// ENEL 301 Lab 2

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


// LCD setup
LiquidCrystal lcd(13,12, 11, 10, 9, 8);

// Threshold distance for the door opener
double thresholdDistance; // (cm)

// The state of the door
bool isOpen = false;

// Defining the Servo variable
Servo myServo;

// Opens the door
void openDoor() {
  isOpen = true;
  myServo.write(180);
  delay(1000);
}

// Closes the door
void closeDoor() {
  isOpen = false;
  myServo.write(0);
  delay(1000);
}

// Updates the LCD display
void updateLCD(double distance) {
  lcd.setCursor(0,0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print("        ");
  lcd.setCursor(0,1);
  if(isOpen) {lcd.print("Open  ");}
  else {lcd.print("Closed");}
}

// Returns the distance currently being read by the HDS
double getDistance() {
  
  // Sends pulse
  digitalWrite(23, HIGH);
  delayMicroseconds(10);
  digitalWrite(23, LOW);
  
  // Receives pulse
  double duration = pulseIn(25, HIGH);

  // Calulates distance
  double distance = 0.0344 * duration / 2;
  return distance;

}

// Enters a mode so that the threshold value can be set
void setupMode() {
  
  // Waits for the button to be released
  while (true) {
    int buttonState = digitalRead(53);
    if (buttonState == 1) {
      break;
    }
  }
  
  // Prints data to the LCD
  lcd.clear();
  lcd.print("SETUP MODE");
  lcd.setCursor(0,1);
  lcd.print("DISTANCE: ");

  // Reads the distance while the button has not been pressed
  while(true) {
    delay(100);
    lcd.setCursor(10,1);
    lcd.print(getDistance());
    lcd.print("    ");

    // If the button is pressed, then set the thresholdDistance and exit the loop
    int buttonState = digitalRead(53);
    if (buttonState == 0) {
      thresholdDistance = getDistance();
      EEPROM.write(0, thresholdDistance);
      break;
    }
  }

  // Displays the new thresholdDistance
  lcd.clear();
  lcd.print("NEW THRESHOLD");
  lcd.setCursor(0,1);
  lcd.print(thresholdDistance);
  delay(2000);
  return;
}


void setup() {
  Serial.begin(9600);
  
  // LCD Setup
  lcd.begin(16,2);

  // Distance Sensor Pin Setup
  pinMode(23, OUTPUT);
  pinMode(25, INPUT);

  // Button
  pinMode(53, INPUT_PULLUP);

  // Servo
  myServo.attach(7);

  // Reading thresholdDistance from the EEPROM
  thresholdDistance = EEPROM.read(0);

  // Setting the inital value of the 
}

void loop() {

  delay(100);   // Delay to reduce flashing on the LCD

  // Gets the current distance
  double distance = getDistance();
  
  // If the button is pressed, enter setup mode
  int buttonState = digitalRead(53);
  if(buttonState == 0) {setupMode();}

  // If the thresholdDistance is crossed, then the door will open or close
  if (distance < thresholdDistance & isOpen == false) {openDoor();}
  else if (distance > thresholdDistance & isOpen == true) {closeDoor();}

  updateLCD(distance);
}