Enigma.java

import java.util.Scanner;

/**
 * Enigma
 */
public class Enigma {
    public static String[] cipherNames = { "Atbash Cipher", "ROT13 Cipher", "Caesar Cipher", "Affine Cipher",
            "Rail-fence Cipher", "Baconian Cipher" };

    public static void main(String[] args) {
        if (args.length != 0)
            handleCLArguments(args);
        else {
            printCiphers();
            System.out.println();
            String chosenCipher = getChoice("Choose your Cipher: ");
            String chosenOperation = getChoice("Enter -e to encrypt, -d to decrypt: ");

            if (chosenCipher.equals("4")) {
                String keyA = getChoice("Enter first key: ");
                String keyB = getChoice("Enter second key: ");
                String[] choices = { chosenOperation, chosenCipher, keyA, keyB };
                runCipher(choices);
            } else {
                String[] choices = { chosenOperation, chosenCipher };

                runCipher(choices);
            }
        }
    }

    public static void handleCLArguments(String[] args) {
        if (args[0].equalsIgnoreCase("-l"))
            printCiphers();
        else if (args[0].equalsIgnoreCase("-h"))
            displayHelp();
        else {
            try {
                runCipher(args);
            } catch (Exception e) {
                System.out.println("Invalid arguments, or broken cipher");
            }
        }
    }

    public static void displayHelp() {
        System.out.println("-l to list all available ciphers.");
        System.out.println("-e and cipher number to encrypt.");
        System.out.println("-d and cipher number to decrypt.");
        System.out.println("< filename.txt to specify text file for input.");
        System.out.println("If cipher requires a key, type it after cipher number.");
        System.out.println(
                "Affine cipher requires two keys (numbers), from which first one should be relatively prime with alphabet length (26).");
    }

    public static void printCiphers() {
        for (byte i = 0; i < cipherNames.length; i++) {
            System.out.println((i + 1) + " " + cipherNames[i]);
        }
    }

    public static String getChoice(String message) {
        System.out.print(message);
        Scanner input = new Scanner(System.in);
        String userChoice = input.nextLine();
        return userChoice;
    }

    public static void runCipher(String[] args) {
        switch (args[1]) {
            case "1":
                System.out.println(AtbashCipher.encrypt(getUserInput()));
                break;

            case "2":
                System.out.println(ROT13Cipher.encrypt(getUserInput()));
                break;

            case "3":
                if (args[0].equals("-e"))
                    System.out.println(CaesarCipher.encrypt(getUserInput()));
                else
                    System.out.println(CaesarCipher.decrypt(getUserInput()));
                break;

            case "4":
                byte keyA = Byte.parseByte(args[2]);
                byte keyB = Byte.parseByte(args[3]);
                if (args[0].equals("-e"))
                    System.out.println(AffineCipher.encrypt(getUserInput(), keyA, keyB));
                else
                    System.out.println(AffineCipher.decrypt(getUserInput(), keyA, keyB));
                break;

            case "5":
                if (args[0].equals("-e"))
                    System.out.println(RailFenceCipher.encrypt(getUserInput()));
                else
                    System.out.println(RailFenceCipher.decrypt(getUserInput()));
                break;

            case "6":
                if (args[0].equals("-e"))
                    System.out.println(BaconianCipher.encrypt(getUserInput()));
                else
                    System.out.println(BaconianCipher.decrypt(getUserInput()));
                break;

            default:
                break;
        }
    }

    public static String getUserInput() {
        try (Scanner input = new Scanner(System.in)) {
            String userInput = "";
            try {
                if (System.in.available() > 0) {
                    while (input.hasNextLine())
                        userInput += input.nextLine() + "\n";
                } else
                    System.out.println("Enter your text");
                userInput = input.nextLine();
            } catch (Exception e) {
                ;
            }
            return userInput;
        }
    }
}