// BCD IC A (ones digit)
const int bcdA_A = 22 ;
const int bcdA_B = 24 ;
const int bcdA_C = 26 ;
const int bcdA_D = 28 ;

// BCD IC B (tens digit)
const int bcdB_A = 30 ;
const int bcdB_B = 32 ;
const int bcdB_C = 34 ;
const int bcdB_D = 36 ;

// BCD IC C (hundreds digit)
const int bcdC_A = 38 ;
const int bcdC_B = 40 ;
const int bcdC_C = 42 ;
const int bcdC_D = 44 ;

// BCD IC D (thousands digit)
const int bcdD_A = 46 ;
const int bcdD_B = 48 ;
const int bcdD_C = 50 ;
const int bcdD_D = 52 ;


int counterValue = 0 ; // stores counter value from 0 - 9999
bool counting = false; // Flag to indicate counting state
bool countUp = true;   // Flag to indicate counting direction

// Toggle switch pins
const int startStopSwitchPin = 10;
const int countUpSwitchPin = 11;
const int countDownSwitchPin = 12;


void setup() {

  // BCD IC A (ones digit)
  pinMode(bcdA_A, OUTPUT);
  pinMode(bcdA_B, OUTPUT);
  pinMode(bcdA_C, OUTPUT);
  pinMode(bcdA_D, OUTPUT);

  // BCD IC B (tens digit)
  pinMode(bcdB_A, OUTPUT);
  pinMode(bcdB_B, OUTPUT);
  pinMode(bcdB_C, OUTPUT);
  pinMode(bcdB_D, OUTPUT);

  // BCD IC C (hundreds digit)
  pinMode(bcdC_A, OUTPUT);
  pinMode(bcdC_B, OUTPUT);
  pinMode(bcdC_C, OUTPUT);
  pinMode(bcdC_D, OUTPUT);

  // BCD IC D (thousands digit)
  pinMode(bcdD_A, OUTPUT);
  pinMode(bcdD_B, OUTPUT);
  pinMode(bcdD_C, OUTPUT);
  pinMode(bcdD_D, OUTPUT);

  // Toggle switch setup
  pinMode(startStopSwitchPin, INPUT);
  pinMode(countUpSwitchPin, INPUT);
  pinMode(countDownSwitchPin, INPUT);

}

void loop() {
  
  // Read the state of the toggle switches
  int startStopSwitchState = digitalRead(startStopSwitchPin);
  int countUpSwitchState = digitalRead(countUpSwitchPin);
  int countDownSwitchState = digitalRead(countDownSwitchPin);

  // Toggle counting state based on start/stop switch
  if (startStopSwitchState == HIGH)
  {
    counting = !counting;
    delay(500); // Add a small delay to debounce the switch
  }

  // Update counting direction based on count up and count down switches
  if (countUpSwitchState == HIGH)
  {
    countUp = true;
  }
  else if (countDownSwitchState == HIGH)
  {
    countUp = false;
  }

  // Check if counting is enabled
  if (counting)
  {
    // Update counter based on counting direction
    if (countUp)
    {
      counterValue++;
      if (counterValue > 9999)
      {
        counterValue = 0; // Reset to 0 after reaching 9999
      }
    }
    else
    {
      counterValue--;
      if (counterValue < 0)
      {
        counterValue = 9999; // Reset to 9999 after reaching 0
      }
    }

 
  displayCounter();

  delay(250);
}

}


void displayCounter() {

  // get each digit in different place
  int ones = counterValue%10;
  int tens = (counterValue/10)%10;
  int hundreds = (counterValue/100)%10;
  int thousands = counterValue/1000;

  // Display ones digit
  switch (ones) {
    case 0:
        digitalWrite(bcdA_A, LOW);  
        digitalWrite(bcdA_B, LOW);  
        digitalWrite(bcdA_C, LOW);  
        digitalWrite(bcdA_D, LOW);  
        break;

    case 1:
        digitalWrite(bcdA_A, HIGH);  
        digitalWrite(bcdA_B, LOW);  
        digitalWrite(bcdA_C, LOW);  
        digitalWrite(bcdA_D, LOW); 
        break;

    case 2:
        digitalWrite(bcdA_A, LOW);  
        digitalWrite(bcdA_B, HIGH);  
        digitalWrite(bcdA_C, LOW);  
        digitalWrite(bcdA_D, LOW); 
        break;

