/*
 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 *******************************************************************************
 * Copyright (C) 2003-2004, International Business Machines Corporation and    *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.text.ParseException;

import sun.net.idn.StringPrep;
import sun.text.normalizer.UCharacterIterator;

/**
 * @author ram
 *
 * This is a dumb implementation of NFS4 profiles. It is a direct port of
 * C code, does not use Object Oriented principles. Quick and Dirty implementation
 * for testing.
 */
public final class NFS4StringPrep {

    private StringPrep nfscss = null;
    private StringPrep nfscsi = null;
    private StringPrep nfscis = null;
    private StringPrep nfsmxp = null;
    private StringPrep nfsmxs = null;
    //singleton instance
    private static final NFS4StringPrep prep = new NFS4StringPrep();


    private  NFS4StringPrep (){
        ClassLoader loader = NFS4StringPrep.class.getClassLoader();
      try{
          InputStream  nfscsiFile = loader.getResourceAsStream("nfscsi.spp");
          nfscsi = new StringPrep(nfscsiFile);
          nfscsiFile.close();

          InputStream  nfscssFile = loader.getResourceAsStream("nfscss.spp");
          nfscss = new StringPrep(nfscssFile);
          nfscssFile.close();

          InputStream  nfscisFile = loader.getResourceAsStream("nfscis.spp");
          nfscis = new StringPrep(nfscisFile);
          nfscisFile.close();

          InputStream  nfsmxpFile = loader.getResourceAsStream("nfsmxp.spp");
          nfsmxp = new StringPrep(nfsmxpFile);
          nfsmxpFile.close();

          InputStream  nfsmxsFile = loader.getResourceAsStream("nfsmxs.spp");
          nfsmxs = new StringPrep(nfsmxsFile);
          nfsmxsFile.close();
      }catch(IOException e){
          throw new RuntimeException(e.toString());
      }
    }

    private static byte[] prepare(byte[] src, StringPrep prep)
                throws ParseException, UnsupportedEncodingException{
        String s = new String(src, "UTF-8");
        UCharacterIterator iter =  UCharacterIterator.getInstance(s);
        StringBuffer out = prep.prepare(iter,StringPrep.DEFAULT);
        return out.toString().getBytes("UTF-8");
    }

    public static byte[] cs_prepare(byte[] src, boolean isCaseSensitive)
                         throws ParseException, UnsupportedEncodingException{
        if(isCaseSensitive == true ){
            return prepare(src, prep.nfscss);
        }else{
            return prepare(src, prep.nfscsi);
        }
    }

    public static byte[] cis_prepare(byte[] src)
                         throws IOException, ParseException, UnsupportedEncodingException{
        return prepare(src, prep.nfscis);
    }

    /* sorted array for binary search*/
    private static final String[] special_prefixes={
        "ANONYMOUS",
        "AUTHENTICATED",
        "BATCH",
        "DIALUP",
        "EVERYONE",
        "GROUP",
        "INTERACTIVE",
        "NETWORK",
        "OWNER",
    };


    /* binary search the sorted array */
    private static final int findStringIndex(String[] sortedArr,String target){

        int left, middle, right,rc;

        left =0;
        right= sortedArr.length-1;

        while(left <= right){
            middle = (left+right)/2;
            rc= sortedArr[middle].compareTo(target);

            if(rc<0){
                left = middle+1;
            }else if(rc >0){
                right = middle -1;
            }else{
                return middle;
            }
        }
        return -1;
    }
    private static final char AT_SIGN = '@';

    public static byte[] mixed_prepare(byte[] src)
                         throws IOException, ParseException, UnsupportedEncodingException{
        String s = new String(src, "UTF-8");
        int index = s.indexOf(AT_SIGN);
        StringBuffer out = new StringBuffer();

        if(index > -1){
            /* special prefixes must not be followed by suffixes! */
            String prefixString = s.substring(0,index);
            int i= findStringIndex(special_prefixes, prefixString);
            String suffixString = s.substring(index+1, s.length());
            if(i>-1 && !suffixString.equals("")){
                throw new ParseException("Suffix following a special index", -1);
            }
            UCharacterIterator prefix = UCharacterIterator.getInstance(prefixString);
            UCharacterIterator suffix = UCharacterIterator.getInstance(suffixString);
            out.append(prep.nfsmxp.prepare(prefix,StringPrep.DEFAULT));
            out.append(AT_SIGN); // add the delimiter
            out.append(prep.nfsmxs.prepare(suffix, StringPrep.DEFAULT));
        }else{
            UCharacterIterator iter = UCharacterIterator.getInstance(s);
            out.append(prep.nfsmxp.prepare(iter,StringPrep.DEFAULT));

        }
       return out.toString().getBytes("UTF-8");
    }

}