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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const int decrementButtonPin = 18;  // GPIO 18 for decrement button
const int incrementButtonPin = 19;  // GPIO 19 for increment button

int keyCount = 10;
bool decrementButtonState = HIGH;  // initial state of decrement button
bool incrementButtonState = HIGH;  // initial state of increment button

void setup() {
  pinMode(decrementButtonPin, INPUT_PULLUP); // configure decrement button with pull-up
  pinMode(incrementButtonPin, INPUT_PULLUP); // configure increment button with pull-up

  // Initialize display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print("Key Available: ");
  display.println(keyCount);
  display.display();
}

void loop() {
  // Read the state of both buttons
  bool currentDecrementState = digitalRead(decrementButtonPin);
  bool currentIncrementState = digitalRead(incrementButtonPin);

  // Detect a falling edge (decrement button pressed)
  if (decrementButtonState == HIGH && currentDecrementState == LOW) {
    if (keyCount > 0) {
      keyCount--;  // Decrement key count
      updateDisplay();
    }
  }

  // Detect a falling edge (increment button pressed)
  if (incrementButtonState == HIGH && currentIncrementState == LOW) {
    if (keyCount < 10) {
      keyCount++;  // Increment key count
      updateDisplay();
    }
  }

  // Update button states
  decrementButtonState = currentDecrementState;
  incrementButtonState = currentIncrementState;
}

void updateDisplay() {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Key Available: ");
  display.println(keyCount);
  display.display();
}