//Sakshi Lende
//Cryptography
//Spec: Shift alphabet forwards or backwards depending on inputted key

public class Cryptography {
    public int key;
    public String ciphertext, plaintext = "";
    public char position;
    // public String message, encryptedMessage = "";
    public char ch;

    public Cryptography() {
        key = 0;
        plaintext = "";
        ciphertext = "";
    }

    public Cryptography(int k, String message) {
        key = k;
        plaintext = message;
    }

    public String getEncrypt() {
        if (key > 25) {
            return "Please enter a key between 1 and 25";
        } else {
            for (int i = 0; i < plaintext.length(); i++) {
                position = plaintext.charAt(i);

                if (position >= 'a' && position <= 'z') {
                    position = (char) (position + key);

                    if (position > 'z') {
                        position = (char) (position - 'z' + 'a' - 1);
                    }
                    ciphertext += position;
                }

                else {
                    ciphertext += position;
                }
            }
            return ciphertext;
        }
    }

    public String getDecrypt() {
        if (key > 25) {
            return "Please enter a key between 1 and 25";
        } else {
            for (int i = 0; i < plaintext.length(); i++) {
                position = plaintext.charAt(i);

                if (position >= 'a' && position <= 'z') {
                    position = (char) (position - key);

                    if (position > 'z') {
                        position = (char) (position + 'z' - 'a' + 1);
                    }
                    ciphertext += position;
                }

                else {
                    ciphertext += position;
                }
            }
            return ciphertext.substring(4);

        }
    }

    public String test()
    {
        for (int i = 0; i < plaintext.length(); ++i)
        {
            ch = plaintext.charAt(i);

            if (ch >= 'a' && ch <= 'z')
            {
                ch = (char) (ch + key);

                if (ch > 'z')
                {
                    ch = (char) (ch - 'z' + 'a' - 1);
                }
                ciphertext += ch;
            }

            else if (ch >= 'A' && ch <= 'Z')
            {
                ch = (char) (ch + key);

                if (ch > 'Z')
                {
                    ch = (char) (ch - 'Z' + 'A' - 1);
                }
                ciphertext += ch;
            }
            else
            {
                ciphertext += ch;
            }
        }
        return ciphertext;
    }

    public String pleaseWork()
    {
        for (int i = 0; i < plaintext.length(); i++)
        {
            ch = plaintext.charAt(i);

            if (ch >= 'a' && ch <= 'z')
            {
                ch = (char) (ch + key);

                if (ch > 'z')
                {
                    ch = (char) (ch - 'z' + 'a' - 1);
                }

                ciphertext += ch;
            }
            else
            {
                ciphertext += ch;
            }
        }

        return ciphertext.substring(4);
    }
}