    case 3:
        digitalWrite(bcdA_A, HIGH);  
        digitalWrite(bcdA_B, HIGH);  
        digitalWrite(bcdA_C, LOW);  
        digitalWrite(bcdA_D, LOW);  
        break;

    case 4:
        digitalWrite(bcdA_A, LOW);  
        digitalWrite(bcdA_B, LOW);  
        digitalWrite(bcdA_C, HIGH);  
        digitalWrite(bcdA_D, LOW);  
        break;

    case 5:
        digitalWrite(bcdA_A, HIGH);  
        digitalWrite(bcdA_B, LOW);  
        digitalWrite(bcdA_C, HIGH);  
        digitalWrite(bcdA_D, LOW); 
        break;

    case 6:
        digitalWrite(bcdA_A, LOW);  
        digitalWrite(bcdA_B, HIGH);  
        digitalWrite(bcdA_C, HIGH);  
        digitalWrite(bcdA_D, LOW);  
        break;

    case 7:
        digitalWrite(bcdA_A, HIGH);  
        digitalWrite(bcdA_B, HIGH);  
        digitalWrite(bcdA_C, HIGH);  
        digitalWrite(bcdA_D, LOW); 
        break;

    case 8:
        digitalWrite(bcdA_A, LOW); 
        digitalWrite(bcdA_B, LOW);  
        digitalWrite(bcdA_C, LOW);  
        digitalWrite(bcdA_D, HIGH);  
        break;

    case 9:
        digitalWrite(bcdA_A, HIGH);  
        digitalWrite(bcdA_B, LOW);  
        digitalWrite(bcdA_C, LOW);  
        digitalWrite(bcdA_D, HIGH); 
        break;
  }

  // Display tens digit
  switch (tens) {
    case 0:
        digitalWrite(bcdB_A, LOW);  
        digitalWrite(bcdB_B, LOW);  
        digitalWrite(bcdB_C, LOW);  
        digitalWrite(bcdB_D, LOW);  
        break;

    case 1:
        digitalWrite(bcdB_A, HIGH);  
        digitalWrite(bcdB_B, LOW);  
        digitalWrite(bcdB_C, LOW);  
        digitalWrite(bcdB_D, LOW); 
        break;

    case 2:
        digitalWrite(bcdB_A, LOW);  
        digitalWrite(bcdB_B, HIGH);  
        digitalWrite(bcdB_C, LOW);  
        digitalWrite(bcdB_D, LOW); 
        break;

    case 3:
        digitalWrite(bcdB_A, HIGH);  
        digitalWrite(bcdB_B, HIGH);  
        digitalWrite(bcdB_C, LOW);  
        digitalWrite(bcdB_D, LOW);  
        break;

    case 4:
        digitalWrite(bcdB_A, LOW);  
        digitalWrite(bcdB_B, LOW);  
        digitalWrite(bcdB_C, HIGH);  
        digitalWrite(bcdB_D, LOW);  
        break;

    case 5:
        digitalWrite(bcdB_A, HIGH);  
        digitalWrite(bcdB_B, LOW);  
        digitalWrite(bcdB_C, HIGH);  
        digitalWrite(bcdB_D, LOW); 
        break;

    case 6:
        digitalWrite(bcdB_A, LOW);  
        digitalWrite(bcdB_B, HIGH);  
        digitalWrite(bcdB_C, HIGH);  
        digitalWrite(bcdB_D, LOW);  
        break;

    case 7:
        digitalWrite(bcdB_A, HIGH);  
        digitalWrite(bcdB_B, HIGH);  
        digitalWrite(bcdB_C, HIGH);  
        digitalWrite(bcdB_D, LOW); 
        break;

    case 8:
        digitalWrite(bcdB_A, LOW); 
        digitalWrite(bcdB_B, LOW);  
        digitalWrite(bcdB_C, LOW);  
        digitalWrite(bcdB_D, HIGH);  
        break;

    case 9:
        digitalWrite(bcdB_A, HIGH);  
        digitalWrite(bcdB_B, LOW);  
        digitalWrite(bcdB_C, LOW);  
        digitalWrite(bcdB_D, HIGH); 
        break;
  }

