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

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);   // change if your I2C scanner shows different

// Servo setup
Servo lockServo;
int servoPin = 9;

// Buzzer setup
int buzzer = 8;

// RGB LED pins
int redPin = 5;
int greenPin = 3;
int bluePin = 2;

// Password setup
String correctPassword = "1234";
String inputPassword = "";

// Flag for new password entry
bool waitingForNewCode = false;

void setup() {
  // Servo attach
  lockServo.attach(servoPin);
  lockServo.write(0); // locked position
  
  // Buzzer
  pinMode(buzzer, OUTPUT);
  digitalWrite(buzzer, LOW);

  // RGB LED
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
  turnOffRGB();

  // LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("Safe Door System");
  delay(2000);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Enter Code:");
  
  // Serial for Bluetooth / Monitor
  Serial.begin(9600);
  Serial.println("System Ready. Type 4 characters for password.");
  Serial.println("Type R,G,B,Y,C,M to control RGB LED.");
}

void loop() {
  recvCode();

  // Once 4 chars are entered → check password
  if (inputPassword.length() == 4) {
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Checking...");
    Serial.print("Password entered: ");
    Serial.println(inputPassword);

    if (!waitingForNewCode) {
      // Normal login
      if (inputPassword == correctPassword) {
        lcd.setCursor(0,1);
        lcd.print("Access Granted");
        Serial.println("Access Granted");
        unlockDoor();

        // Ask for new code
        lcd.clear();
        lcd.setCursor(0,0);
        lcd.print("Enter New Code:");
        Serial.println("Waiting for new 4-digit code...");
        inputPassword = "";
        waitingForNewCode = true;
      } else {
        lcd.setCursor(0,1);
        lcd.print("Access Denied");
        Serial.println("Access Denied Wrong code.");
        alarm();
        resetPrompt();
      }
    } else {
      // Saving new code
      correctPassword = inputPassword;
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("New Code Saved");
      Serial.print("New password set: ");
      Serial.println(correctPassword);
      delay(2000);
      lockDoor();
      resetPrompt();
      waitingForNewCode = false;
    }

    // Reset after checking
    inputPassword = "";
  }

  // Also check for LED commands separately
  recvLEDControl();
}

void recvCode() {
  while (Serial.available() > 0) {
    char rc = Serial.peek(); // look at next char without removing

    // Check if it's a LED command
    if (rc == 'R' || rc == 'G' || rc == 'B' || rc == 'Y' || rc == 'C' || rc == 'M') {
      recvLEDControl();
      return;
    }

    // Now read normally
    rc = Serial.read();

    // Ignore newline/carriage return
    if (rc == '\n' || rc == '\r') {
      return;
    }

    // Limit input to 4 chars
    if (inputPassword.length() < 4) {
      inputPassword += rc;

      // Show * instead of real digits
      lcd.setCursor(0,1);
      for (int i = 0; i < inputPassword.length(); i++) {
        lcd.print("*");
      }
    }
  }
}

void recvLEDControl() {
  if (Serial.available() > 0) {
    char cmd = Serial.read();
    switch (cmd) {
      case 'R': setColor(1,0,0); Serial.println("LED: RED"); break;
      case 'G': setColor(0,1,0); Serial.println("LED: GREEN"); break;
      case 'B': setColor(0,0,1); Serial.println("LED: BLUE"); break;
      case 'Y': setColor(1,1,0); Serial.println("LED: YELLOW"); break;
      case 'C': setColor(0,1,1); Serial.println("LED: CYAN"); break;
      case 'M': setColor(1,0,1); Serial.println("LED: MAGENTA"); break;
    }
  }
}

void setColor(bool r, bool g, bool b) {
  digitalWrite(redPin, r ? HIGH : LOW);
  digitalWrite(greenPin, g ? HIGH : LOW);
  digitalWrite(bluePin, b ? HIGH : LOW);
}

void turnOffRGB() {
  digitalWrite(redPin, LOW);
  digitalWrite(greenPin, LOW);
  digitalWrite(bluePin, LOW);
}

void unlockDoor() {
  Serial.println("Unlocking door...");
  lockServo.write(90); // unlock position
  delay(2000);         // wait while open
}

void lockDoor() {
  Serial.println("Locking door...");
  lockServo.write(0);  // lock position
  // make click sound
  digitalWrite(buzzer, HIGH);
  delay(100);
  digitalWrite(buzzer, LOW);
}

void alarm() {
  Serial.println("Alarm triggered!");
  for (int i = 0; i < 5; i++) {
    digitalWrite(buzzer, HIGH);
    delay(200);
    digitalWrite(buzzer, LOW);
    delay(200);
  }
}

void resetPrompt() {
  delay(2000);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Enter Code:");
}