#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Keypad.h>
#include <ESP32Servo.h>

// OLED Settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Servo Settings
Servo myServo;
const int servoPin = 33;

// 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] = {19, 18, 5, 17}; 
byte colPins[COLS] = {16, 4, 0, 2}; 

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Credentials
String targetID = "123";
String targetPass = "ABC";
String inputBuffer = "";
bool isEnteringPass = false;

void updateOLED(String topMsg, String bottomMsg, bool isSecret = false) {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 5);
  display.println(topMsg);
  
  display.setTextSize(2);
  display.setCursor(0, 30);
  
  if(isSecret) {
    String masked = "";
    for(int i=0; i<bottomMsg.length(); i++) masked += "*";
    display.println(masked);
  } else {
    display.println(bottomMsg);
  }
  display.display();
}

void setup() {
  Serial.begin(115200);
  myServo.attach(servoPin);
  myServo.write(0); // Door Closed

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("Display failed");
    for(;;);
  }
  
  updateOLED("SYSTEM LOCKED", "Enter ID:");
}

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

  if (key) {
    Serial.print("Pressed: "); Serial.println(key);
    
    if (key == '#') { // Action: Enter/Confirm
      if (!isEnteringPass) {
        if (inputBuffer == targetID) {
          isEnteringPass = true;
          inputBuffer = "";
          updateOLED("ID VERIFIED", "Enter PASS:");
        } else {
          updateOLED("INVALID ID", "Try Again:");
          inputBuffer = "";
        }
      } else {
        if (inputBuffer == targetPass) {
          updateOLED("ACCESS GRANTED", "OPENING...");
          myServo.write(90); // Open glass
          delay(5000);       // Wait 5 seconds
          myServo.write(0);  // Close glass
          isEnteringPass = false;
          inputBuffer = "";
          updateOLED("LOCKED", "Enter ID:");
        } else {
          updateOLED("WRONG PASS", "Enter PASS:");
          inputBuffer = "";
        }
      }
    } 
    else if (key == '*') { // Action: Clear
      inputBuffer = "";
      updateOLED(isEnteringPass ? "Enter PASS:" : "Enter ID:", "");
    } 
    else { // Append numbers or letters (A, B, C)
      inputBuffer += key;
      updateOLED(isEnteringPass ? "Enter PASS:" : "Enter ID:", inputBuffer, isEnteringPass);
    }
    delay(100); // Debounce delay
  }
}