// Sensor pin definitions
const int sensor1A = 2; // First sensor at Point A
const int sensor1B = 3; // Second sensor at Point A
const int sensor2A = 4; // First sensor at Point B
const int sensor2B = 5; // Second sensor at Point B

// Counter for the number of objects in the area
int objectsInArea = 0;

// Timing variables
unsigned long lastTime1A = 0;
unsigned long lastTime1B = 0;
unsigned long lastTime2A = 0;
unsigned long lastTime2B = 0;
unsigned long lastMotionTime = 0;
const unsigned long timeout = 500; // 500 milliseconds to complete passage
const unsigned long resetTimeout = 15000; // 60 seconds to reset counter

// State tracking for each sensor
bool lastState1A = LOW;
bool lastState1B = LOW;
bool lastState2A = LOW;
bool lastState2B = LOW;

void setup() {
  // Initialize sensor pins as inputs
  pinMode(sensor1A, INPUT);
  pinMode(sensor1B, INPUT);
  pinMode(sensor2A, INPUT);
  pinMode(sensor2B, INPUT);

  // Start the serial communication
  Serial.begin(9600);
}

void loop() {
  // Read sensor states
  bool currentState1A = digitalRead(sensor1A);
  bool currentState1B = digitalRead(sensor1B);
  bool currentState2A = digitalRead(sensor2A);
  bool currentState2B = digitalRead(sensor2B);

  unsigned long currentTime = millis();

  // Detect object entering the area from A to B
  if (lastState1A == LOW && currentState1A == HIGH) {
    lastTime1A = currentTime;
    lastMotionTime = currentTime;
  }
  if (lastState1B == LOW && currentState1B == HIGH && (currentTime - lastTime1A) < timeout) {
    objectsInArea++;
    lastTime1A = 0; // Reset the timer
    lastMotionTime = currentTime;
    Serial.print("Objects in area: ");
    Serial.println(objectsInArea);
    Serial.println("Entry at A");
  }

  // Detect object entering the area from B to A
  if (lastState2A == LOW && currentState2A == HIGH) {
    lastTime2A = currentTime;
    lastMotionTime = currentTime;
  }
  if (lastState2B == LOW && currentState2B == HIGH && (currentTime - lastTime2A) < timeout) {
    objectsInArea++;
    lastTime2A = 0; // Reset the timer
    lastMotionTime = currentTime;
    Serial.print("Objects in area: ");
    Serial.println(objectsInArea);
    Serial.println("Entry at B");
  }

  // Detect object leaving the area from B to A
  if (lastState2B == LOW && currentState2B == HIGH) {
    lastTime2B = currentTime;
    lastMotionTime = currentTime;
  }
  if (lastState2A == LOW && currentState2A == HIGH && (currentTime - lastTime2B) < timeout) {
    objectsInArea--;
    lastTime2B = 0; // Reset the timer
    lastMotionTime = currentTime;
    Serial.print("Objects in area: ");
    Serial.println(objectsInArea);
    Serial.println("Exit at B");
  }

  // Detect object leaving the area from A to B
  if (lastState1B == LOW && currentState1B == HIGH) {
    lastTime1B = currentTime;
    lastMotionTime = currentTime;
  }
  if (lastState1A == LOW && currentState1A == HIGH && (currentTime - lastTime1B) < timeout) {
    objectsInArea--;
    lastTime1B = 0; // Reset the timer
    lastMotionTime = currentTime;
    Serial.print("Objects in area: ");
    Serial.println(objectsInArea);
    Serial.println("Exit at A");
  }

  // Reset counter if no motion detected for resetTimeout duration
  if (currentTime - lastMotionTime > resetTimeout) {
    objectsInArea = 0;
    Serial.println("Objects in area reset to 0 due to inactivity.");
    lastMotionTime = currentTime; // Reset the last motion time to avoid repeated reset messages
  }

  // Update last states
  lastState1A = currentState1A;
  lastState1B = currentState1B;
  lastState2A = currentState2A;
  lastState2B = currentState2B;

  // Small delay to avoid bouncing issues
  delay(50);
}