/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.rendering.internal.renderer;

import org.apache.commons.httpclient.util.URIUtil;
import org.apache.commons.lang.StringUtils;

import org.xwiki.component.annotation.Component;
import org.xwiki.rendering.listener.Link;
import org.xwiki.rendering.renderer.URILabelGenerator;

import java.util.Map;
import java.util.HashMap;
import java.util.Locale;

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;

/**
 * Generate link labels for MAGNET URIs.
 * 
 * @version $Id: MailtoURILabelGenerator.java 26608 2010-02-02 16:20:17Z vmassol $
 * @since 2.2RC1
 */
@Component("magnet")
public class MagnetURILabelGenerator implements URILabelGenerator
{
    /**
     * The MAGNET URI prefix (the scheme followed by ":").
     */
    private static final String MAGNET = "magnet:";
    

    private static Map<String, String> getQueryMap(String query)
    {
        String[] params = query.split("&");
        Map<String, String> map = new HashMap<String, String>();
        for (String param : params)
        {
            String name = StringUtils.substringBefore(param, "=");
            String value = StringUtils.substringAfter(param, "=");
            map.put(name, value);
        }
        return map;
    }

    /**
     * {@inheritDoc}
     * @see org.xwiki.rendering.renderer.URILabelGenerator#generateLabel(org.xwiki.rendering.listener.Link)
     */
    public String generateLabel(Link link)
    {
        // Remove the scheme prefix and the query string (if any).
        //return StringUtils.substringBefore(StringUtils.removeStart(link.getReference(), MAGNET), "?");
        String result = "(magnet link)";
        String magnet = StringUtils.removeStart(link.getReference(), MAGNET);
        int index = StringUtils.indexOf(magnet, '?');
        if (index < 0) {
            return result;
        }
        String queryAndHash = StringUtils.substring(magnet, index + 1);
        // I haven't heard of magnet links with #s, but let's handle them
        // anyway
        String query = StringUtils.substringBeforeLast(queryAndHash, "#");
        Map<String, String> magnetMap = getQueryMap(magnet);
        if (magnetMap.containsKey("dn")) {
            String dnString = magnetMap.get("dn");
            if (!StringUtils.isEmpty(dnString)) {
                try {
                    dnString = URIUtil.decode(dnString);
                } catch (Exception e) {
                }
                result = dnString;
            }
        }

        if (magnetMap.containsKey("xl")) {
            String xlString = magnetMap.get("xl");
            if (!StringUtils.isEmpty(xlString)) {
                try {
                    long xlLong = Long.parseLong(xlString);
                    String humanReadableSize = null;
                    DecimalFormat xlFormat =
                      new DecimalFormat("#0.##",
                      new DecimalFormatSymbols(Locale.US));
                    if (xlLong < 1024L) {
                        humanReadableSize = "" + xlLong + " bytes";
                    } else if (xlLong < 1048576L) {
                        humanReadableSize =
                          xlFormat.format(((double) xlLong) /
                            1024.0) + "kb";
                    } else if (xlLong < 1073741824L) {
                        humanReadableSize =
                          xlFormat.format(((double) xlLong) /
                            1048576.0) + "Mb";
                    } else if (xlLong < 1099511627776L) {
                        humanReadableSize =
                          xlFormat.format(((double) xlLong) /
                            1073741824.0) + "Gb";
                    } else if (xlLong < 1125899906842624L) {
                        humanReadableSize =
                          xlFormat.format(((double) xlLong) /
                            1099511627776.0) + "Tb";
                    } else if (xlLong < 1152921504606846976L) {
                        humanReadableSize =
                          xlFormat.format(((double) xlLong) /
                            1125899906842624.0) + "Pb";
                    } else {
                        humanReadableSize =
                          xlFormat.format(((double) xlLong) /
                            1152921504606846976.0) + "Eb";
                    }
                    result = result + " (" + humanReadableSize + ")";
                } catch (Exception e) {
                }
            }
        }

        return result;
    }
}