/* This code works with 4x4 Keypad Matrix, LCD ic, relay module and a  push button
   It's a lock where the relay can control a lock you can open either  with correct code
   or by the push button from inside
   The code can be  changed directly by the keypad and doesn't require uploading code again
   Code  is stored in EEPROM
   Refer to www.surtrtech.com for more details
*/

#include  <Keypad.h>
#include <EEPROM.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 02);
#define  Relay 11                //Controls the Relay
#define O_Button 10             //Push  Button


const  byte numRows = 4;         //number of rows on the keypad
const byte numCols =  4;         //number of columns on the keypad

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

char keypressed;                 //Where the keys are  stored it changes very often
char code[] = {'6', '6', '0', '1'}; //The default code,  you can change it or make it a 'n' digits one

char code_buff1[sizeof(code)];  //Where the new key is stored
char code_buff2[sizeof(code)];  //Where the new  key is stored again so it's compared to the previous one

short a = 0, i = 0, s = 0, j = 0; //Variables used later

byte rowPins[numRows] = {9, 8, 7, 6}; //Rows  0 to 3 //if you modify your pins you should modify this too
byte colPins[numCols] =  {5, 4, 3, 2}; //Columns 0 to 3

Keypad  myKeypad = Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols);

void  setup()
{
  lcd.init();
  lcd.backlight();


  lcd.home ();
  lcd.setCursor(2,0);
  lcd.print("Door is Lock");      //What's written on the LCD you can change

  pinMode(Relay, OUTPUT);
  pinMode(O_Button, INPUT);

  //          for(i=0 ; i<sizeof(code);i++){        //When  you upload the code the first time keep it commented
  //            EEPROM.get(i,  code[i]);             //Upload the code and change it to store it in the EEPROM
  //             }                                  //Then uncomment this for loop and  reupload the code (It's done only once)

}


void loop()
{

  keypressed = myKeypad.getKey();               //Constantly waiting for a key to  be pressed
  if (keypressed == '*') {                    // * to open the lock
    lcd.clear();
    lcd.setCursor(2, 0);
    lcd.print("Enter  code");            //Message to show
    GetCode();                          //Getting  code function
    if (a == sizeof(code))        //The GetCode function  assign a value to a (it's correct when it has the size of the code array)
      OpenDoor();                   //Open lock function if code is correct
    else {
      lcd.clear();
      lcd.setCursor(1,0);
      lcd.print("Wrong Password");          //Message to print when the code is wrong
    }
    delay(2000);
    lcd.clear();
    lcd.setCursor(2,0);
    lcd.print("Door is Lock");             //Return  to standby mode it's the message do display when waiting
  }

  if (keypressed  == '#') {                //To change the code it calls the changecode function
    ChangeCode();
    lcd.clear();
    lcd.setCursor(2,0);
    lcd.print("Door is Lock");                 //When  done it returns to standby mode
  }

  if (digitalRead(O_Button) == HIGH) {  //Opening by the push button
    digitalWrite(Relay, LOW);
    delay(3000);                        //Opens for 3s you can change
    digitalWrite(Relay, HIGH);

  }

}

void GetCode() {                 //Getting  code sequence
  i = 0;                    //All variables set to 0
  a = 0;
  j = 0;

  while (keypressed !=  'A') {                                   //The user press A to confirm the code  otherwise he can keep typing
    keypressed = myKeypad.getKey();
    if (keypressed != NO_KEY && keypressed != 'A' ) {     //If the char  typed isn't A and neither "nothing"
      lcd.setCursor(j, 1);                                 //This  to write "*" on the LCD whenever a key is pressed it's position is controlled  by j
      lcd.print("*");
      j++;
      if (keypressed  == code[i] && i < sizeof(code)) {       //if the char typed is correct a and i  increments to verify the next caracter
        a++;                                              //Now  I think maybe I should have use only a or i ... too lazy to test it -_-'
        i++;
      }
      else
        a--;                                               //if  the character typed is wrong a decrements and cannot equal the size of code []
    }
  }
  keypressed = NO_KEY;

}

void  ChangeCode() {                     //Change code sequence
  lcd.clear();
  lcd.setCursor(2,0);
  lcd.print("Change code");
  delay(2000);
  lcd.clear();
  lcd.setCursor(1,0);
  lcd.print("Enter old code");
  GetCode();                      //verify  the old code first so you can change it

  if (a == sizeof(code)) {  //again verifying the a value
    lcd.clear();
    lcd.print("Changing  code");
    GetNewCode1();            //Get the new code
    GetNewCode2();            //Get the new code again to confirm it
    s = 0;
    for (i = 0  ; i < sizeof(code) ; i++) { //Compare codes in array 1 and array 2 from two previous  functions
      if (code_buff1[i] == code_buff2[i])
        s++;                                //again this how we verifiy, increment s whenever  codes are matching
    }
    if (s == sizeof(code)) {        //Correct is always the size of the array

      for (i = 0 ; i < sizeof(code) ; i++) {
        code[i] = code_buff2[i];       //the code array now receives the new code
        EEPROM.put(i,  code[i]);        //And stores it in the EEPROM

      }
      lcd.clear();
      lcd.print("Code Changed");
      delay(2000);
    }
    else {                        //In case the new codes aren't matching
      lcd.clear();
      lcd.print("Codes are not");
      lcd.setCursor(0, 1);
      lcd.print("matching !!");
      delay(2000);
    }

  }

  else {                    //In case the old code is wrong you can't change it
    lcd.clear();
    lcd.setCursor(1,0);
    lcd.print("Wrong Password");
    delay(2000);
  }
}

void  GetNewCode1() {
  i = 0;
  j = 0;
  lcd.clear();
  lcd.print("Enter  new code");   //tell the user to enter the new code and press A
  lcd.setCursor(0, 1);
  lcd.print("and press A");
  delay(2000);
  lcd.clear();
  lcd.setCursor(0, 1);
  lcd.print("and press A");     //Press A keep showing while the top row print  ***

  while (keypressed != 'A') {          //A to confirm  and quits the loop
    keypressed = myKeypad.getKey();
    if (keypressed  != NO_KEY && keypressed != 'A' ) {
      lcd.setCursor(j, 0);
      lcd.print("*");               //On the new code you can show * as I did or change it to keypressed  to show the keys
      code_buff1[i] = keypressed;   //Store caracters  in the array
      i++;
      j++;
    }
  }
  keypressed = NO_KEY;
}

void  GetNewCode2() {                        //This is exactly like the GetNewCode1 function  but this time the code is stored in another array
  i = 0;
  j = 0;

  lcd.clear();
  lcd.print("Confirm code");
  lcd.setCursor(0, 1);
  lcd.print("and  press A");
  delay(3000);
  lcd.clear();
  lcd.setCursor(0, 1);
  lcd.print("and  press A");

  while (keypressed != 'A') {
    keypressed  = myKeypad.getKey();
    if (keypressed != NO_KEY && keypressed !=  'A' ) {
      lcd.setCursor(j, 0);
      lcd.print("*");
      code_buff2[i] = keypressed;
      i++;
      j++;
    }
  }
  keypressed = NO_KEY;
}

void  OpenDoor() {            //Lock opening function open for 3s
  lcd.clear();
  lcd.setCursor(1,0);
  lcd.print("Door Unlocked");
    lcd.setCursor(4,2);
   lcd.print("Come In");             //With a message printed
  digitalWrite(Relay, HIGH);
  delay(3000);
  digitalWrite(Relay, LOW);
}