#include <Wire.h>
#include <LiquidCrystal_I2C.h>
//#include <stdio.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

int relay = 8;
int relay2 = 9;
int buzzer = 10;

String str;
int blueToothVal;

int timer_started_flag = 0;
long int total_Seconds = 0;

// Tracks the time since last event fired
unsigned long int previoussecs = 0;
unsigned long int currentsecs = 0;
unsigned long currentMillis = 0;
int interval = 1 ; // updated every 1 second

void setup()
{
  Serial.begin(9600);
  pinMode(relay, OUTPUT);
  pinMode(relay2, OUTPUT);
  pinMode(buzzer, OUTPUT);
  digitalWrite(relay, HIGH);// relay is OFF
  digitalWrite(relay2, HIGH);// relay is OFF
  digitalWrite(buzzer, LOW);

  lcd.init();
  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print("Hello, world!");
  lcd.setCursor(0, 1);
  lcd.print("Ywrobot Arduino!");
}


void loop()
{
  bluetooth();
  countdown();
}


void bluetooth()
{
  while (Serial.available() && timer_started_flag == 0)
  {
    {
      str = Serial.readStringUntil('\n');
    }

    blueToothVal = (str.toInt());
    if (blueToothVal > 12) {
      blueToothVal = 12;
    }
    total_Seconds = blueToothVal * 60;// convert to sec
    timer_started_flag = 1;
    lcd.clear();
    lcd.print("T Seconds:");
    lcd.setCursor(11, 0);
    lcd.print( total_Seconds );
    delay(1000);
  }
}


void countdown() {
  while (timer_started_flag == 1) {
    lcd.setCursor(0, 0);
    lcd.print("T Seconds:");
    lcd.setCursor(11, 0);
    lcd.print( total_Seconds );
    lcd.setCursor(0, 1);
    if ( total_Seconds > 0)
    {
      digitalWrite(relay, LOW);// turn ON relay 1
      digitalWrite(relay2, LOW);// turn ON relay 2
      lcd.print("load ON ");
    }

    if ( total_Seconds <= 0)
    {
      total_Seconds = 0;
      timer_started_flag = 0;
      digitalWrite(relay, HIGH);// turn OFF Relay 1
      digitalWrite(relay2, HIGH);// turn OFF Relay 2
      lcd.print("load OFF");
      //------------------------------Buzzer Tone
      digitalWrite(buzzer, HIGH);
      delay(500);
      digitalWrite(buzzer, LOW);
      delay(500);
      digitalWrite(buzzer, HIGH);
      delay(1500);
      digitalWrite(buzzer, LOW);
      delay(500);
      /////////////////////////////////////////////
    }

    currentMillis = millis();
    currentsecs = currentMillis / 1000;
    if ((unsigned long)(currentsecs - previoussecs) >= interval) {
      total_Seconds = total_Seconds - 1;
      lcd.clear();
      previoussecs = currentsecs;
    }
  }//end of while loop
}