package de.romjaki.selfbot;

import java.util.ArrayList;

/**
 * COMP 249 - Assignment 4 Q1
 * Due Friday, April 11, 2014
 *
 * Rot-N algorithm, Encryption / Decryption
 * @version 1.0
 * */
public class Rot {
    private ArrayList<String> letters;
    private ArrayList<String> encryptedLetters;

    public Rot(){
        letters = new ArrayList<String>();
        encryptedLetters = new ArrayList<String>();
    }

    /**
     * Encrypt text
     * @param message Message to encrypt
     * @param rotN Rot number
     * @param encryptDigit True or False
     * @return encrypted message
     * */
    public String encrypt(String message, int rotN, boolean encryptDigit){
        String out = "";
        char encryptedCurrent;
        char current;
        int typeAlpha;

        //clear arrays
        letters.clear();
        encryptedLetters.clear();

        for(int i=0; i<message.length();i++){
            current = message.charAt(i);
            if((typeAlpha = typeAlpha(current)) != 0){
                encryptedCurrent = (char) (current + rotN);
                if(typeAlpha == 1 && encryptedCurrent > 'z' || typeAlpha == 2 && encryptedCurrent > 'Z')
                    encryptedCurrent -= 'z' - 'a' + 1;
            }else if(encryptDigit && isNumeric(current)){
                encryptedCurrent = (char) (current + rotN%10);
                if(encryptedCurrent > '9')
                    encryptedCurrent -= '9' - '0' + 1;
            } else {
                encryptedCurrent = current;
            }

            if((typeAlpha != 0 || (isNumeric(current) && encryptDigit)) && letters.indexOf(current+"") == -1){
                letters.add(current+"");
                encryptedLetters.add(encryptedCurrent+"");
            }

            out += encryptedCurrent;
        }
        return out;
    }

    /**
     * Decrypt text
     * @param message Message to decrypt
     * @param rotN Rot number
     * @param decryptDigit True or False
     * @return decrypted message
     * */
    public String decrypt(String message, int rotN, boolean decryptDigit){
        String out = "";
        char encryptedCurrent;
        char current;
        int typeAlpha;

        //clear arrays
        letters.clear();
        encryptedLetters.clear();

        for(int i=0; i<message.length();i++){
            current = message.charAt(i);
            if((typeAlpha = typeAlpha(current)) != 0){
                encryptedCurrent = (char) (current - rotN);
                if(typeAlpha == 1 && encryptedCurrent < 'a' || typeAlpha == 2 && encryptedCurrent < 'A')
                    encryptedCurrent += 'z' - 'a' + 1;
            }else if(decryptDigit && isNumeric(current)){
                encryptedCurrent = (char) (current - rotN%10);
                if(encryptedCurrent < '0')
                    encryptedCurrent += '9' - '0' + 1;
            } else {
                encryptedCurrent = current;
            }

            if((typeAlpha != 0 || (isNumeric(current) && decryptDigit)) && letters.indexOf(current+"") == -1){
                letters.add(current+"");
                encryptedLetters.add(encryptedCurrent+"");
            }

            out += encryptedCurrent;
        }
        return out;
    }

    /**
     * Check if the character is alphabetic
     * @param c Character
     * @return 1 => Lowercase, 2 => Uppercase, 3 => Not alpha
     * */
    public int typeAlpha(char c) {
        if(c >= 'a' && c <= 'z')
            return 1;
        if(c >= 'A' && c <= 'Z')
            return 2;
        return 0;
    }

    /**
     * Check if character is a number
     * @param c Character
     * @return true or false
     * */
    public boolean isNumeric(char c) {
        return c >= '0' && c <= '9';
    }

    /**
     * Get original letters
     * @return original letters
     * */
    public ArrayList<String> getLetters(){
        return letters;
    }

    /**
     * Get encrypted letters
     * @return encrypted/decrypted letters
     * */
    public ArrayList<String> getEncryptedLetters(){
        return encryptedLetters;
    }
}