/*

 * Copyright (c) 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

package javax.xml.catalog;

import java.io.UnsupportedEncodingException;

import java.net.URLDecoder;

import java.net.URLEncoder;

/**

 * The Normalizer is responsible for normalizing Public and System Identifiers

 * as specified in section 6.2, 6.3 and 6.4 of the specification

 *  * <a

 * href="https://www.oasis-open.org/committees/download.php/14809/xml-catalogs.html">

 * XML Catalogs, OASIS Standard V1.1, 7 October 2005</a>.

 *

 * @since 9

 */

class Normalizer {

    /**

     * Normalize a public identifier in accordance with section 6.2 of the

     * Catalog specification.

     *

     * <p>

     * All strings of white space in public identifiers must be normalized to

     * single space characters (#x20), and leading and trailing white space must

     * be removed.

     *

     * @param publicId The unnormalized public identifier

     *

     * @return The normalized identifier

     */

    static String normalizePublicId(String publicId) {

        if (publicId == null) return null;

        StringBuilder sb = new StringBuilder(publicId.length());

        char last = 'a';

        for (char c : publicId.toCharArray()) {

            //skip beginning and duplicate space

            if ((c == ' ') && (sb.length() == 0 || last == ' ')) {

                continue;

            }

            //replace whitespace with space

            if (c == '\t' || c == '\r' || c == '\n') {

                if (last != ' ') {

                    sb.append(' ');

                    last = ' ';

                }

            } else {

                sb.append(c);

                last = c;

            }

        }

        //remove the last space

        if (last == ' ') {

            sb.deleteCharAt(sb.length() - 1);

        }

        return sb.toString();

    }

    /**

     * Encode a public identifier as a "publicid" URN.

     *

     * @param publicId The unnormalized public identifier

     *

     * @return The normalized identifier

     * @throws CatalogException if encoding failed

     */

    static String encodeURN(String publicId) {

        String urn = normalizePublicId(publicId);

        try {

            urn = URLEncoder.encode(urn, "UTF-8");

            urn = urn.replace("::", ";");

            urn = urn.replace("//", ":");

        } catch (UnsupportedEncodingException ex) {

            CatalogMessages.reportRunTimeError(CatalogMessages.ERR_OTHER, ex);

        }

        return Util.URN + urn;

    }

    /**

     * Decode a "publicid" URN into a public identifier.

     *

     * @param urn The urn:publicid: URN

     *

     * @return The normalized identifier

     * @throws CatalogException if decoding failed

     */

    static String decodeURN(String urn) {

        String publicId;

        if (urn != null && urn.startsWith(Util.URN)) {

            publicId = urn.substring(13);

        } else {

            return urn;

        }

        try {

            publicId = publicId.replace(":", "//");

            publicId = publicId.replace(";", "::");

            publicId = URLDecoder.decode(publicId, "UTF-8");

        } catch (UnsupportedEncodingException ex) {

            CatalogMessages.reportRunTimeError(CatalogMessages.ERR_OTHER, ex);

        }

        return publicId;

    }

    /**

     * Perform character normalization on a URI reference.

     *

     * @param uriref The URI reference

     * @return The normalized URI reference

     */

    static String normalizeURI(String uriref) {

        if (uriref == null) {

            return null;

        }

        byte[] bytes;

        uriref = uriref.trim();

        try {

            bytes = uriref.getBytes("UTF-8");

        } catch (UnsupportedEncodingException uee) {

            // this can't happen

            return uriref;

        }

        StringBuilder newRef = new StringBuilder(bytes.length);

        for (int count = 0; count < bytes.length; count++) {

            int ch = bytes[count] & 0xFF;

            if ((ch <= 0x20) // ctrl

                    || (ch > 0x7F) // high ascii

                    || (ch == 0x22) // "

                    || (ch == 0x3C) // <

                    || (ch == 0x3E) // >

                    || (ch == 0x5C) // \

                    || (ch == 0x5E) // ^

                    || (ch == 0x60) // `

                    || (ch == 0x7B) // {

                    || (ch == 0x7C) // |

                    || (ch == 0x7D) // }

                    || (ch == 0x7F)) {

                newRef.append("%").append(String.format("%02X", ch));

            } else {

                newRef.append((char) bytes[count]);

            }

        }

        return newRef.toString().trim();

    }

}