/*
    Licensed to the Apache Software Foundation (ASF) under one
    or more contributor license agreements.  See the NOTICE file
    distributed with this work for additional information
    regarding copyright ownership.  The ASF licenses this file
    to you 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 org.apache.wiki;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.time.StopWatch;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
import org.apache.wiki.api.engine.AdminBeanManager;
import org.apache.wiki.api.engine.FilterManager;
import org.apache.wiki.api.engine.PluginManager;
import org.apache.wiki.api.exceptions.FilterException;
import org.apache.wiki.api.exceptions.NoRequiredPropertyException;
import org.apache.wiki.api.exceptions.NoSuchVariableException;
import org.apache.wiki.api.exceptions.ProviderException;
import org.apache.wiki.api.exceptions.WikiException;
import org.apache.wiki.attachment.Attachment;
import org.apache.wiki.attachment.AttachmentManager;
import org.apache.wiki.auth.AuthenticationManager;
import org.apache.wiki.auth.AuthorizationManager;
import org.apache.wiki.auth.UserManager;
import org.apache.wiki.auth.acl.AclManager;
import org.apache.wiki.auth.authorize.GroupManager;
import org.apache.wiki.content.PageRenamer;
import org.apache.wiki.diff.DifferenceManager;
import org.apache.wiki.event.WikiEngineEvent;
import org.apache.wiki.event.WikiEventListener;
import org.apache.wiki.event.WikiEventManager;
import org.apache.wiki.event.WikiPageEvent;
import org.apache.wiki.event.WikiPageRenameEvent;
import org.apache.wiki.i18n.InternationalizationManager;
import org.apache.wiki.pages.PageManager;
import org.apache.wiki.pages.PageTimeComparator;
import org.apache.wiki.parser.MarkupParser;
import org.apache.wiki.parser.WikiDocument;
import org.apache.wiki.providers.WikiPageProvider;
import org.apache.wiki.render.RenderingManager;
import org.apache.wiki.rss.RSSGenerator;
import org.apache.wiki.rss.RSSThread;
import org.apache.wiki.search.SearchManager;
import org.apache.wiki.tasks.TasksManager;
import org.apache.wiki.ui.Command;
import org.apache.wiki.ui.CommandResolver;
import org.apache.wiki.ui.EditorManager;
import org.apache.wiki.ui.TemplateManager;
import org.apache.wiki.ui.progress.ProgressManager;
import org.apache.wiki.url.URLConstructor;
import org.apache.wiki.util.ClassUtil;
import org.apache.wiki.util.PropertyReader;
import org.apache.wiki.util.TextUtil;
import org.apache.wiki.workflow.Decision;
import org.apache.wiki.workflow.DecisionRequiredException;
import org.apache.wiki.workflow.Fact;
import org.apache.wiki.workflow.Step;
import org.apache.wiki.workflow.Workflow;
import org.apache.wiki.workflow.WorkflowBuilder;
import org.apache.wiki.workflow.WorkflowManager;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.security.Principal;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.TimeZone;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;


/**
 *  Provides Wiki services to the JSP page.
 *
 *  <P>
 *  This is the main interface through which everything should go.
 *
 *  <P>
 *  Using this class:  Always get yourself an instance from JSP page
 *  by using the WikiEngine.getInstance() method.  Never create a new
 *  WikiEngine() from scratch, unless you're writing tests.
 *  <p>
 *  There's basically only a single WikiEngine for each web application, and
 *  you should always get it using the WikiEngine.getInstance() method.
 */
public class WikiEngine
{
    private static final String ATTR_WIKIENGINE = "org.apache.wiki.WikiEngine";

    private static final Logger log = Logger.getLogger(WikiEngine.class);

    /** True, if log4j has been configured. */
    // FIXME: If you run multiple applications, the first application
    // to run defines where the log goes.  Not what we want.
    private static boolean   c_configured = false;

    /** Stores properties. */
    private Properties       m_properties;

    /** The default inlining pattern.  Currently "*.png" */
    public static final String DEFAULT_INLINEPATTERN = "*.png";

    /** The name used for the default template. The value is {@value}. */
    public static final String DEFAULT_TEMPLATE_NAME = "default";

