// CipherTester.java
// Use AS-IS to test CS 10 assignment 5, part 2, Fall 2008
// cmc, updated 11/18/08

import java.io.IOException;
import java.util.Scanner;

public class CipherTester {
    public static void main(String[] args) throws IOException {
        
        if (args.length < 1 || args.length > 2)
            fatalMessage("usage: java CipherTester [-d] -kKEY");

        String key = null;
        boolean encrypt = true; // default action
        
        for (String arg : args)
            if (arg.charAt(0) == '-') {                  // an option
                String option = arg.substring(1, 2);
                if (option.equals("d"))
                    encrypt = false;
                else if (option.equals("k")) {
                    if (arg.length() < 3)
                        fatalMessage("missing key string with -k option");
                    key = arg.substring(2);
                }
                else
                    fatalMessage("bad option: " + arg);
            }
            else
                fatalMessage("argument not an option: " + arg);

        // verify a key was entered
        if (key == null)
            fatalMessage("did not enter a key");

        // accumulate all text in a StringBuilder and retrieve string
        StringBuilder buffer = new StringBuilder();
        Scanner input = new Scanner(System.in);
        String newline = String.format("%n"); // to replace what Scanner strips
        while (input.hasNextLine())
            buffer.append( input.nextLine() + newline );
        String text = buffer.toString();

        // create cipher object, then encrypt or decrypt the text and print
        Cipher cipher = new VigCipher(key);
        String result;
        if (encrypt)
            result = cipher.encrypt(text);
        else
            result = cipher.decrypt(text);
        System.out.print(result);
    }

    // utility prints error message and exits
    private static void fatalMessage(String message) {
        System.err.println(message);
        System.exit(1);
    }
}