
          delay(50);
          break;
      }
      break;
    case 2 :
      if(cw==0)
      {
        time();
      }

      if(cw==1)
      {
        room_condition();
      }
      break;
    case 3:
    menu = 0;
    cw = 0;
    break;
  }

  if(cw>1)
  {
    cw=0;
  }

  if(cw<0)
  {
    cw=1;
  }

  if(digitalRead(LDR_sensor)==1)
  {
   digitalWrite(contrast, HIGH);
  }
  if(digitalRead(LDR_sensor)==0)
  {
   digitalWrite(contrast , LOW);
  }

}

void room_condition(){
   lcd.clear();
  int analogValue = analogRead(A0);                                                             //to convert from Kelv to C
      float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  lcd.print(" Temp : ");
  lcd.print(celsius);
  lcd.println(" *c");
  lcd.setCursor(0,1);
  if (digitalRead(LDR_sensor) == LOW) {
    lcd.print(" -Room Light!-");
  } 
  else {
    lcd.print(" -Room Dark-");
  }
  delay(50);
 }