#define LDR_PIN A0
#define LED_PIN 13
#define RELAY_PIN 9
#define BUZZER_PIN 8

const int LARGE_BAG_THRESHOLD = 300; // Lux value below this is considered a large bag
const int SMALL_BAG_THRESHOLD = 600; // Lux value below this and above large threshold is considered a small bag
const unsigned long RELAY_RUN_TIME = 2000; // Time to run relay for removal (2 seconds)
const unsigned long SAFETY_TIMEOUT = 5000; // 5 seconds timeout for safety

unsigned long lastDetectionTime = 0;
int largeBagCount = 0;
int smallBagCount = 0;
unsigned long startTime = 0;

void setup() {
  Serial.begin(9600);
  pinMode(LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  startTime = millis();
}

void loop() {
  int sensorValue = analogRead(LDR_PIN); // Read value from LDR
  int lux = map(sensorValue, 0, 1023, 0, 1000); // Convert sensor value to lux

  Serial.print("Lux: ");
  Serial.println(lux);

  if (lux < LARGE_BAG_THRESHOLD) { // If large bag detected
    largeBagCount++;
    Serial.println("Large bag detected");
  } else if (lux < SMALL_BAG_THRESHOLD) { // If small bag detected
    smallBagCount++;
    Serial.println("Small bag detected");
  } else { // Non-defective product detected
    Serial.println("Defective product detected");
    handleProductDetection();
  }

  if (millis() - startTime > 10000) { // 10 seconds window for large bags
    largeBagCount = 0;
    startTime = millis();
  }

  if (millis() - startTime > 6000) { // 6 seconds window for small bags
    smallBagCount = 0;
    startTime = millis();
  }

  if (largeBagCount > 2 || smallBagCount > 2) {
    digitalWrite(BUZZER_PIN, HIGH); // Sound buzzer to indicate failure
    Serial.println("System failure! Halting assembly line.");
    // Additional code to halt the assembly line can be added here
  } else {
    digitalWrite(BUZZER_PIN, LOW); // Ensure buzzer is off if system is operating normally
  }

  delay(1000); // Small delay to debounce sensor readings
}

void handleProductDetection() {
  digitalWrite(LED_PIN, HIGH); // Turn on LED to indicate detection
  digitalWrite(RELAY_PIN, HIGH); // Turn on relay to remove product
  delay(RELAY_RUN_TIME); // Wait for product to be removed
  digitalWrite(RELAY_PIN, LOW); // Turn off relay
  digitalWrite(LED_PIN, LOW); // Turn off LED
  lastDetectionTime = millis();
}