  // Display hundreds digit
  switch (hundreds) {
    case 0:
        digitalWrite(bcdC_A, LOW);  
        digitalWrite(bcdC_B, LOW);  
        digitalWrite(bcdC_C, LOW);  
        digitalWrite(bcdC_D, LOW);  
        break;

    case 1:
        digitalWrite(bcdC_A, HIGH);  
        digitalWrite(bcdC_B, LOW);  
        digitalWrite(bcdC_C, LOW);  
        digitalWrite(bcdC_D, LOW); 
        break;

    case 2:
        digitalWrite(bcdC_A, LOW);  
        digitalWrite(bcdC_B, HIGH);  
        digitalWrite(bcdC_C, LOW);  
        digitalWrite(bcdC_D, LOW); 
        break;

    case 3:
        digitalWrite(bcdC_A, HIGH);  
        digitalWrite(bcdC_B, HIGH);  
        digitalWrite(bcdC_C, LOW);  
        digitalWrite(bcdC_D, LOW);  
        break;

    case 4:
        digitalWrite(bcdC_A, LOW);  
        digitalWrite(bcdC_B, LOW);  
        digitalWrite(bcdC_C, HIGH);  
        digitalWrite(bcdC_D, LOW);  
        break;

    case 5:
        digitalWrite(bcdC_A, HIGH);  
        digitalWrite(bcdC_B, LOW);  
        digitalWrite(bcdC_C, HIGH);  
        digitalWrite(bcdC_D, LOW); 
        break;

    case 6:
        digitalWrite(bcdC_A, LOW);  
        digitalWrite(bcdC_B, HIGH);  
        digitalWrite(bcdC_C, HIGH);  
        digitalWrite(bcdC_D, LOW);  
        break;

    case 7:
        digitalWrite(bcdC_A, HIGH);  
        digitalWrite(bcdC_B, HIGH);  
        digitalWrite(bcdC_C, HIGH);  
        digitalWrite(bcdC_D, LOW); 
        break;

    case 8:
        digitalWrite(bcdC_A, LOW); 
        digitalWrite(bcdC_B, LOW);  
        digitalWrite(bcdC_C, LOW);  
        digitalWrite(bcdC_D, HIGH);  
        break;

    case 9:
        digitalWrite(bcdC_A, HIGH);  
        digitalWrite(bcdC_B, LOW);  
        digitalWrite(bcdC_C, LOW);  
        digitalWrite(bcdC_D, HIGH); 
        break;
  }

  // Display thousands digit
  switch (thousands) {
    case 0:
        digitalWrite(bcdD_A, LOW);  
        digitalWrite(bcdD_B, LOW);  
        digitalWrite(bcdD_C, LOW);  
        digitalWrite(bcdD_D, LOW);  
        break;

    case 1:
        digitalWrite(bcdD_A, HIGH);  
        digitalWrite(bcdD_B, LOW);  
        digitalWrite(bcdD_C, LOW);  
        digitalWrite(bcdD_D, LOW); 
        break;

    case 2:
        digitalWrite(bcdD_A, LOW);  
        digitalWrite(bcdD_B, HIGH);  
        digitalWrite(bcdD_C, LOW);  
        digitalWrite(bcdD_D, LOW); 
        break;

    case 3:
        digitalWrite(bcdD_A, HIGH);  
        digitalWrite(bcdD_B, HIGH);  
        digitalWrite(bcdD_C, LOW);  
        digitalWrite(bcdD_D, LOW);  
        break;

    case 4:
        digitalWrite(bcdD_A, LOW);  
        digitalWrite(bcdD_B, LOW);  
        digitalWrite(bcdD_C, HIGH);  
        digitalWrite(bcdD_D, LOW);  
        break;

    case 5:
        digitalWrite(bcdD_A, HIGH);  
        digitalWrite(bcdD_B, LOW);  
        digitalWrite(bcdD_C, HIGH);  
        digitalWrite(bcdD_D, LOW); 
        break;

    case 6:
        digitalWrite(bcdD_A, LOW);  
        digitalWrite(bcdD_B, HIGH);  
        digitalWrite(bcdD_C, HIGH);  
        digitalWrite(bcdD_D, LOW);  
        break;

    case 7:
        digitalWrite(bcdD_A, HIGH);  
        digitalWrite(bcdD_B, HIGH);  
        digitalWrite(bcdD_C, HIGH);  
        digitalWrite(bcdD_D, LOW); 
        break;

    case 8:
        digitalWrite(bcdD_A, LOW); 
        digitalWrite(bcdD_B, LOW);  
        digitalWrite(bcdD_C, LOW);  
        digitalWrite(bcdD_D, HIGH);  
        break;

    case 9:
        digitalWrite(bcdD_A, HIGH);  
        digitalWrite(bcdD_B, LOW);  
        digitalWrite(bcdD_C, LOW);  
        digitalWrite(bcdD_D, HIGH); 
        break;
  }

}