/*
   Copyright 2010 Dmitry Naumenko (dm.naumenko@gmail.com)

   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 difflib;

import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

public class Utils {
    public static Charset UTF_8 = Charset.forName("UTF-8");

    /**
     * Replaces all tabs with 4 spaces.
     * @param str The string.
     * @return
     */
    public static String expandTabs(String str) {
        return str.replace("\t", "    ");
    }

    /**
     * Replaces all opening an closing tags with <code>&lt;</code> or <code>&gt;</code>.
     * @param str
     * @return
     */
    public static String htmlEntites(String str) {
        return str.replace("<", "&lt;").replace(">", "&gt;");
    }

    public static String normalize(String str) {
        return expandTabs(htmlEntites(str));
    }

    public static List<String> normalize(List<String> list) {
        List<String> result = new LinkedList<String>();
        for (String line : list) {
            result.add(normalize(line));
        }
        return result;
    }

    public static List<String> wrapText(List<String> list, int columnWidth) {
        List<String> result = new LinkedList<String>();
        for (String line : list) {
            result.add(wrapText(line, columnWidth));
        }
        return result;
    }

    /**
     * Wrap the text with the given column width
     * @param line        the text
     * @param columnWidth the given column
     * @return the wrapped text
     */
    public static String wrapText(String line, int columnWidth) {
        int lenght = line.length();
        int delimiter = "<br>".length();
        int widthIndex = columnWidth;

        for (int count = 0; lenght > widthIndex; count++) {
            line = line.subSequence(0, widthIndex + delimiter * count) + "<br>"
                    + line.substring(widthIndex + delimiter * count);
            widthIndex += columnWidth;
        }

        return line;
    }

    /**
     * Join a list of strings using a specified separator.
     * @param strList List of strings.
     * @param sep     String to put between items when joining.
     * @return Joined string.
     */
    static String join(List<String> strList, String sep) {
        StringBuilder builder = new StringBuilder();
        for (final Iterator<String> i = strList.iterator(); i.hasNext(); ) {
            final String s = i.next();
            builder.append(s);
            if (i.hasNext()) builder.append(sep);
        }
        return builder.toString();
    }
}