#include <LiquidCrystal_I2C.h>
#include <Servo.h>
#include <Encoder.h>

int btnNext = 10;
int iCount1 = 0;
int iCount2 = 0;
int iCount3 = 0;
int iCount4 = 0;
int iPin = 0;
int digitEdit = 1;
Servo servo_11;

// Rotary encoder value setup
int prevVal = 0;
int codeVal = 0;
long oldPosition  = -999;
Encoder myEnc(5, 6); //data, clock

LiquidCrystal_I2C lcd_1(0x27, 16, 2);

// Define LED and Buzzer pins
const int redLED = 8;
const int greenLED = 9;
const int buzzer = 12; // Pin for Piezo Buzzer

// Distance sensor pins
const int triggerPin = 2;
const int echoPin = 3;

// Debounce variables
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 500; // Debounce delay in milliseconds

// Variable to store distance reading
int currentDistance = 0;

void setup(){
  pinMode(btnNext, INPUT_PULLUP);

  // Initialize LED and Buzzer pins
  pinMode(redLED, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(buzzer, OUTPUT);

  // Set LEDs and Buzzer to off initially
  digitalWrite(redLED, LOW);
  digitalWrite(greenLED, LOW);
  digitalWrite(buzzer, LOW);

  // Initialize distance sensor pins
  pinMode(triggerPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // Serial monitor setup
  Serial.begin(9600);

  // LCD screen setup
  lcd_1.init();
  lcd_1.backlight();
  lcd_1.blink();
  lcd_1.setCursor(1, 0);
  lcd_1.print("0");
  lcd_1.setCursor(3, 0);
  lcd_1.print("0");
  lcd_1.setCursor(5, 0);
  lcd_1.print("0");
  lcd_1.setCursor(7, 0);
  lcd_1.print("0");
  lcd_1.setCursor(1, 0);

  // Servo Motor setup
  servo_11.attach(11);
  servo_11.write(0);
}

void loop() {
  int val = encVal(); // Read value change from rotary encoder
  String valChange;

  // Respond to change in encoder value
  if (val != prevVal) {
    if (val > prevVal) {
      valChange = "increase";
    } else if (val < prevVal) {
      valChange = "decrease";
    }
    Serial.println(valChange);
    prevVal = val; // Reset previous value to new value

    // Update counts based on selected digit
    updateCounts(valChange);

    // Display updated count on LCD
    displayCounts();
  }

  // Move to next number
  next();

  // Check if passcode is correct and distance is valid
  checkPasscode();

  // Handle distance sensor reading with debounce
  handleDistanceSensor();
}

// Method to update counts based on the value change
void updateCounts(const String &valChange) {
  if (iPin == 0) {
    if (valChange.equals("increase")) {
      iCount1++;
      if (iCount1 > 9) {
        iCount1 = 0;
      }
    } else if (valChange.equals("decrease")) {
      iCount1--;
      if (iCount1 < 0) {
        iCount1 = 9;
      }
    }
  } else if (iPin == 1) {
    if (valChange.equals("increase")) {
      iCount2++;
      if (iCount2 > 9) {
        iCount2 = 0;
      }
    } else if (valChange.equals("decrease")) {
      iCount2--;
      if (iCount2 < 0) {
        iCount2 = 9;
      }
    }
  } else if (iPin == 2) {
    if (valChange.equals("increase")) {
      iCount3++;
      if (iCount3 > 9) {
        iCount3 = 0;
      }
    } else if (valChange.equals("decrease")) {
      iCount3--;
      if (iCount3 < 0) {
        iCount3 = 9;
      }
    }
  } else if (iPin == 3) {
    if (valChange.equals("increase")) {
      iCount4++;
      if (iCount4 > 9) {
        iCount4 = 0;
      }
    } else if (valChange.equals("decrease")) {
      iCount4--;
      if (iCount4 < 0) {
        iCount4 = 9;
      }
    }
  }
}

// Method to display counts on LCD
void displayCounts() {
  lcd_1.setCursor(digitEdit, 0);
  if (iPin == 0) lcd_1.print(iCount1);
  else if (iPin == 1) lcd_1.print(iCount2);
  else if (iPin == 2) lcd_1.print(iCount3);
  else if (iPin == 3) lcd_1.print(iCount4);
  lcd_1.setCursor(digitEdit, 0);
  Serial.println(iCount1);
}