    /** Property for application name */
    public static final String PROP_APPNAME = "jspwiki.applicationName";

    /** This property defines the inline image pattern.  It's current value is {@value} */
    public static final String PROP_INLINEIMAGEPTRN  = "jspwiki.translatorReader.inlinePattern";

    /** Property start for any interwiki reference. */
    public static final String PROP_INTERWIKIREF = "jspwiki.interWikiRef.";

    /** If true, then the user name will be stored with the page data.*/
    public static final String PROP_STOREUSERNAME= "jspwiki.storeUserName";

    /** Define the used encoding.  Currently supported are ISO-8859-1 and UTF-8 */
    public static final String PROP_ENCODING     = "jspwiki.encoding";

    /** Do not use encoding in WikiJSPFilter, default is false for most servers.
    Double negative, cause for most servers you don't need the property */
    public static final String PROP_NO_FILTER_ENCODING     = "jspwiki.nofilterencoding";

    /** The name for the property which allows you to set the current reference
     *  style.  The value is {@value}.
     */
    public static final String PROP_REFSTYLE     = "jspwiki.referenceStyle";

    /** Property name for the "spaces in titles" -hack. */
    public static final String PROP_BEAUTIFYTITLE = "jspwiki.breakTitleWithSpaces";

    /** Property name for where the jspwiki work directory should be.
        If not specified, reverts to ${java.tmpdir}. */
    public static final String PROP_WORKDIR      = "jspwiki.workDir";

    /** The name of the cookie that gets stored to the user browser. */
    public static final String PREFS_COOKIE_NAME = "JSPWikiUserProfile";

    /** Property name for the "match english plurals" -hack. */
    public static final String PROP_MATCHPLURALS     = "jspwiki.translatorReader.matchEnglishPlurals";

    /** Property name for the template that is used. */
    public static final String PROP_TEMPLATEDIR  = "jspwiki.templateDir";

    /** Property name for the default front page. */
    public static final String PROP_FRONTPAGE    = "jspwiki.frontPage";

    /** Property name for setting the url generator instance */

    public static final String PROP_URLCONSTRUCTOR = "jspwiki.urlConstructor";

    /** If this property is set to false, all filters are disabled when translating. */
    public static final String PROP_RUNFILTERS   = "jspwiki.runFilters";

    /** Does the work in renaming pages. */
    private PageRenamer    m_pageRenamer = null;

    /** The name of the property containing the ACLManager implementing class.
     *  The value is {@value}. */
    public static final String PROP_ACL_MANAGER_IMPL = "jspwiki.aclManager";

    /** If this property is set to false, we don't allow the creation of empty pages */
    public static final String PROP_ALLOW_CREATION_OF_EMPTY_PAGES = "jspwiki.allowCreationOfEmptyPages";

    /** Should the user info be saved with the page data as well? */
    private boolean          m_saveUserInfo = true;

    /** If true, uses UTF8 encoding for all data */
    private boolean          m_useUTF8      = true;

    /** Store the file path to the basic URL.  When we're not running as
        a servlet, it defaults to the user's current directory. */
    private String           m_rootPath = System.getProperty("user.dir");

    /** Stores references between wikipages. */
    private ReferenceManager m_referenceManager = null;

    /** Stores the Plugin manager */
    private PluginManager    m_pluginManager;

    /** Stores the Variable manager */
    private VariableManager  m_variableManager;

    /** Stores the Attachment manager */
    private AttachmentManager m_attachmentManager = null;

    /** Stores the Page manager */
    private PageManager      m_pageManager = null;

    /** Stores the authorization manager */
    private AuthorizationManager m_authorizationManager = null;

    /** Stores the authentication manager.*/
    private AuthenticationManager      m_authenticationManager = null;

    /** Stores the ACL manager. */
    private AclManager       m_aclManager = null;

    /** Resolves wiki actions, JSPs and special pages. */
    private CommandResolver m_commandResolver = null;

    private TemplateManager  m_templateManager = null;

    /** Does all our diffs for us. */
    private DifferenceManager m_differenceManager;

    /** Handlers page filters. */
    private FilterManager    m_filterManager;

