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

// Define LED and switch connections
const byte ledPin1 = 13;
const byte ledPin2 = 12;
const byte buttonPin1 = 2;
// Boolean to represent toggle state
volatile bool toggleState = false;
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows

void setup() {
  // Set LED pin as output
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  // Set switch pin as INPUT with pullup
  pinMode(buttonPin1, INPUT_PULLUP);
  Serial.begin(9600);
  lcd.init(); // initialize the lcd
  lcd.backlight();
  // Attach Interrupt to Interrupt Service Routine
  attachInterrupt(digitalPinToInterrupt(buttonPin1),checkSwitch, FALLING);
  /*Interrupt Vector – the interrupt that you wish to use. Note that this is the internal Interrupt Vector number and NOT the pin number.
  ISR – The name of the Interrupt Service Routine function that you are gluing to the interrupt.
  Mode – How you want to trigger the interrupt.
  For Mode, there are four selections:

  RISING – Triggers when an input goes from LOW to HIGH.
  FALLING – Triggers when an input goes from HIGH to LOW.
  LOW – Triggered when the input stays LOW.
  CHANGE – Triggers whenever the input changes state from HIGH to LOW or LOW to HIGH. 
*/
}

void loop() {
 if (digitalRead(buttonPin1) == LOW) {
    Serial.println("Interrupt detected for 6 Seconds");
    lcd.clear();                 // clear display
    lcd.setCursor(4, 0);         // move cursor to   (4, 0)
    lcd.print("INTERRUPT");        // print message at (4, 0)
    lcd.setCursor(4, 1);         // move cursor to   (4, 1)
    lcd.print("6 Seconds"); // print message at (4, 1)
    // Indicate state on LED
    digitalWrite(ledPin1, HIGH);
    delay (6000); // delay for 6 seconds
    // Indicate state off LED
    digitalWrite(ledPin1, LOW);
    toggleState = false;
    lcd.clear(); 
  }
  blink();
}

void blink (){
  // 500 ms delay
  lcd.setCursor(4, 0);         // move cursor to   (4, 0)
  lcd.print("BLINKING");        // print message at (4, 0)
  lcd.setCursor(4, 1);         // move cursor to   (4, 1)
  lcd.print("LED 1"); // print message at (4, 1)
  digitalWrite(ledPin2, HIGH);
  Serial.println("Blink LED 1");
  delay(500);
  digitalWrite(ledPin2, LOW);
  delay(500);
  Serial.println("..............");
}

void checkSwitch(){
    toggleState = true;
}