#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <Wire.h>
LiquidCrystal_I2C lcd(0x27,20,4);

/* Display */


/* Keypad setup */
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {12, 11, 10, 9};
byte colPins[KEYPAD_COLS] = {8, 7, 6, 5};
char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);

uint64_t value = 0;

bool button = 0;



void showSpalshScreen() {

  lcd.setCursor(2, 0);
  String message = "PasswordSafe";
  for (byte i = 0; i < message.length(); i++) {
    lcd.print(message[i]);
    delay(100);
  }
  delay(500);
}

void updateCursor() {
  if (millis() / 250 % 2 == 0 ) {
    lcd.cursor();
  } else {
    lcd.noCursor();
  }
}

void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.clear();         
  lcd.backlight();

  pinMode(A0, INPUT_PULLUP);
  pinMode(A2, OUTPUT);
  pinMode(A3, OUTPUT);

 showSpalshScreen();
  

  
}
String password = "1234";
String passMem = "";
String UnitPrice = "";
unsigned int unitPrice = 15;

char operation = 0;
String memory = "";
String current = "";
uint64_t currentDecimal;
bool decimalPoint = false;

double calculate(char operation, double left, double right) {
  switch (operation) {
    case '+': return left + right;
    case '-': return left - right;
    case '*': return left * right;
    case '/': return left / right;
  }
}

void processInput(char key) {
  // if ('-' == key && current == "") {
  //   current = "-";
  //   lcd.print("-");
  //   return;
  // }

  // switch (key) {
  //   case '+':
  //   case '-':
  //   case '*':
  //   case '/':
  //     if (!operation) {
  //       memory = current;
  //       current = "";
  //     }
  //     operation = key;
  //     lcd.setCursor(0, 1);
  //     lcd.print(key);
  //     lcd.setCursor(current.length() + 1, 1);
  //     return;

  //   case '=':
  //     float leftNum = memory.toDouble();
  //     float rightNum = current.toDouble();
  //     memory = String(calculate(operation, leftNum, rightNum));
  //     current = "";
  //     lcd.clear();
  //     lcd.setCursor(1, 0);
  //     lcd.print(memory);
  //     lcd.setCursor(0, 1);
  //     lcd.print(operation);
  //     return;

  // }

  // if ('.' == key && current.indexOf('.') >= 0) {
  //   return;
  // }

  // if ('.' != key && current == "0") {
  //   current = String(key);
  // } else if (key) {
  //   current += String(key);
  // }

  // lcd.print(key);


  switch (key) {
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
    case '0':
      lcd.setCursor(0, 1);
      passMem = passMem + key;
      lcd.setCursor(passMem.length(), 1);
      lcd.print(key);
      break;
    case '=' :
      if (passMem == password) {
        tone(A5, 500, 1000);
        lcd.setCursor(0, 0);
        String message = "Unlocking Device";
        for (byte i = 0; i < message.length(); i++) {
          lcd.print(message[i]);
          delay(100);
        }
        delay(500);
        lcd.clear();
      } else {
        tone(A5, 300, 1000);
        lcd.setCursor(0, 0);
        String message = "Wrong Password";
        for (byte i = 0; i < message.length(); i++) {
          lcd.print(message[i]);
          delay(100);
        }
        delay(500);
        lcd.clear();

      }
      break;




  }

}

void loop() {
  updateCursor();

  char key = keypad.getKey();
  if (key) {
    processInput(key);
  }
}