import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Scanner;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class CipherFeedback {

    public byte[] key;
	public String iv;
    private static final String ALGORITHM = "AES/CBC/NoPadding"; //
	String  tekst_jawny;
    SecretKeySpec secretKey;

    public CipherFeedback(String klucz, String initVector)
    {
        key = klucz.getBytes(StandardCharsets.US_ASCII);
        iv = initVector;
        secretKey= new SecretKeySpec(key, "AES");
    }

    public String encrypt(String plainText) throws Exception
    {
    	byte[] ivs = new byte[] { 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF };
    	IvParameterSpec ivSpec = new IvParameterSpec(ivs);
        Cipher cipherr = Cipher.getInstance(ALGORITHM);
        cipherr.init(Cipher.ENCRYPT_MODE, secretKey,ivSpec);
        byte[] crypted = cipherr.doFinal(plainText.getBytes());
		return new String(crypted);
    }

    public String decrypt(String cipherText) throws Exception
    {
    	byte[] ivs = new byte[] { 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF };
    	IvParameterSpec ivSpec = new IvParameterSpec(ivs);
        Cipher cipherr = Cipher.getInstance(ALGORITHM);

        cipherr.init(Cipher.ENCRYPT_MODE, secretKey,ivSpec);
        byte[] output = cipherr.doFinal(cipherText.getBytes());
        return new String(output);
    }
    public byte[] wykonajXor(byte[] p, byte[] q)
    {
    	for( int i = 0; i < q.length; i++)
    	{
    		q[i] = (byte) (q[i] ^ p[i]);
    	}
		return q;

    }
    public String encryptWithCFB(String tekst_jaw) throws Exception
    {
    	byte[] tablica_bajtow_tekstu_jawnego = tekst_jaw.getBytes(StandardCharsets.US_ASCII);
    	String cipherIV = encrypt(iv);

    	byte[] tablica_bajtow_iv = cipherIV.getBytes(StandardCharsets.US_ASCII);

    	tablica_bajtow_iv = wykonajXor(tablica_bajtow_tekstu_jawnego, tablica_bajtow_iv);
    	String wynik = new String(tablica_bajtow_iv);
    	iv = wynik;
    	return wynik;
    }

    public String decryptWithCFB(String tekst_jaw) throws Exception
    {
    	byte[] tablica_bajtow_tekstu_jawnego = tekst_jaw.getBytes(StandardCharsets.US_ASCII);
    	String cipherIV = encrypt(iv);

    	byte[] tablica_bajtow_iv = cipherIV.getBytes(StandardCharsets.US_ASCII);
    	String wynikiv=new String(tablica_bajtow_tekstu_jawnego);
    	iv = wynikiv;
    	tablica_bajtow_iv = wykonajXor(tablica_bajtow_tekstu_jawnego, tablica_bajtow_iv);
    	String wynik = new String(tablica_bajtow_iv);

    	return wynik;
    }
    public String read(String filename) throws IOException
    {
        String content;
        content = new String(Files.readAllBytes(Paths.get(filename)));
        return content;
    }
    public void szyfrujPlik() throws Exception
    {
		CipherFeedback cfb = new CipherFeedback("stereokomparator", "qwertyuiopasdfgh");
		cfb.iv="qwertyuiopasdfgh";

		BufferedWriter bw = null;
		FileWriter fw = null;


		fw = new FileWriter("2.txt");
		bw = new BufferedWriter(fw);
		try {


		    cfb.tekst_jawny = read("15mb.txt");
		    //System.out.println(cfb.tekst_jawny.length());
		    for(int i=0;i<(cfb.tekst_jawny.length()/16);i++)
    		{
    			String wiadomosc = cfb.encrypt(cfb.tekst_jawny.substring(0+(16*i),16+(16*i)));
    			//System.out.println(wiadomosc);
    			bw.write(wiadomosc);
    		}


		}
		finally
		{


		}
		bw.close();

    }
    public void deszyfrujPlik() throws Exception
    {
		CipherFeedback cfb = new CipherFeedback("stereokomparator", "qwertyuiopasdfgh");
		cfb.iv="qwertyuiopasdfgh";

		BufferedWriter bw = null;
		FileWriter fw = null;


		fw = new FileWriter("1.txt");
		bw = new BufferedWriter(fw);
		try {


		    cfb.tekst_jawny = read("2.txt");
		    System.out.println(cfb.tekst_jawny.length());
		    for(int i=0;i<(cfb.tekst_jawny.length()/16);i++)
    		{
    			String wiadomosc= cfb.decrypt(cfb.tekst_jawny.substring(0+(16*i),16+(16*i)));
    			//System.out.println(wiadomosc);
    			bw.write(wiadomosc);
    		}


		}
		finally
		{


		}
		bw.close();

    }


    	public static void main(String[] args) throws Exception {
    		CipherFeedback cfb = new CipherFeedback("stereokomparator","qwertyuiopasdfgh");
    		long startTime = System.nanoTime();

    		cfb.deszyfrujPlik();
    		long endTime = System.nanoTime();

    		long duration = (endTime - startTime)/1000000;
    		System.out.println(duration+ " ms");
    		//cfb.deszyfrujPlik();
    		try
    		{
//    			cfb.tekst_jawny = "szymonchojnowski";
//    			String wiadomosc = null;
//    			for(int i=0;i<(cfb.tekst_jawny.length()/16);i++)
//        		{
//        			wiadomosc= cfb.encryptWithCFB(cfb.tekst_jawny.substring(0+(16*i),16+(16*i)));
//        			System.out.println(wiadomosc);
//        		}
//
//    			cfb.iv = "qwertyuiopasdfgh";
//				for(int i=0;i<(cfb.tekst_jawny.length()/16);i++)
//				{
//					String wiadomosc2 = cfb.encryptWithCFB(wiadomosc.substring(0+(16*i),16+(16*i)));
//        			System.out.println(wiadomosc2);
//				}
    			System.out.println("success");
			}
    		catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

    	}

}