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

LiquidCrystal_I2C myLCD(0x27,16,2);

// user input array
char userInput[4] = {'1','1','1','1'};

// our keypad bytes
const byte ROWS = 4;
const byte COLS = 4;
// our char array
char keys[ROWS][COLS] = 
{
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
// assigning row pins and col pins
byte rowPin[ROWS] = {9,8,7,6};
byte colPin[COLS] = {5,4,3,2};
// our keypad object
Keypad pad = Keypad(makeKeymap(keys), rowPin, colPin, ROWS, COLS);

// helper method to light up led
void rgbL(bool ans)
{
  if(ans)
  {
    // light up green for two seconds
    pinMode(12, OUTPUT);
    analogWrite(12, 255);
  }else
  {
    // light up red for two seconds
    pinMode(13, OUTPUT);
    analogWrite(13, 255);
  }
  delay(2000);
  analogWrite(12,0);
  analogWrite(13,0);
}
// helper method to clear second row of LCD
void clr()
{
  myLCD.setCursor(0,1);
  myLCD.print("                "); // clear our row
}
// helper method to check if a password is correct
// Our Password
char pass[4] = {'4','8','7','3'};
void passCheck(char passUser[])
{
  bool same = true;
  for(int i = 0; i < 4; i++)
  {
    if(passUser[i] != pass[i])
    {
      same = false;
    }
  }

  // print information to LCD
  clr();
  myLCD.setCursor(0,1);
  if(same)
  {
    // is correct
    myLCD.print("Correct!");
  }else
  {
    myLCD.print("Incorrect!");
  }

  // send our boolean to our rgb LED
  rgbL(same);
  clr();
}

void setup() {
  Serial.begin(9600);
  // starting our LCD variable  
  myLCD.init();
  myLCD.backlight();
  // setup our LCD
  myLCD.setCursor(0,0);
  myLCD.print("Enter your code:");

  // Initialize userInput array to be empty
  for(int i = 0; i < 4; i++) {
    userInput[i] = '\0';
  }
}

bool loopEnder = true;
void loop() {
  // our user input tracking
  int trackIn = -1;

  while (loopEnder) {
    char userKey = pad.getKey(); // Get key pressed
    // Check if a key is pressed
    if (userKey) {
      trackIn++;
      if (userKey == '#' && trackIn >= 4) {
        // send our array to check our password
        passCheck(userInput);
        loopEnder = false; // Exit loop after checking password
      } else {
        if(userKey != '#' && trackIn < 4)
        {
          // insert user input into array and print *
          userInput[trackIn] = userKey;
          myLCD.setCursor(trackIn, 1);
          myLCD.print("*");
        }
      }
    }
  }
  // reset loop ender
  loopEnder = true;
}