// importing the neccassary library for code servo
#include <ESP32Servo.h>

// create a servo object
Servo myservo;

// config the trig and echo pins
const int trigPin = 2;
const int echoPin = 4;

// config the LED bulbs
const int redLED = 5;
const int greenLED = 14;

// create two vars to store duration and distance
long duration;
int distance;

// config the PIR sensor and create a var to store the bool expression of PIR sensor
const int sensor = 12;                        
int val = 0;

// config the servo motor and create a var to store the position of the servo
const int servo = 32;
int pos = 20;

// config the buzzer
const int buzzer = 33;

// create a func to handle when the bin is full
void handleFill(){
  digitalWrite(greenLED,LOW);
  digitalWrite(redLED,HIGH);
  tone(buzzer, 349);
}

// create a func to handle when the bin is not full
void clearHandleFill(){
  digitalWrite(greenLED,HIGH);
  digitalWrite(redLED, LOW);
  noTone(buzzer);
}

// create a func to open the bin
void openTheBin(){
  for (pos = 20; pos <= 180; pos += 1) {
    myservo.write(pos);             
    delay(15);                       
  }
  delay(5000);
}

// create a func to close the bin
void closeTheBin(){
  for (pos = 180; pos >= 20; pos -= 1) {
    myservo.write(pos);             
    delay(15);                       
  }
}

void setup() {

  // initialize the pins of the components
  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT); 
  pinMode(redLED,OUTPUT);
  pinMode(sensor, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(greenLED, OUTPUT);

  myservo.attach(servo);

  // keep the servo motor at 20 position
  myservo.write(20);
}

void loop() {
  // control the trigPin to get ultrasonic sensor input
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // get the duration
  duration = pulseIn(echoPin, HIGH);

  // calculate the distance according to distance
  distance = duration * 0.034 / 2;

  // get the PIR sensor input
  val = digitalRead(sensor);  

  // if PIR detect someone infront of the sensor, then open the bin for some time and close it
  if (val == HIGH) {           
    openTheBin();
    delay(1000);
    closeTheBin();
  } 

  // check whether the bin is full and if not run the clearHandleFill() and otherwise run the handleFill()
  if(distance <= 5){
    handleFill();
  }else{
    clearHandleFill();
  }
}