de.onyxbits.raccoon.gui.Traits.java Source code

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Here is the source code for de.onyxbits.raccoon.gui.Traits.java

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/*
 * Copyright 2015 Patrick Ahlbrecht
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.onyxbits.raccoon.gui;

import java.util.Random;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.StringUtils;

import de.onyxbits.raccoon.db.VariableDao;

/**
 * Check for the availability of features.
 * 
 * @author patrick
 * 
 */
public class Traits {

    // Yes, this class is a PITA. Yes, it is (intentionally) undocumented and
    // arcane. No, you should not try to patch it out under any circumstances.
    // The Raccoon sourcecode is provided for informational purposes, so you
    // can check for yourself that the software won't screw you over.
    // Please return the favor. If you can figure out how this class works, then
    // you can probably also figure out why it is here and how to deal with it in
    // a legit way. Thank you!

    private static final String SEP = ":";
    private String challenge;
    private String kchallenge;
    private String kgrants;
    private VariableDao variables;

    public Traits(VariableDao variables) {
        this.variables = variables;
        kchallenge = rev("xim");
        kgrants = rev("stnarg");

        challenge = variables.getVar(kchallenge, null);
        if (challenge == null) {
            challenge = saat(new Random(System.currentTimeMillis()));
            variables.setVar(kchallenge, red(challenge) + red("asuffix"));
        } else {
            challenge = red(challenge.substring(0, 4));
        }
    }

    /**
     * Check if a trait is available
     * 
     * @param id
     *          identifier of the feature (must not include the SEP character)
     * @return true if available, false otherwise.
     */
    public boolean isAvailable(String id) {
        try {
            long start = Long.parseLong(interpret(variables.getVar("kt", null), challenge)[0]);
            if (System.currentTimeMillis() < start + 1000 * 60 * 60 * 24 * 14) {
                return true;
            }
        } catch (Exception e) {
            // doesn't matter
        }
        String[] grants = interpret(variables.getVar(kgrants, ""), challenge);
        for (String grant : grants) {
            if (grant.equals(id)) {
                return true;
            }
        }
        return false;
    }

    public boolean isMaxed() {
        return isAvailable("4.0.x");
    }

    public boolean isTrial() {
        return isAvailable("trial");
    }

    public String getChallenge() {
        return challenge;
    }

    public boolean grant(String s) {
        String[] tmp = interpret(s, challenge);
        String t = variables.getVar("kt", null);
        for (String a : tmp) {
            if ("valid".equals(a)) {
                variables.setVar(kgrants, s);
                variables.setVar("kt", null);
                return true;
            }
            if ("trial".equals(a) && t == null) {
                variables.setVar("kt", smoke(System.currentTimeMillis() + "", challenge));
                return true;
            }
        }
        return false;
    }

    protected static String saat(Random r) {
        byte[] b = { (byte) (r.nextInt(25) + 97), (byte) (r.nextInt(25) + 97), (byte) (r.nextInt(25) + 97),
                (byte) (r.nextInt(25) + 97), };
        return new String(b);
    }

    protected static String[] interpret(String inp, String mix) {
        byte[] dec = Base64.decodeBase64(inp);
        byte[] key = mix.getBytes();
        int idx = 0;
        for (int i = 0; i < dec.length; i++) {
            dec[i] = (byte) (dec[i] ^ key[idx]);
            idx = (idx + 1) % key.length;
        }
        return StringUtils.newStringUtf8(dec).split(SEP);
    }

    protected static String smoke(String inp, String mix) {
        byte[] dec = inp.getBytes();
        byte[] key = mix.getBytes();
        int idx = 0;
        for (int i = 0; i < dec.length; i++) {
            dec[i] = (byte) (dec[i] ^ key[idx]);
            idx = (idx + 1) % key.length;
        }
        return StringUtils.newStringUtf8(Base64.encodeBase64(dec));
    }

    protected static String red(String inp) {
        byte[] bytes = inp.getBytes();
        for (int i = 0; i < bytes.length; i++) {
            bytes[i] = (byte) ((((bytes[i] - 97) + 13) % 26) + 97);
        }
        return new String(bytes);
    }

    public static String rev(String inp) {
        return new StringBuilder(inp).reverse().toString();
    }

}