// Pin definitions for shift register
const int dataPin = 2;    // DS pin of 74HC595
const int clockPin = 3;   // SHCP pin of 74HC595
const int latchPin = 4;   // STCP pin of 74HC595

// Pin definitions for LEDs
const int evenLedPin = 5; // LED for even numbers
const int oddLedPin = 6;  // LED for odd numbers

// Pin definitions for bar graph
const int barGraphPins[10] = {22, 23, 24, 25, 26, 27, 28, 29, 30, 31};

// 7-segment display patterns for common anode (0-9)
// Each bit represents a segment (0 = ON, 1 = OFF for common anode)
// Bit order: DP G F E D C B A
const byte digitPatterns[10] = {
  B11000000,  // 0 - segments A,B,C,D,E,F on, G,DP off
  B11111001,  // 1 - segments B,C on, others off
  B10100100,  // 2 - segments A,B,D,E,G on, C,F,DP off
  B10110000,  // 3 - segments A,B,C,D,G on, E,F,DP off
  B10011001,  // 4 - segments B,C,F,G on, A,D,E,DP off
  B10010010,  // 5 - segments A,C,D,F,G on, B,E,DP off
  B10000010,  // 6 - segments A,C,D,E,F,G on, B,DP off
  B11111000,  // 7 - segments A,B,C on, others off
  B10000000,  // 8 - segments A,B,C,D,E,F,G on, DP off
  B10010000   // 9 - segments A,B,C,D,F,G on, E,DP off
};

// Global variables
int currentNumber = 0;
unsigned long lastChangeTime = 0;
const unsigned long displayDuration = 2000; // 2 seconds in milliseconds

void setup() {
  // Initialize shift register pins
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
  
  // Initialize LED pins
  pinMode(evenLedPin, OUTPUT);
  pinMode(oddLedPin, OUTPUT);
  
  // Initialize bar graph pins
  for (int i = 0; i < 10; i++) {
    pinMode(barGraphPins[i], OUTPUT);
    digitalWrite(barGraphPins[i], LOW); // Start with all segments off
  }
  
  // Initialize LEDs to off
  digitalWrite(evenLedPin, LOW);
  digitalWrite(oddLedPin, LOW);
  
  // Initialize 7-segment display to show 0
  updateDisplay();
  
  // Start the timer
  lastChangeTime = millis();
}

void loop() {
  // Check if 2 seconds have passed
  if (millis() - lastChangeTime >= displayDuration) {
    // Increment the number
    currentNumber = (currentNumber + 1) % 10; // Cycle from 0 to 9
    
    // Update all components
    updateDisplay();
    
    // Reset the timer
    lastChangeTime = millis();
  }
}

void updateDisplay() {
  // Update 7-segment display via shift register
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, digitPatterns[currentNumber]);
  digitalWrite(latchPin, HIGH);
  
  // Update LEDs based on parity
  if (currentNumber % 2 == 0) {
    // Even number
    digitalWrite(evenLedPin, HIGH);
    digitalWrite(oddLedPin, LOW);
  } else {
    // Odd number
    digitalWrite(evenLedPin, LOW);
    digitalWrite(oddLedPin, HIGH);
  }
  
  // Update bar graph - light up segments equal to current number
  for (int i = 0; i < 10; i++) {
    if (i < currentNumber) {
      digitalWrite(barGraphPins[i], HIGH); // Turn on segments up to current number
    } else {
      digitalWrite(barGraphPins[i], LOW);  // Turn off remaining segments
    }
  }
}