#include <Keypad.h>
#include <LiquidCrystal_I2C.h>



// set the LCD number of columns and rows
int lcdColumns = 16;
int lcdRows = 2;
LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows); 

byte LIGHT  = A0; // the Arduino pin, which connects to the IN pin of relay
const int ROW_NUM    = 4; // four rows
const int COLUMN_NUM = 4; // four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3', 'A'},
  {'4','5','6', 'B'},
  {'7','8','9', 'C'},
  {'*','0','#', 'D'}
};

byte pin_rows[ROW_NUM] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );

const String password= "ABC9"; // TURN ON THE LED (A0)
const String turnOFF= "ABC8"; // TURN OFF THE LED (A0)

String input_password;

void setup() {
    // initialize LCD
  lcd.init();
  // turn on LCD backlight                      
  lcd.backlight();
  input_password.reserve(32); // maximum input characters is 33, change if needed
  pinMode(LIGHT, OUTPUT); // initialize pin as an output.
  lcd.setCursor(0,0);

  lcd.print("KEYWORD: ");

}

void loop() {
  char key = keypad.getKey();

  if (key){
    Serial.println(key);

    if(key == '*') {
      input_password = ""; // reset the input password
    }
    
     else if(key == '#') {
      if(input_password == password ) {
         lcd.clear();
        delay(500);
        lcd.print("LIGHT ON");
         digitalWrite(LIGHT, 1);
          delay(3000);
         
         lcd.setCursor(0,0);
        lcd.clear();
        lcd.print("KEYWORD:");

        lcd.setCursor(0,1);
        lcd.print("LIGHT ON");

      }else if(input_password == turnOFF){

        lcd.clear();
        delay(500);
        lcd.print("LIGHT OFF");
        digitalWrite(LIGHT, 0);
        delay(3000);
         
         lcd.setCursor(0,0);
        lcd.clear();
        lcd.print("KEYWORD:");

        lcd.setCursor(0,1);
        lcd.print("LIGHT OFF");

       }
       else {
  
         lcd.setCursor(9,0);
        lcd.print("WRONG");
         delay(2000);
         
         lcd.setCursor(0,0);
        lcd.clear();
        lcd.print("KEYWORD: ");
      }

      input_password = ""; // reset the input password
    } else {
      input_password += key; // append new character to input password string
    }
  }
}