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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET    -1 // Reset pin # (or -1 if sharing Arduino reset pin)

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const byte ROWS = 4; // Jumlah baris keypad
const byte COLS = 4; // Jumlah kolom keypad

char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

byte rowPins[ROWS] = {14, 12, 19, 18}; // R1, R2, R3, R4
byte colPins[COLS] = {5, 4, 2, 15};     // C1, C2, C3, C4

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

const char *password = "1234";
char enteredPassword[5];
int passwordIndex = 0;

void setup() {
  Serial.begin(115200);

  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  
  display.display(); // Show initial display buffer contents on the screen
  display.clearDisplay(); // Clear the buffer
  display.setTextSize(1); // Set text size
  display.setTextColor(SSD1306_WHITE); // Set text color
  display.setCursor(20,25); // Set cursor position
  display.println("Selamat Datang"); // Display welcome message
  display.display(); // Show initial display buffer contents on the screen
  delay(2000); // Pause for 2 seconds
  display.clearDisplay(); // Clear the buffer

  display.display(); // Show initial display buffer contents on the screen
  display.clearDisplay(); // Clear the buffer
  display.setTextSize(1); // Set text size
  display.setTextColor(SSD1306_WHITE); // Set text color
  display.setCursor(0, 0); // Set cursor position
  display.println("Input Password:"); // Display input password message
  display.display(); // Show initial display buffer contents on the screen
}

void loop() {
  char key = keypad.getKey();
  
  if (key) {
    if (key == '#') { // Tombol untuk memeriksa password
      if (strcmp(enteredPassword, password) == 0) {
        display.clearDisplay();
        display.setTextSize(1);
        display.setTextColor(SSD1306_WHITE);
        display.setCursor(0,0);
        display.println("Access Accepted");
        display.display();
      } else {
        display.clearDisplay();
        display.setTextSize(1);
        display.setTextColor(SSD1306_WHITE);
        display.setCursor(0,0);
        display.println("Invalid password");
        display.display();
      }
      delay(2000);
      display.clearDisplay();
      memset(enteredPassword, 0, sizeof(enteredPassword));
      passwordIndex = 0;
      display.setCursor(0, 0); // Set cursor position
      display.println("Input Password:"); // Display input password message
      display.display(); // Show initial display buffer contents on the screen
    } else if (key == '*') { // Tombol untuk menghapus layar
      display.clearDisplay();
      memset(enteredPassword, 0, sizeof(enteredPassword));
      passwordIndex = 0;
      display.setCursor(0, 0); // Set cursor position
      display.println("Input Password:"); // Display input password message
      display.display(); // Show initial display buffer contents on the screen
    } else {
      if (passwordIndex < 4) {
        enteredPassword[passwordIndex] = key;
        passwordIndex++;
        display.clearDisplay();
        display.setTextSize(1);
        display.setTextColor(SSD1306_WHITE);
        display.setCursor(0, 0);
        display.println("Input Password:"); // Display input password message
        for (int i = 0; i < passwordIndex; i++) {
          display.print("*");
        }
        display.display(); // Show initial display buffer contents on the screen
      }
    }
  }
}