#include <Arduino.h>

const int switchUpPin = 13;    // Connect the up counter push button to digital pin 13
const int switchDownPin = 12;  // Connect the down counter push button to digital pin 12
const int ledPins[] = {23, 22, 21, 4};  // Connect the LEDs to digital pins 23, 22, 21, and 4
const int numLeds = sizeof(ledPins) / sizeof(ledPins[0]);  // Calculate the number of LEDs

bool buttonUpState = false;    // Variable to store the state of the up counter push button
bool lastButtonUpState = false;    // Variable to store the previous state of the up counter push button
bool buttonDownState = false;  // Variable to store the state of the down counter push button
bool lastButtonDownState = false;  // Variable to store the previous state of the down counter push button
int ledState = 0;   // Variable to store the LED pattern, starts from 0 (binary: 0000)

void setup() {
  Serial.begin(9600);
  
  pinMode(switchUpPin, INPUT_PULLUP);   // Enable internal pull-up resistor for the up counter push button
  pinMode(switchDownPin, INPUT_PULLUP); // Enable internal pull-up resistor for the down counter push button
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);    // Set LED pins as OUTPUTs
  }
  updateLeds(); // Initially update LEDs based on the initial ledState
}

void loop() {
  buttonUpState = digitalRead(switchUpPin);
  buttonDownState = digitalRead(switchDownPin);

  if (buttonUpState != lastButtonUpState) {
    if (buttonUpState == LOW) {
      // Increment ledState for up counter
      ledState++;
      if (ledState > 15) {
        ledState = 0; // Reset ledState if it exceeds 15
      }
      updateLeds(); // Update LEDs based on the new ledState
    }
    lastButtonUpState = buttonUpState;
    delay(50); // Debounce delay
  }

  if (buttonDownState != lastButtonDownState) {
    if (buttonDownState == LOW) {
      // Decrement ledState for down counter
      ledState--;
      if (ledState < 0) {
        ledState = 15; // Reset ledState if it goes below 0
      }
      updateLeds(); // Update LEDs based on the new ledState
    }
    lastButtonDownState = buttonDownState;
    delay(50); // Debounce delay
  }
}

// Function to update the LEDs based on the current ledState
void updateLeds() {
  for (int i = 0; i < numLeds; i++) {
    digitalWrite(ledPins[i], bitRead(ledState, numLeds - 1 - i)); // Set LED based on bit value of ledState
  }
}