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

// Pin definitions
#define LDR_PIN 34          // Light sensor (analog)
#define SMOKE_PIN 35        // Smoke sensor (analog)
#define IR_PIN 2            // IR motion sensor (digital)
#define LED_PIN 16          // LED
#define BUZZER_PIN 18       // Buzzer
#define SERVO_PIN 15        // Servo motor

// Keypad setup
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {13, 12, 14, 27};  // Keypad row pins
byte colPins[COLS] = {26, 25, 33, 32};  // Keypad column pins
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// I2C LCD (address 0x27, 16 columns, 2 rows)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// System state variables
bool smokeDetected = false;
bool smokeAlarmActive = false;
bool isDark = false;
bool ledOn = false;
bool doorOpen = false;
bool motionDetected = false;
bool motionAlarmActive = false;

// Password system
String correctPassword = "1234";
String enteredPassword = "";
bool passwordMode = false;
unsigned long passwordStartTime = 0;
const unsigned long PASSWORD_TIMEOUT = 10000; // 10 seconds to enter password

// Timing variables
unsigned long doorOpenTime = 0;
unsigned long buzzerStartTime = 0;
unsigned long lastUpdate = 0;

// Constants
const int SMOKE_THRESHOLD = 2000;
const int LIGHT_THRESHOLD = 1500;
const int DOOR_OPEN_DURATION = 5000; // 5 seconds
const int BUZZER_DURATION = 500;

void setup() {
  Serial.begin(115200);
  
  // Initialize pins
  pinMode(IR_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  
  // Initialize servo
  ledcAttach(SERVO_PIN, 50, 12);
  setServoAngle(90); // Door closed position
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.print("Smart Home");
  lcd.setCursor(0, 1);
  lcd.print("System Ready");
  delay(2000);
  lcd.clear();
  
  Serial.println("Smart Home Security System Started");
  Serial.println("Press * to enter password mode");
}

void loop() {
  // Read all sensors
  readSensors();
  
  // Handle keypad input
  handleKeypad();
  
  // Handle smoke detection
  handleSmoke();
  
  // Handle light control
  handleLighting();
  
  // Handle door control
  handleDoor();
  
  // Handle motion detection
  handleMotion();
  
  // Update display every 500ms
  if (millis() - lastUpdate > 500) {
    updateDisplay();
    lastUpdate = millis();
  }
  
  delay(100);
}

void readSensors() {
  // Read smoke sensor
  int smokeLevel = analogRead(SMOKE_PIN);
  smokeDetected = (smokeLevel > SMOKE_THRESHOLD);
  
  // Read light sensor
  int lightLevel = analogRead(LDR_PIN);
  isDark = (lightLevel < LIGHT_THRESHOLD);
  
  // Read motion sensor
  motionDetected = digitalRead(IR_PIN);
  
  // Debug output
  Serial.print("Smoke: "); Serial.print(smokeLevel);
  Serial.print(", Light: "); Serial.print(lightLevel);
  Serial.print(", Motion: "); Serial.print(motionDetected);
  Serial.println();
}

void handleKeypad() {
  char key = keypad.getKey();
  
  if (key) {
    Serial.print("Key pressed: ");
    Serial.println(key);
    
    if (key == '*' && !passwordMode) {
      // Start password entry mode
      passwordMode = true;
      enteredPassword = "";
      passwordStartTime = millis();
      Serial.println("Password mode activated. Enter 4-digit password:");
      
    } else if (passwordMode) {
      if (key == '#') {
        // Submit password
        checkPassword();
        
      } else if (key == '*') {
        // Cancel password entry
        passwordMode = false;
        enteredPassword = "";
        Serial.println("Password entry cancelled");
        
      } else if (enteredPassword.length() < 6) { // Max 6 digits
        // Add digit to password
        enteredPassword += key;
        Serial.print("Password: ");
        for (int i = 0; i < enteredPassword.length(); i++) {
          Serial.print("*");
        }
        Serial.println();
      }
    }
  }
  
  // Password timeout
  if (passwordMode && (millis() - passwordStartTime > PASSWORD_TIMEOUT)) {
    passwordMode = false;
    enteredPassword = "";
    Serial.println("Password entry timeout");
  }
}

void checkPassword() {
  if (enteredPassword == correctPassword) {
    // Correct password - open door
    Serial.println("Password CORRECT! Opening door...");
    openDoor();
    
