#include <Servo.h>
#include <LiquidCrystal.h>
#include <EEPROM.h>

LiquidCrystal lcd(13, 12, 11, 10, 9, 8);
Servo MyServo;

// Declaring variables
uint8_t trigPin = A1;
uint8_t echoPin = A0;
uint8_t servoPin = A2;
int distance;
int threshold = EEPROM.read(0); // reads the 0 index threshold
int duration;
bool open = false;

void setup() {
  lcd.begin(16, 2);
  Serial.begin(9600);
  Serial.print("Current threshold distance is " + String(threshold) + "cm\n");
  Serial.print("Enter desired threshold activation distance in centimeters\n");
  Serial.print("Interger numbers only, type in the value and hit enter\n");
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  MyServo.attach(servoPin); // Set up the servo motor
  MyServo.write(0);
  delay(1000);
}

void loop() {
  digitalWrite(trigPin, LOW); //Ultrasonic trigger pin set up
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH); //Echo pin set up
  distance = (duration * 0.0343) / 2; // conversion of time to distance
  lcd.clear();

  if (distance > 0) // prints distance in real time
    lcd.print("Distance: " + String(distance) + " cm");
  if (distance <= 0)// distance only 0 when nothing is sensed, no value should be displayed
    lcd.print("Distance: N/A");
  
  lcd.setCursor(0, 1);
  if (distance <= threshold) {
    lcd.print("Open");
    if (open == false) {
      open = true;
      MyServo.write(180);// Move the servo to 180 degrees
      delay(1000);// time to let motor "open"
    }
  }
   else {
    MyServo.write(0);
    lcd.setCursor(0, 1);
    lcd.print("Closed");
    open = false;
  }
  if (Serial.available() > 0) {//checks for any input from the serial monitor
    threshold = Serial.readStringUntil('\n').toInt();// \n is the delimiter
    EEPROM.write(0, threshold);
    Serial.print("Threshold value updated to: " + String(threshold)+ "cm\n");
    }
  delay(150);
}