#include <Keypad.h>
#include <EEPROM.h> 

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] = {2, 3, 4, 5}; // Connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 7, 8, 9}; // Connect to the column pinouts of the keypad 

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

const int relayPin = 10;
String inputCode = "";
const int maxCodes = 5;
String authorizedCodes[maxCodes] = {"1001", "2002"}; // Default codes with IDs
int currentCodeIndex = 2; // Number of currently stored codes
String masterCode = "9999"; // Master code for adding/deleting codes 

void setup() {
  Serial.begin(9600);
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);
  
  // Read the stored codes from EEPROM
  for (int i = 0; i < maxCodes; i++) {
    String code = "";
    for (int j = 0; j < 4; j++) {
      char c = EEPROM.read(i * 4 + j);
      if (c >= '0' && c <= '9') {
        code += c;
      }
    }
    if (code.length() == 4) {
      authorizedCodes[i] = code;
    }
  }
  Serial.println("Setup complete. Ready to receive input.");
} 

void loop() {
  char key = keypad.getKey();
  if (key) {
    Serial.print("Key pressed: ");
    Serial.println(key);
    inputCode += key;
    Serial.print("Current input code: ");
    Serial.println(inputCode);
    if (inputCode.length() == 4) {
      Serial.print("Final input code: ");
      Serial.println(inputCode);
      if (isAuthorized(inputCode)) {
        Serial.println("Access Granted");
        digitalWrite(relayPin, HIGH); // Activate relay
        delay(5000); // Keep relay on for 5 seconds
        digitalWrite(relayPin, LOW); // Deactivate relay
      } else if (inputCode == masterCode) {
        Serial.println("Master Code Entered");
        inputCode = ""; // Reset input code
        processMasterMode();
      } else {
        Serial.println("Access Denied");
      }
      inputCode = ""; // Reset input code
    }
  }
} 

void processMasterMode() {
  Serial.println("Press * to add a code or # to delete a code");
  while (true) {
    char key = keypad.getKey();
    if (key) {
      Serial.print("Master mode key pressed: ");
      Serial.println(key);
      if (key == '*') {
        addCode();
        break;
      } else if (key == '#') {
        deleteCode();
        break;
      }
    }
  }
} 

bool isAuthorized(String code) {
  for (int i = 0; i < maxCodes; i++) {
    if (authorizedCodes[i] == code) {
      return true;
    }
  }
  return false;
} 

void addCode() {
  if (currentCodeIndex >= maxCodes) {
    Serial.println("Max number of codes reached.");
    return;
  } 

  Serial.println("Enter ID Number:");
  String id = "";
  while (id.length() < 1) {
    char key = keypad.getKey();
    if (key) {
      Serial.print("ID key pressed: ");
      Serial.println(key);
      id += key;
    }
  } 

  Serial.println("Enter New 4-Digit Code:");
  String newCode = "";
  while (newCode.length() < 4) {
    char key = keypad.getKey();
    if (key) {
      Serial.print("New code key pressed: ");
      Serial.println(key);
      newCode += key;
    }
  } 

  String codeWithID = id + newCode;
  authorizedCodes[currentCodeIndex] = codeWithID;
  currentCodeIndex++; 

  // Save the new code to EEPROM
  for (int i = 0; i < 4; i++) {
    EEPROM.write((currentCodeIndex - 1) * 4 + i, codeWithID[i]);
  } 

  Serial.println("New Code Set");
} 

void deleteCode() {
  Serial.println("Enter ID to Delete:");
  String id = "";
  while (id.length() < 1) {
    char key = keypad.getKey();
    if (key) {
      Serial.print("Delete ID key pressed: ");
      Serial.println(key);
      id += key;
    }
  } 

  for (int i = 0; i < maxCodes; i++) {
    if (authorizedCodes[i].startsWith(id)) {
      authorizedCodes[i] = "";
      for (int j = 0; j < 4; j++) {
        EEPROM.write(i * 4 + j, 0);
      }
      Serial.println("Code Deleted");
      return;
    }
  } 

  Serial.println("ID not found");
}