#include <SoftwareSerial.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

// --- Hardware Pin Definitions ---
// Keypad 4x4
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {A2, 3, 1, A1}; // Connect to Arduino pins
byte colPins[COLS] = {13, 11, 10, 9}; // Connect to Arduino pins
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// LED for Lock Status
#define lockLedPin 12

// Seatbelt Switch Pin
#define seatbeltPin A3

// Relay Control Pin
#define relayPin 4

// Buzzer Pin
#define buzzerPin 5

// Ultrasonic Sensor Pins
#define trigPin 8
#define echoPin 7

// LCD I2C Address and Size
#define LCD_ADDRESS 0x27
#define LCD_COLUMNS 16
#define LCD_ROWS 2
LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_COLUMNS, LCD_ROWS);

// --- Global Variables ---
const String correctCode = "1234"; // Change this to your desired code
String enteredCode = "";
bool ignitionEnabled = false;
bool isSeatbeltOn = false;

// --- Function Prototypes ---
void displayLCD(int row, String text);
void checkKeypad();
void checkSeatbelt();
void checkObstacle();
void checkAlcohol();
void checkSpeed();

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();

  pinMode(lockLedPin, OUTPUT);
  pinMode(seatbeltPin, INPUT_PULLUP);
  pinMode(relayPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  digitalWrite(lockLedPin, LOW);
  digitalWrite(relayPin, LOW); // Initially lock is engaged (relay off)

  displayLCD(0, "Enter Code:");
}

void loop() {
  checkKeypad();
  checkSeatbelt();

  if (ignitionEnabled) {
    checkObstacle();
    checkAlcohol();
    checkSpeed();

    if (!isSeatbeltOn) {
      Serial.println("Warning: Seatbelt not on!");
      displayLCD(0, "Warning: Seatbelt!");
      displayLCD(1, "Please fasten!");
      // Optionally trigger buzzer
      tone(buzzerPin, 1000, 500);
    }
  }

  delay(100);
}

void displayLCD(int row, String text) {
  lcd.setCursor(0, row);
  lcd.print(text);
}

void checkKeypad() {
  char key = keypad.getKey();

  if (key) {
    enteredCode += key;
    displayLCD(1, enteredCode);

    if (enteredCode.length() == correctCode.length()) {
      if (enteredCode == correctCode) {
        displayLCD(0, "Vehicle Unlocked");
        digitalWrite(lockLedPin, HIGH);
        digitalWrite(relayPin, HIGH); // Disengage lock (relay on)
        ignitionEnabled = true;
      } else {
        displayLCD(0, "Incorrect Code");
        digitalWrite(lockLedPin, LOW);
        digitalWrite(relayPin, LOW); // Engage lock (relay off)
        ignitionEnabled = false;
      }
      enteredCode = "";
      delay(2000);
      displayLCD(0, "Enter Code:");
      displayLCD(1, "");
    }
  }
}

void checkSeatbelt() {
  if (digitalRead(seatbeltPin) == LOW) {
    isSeatbeltOn = true;
  } else {
    isSeatbeltOn = false;
  }
}

void checkObstacle() {
  long duration;
  int distance;

  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2; // Speed of sound wave divided by 2

  if (distance < 50) { // Obstacle detected within 50 cm
    Serial.println("Obstacle Detected!");
    displayLCD(0, "Obstacle Ahead!");
    tone(buzzerPin, 1500, 500);
    delay(1000);
  }
}

void checkAlcohol() {
  int alcoholValue = analogRead(A4); // Assuming MQ6 is connected to A4
  Serial.print("Alcohol Value: ");
  Serial.println(alcoholValue);

  if (alcoholValue > 200) { // Adjust threshold based on your MQ6 sensor
    Serial.println("Alcohol Detected! Engine Disabled.");
    displayLCD(0, "Alcohol Detected!");
    displayLCD(1, "Engine Disabled!");
    digitalWrite(relayPin, LOW); // Engage lock (disable engine)
    ignitionEnabled = false;
    tone(buzzerPin, 2000, 1000);
    delay(5000);
  }
}

void checkSpeed() {
  // Simulate speed sensor using a button connected to A5
  int speedSensorValue = digitalRead(A5);
  static unsigned long lastPulseTime = 0;
  static unsigned int pulseCount = 0;
  unsigned long currentTime = millis();
  static unsigned long lastSpeedTime = 0; // Declare lastSpeedTime

  if (speedSensorValue == LOW) { // Simulate a pulse
    if (currentTime - lastPulseTime >= 50) { // Debounce
      pulseCount++;
      lastPulseTime = currentTime;
    }
  }

  if (currentTime - lastSpeedTime >= 1000) {
    // Assuming each pulse corresponds to a certain distance traveled
    float speed = (pulseCount / (float)(currentTime - lastSpeedTime)) * 3.6; // km/h (adjust calculation)
    Serial.print("Speed: ");
    Serial.print(speed);
    Serial.println(" km/h");
    displayLCD(1, String(speed) + " km/h");
    lastSpeedTime = currentTime;
    pulseCount = 0;

    if (speed > 60) {
      Serial.println("Speed Limit Exceeded! Alerting...");
      displayLCD(0, "Speed Limit Exceeded!");
      tone(buzzerPin, 2500, 1000);
    }
  }
}