import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;
public class test {
	static ArrayList <String> ciphers = new ArrayList<String>();
	static ArrayList <String> keys = new ArrayList<String>();
	static ArrayList <String> newKeys = new ArrayList<String>();
	static ArrayList <String> output = new ArrayList<String>();
	static ArrayList <String> plain = new ArrayList<String>();
public static void main (String[] args)
{
	loadCiphersandKeys();
	fixKeys();
	processCiphers();
	generateOutput();
	
}
public static void loadCiphersandKeys()
{
	File f = new File("cipher.txt");
	Scanner input = null;
	boolean cipherData = true;
	try //try...catch is used when the possibility of an error could result and we want to catch it without causing a runtime error
	{
		input = new Scanner(f);  	//Scanner is build based on input from the text, not the console
	} 
	catch (FileNotFoundException e) 
	{
		e.printStackTrace();
	}
	while (input.hasNext())
	{
		String st = input.nextLine();
		if (cipherData) ciphers.add(st);
		else 
			{
				keys.add(st);
				newKeys.add(st);
			}
		cipherData = !cipherData;
	}
	input.close();
	System.out.println(ciphers.size() + " ciphers loaded.");  //outputs the size of the ArrayList built
	System.out.println(keys.size() + " keys loaded.");  //outputs the size of the ArrayList built
}
public static void fixKeys()
{
	
	for(int x=0; x < keys.size(); x++)
	{
		if(keys.get(x).length() < ciphers.get(x).length()) //adding letters to the key to make same length as cipher
		{
			String newKey = keys.get(x);
			int keyLength = keys.get(x).length();
			int cipherLength = ciphers.get(x).length()-1;
			int index = keys.get(x).length();
			while(index <= cipherLength)
			{
				newKey = keys.get(x) + keys.get(x).substring(index % keyLength, index % keyLength + 1); 
				keys.set(x, newKey);
				index++;
			}
		}
		else if(keys.get(x).length() > ciphers.get(x).length())
		{
			int cipherLength = ciphers.get(x).length();
			String newKey = keys.get(x).substring(0,cipherLength);
			keys.set(x, newKey);
		}
	}
}
public static void processCiphers()
{
	
	for(int x =0; x < ciphers.size(); x++)
	{
		String result = null;
		char[] temp = new char[ciphers.get(x).length()];
		for(int i=0; i < temp.length; i++)
		{
			int cipherChar = (ciphers.get(x).charAt(i))-65;

			int keyChar = (keys.get(x).charAt(i))-65;

			if (cipherChar < keyChar) cipherChar += 26;
			int n = cipherChar - keyChar +64;
			char newChar = (char) (n);

			temp[i] = newChar;
		}
		result = new String(temp);
		plain.add(result);

	}

}
public static void generateOutput()
{
	for(int x = 0; x < ciphers.size(); x++)
	{
		output.add(ciphers.get(x) +"/"+newKeys.get(x) + " = " + plain.get(x) );
	}
	for(int x = 0; x < ciphers.size(); x++)
	{
		System.out.println(output.get(x));
	}
}
}