#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Keypad.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Keypad setup
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {2, 3, 4, 5}; // Connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 7, 8, 9}; // Connect to the column pinouts of the keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Clear button setup
const int clearButtonPin = 10; // Pin connected to the clear button

void setup() {
  Serial.begin(9600);
  pinMode(clearButtonPin, INPUT_PULLUP); // Set the clear button pin as input with internal pull-up resistor
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.clearDisplay();
  display.setTextSize(3);
  display.setTextColor(SSD1306_WHITE);
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    display.clearDisplay();
    display.setCursor(0, 10);
    display.print("Key : ");
    display.print(key);
    display.display();
    delay(500);
  }

  // Check if the clear button is pressed
  if (digitalRead(clearButtonPin) == LOW) {
    display.clearDisplay();
    display.display();
    delay(500); // Debounce delay
  }
}