/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.usergrid.security.crypto.command;


import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.UUID;

import org.springframework.beans.factory.annotation.Autowired;
import org.apache.usergrid.security.salt.SaltProvider;


/**
 * Class that provides salt options
 *
 * @author tnine
 */
public abstract class SaltedHasherCommand extends EncryptionCommand {

    protected static final Charset UTF8 = Charset.forName( "UTF-8" );

    @Autowired
    private SaltProvider provider;


    /** Possibly salt the input bytes if the salt provider gives us back data. */
    protected byte[] maybeSalt( byte[] input, UUID applicationId, UUID userId ) {
        if ( provider == null ) {
            return input;
        }

        String salt = provider.getSalt( applicationId, userId );

        /**
         * Nothing to do
         */
        if ( salt == null || salt.length() == 0 ) {
            return input;
        }

        byte[] saltBytes = salt.getBytes( UTF8 );

        byte[] outputBytes = new byte[input.length + saltBytes.length];

        // wrap it for ease of use
        ByteBuffer buff = ByteBuffer.wrap( outputBytes );

        buff.put( saltBytes );
        buff.put( input );

        return outputBytes;
    }
}