package fixedxor;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

public class FixedXor {

	private String someString;

	public FixedXor(String someString) {
		this.someString = someString;
	}

	public ArrayList<Integer> stringToHex() {
		ArrayList<Integer> asciiList = new ArrayList<Integer>();
		for(int i=0; i<someString.length(); i++) {
			//asciiList.add((int)word.charAt(i));
			asciiList.add(hexTable(someString.toUpperCase().charAt(i)));
		}
		return asciiList;
	}

	private int hexTable(Character c) {
		Map<Character, Integer> table = new HashMap<Character, Integer>();
		table.put('0', 0);
		table.put('1', 1);
		table.put('2', 2);
		table.put('3', 3);
		table.put('4', 4);
		table.put('5', 5);
		table.put('6', 6);
		table.put('7', 7);
		table.put('8', 8);
		table.put('9', 9);
		table.put('A', 10);
		table.put('B', 11);
		table.put('C', 12);
		table.put('D', 13);
		table.put('E', 14);
		table.put('F', 15);
		return table.get(c);
	}

	public ArrayList<String> hexToBinary(ArrayList<Integer> hex){
		ArrayList<String> binary = new ArrayList<String>();
		for(int i=0; i<hex.size(); i++) {
			if(hex.get(i) == 0) {
				binary.add("0000");
			}else if(hex.get(i) == 1) {
				binary.add("0001");
			}else {
				binary.add(convertToBinary(hex.get(i)));
			}
		}
		return binary;
	}

	public String convertToBinary(int number) {
		String binary = "";
		while (number != 1) {
			binary += number % 2;
			number = number / 2;
		}
		binary += number % 2;
		if(binary.length() == 2) {
			//return "0"+new StringBuilder(binary).reverse().toString();
			binary = binary+"00";
		}else if(binary.length() == 3) {
			binary = binary+"0";
		}
		return new StringBuilder(binary).reverse().toString();
	}

	public String binaryCombiner(ArrayList<String> binary) {
		String combinedBinary = "";
		for (String binaries : binary) {
			combinedBinary += binaries;
		}
		return combinedBinary;
	}

	public static ArrayList<String> fourDigitBinary(String binaryXored) {
		ArrayList<String> fourValuedBinary = new ArrayList<String>();
		String fourBinary = "";
		int count = 0;

		for(int i=0; i<binaryXored.length(); i++) {
			if(count != 4) {
				fourBinary += binaryXored.charAt(i);
				count++;
			}else {
				fourValuedBinary.add(fourBinary);
				count = 0;
				fourBinary = "";
				i-=1;
			}
		}
		fourValuedBinary.add(fourBinary);
		return fourValuedBinary;
	}

	public static ArrayList<String> binaryToBytes(ArrayList<String> fourBinary){
		ArrayList<String> bytes = new ArrayList<String>();
		for (String binaries : fourBinary) {
			int count = 3;
			int byteValue = 0;
			for(int i=0; i<binaries.length(); i++) {
				if(i == 3 && binaries.charAt(i) == '1') {
					byteValue += 1;
				}
				else if(binaries.charAt(i) == '1') {
					byteValue += Math.pow(2, count);
				}
				count--;
			}
			bytes.add(String.valueOf(byteValue));
		}
		return bytes;
	}

	public static void main(String[] args) {
		String binaryXored = "";
		String HexValue = "";
		//String finalHexValue = "";
		String[] hextable = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};
		FixedXor fx = new FixedXor("1c0111001f010100061a024b53535009181c");
		ArrayList<Integer> hexValues = fx.stringToHex();
		ArrayList<String> binaries = fx.hexToBinary(hexValues);
		String combinedBinary1 = fx.binaryCombiner(binaries);

		FixedXor fx1 = new FixedXor("686974207468652062756c6c277320657965");
		ArrayList<Integer> hexValue1 = fx1.stringToHex();
		ArrayList<String> binaries1 = fx1.hexToBinary(hexValue1);
		String combinedBinary2 = fx1.binaryCombiner(binaries1);

		for(int i=0; i<combinedBinary1.length(); i++) {
			if((combinedBinary1.charAt(i) == '0' && combinedBinary2.charAt(i) == '0') ||
					(combinedBinary1.charAt(i) == '1' && combinedBinary2.charAt(i) == '1')) {
				binaryXored += '0';
			}else {
				binaryXored += '1';
			}
		}

		ArrayList<String> hexDecoded = fourDigitBinary(binaryXored);
		ArrayList<String> bytes = binaryToBytes(hexDecoded);
		for (String s : bytes) {
			HexValue += hextable[Integer.valueOf(s)];
		}
		System.out.println(HexValue);
	}
}