/*
 * Copyright (C) 2010 The IDEAL Group
 *
 * 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 com.ideal.webaccess;

import java.util.*;

/**
 * Class for escaping HTML content. Code from tutorial at:
 * http://www.rgagnon.com/javadetails/java-0307.html
 */
public class StringUtils {

    private StringUtils() {
    }

    private static HashMap<String, String> htmlEntities;
    static {
        htmlEntities = new HashMap<String, String>();
        htmlEntities.put("&lt;", "<");
        htmlEntities.put("&gt;", ">");
        htmlEntities.put("&amp;", "&");
        htmlEntities.put("&quot;", "\"");
        htmlEntities.put("&agrave;", "ŕ");
        htmlEntities.put("&Agrave;", "Ŕ");
        htmlEntities.put("&acirc;", "â");
        htmlEntities.put("&auml;", "ä");
        htmlEntities.put("&Auml;", "Ä");
        htmlEntities.put("&Acirc;", "Â");
        htmlEntities.put("&aring;", "ĺ");
        htmlEntities.put("&Aring;", "Ĺ");
        htmlEntities.put("&aelig;", "ć");
        htmlEntities.put("&AElig;", "Ć");
        htmlEntities.put("&ccedil;", "ç");
        htmlEntities.put("&Ccedil;", "Ç");
        htmlEntities.put("&eacute;", "é");
        htmlEntities.put("&Eacute;", "É");
        htmlEntities.put("&egrave;", "č");
        htmlEntities.put("&Egrave;", "Č");
        htmlEntities.put("&ecirc;", "ę");
        htmlEntities.put("&Ecirc;", "Ę");
        htmlEntities.put("&euml;", "ë");
        htmlEntities.put("&Euml;", "Ë");
        htmlEntities.put("&iuml;", "ď");
        htmlEntities.put("&Iuml;", "Ď");
        htmlEntities.put("&ocirc;", "ô");
        htmlEntities.put("&Ocirc;", "Ô");
        htmlEntities.put("&ouml;", "ö");
        htmlEntities.put("&Ouml;", "Ö");
        htmlEntities.put("&oslash;", "ř");
        htmlEntities.put("&Oslash;", "Ř");
        htmlEntities.put("&szlig;", "ß");
        htmlEntities.put("&ugrave;", "ů");
        htmlEntities.put("&Ugrave;", "Ů");
        htmlEntities.put("&ucirc;", "ű");
        htmlEntities.put("&Ucirc;", "Ű");
        htmlEntities.put("&uuml;", "ü");
        htmlEntities.put("&Uuml;", "Ü");
        htmlEntities.put("&nbsp;", " ");
        htmlEntities.put("&copy;", "\u00a9");
        htmlEntities.put("&reg;", "\u00ae");
        htmlEntities.put("&euro;", "\u20a0");
    }

    /*
     * Here the original recursive version. It is fine unless you pass a big
     * string then a Stack Overflow is possible :-( public static final String
     * unescapeHTML(String source, int start){ int i,j; i = source.indexOf("&",
     * start); if (i > -1) { j = source.indexOf(";" ,i); if (j > i) { String
     * entityToLookFor = source.substring(i , j + 1); String value =
     * (String)htmlEntities.get(entityToLookFor); if (value != null) { source =
     * new StringBuffer().append(source.substring(0 , i)) .append(value)
     * .append(source.substring(j + 1)) .toString(); return unescapeHTML(source,
     * i + 1); // recursive call } } } return source; } M. McNeely Jr. has sent
     * a version with do...while()loop which is more robust. Thanks to him!
     */

    public static final String unescapeHTML(String source) {
        int i, j;

        boolean continueLoop;
        int skip = 0;
        do {
            continueLoop = false;
            i = source.indexOf("&", skip);
            if (i > -1) {
                j = source.indexOf(";", i);
                if (j > i) {
                    String entityToLookFor = source.substring(i, j + 1);
                    String value = htmlEntities.get(entityToLookFor);
                    if (value != null) {
                        source = source.substring(0, i) + value + source.substring(j + 1);
                        continueLoop = true;
                    } else if (value == null) {
                        skip = i + 1;
                        continueLoop = true;
                    }
                }
            }
        } while (continueLoop);
        return source;
    }
}