#include "RTClib.h"
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

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

RTC_DS1307 rtc;

void calculate () {


float bober = 0;
int nissanskyline = 0;
char peremennaya = '+';
float vtoroybober = 0;
float result = 0;

Serial.println("vvedi suda first chislo");
delay(4999);
if(Serial.available()>0)
{
  bober = Serial.parseFloat();
}
delay(1000);
Serial.println("spasibo ura");
lcd.print(bober);
lcd.leftToRight();
Serial.println("vvedi suda deystvie pozhalusta 1+, 2-, 3*,4/,5^");
delay(4999);
if(Serial.available()>0)
{
  nissanskyline = Serial.parseInt();
}
Serial.println("spasibo ura");
switch (nissanskyline) {
  case 1:
    peremennaya = '+';
    break;
  case 2:
    peremennaya = '-';
    break;
  case 3:
    peremennaya = '*';
    break;
  case 4:
    peremennaya = '/';
    break;
  case 5:
    peremennaya = '^';
    break;
  default:
    lcd.setCursor(0, 1);
    lcd.print("Error");
    break;
}
lcd.print(peremennaya);
Serial.println("vvedi suda second chislo");
delay(4999);
if(Serial.available()>0)
{
  vtoroybober = Serial.parseFloat();
}
lcd.print(vtoroybober);
delay(999);
lcd.setCursor(0, 1);
lcd.print("Calculating...");
Serial.println("u teba poluchilos:");
switch (nissanskyline) {
  case 1:
    result = bober + vtoroybober;
    break;
  case 2:
    result = bober - vtoroybober;
    break;
  case 3:
    result = bober * vtoroybober;
    break;
  case 4:
    result = bober / vtoroybober;
    break;
  case 5:
    result = pow(bober, vtoroybober);
    break;
  default:
    Serial.println("NEPRAVILNO(((((((");
}
delay(2222);
Serial.print(bober); Serial.print(peremennaya); Serial.print(vtoroybober);
lcd.clear();
lcd.print(result);
}

  void clock() {
  DateTime now = rtc.now();
  lcd.clear();
  lcd.print(now.day(), DEC);
  lcd.print("/");
  lcd.print(now.month(), DEC);
  lcd.print("/");
  lcd.print(now.year(), DEC);
  lcd.print("  ");
  lcd.print(daysOfTheWeek[now.dayOfTheWeek()]);
  lcd.setCursor(0,1);
  lcd.print(now.hour(), DEC);
  lcd.print(":");
  lcd.print(now.minute(), DEC);
  lcd.print(":");
  lcd.print(now.second(), DEC);
delay(999);
  }

void setup() {
Serial.begin(115200);
short appid;
lcd.init();
lcd.backlight();
pinMode(A0, INPUT);

  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort(); }
}

void loop() {
  short appid;
  short button;

 button = analogRead(A0);
 button = map(button, 0, 1023, 1, 3);
 appid = button;
 Serial.println(appid);
  if (appid == 1) {
    calculate();
    lcd.clear();
  }
  else if(appid == 2) {
    clock();
    lcd.clear();
  }
  else {
    lcd.clear();
    lcd.print("programm error");
  }
  }