#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
#include<Keypad.h>
// char customKey=0;

#include <TM1637Display.h>
#define CLK 3
#define DIO 2
TM1637Display display = TM1637Display(CLK, DIO);

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char hexaKeys[ROWS][COLS] = {
{'1','2','3','A'},
{'4','5','6','B'},
{'7','8','9','C'},
{'*','0','#','D'}
};
byte rowPins[ROWS] = {A15, A14, A13, A12}; //row pinouts of the keypad
byte colPins[COLS] = {A11, A10, A9, A8}; //column pinouts of the keypad

Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);  //initialize an instance of class NewKeypad

int LCDCol = 1;
int LCDRow = 1;

char digits[4];
byte d = 0;

int count = 0;

void setup() 
{
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.setCursor(LCDCol, LCDRow);
  // Set "digit" buffer string to an empty string
  digits[0] = 0x0;
}

void loop() 
{
  display.setBrightness(4);
  
  char key = customKeypad.getKey();
  if (key)
  {
    lcd.setCursor(LCDCol,LCDRow);
    switch (key)
    {
      case '0' ... '9': // Numbers
        if(d < 3)
        {
          // Store the new digit as the last one
          digits[d++] = key;
          // End of the string
          digits[d] = 0x0;
          // Print the new "digits" string
          showDigits();

        } else {
          // No more than 3 digits! Ignore exceeding one!
          Serial.print("Ignored key '"); 
          Serial.print(key); 
          Serial.println("'");
        }
        break;

      case 'B': // Backspace (delete last)
      if(LCDCol>1)
      {
        LCDCol--; // Decrease column
        // But not less than column 1
        if(LCDCol<1) 
        LCDCol=1;
        // End of the string at 1 character less than before
        digits[--d] = 0x0;
        lcd.setCursor(LCDCol,LCDRow);
        lcd.print(' ');
        Serial.println("Backspace!");
      }
        break;

      case '#': // Display current typed number
        showDisplay();
        break;
        
      case 'C': // Increment counter
        ++count;
        updateDigits();
        showDisplay();
        break;

      case 'D': // Decrement counter
        --count;
        updateDigits();
        showDisplay();
        break;

      case '*': // CLEAR ALL
        updateDigits();
        // showDisplay();
        Serial.println("Clear!");// Uncomment this if the clear should reset the digits at col 11 also
        break;

      default:
        Serial.print("Unmapped key '"); 
        Serial.print(key); 
        Serial.println("'");
    }
  } // end of key

} // end of void loop

void showDisplay() 
{ // Read the "digits"and show the value on the external display
  lcd.setCursor(11,1);
  lcd.print("   ");
  lcd.setCursor(11,1);
  lcd.print(digits);
  // Read "digits" string and convert it into integer value
  count = atoi(digits);
  display.showNumberDec(count);
  // Resets local LCD "digits"
  resetDigits();

}

void resetDigits() 
{ // Resets the locally typed digits (LCD)
  lcd.setCursor(1,1);
  lcd.print("   ");
  LCDCol = 1;
  d = 0;
  // digits[0] = 0x0;
  // showDigits();
}

void showDigits()
{ // Print on LCD the locally typed digits
  lcd.setCursor(1,1);
  lcd.print("   ");
  lcd.setCursor(1,1);
  lcd.print(digits);
}

void updateDigits()
{ // Convert back "count" value into "digits" string
  itoa(count, digits, 10);
  lcd.setCursor(1,1);
  lcd.print("   ");
  LCDCol = 1;
  d = 0;
}