  } else {
    // Wrong password
    Serial.println("Password INCORRECT!");
    // Short error beep
    digitalWrite(BUZZER_PIN, HIGH);
    delay(200);
    digitalWrite(BUZZER_PIN, LOW);
    delay(100);
    digitalWrite(BUZZER_PIN, HIGH);
    delay(200);
    digitalWrite(BUZZER_PIN, LOW);
  }
  
  passwordMode = false;
  enteredPassword = "";
}

void openDoor() {
  if (!doorOpen) {
    doorOpen = true;
    doorOpenTime = millis();
    setServoAngle(0); // Open position
    
    // Success beep
    digitalWrite(BUZZER_PIN, HIGH);
    buzzerStartTime = millis();
    
    Serial.println("Door OPENING");
  }
}

void handleSmoke() {
  if (smokeDetected && !smokeAlarmActive) {
    smokeAlarmActive = true;
    digitalWrite(BUZZER_PIN, HIGH);
    Serial.println("SMOKE DETECTED! Alarm ON");
  }
  
  if (!smokeDetected && smokeAlarmActive) {
    smokeAlarmActive = false;
    digitalWrite(BUZZER_PIN, LOW);
    Serial.println("Smoke cleared. Alarm OFF");
  }
}

void handleLighting() {
  if (isDark && !ledOn) {
    ledOn = true;
    digitalWrite(LED_PIN, HIGH);
    Serial.println("Dark detected. LED ON");
  } else if (!isDark && ledOn) {
    ledOn = false;
    digitalWrite(LED_PIN, LOW);
    Serial.println("Light detected. LED OFF");
  }
}

void handleDoor() {
  // Auto-close door after timeout
  if (doorOpen && (millis() - doorOpenTime > DOOR_OPEN_DURATION)) {
    doorOpen = false;
    setServoAngle(90); // Closed position
    
    // Closing beep
    digitalWrite(BUZZER_PIN, HIGH);
    buzzerStartTime = millis();
    
    Serial.println("Door CLOSING (auto)");
  }
  
  // Turn off buzzer after beep duration
  if (millis() - buzzerStartTime > BUZZER_DURATION && !smokeAlarmActive) {
    digitalWrite(BUZZER_PIN, LOW);
  }
}

void handleMotion() {
  if (motionDetected && !doorOpen && !motionAlarmActive) {
    motionAlarmActive = true;
    Serial.println("MOTION DETECTED! Door is closed - ALARM!");
  } else if (!motionDetected && motionAlarmActive) {
    motionAlarmActive = false;
    Serial.println("Motion stopped. Alarm cleared.");
  }
  
  // Motion alarm uses buzzer alternating pattern
  if (motionAlarmActive && !smokeAlarmActive) {
    static unsigned long lastToggle = 0;
    static bool buzzerState = false;
    
    if (millis() - lastToggle > 200) {
      buzzerState = !buzzerState;
      digitalWrite(BUZZER_PIN, buzzerState);
      lastToggle = millis();
    }
  }
}

void setServoAngle(int angle) {
  int pulseWidth = map(angle, 0, 180, 204, 410);
  ledcWrite(SERVO_PIN, pulseWidth);
}

void updateDisplay() {
  lcd.clear();
  
  // Line 1: Main status or password entry
  lcd.setCursor(0, 1);
  if (passwordMode) {
    lcd.print("Enter Password:");
    lcd.setCursor(0, 1);
    for (int i = 0; i < enteredPassword.length(); i++) {
      lcd.print("*");
    }
  } else if (smokeAlarmActive) {
    lcd.print("SMOKE ALARM!");
  } else if (motionAlarmActive) {
    lcd.print("MOTION ALARM!");
  } else {
    // Normal status display
    lcd.setCursor(0, 0);
    lcd.print("Status: OK");
    lcd.setCursor(0, 1);
    lcd.print("L:");
    lcd.print(ledOn ? "ON" : "OFF");
    lcd.print(" D:");
    lcd.print(doorOpen ? "OPEN" : "SHUT");
    lcd.print(" M:");
    lcd.print(motionDetected ? "Y" : "N");
  }
}