package com.sulake.habbo.security;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;

public class RC4Provider extends RC4Core {
	private int i, j;

	private short[] key = new short[256];
	private short[] table = new short[256];

	public RC4Provider(String publicKey) {
		this.i = 0;
		this.j = 0;

		this.initialize(this.decodeKey(publicKey));
		this.premixTable(this.premixString);
	}

	private void initialize(String checksum) {
		int keyValue = Integer.parseInt(checksum);
		int keyLength = (keyValue & 0xf8) / 8;
		if (keyLength < 20)
			keyLength += 20;
		int keyOffset = keyValue % keyWindow.length;
		int keySkip = 0;
		int prevKey = 0;
		int m = 2;
		short w[] = new short[keyLength];
		for (int i = 0; i < keyLength; i++) {
			keySkip = prevKey % 29 - i % 6;
			m *= -1;
			w[i] = keyWindow[Math.abs(keyOffset + i * m + keySkip)
					% keyWindow.length];
			prevKey = w[i];
		}

		for (short a = 0; a < 256; a++) {
			key[a] = w[a % w.length];
			table[a] = a;
		}

		short t = 0;
		short b = 0;
		for (int a = 0; a < 256; a++) {
			b = (short) ((b + table[a] + key[a]) % 256);
			t = table[a];
			table[a] = table[b];
			table[b] = t;
		}
	}

	private void premixTable(String s) {
		for (int a = 0; a < 17; a++) {
			this.encipher(s.getBytes());
		}
	}

	private byte mixTable() {
		this.i = ((this.i + 1) % 256);
		this.j = ((j + table[i]) % 256);

		short b = table[this.i];
		table[this.i] = table[this.j];
		table[this.j] = b;

		return (byte) table[(table[this.i] + table[this.j]) % 256];
	}

	private byte ConvertTwoHexBytesToByte(byte A, byte B) {
		int C = 0;
		int D = 0;

		while (D < di.length) {
			if (di[D] == (A & 0xff)) {
				C = (D << 4);
				break;
			}
			++D;
		}

		D = 0;
		while (D < di.length) {
			if (di[D] == (B & 0xff)) {
				C += D;
				break;
			}
			++D;
		}

		return (byte) C;
	}

	public ChannelBuffer decipher(ChannelBuffer buffer) {
		if (buffer.readableBytes() % 2 != 0) {
			return null;
		}

		ChannelBuffer res = ChannelBuffers.buffer(buffer.readableBytes());

		@SuppressWarnings("unused")
		int b = 0;

		while (buffer.readableBytes() > 0) {
			byte c = ConvertTwoHexBytesToByte(buffer.readByte(),
					buffer.readByte());
			byte cB = (byte) (c ^ this.mixTable());

			res.writeByte(cB);
			b++;
		}

		return res;
	}

	public byte[] encipher(byte data[]) {
		byte cipher[] = new byte[data.length * 2];
		int pos = 0;

		for (int a = 0; a < data.length; a++) {
			int c = data[a] ^ this.mixTable();

			if (c <= 0) {
				cipher[pos++] = 0;
				cipher[pos++] = 0;
			} else {
				cipher[pos++] = (byte) di[c >> 4 & 0xf];
				cipher[pos++] = (byte) di[c & 0xf];
			}
		}

		return cipher;
	}
}