/*
    JSPWiki - a JSP-based WikiWiki clone.

    Copyright (C) 2001-2005 Janne Jalkanen (Janne.Jalkanen@iki.fi)

    This program 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 program 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 program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package com.ecyrd.jspwiki.plugin;

import org.apache.log4j.Logger;
import com.ecyrd.jspwiki.*;
import java.util.*;

/**
 *   Plugin for displaying an index of the wiki's links, to or from pages that 
 *   do and don't exist. If the parameter <tt>dir</tt> is "in", provides the
 *   referredBy list rather than the default refersTo list.
 *   Uses the ReferenceManager.
 * <p>
 *   Parameters:
 * </p>
 * <dl>
 *   <dt>dir="in|out"</dt>
 *     <dd>The direction of the link index, inbound ("in") or outbound ("out").
 *         The default is "out". </dd>
 *   <dt>nolinktext="[text string]"</dt>
 *     <dd>When a page has no links, this is the descriptive text.
 *         The default is "no links". </dd>
 *   <dt>page="[page]"</dt>
 *     <dd>When this parameter is absent, a link index of all wiki pages is 
 *         returned. If a page parameter is supplied, only the links of that
 *         page are returned. More than one page can be specified when 
 *         separated by whitespace. There is no default. </dd>
 * </dl>
 * <p>
 *   This produces a definition (<tt>&lt;dl&gt;</tt>) list, where the term
 *   (<tt>&lt;dt&gt;</tt>) is the page name and the definition
 *   (<tt>&lt;dd&gt;</tt>) is the list of links. The <tt>&lt;dl&gt;</tt>)
 *   element has a <tt>class</tt> attribute whose value is "linkindex". If
 *   the <tt>page</tt> parameter is provided and the page does not exist,
 *   there will be a single term whose value is "[page] does not exist!".
 * </p>
 * <p>
 *   Also see: <a href="http://www.jspwiki.org/wiki/LinkIndexPlugin">LinkIndexPlugin</a>
 * </p>
 *
 *  @author Murray Altheim
 *  @version JSPWiki 2.2.28
 */
public class LinkIndexPlugin
    extends AbstractReferralPlugin
{
    public static final String PARAM_DIR          = "dir";
    public static final String PARAM_PAGE         = "page";
    public static final String PARAM_NO_LINK_TEXT = "nolinktext";

    /** The default text used to indicate that there are no links for a given page. */
    public static String NO_LINK_TEXT = "no links";

    /** The default text used to indicate that the page specified as a parameter does not exist. */
    public static String DOES_NOT_EXIST = "does not exist!";

    private static Logger log = Logger.getLogger( LinkIndexPlugin.class );

    private static final String // reusable strings
            DLo = "<dl class=\"linkindex\">",         DLc = "</dl>\n",
            DTo = "<dt>",    DTao = "<dt><a href=\"", DTm = "\">",
            DTc = "</dt>\n", DTac = "</a></dt>\n",
            DDo = "  <dd>",  DDc = "</dd>\n",         Comma = ", ",
            Io  = "<i>",     Ic  = "</i>",
            Bo  = "<b>",     Bc  = "</b>";


    public String execute( WikiContext context, Map params )
            throws PluginException
    {
        WikiEngine eng = context.getEngine();
        ReferenceManager refmgr = eng.getReferenceManager();

        try {
            String nlt = (String)params.get(PARAM_NO_LINK_TEXT);
            String noLinkText = ( nlt != null ? nlt : NO_LINK_TEXT );
            boolean omitLinkless = ( nlt != null && nlt.equalsIgnoreCase("OMIT") );

            // obtain Map based on page and direction parameters
            String dir = (String)params.get(PARAM_DIR);
            Map map = ( dir != null && ((String)dir).equals("in") )
                    ? refmgr.getReferredBy()
                    : refmgr.getRefersTo();
            Collection uncreated = refmgr.findUncreated();
            String pageparam = (String)params.get(PARAM_PAGE);
            boolean multipage = pageparam != null
                    && ( ( pageparam.indexOf(' ')  != -1
                        || pageparam.indexOf('\t') != -1
                        || pageparam.indexOf('\n') != -1 ) );

            TreeSet keys = new TreeSet();
            if ( pageparam == null )
            {
                keys.addAll(map.keySet());
            }
            else if ( pageparam.trim().length() == 0 )
            {
                throw new PluginException("no page specified in 'page' parameter"); // I18N
            }
            else if ( !multipage && !context.getEngine().pageExists(pageparam) )
            {
                return DLo + DTo + pageparam + DTc + DDo + Bo + DOES_NOT_EXIST + Bc + DTc + DLc;
            }
            else
            {
                if ( multipage )
                {
                    StringTokenizer stok = new StringTokenizer(pageparam);
                    String token = null;
                    while ( stok.hasMoreTokens() )
                    {
                        token = stok.nextToken().trim();
                        if ( token.length() > 0 )
                        {
                            keys.add(token);
                        }
                    }
                }
                else
                {
                    keys.add(pageparam);
                }
            }

            // begin generating content
            StringBuffer out = new StringBuffer();
            out.append(DLo);

            Iterator it = keys.iterator();
            while( it.hasNext() )
            {
                String key = (String)it.next();
                Collection col = (Collection)map.get(key);
                if ( !context.getEngine().pageExists(key) ) // page doesn't exist ........
                {
                    out.append(DTo + key + DTc);
                    out.append(DDo + Bo + DOES_NOT_EXIST + Bc + DDc);
                }
                else if ( col.isEmpty() ) // page can't be found in map ..................
                {
                    if ( !omitLinkless )
                    {
                        out.append( DTao
                                + context.getEngine().getURL( WikiContext.VIEW, key, null, false )
                                + DTm + key + DTac );
                    //  out.append(DTo + key + DTc); // link-less
                        out.append(DDo + Io + noLinkText + Ic + DDc);
                    }
                }
                else // process set of pages .............................................
                {
                    out.append( DTao
                            + context.getEngine().getURL( WikiContext.VIEW, key, null, false )
                            + DTm + key + DTac );
                    out.append(DDo);
                    Iterator it2 = col.iterator();
                    while ( it2.hasNext() )
                    {
                        String page = (String)it2.next();
                        out.append( uncreated.contains(page)
                                ? Bo + page + Bc
                                : page );
                        if ( it2.hasNext() ) out.append(Comma);
                    }
                    out.append(DDc);
                }
            }
            out.append(DLc);

            super.initialize( context, params );

            return out.toString();

        }
        catch ( PluginException pe )
        {
            return "<span class=\"pluginerror\">error processing LinkIndexPlugin: "
                    + pe.getMessage() + "</span>"; // I18N
        }
    }

} // end com.ecyrd.jspwiki.plugin.LinkIndexPlugin