// Method to check if passcode is correct and distance is valid
void checkPasscode() {
  if (iCount1 == 1 && iCount2 == 2 && iCount3 == 3 && iCount4 == 4) {
    if (currentDistance <= 20) { // Check if distance is 20 cm or less
      servo_11.write(90);
      digitalWrite(greenLED, HIGH); // Turn on green LED
      digitalWrite(redLED, LOW);    // Ensure red LED is off
      buzzerTone(1000, 500);        // Turn on buzzer with tone
      delay(1000);                  // Keep buzzer on for a second

      int iInput = digitalRead(btnNext);
      while (iInput == 1) {
        iInput = digitalRead(btnNext);
      }
      delay(100);

      Reset();
      Serial.println(iPin);
    } else {
      // If distance is not valid, do not open the lock
      digitalWrite(greenLED, LOW);  // Ensure green LED is off
      digitalWrite(redLED, HIGH);   // Turn on red LED
      digitalWrite(buzzer, LOW);    // Ensure buzzer is off
    }
  } else {
    // If passcode is incorrect, do not open the lock
    digitalWrite(greenLED, LOW);  // Ensure green LED is off
    digitalWrite(redLED, HIGH);   // Turn on red LED
    digitalWrite(buzzer, LOW);    // Ensure buzzer is off
  }
}

// Method to handle distance sensor reading with debounce
void handleDistanceSensor() {
  unsigned long currentTime = millis();

  if (currentTime - lastDebounceTime >= debounceDelay) {
    lastDebounceTime = currentTime;

    // Trigger the sensor
    digitalWrite(triggerPin, LOW);
    delayMicroseconds(2);
    digitalWrite(triggerPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(triggerPin, LOW);

    // Read the echo
    long duration = pulseIn(echoPin, HIGH);
    currentDistance = duration * 0.0344 / 2; // Convert to centimetres

    if (currentDistance > 0 && currentDistance <= 100) {
      Serial.print("Distance: ");
      Serial.print(currentDistance);
      Serial.println(" cm");
    } else {
      Serial.println("Out of range");
    }
  }
}

// Method to reset all the code back to its original value
void Reset() {
  servo_11.write(0);

  iCount1 = 0;
  iCount2 = 0;
  iCount3 = 0;
  iCount4 = 0;

  iPin = 0;
  digitEdit = 1;

  lcd_1.setCursor(1, 0);
  lcd_1.print(iCount1);
  lcd_1.setCursor(3,0);
  lcd_1.print(iCount2);
  lcd_1.setCursor(5,0);
  lcd_1.print(iCount3);
  lcd_1.setCursor(7,0);
  lcd_1.print(iCount4);
  lcd_1.setCursor(1, 0);

  lcd_1.setCursor(1, 0);
  delay(100);
}

// Method used when the push button that is inbuilt into the rotary encoder
// is pressed causing it to switch to the next digit of the password
void next() {
  int iNext = digitalRead(btnNext);

  // When clicking the inbuilt push button within the rotary encoder it
  // increases the value of iPin, switching to the next digit of the password
  if (iNext == 0) {
    iPin++;
    if (iPin > 3) {
      iPin = 0;
    }

    if (iPin == 0) {
      digitEdit = 1;
    } else if (iPin == 1) {
      digitEdit = 3;
    } else if (iPin == 2) {
      digitEdit = 5;
    } else if (iPin == 3) {
      digitEdit = 7;
    }
    lcd_1.setCursor(digitEdit, 0);

    Serial.print(iPin);
    delay(300);
  }
}

// Method to read value change from rotary encoder
int encVal() {
  long newPosition = myEnc.read();
  int val = prevVal;
  if (newPosition != oldPosition) {
    oldPosition = newPosition;
    val = newPosition / 4;
  }
  return val;
}

// Method to generate a tone for the buzzer
void buzzerTone(int frequency, int duration) {
  tone(buzzer, frequency, duration);
}