#include <Servo.h>
#include <HX711.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define trigger 10
#define echo 11
#define maxdist 100 
#define servo 9
#define relay 8
#define dt A0
#define sck A1

Servo myservo;
HX711 scale;
LiquidCrystal_I2C lcd(0x27, 16, 2);
unsigned long lastLargeDetectionTime = 0;
unsigned long lastSmallDetectionTime = 0;
int largeBagCount = 0;
int smallBagCount = 0;
bool systemHalted = false;

void setup() {
  Serial.begin(9600);
  myservo.attach(servo);
  pinMode(relay, OUTPUT);
  digitalWrite(relay, HIGH);
  
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);
  
  scale.begin(dt, sck);
  scale.set_scale(420.0983); // Load cell calibration factor

  lcd.init();
  lcd.backlight();
  lcd.print("System Ready");
}

long getDistance() {
  digitalWrite(trigger, LOW);
  delayMicroseconds(2);
  digitalWrite(trigger, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigger, LOW);
  
  long duration = pulseIn(echo, HIGH);
  return duration * 0.034 / 2; // Convert to distance in cm
}

void loop() {
  if (systemHalted) {
    lcd.clear();
    lcd.print("HALT!");
    lcd.setCursor(0, 1);
    lcd.print("OVERLOAD!");
    return;
  }

  int distance = getDistance();
  float weight = scale.get_units(5); 

  if (distance > 0 && distance <= maxdist) {
    if (weight > 23 && weight < 27) { // Large bag (25 kg with some tolerance)
      largeBagCount++;
      lastLargeDetectionTime = millis();
      Serial.println("Large bag");
      
      if (largeBagCount > 2 && (millis() - lastLargeDetectionTime) <= 10000) {
        systemHalted = true;
        digitalWrite(relay, LOW); // Stop the conveyor
        Serial.println("System halted: Overload!");
      }
    } else if (weight > 8 && weight < 12) { // Small bag (10 kg with some tolerance)
      smallBagCount++;
      lastSmallDetectionTime = millis();
      Serial.println("Small bag");
      
      if (smallBagCount > 2 && (millis() - lastSmallDetectionTime) <= 6000) {
        systemHalted = true;
        digitalWrite(relay, LOW); // Stop the conveyor
        Serial.println("System halted: Overload!");
      }
    }

    // Remove the bag from the line
    myservo.write(90); 
    delay(1000);
    myservo.write(0); 
  }

  // Reset counters if time window has passed
  if (millis() - lastLargeDetectionTime > 10000) largeBagCount = 0;
  if (millis() - lastSmallDetectionTime > 6000) smallBagCount = 0;

  // Update LCD
  lcd.clear();
  lcd.print("L:");
  lcd.print(largeBagCount);
  lcd.print(" S:");
  lcd.print(smallBagCount);
  lcd.setCursor(0, 1);
  lcd.print("Dist:");
  lcd.print(distance);
  lcd.print("cm");

  delay(100); // Short delay for stability
}