//by Nissanka Md Weerasinghe @COTM

#include <LiquidCrystal_I2C.h> //++++++++++++++++++++++++
#include <SoftwareSerial.h>

#define I2C_ADDR1    0x27  //++++++++++++++++++++++++
#define I2C_ADDR2    0x29 //++++++++++++++++++++++++
#define LCD_COLUMNS 20    //++++++++++++++++++++++++
#define LCD_LINES   4     //++++++++++++++++++++++++

#define Encription_Key   20
#define Decription_Key   -20

SoftwareSerial link(10,11);
LiquidCrystal_I2C lcd1(I2C_ADDR1, LCD_COLUMNS, LCD_LINES); //++++++++++++++++++++++++
LiquidCrystal_I2C lcd2(I2C_ADDR2, LCD_COLUMNS, LCD_LINES); //++++++++++++++++++++++++

String Incomming_Command;
String Encrypted_Command;
String Decrypted_Command;

void setup() {
  Serial.begin(9600);
  link.begin(9600);


  // Init
  lcd1.init();      //++++++++++++++++++++++++
  lcd1.backlight(); //++++++++++++++++++++++++

  lcd2.init();      //++++++++++++++++++++++++
  lcd2.backlight(); //++++++++++++++++++++++++

  // Print something
  lcd1.setCursor(0, 0);         //++++++++++++++++++++++++
  lcd1.print("Hello, world!");  //++++++++++++++++++++++++
  lcd1.setCursor(0, 1);         //++++++++++++++++++++++++    
  lcd1.print("Wokwi LCD1");     //++++++++++++++++++++++++

  lcd2.setCursor(0, 0);         //++++++++++++++++++++++++  
  lcd2.print("Hello, world!");  //++++++++++++++++++++++++
  link.println("Hello, world!");
  lcd2.setCursor(0, 1);         //++++++++++++++++++++++++
  lcd2.print("Wokwi LCD2");     //++++++++++++++++++++++++
  link.println("Wokwi SoftwareSerial Display");

  delay(2000);
  lcd1.clear();
  lcd2.clear();

  lcd1.setCursor(0, 0);         //++++++++++++++++++++++++  
  lcd1.print("Encripted Commnd");  //++++++++++++++++++++++++
  lcd2.setCursor(0, 0);         //++++++++++++++++++++++++  
  lcd2.print("Decripted Commnd");  //++++++++++++++++++++++++

  Serial.println("Enter the command");

}


void loop() {

bool msg_received = false;  

while(Serial.available() > 0)
{
  msg_received = true;
  Incomming_Command = Serial.readStringUntil('\n');

  
}

//Data Encrioption ///////
if(msg_received)
{
  Serial.println(Incomming_Command);

  int Command_size = Incomming_Command.length();

  for( int i = 0; i< Command_size; i++)
  {
    char Command_Char = Incomming_Command.charAt(i);
    //Serial.print(Command_Char);
    char Encripted_Char = Command_Char + Encription_Key;

    Encrypted_Command += Encripted_Char;
  }

  //Serial.println(Encrypted_Command);
  
  lcd1.setCursor(0, 1); // to clear only the line 1  //++++++++++++++++++++++++
  lcd1.print("                "); // to clear only the line 1  //++++++++++++++++++++++++
  lcd1.setCursor(0, 1);         //++++++++++++++++++++++++  
  lcd1.print(Encrypted_Command);  //++++++++++++++++++++++++

  Serial.print("Encripted Command : ");
  Serial.println(Encrypted_Command);
  //Encrypted_Command = "";

  
}

//Data Decription //////

int Encrpt_Cmd_size = Encrypted_Command.length();

  if(Encrpt_Cmd_size > 0) 
  {
      for( int i = 0; i< Encrpt_Cmd_size; i++)
      {
        char Command_Char = Encrypted_Command.charAt(i);
        //Serial.print(Command_Char);
        char Decripted_Char = Command_Char + Decription_Key;

        Decrypted_Command += Decripted_Char;
      }

      Encrypted_Command = ""; // To accept next one

      //Serial.println(Encrypted_Command);
      
      lcd2.setCursor(0, 1); // to clear only the line 1  //++++++++++++++++++++++++
      lcd2.print("                "); // to clear only the line 1  //++++++++++++++++++++++++
      lcd2.setCursor(0, 1);         //++++++++++++++++++++++++  
      lcd2.print(Decrypted_Command);  //++++++++++++++++++++++++

      Serial.print("Decripted Command : ");
      Serial.println(Decrypted_Command);
      Decrypted_Command = ""; // To accept next one

  }

}