public class CipherKey {

    private String key = "I LOVE ME";
    private String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ";   // Initializing the alphabet as a String for later use





    public CipherKey(){

    };



    public void setKey (String key){

        boolean isValid = true;



        for (char c : key.toCharArray()) {   // Making sure its only uppercase letters and setting isValid to false if it encounters an invalid character
            if (((int)c > 90 || (int)c < 65) && (int)c != 32){
                isValid = false;
            }
        }

        if(key.length() < 1){
            isValid = false;
        }

        if(isValid) {
            this.key = key;
        }


    }

    public  String encrypt(String phrase){


        int times = (phrase.length() / this.key.length()) + 1;
        String k = "";


        if(phrase.length()> this.key.length()) {
            for (int i = 0; i < times; i++) {

                k += this.key;

            }
        } else {
            k = this.key;
        }


        String finalKey = k.substring(0, phrase.length());

        String encrypted ="";


        for (int i = 0; i < phrase.length(); i++) {

            if((int)((alphabet.indexOf(finalKey.toCharArray()[i]+1)+ phrase.toCharArray()[i])) > 126){
                encrypted += (char)((alphabet.indexOf(finalKey.toCharArray()[i])+1 + phrase.toCharArray()[i])-95);
            } else {
                encrypted += (char)(alphabet.indexOf(finalKey.toCharArray()[i])+1 + phrase.toCharArray()[i]);
            }

        }


        return encrypted;

    }


    public  String decrypt ( String phrase){

        int times = (phrase.length() / this.key.length()) + 1;
        String k = "";

        if(phrase.length()>this.key.length()) {
            for (int i = 0; i < times; i++) {

                k += this.key;

            }
        } else {
            k = this.key;
        }


        String finalKeyDecrypt = k.substring(0, phrase.length());

        String decrypted = "";


        for (int i = 0; i < phrase.length() ; i++) {



                decrypted += (char) (phrase.toCharArray()[i] - (alphabet.indexOf(finalKeyDecrypt.toCharArray()[i])+1));


        }

        return decrypted;


    }





}