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

#define ROWS 4
#define COLS 4

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

int Original = 0;
int Converted = 0;

String OriginalChoices[4] = {"  BIN","  DEC","  OCT","  HEX"};

byte rowPins[ROWS] = {9, 8, 7, 6}; // connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2};    // connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  lcd.begin(16, 2); // initialize the LCD
  lcd.backlight(); // turn on the backlight
  lcd.print(" Number System ");
  lcd.setCursor(0,1);
  lcd.print("   Converter");
  delay(1500);
  lcd.clear();
  lcd.print(OriginalChoices[0]);
  lcd.print("  to");

}

void loop() {
  
  Menu();
  GetUserInput();

}

void Menu() {
  char choice = keypad.getKey();
  //Ask user what is the number system to be use
  while(choice != '5') {
    choice = keypad.getKey();
    if(choice == '6' && Original < 3){
      lcd.clear();
      lcd.print(OriginalChoices[++Original]);
      lcd.print("  to");
    }
    else if(choice == '4' && Original > 0) {
      lcd.clear();
      lcd.print(OriginalChoices[--Original]);
      lcd.print("  to");
    }
  }
  //Ask user to what to convert
  choice = keypad.getKey();
  while(choice != '5') {
    choice = keypad.getKey();
    if(choice == '6' && Converted < 3){
      Converted++;
      if(Converted == Original) Converted++;
      if(Converted > 3) Converted = Original-1;
      lcd.clear();
      lcd.print(OriginalChoices[Original]);
      lcd.print("  to");
      lcd.print(OriginalChoices[Converted]);
    }
    else if(choice == '4' && Converted > 0) {
      Converted--;
      if(Converted == Original) Converted--;
      if(Converted < 0) Converted = Original+1;
      lcd.clear();
      lcd.print(OriginalChoices[Original]);
      lcd.print("  to");
      lcd.print(OriginalChoices[Converted]);
    }
    //Converted = (Converted == Original)?(Converted < 2 )? Converted+2 : Converted = 0 : Converted+1;
  }
}

void GetUserInput() {
  char input = keypad.getKey();
  while(input != NO_KEY) {
    
  }
}

void SampleKeyInput() {

  char key = keypad.getKey();

  if (key != NO_KEY ) {
    lcd.clear();
    lcd.print(key);
  }

}