    /** Stores the Search manager */
    private SearchManager    m_searchManager = null;

    /** Facade for managing users */
    private UserManager      m_userManager = null;

    /** Facade for managing users */
    private GroupManager     m_groupManager = null;

    private RenderingManager m_renderingManager;

    private EditorManager    m_editorManager;

    private InternationalizationManager m_internationalizationManager;

    private ProgressManager  m_progressManager;

    private TasksManager m_tasksManager;

    /** Constructs URLs */
    private URLConstructor   m_urlConstructor;

    /** Generates RSS feed when requested. */
    private RSSGenerator     m_rssGenerator;

    /** The RSS file to generate. */
    private String           m_rssFile;

    /** Store the ServletContext that we're in.  This may be null if WikiEngine
        is not running inside a servlet container (i.e. when testing). */
    private ServletContext   m_servletContext = null;

    /** If true, all titles will be cleaned. */
    private boolean          m_beautifyTitle = false;

    /** Stores the template path.  This is relative to "templates". */
    private String           m_templateDir;

    /** The default front page name.  Defaults to "Main". */
    private String           m_frontPage;

    /** The time when this engine was started. */
    private Date             m_startTime;

    /** The location where the work directory is. */
    private String           m_workDir;

    /** Each engine has their own application id. */
    private String           m_appid = "";

    private boolean          m_isConfigured = false; // Flag.


    /** Each engine has its own workflow manager. */
    private WorkflowManager m_workflowMgr = null;

    private AdminBeanManager m_adminBeanManager;

    /** Stores wikiengine attributes. */
    private Map<String,Object> m_attributes = new ConcurrentHashMap<>();

    /**
     *  Gets a WikiEngine related to this servlet.  Since this method
     *  is only called from JSP pages (and JspInit()) to be specific,
     *  we throw a RuntimeException if things don't work.
     *
     *  @param config The ServletConfig object for this servlet.
     *
     *  @return A WikiEngine instance.
     *  @throws InternalWikiException in case something fails.  This
     *          is a RuntimeException, so be prepared for it.
     */

    // FIXME: It seems that this does not work too well, jspInit()
    // does not react to RuntimeExceptions, or something...

    public static synchronized WikiEngine getInstance( ServletConfig config )
        throws InternalWikiException
    {
        return getInstance( config.getServletContext(), null );
    }

    /**
     *  Gets a WikiEngine related to the servlet. Works like getInstance(ServletConfig),
     *  but does not force the Properties object. This method is just an optional way
     *  of initializing a WikiEngine for embedded JSPWiki applications; normally, you
     *  should use getInstance(ServletConfig).
     *
     *  @param config The ServletConfig of the webapp servlet/JSP calling this method.
     *  @param props  A set of properties, or null, if we are to load JSPWiki's default
     *                jspwiki.properties (this is the usual case).
     *
     *  @return One well-behaving WikiEngine instance.
     */
    public static synchronized WikiEngine getInstance( ServletConfig config,
                                                       Properties props )
    {
        return getInstance( config.getServletContext(), props );
    }

    /**
     *  Gets a WikiEngine related to the servlet. Works just like getInstance( ServletConfig )
     *
     *  @param context The ServletContext of the webapp servlet/JSP calling this method.
     *  @param props  A set of properties, or null, if we are to load JSPWiki's default
     *                jspwiki.properties (this is the usual case).
     *
     *  @return One fully functional, properly behaving WikiEngine.
     *  @throws InternalWikiException If the WikiEngine instantiation fails.
     */

    // FIXME: Potential make-things-easier thingy here: no need to fetch the wikiengine anymore
    //        Wiki.jsp.jspInit() [really old code]; it's probably even faster to fetch it
    //        using this method every time than go to pageContext.getAttribute().

    public static synchronized WikiEngine getInstance( ServletContext context,
                                                       Properties props )
        throws InternalWikiException
    {
        WikiEngine engine = (WikiEngine) context.getAttribute( ATTR_WIKIENGINE );

        if( engine == null )
        {
            String appid = Integer.toString(context.hashCode()); //FIXME: Kludge, use real type.

            context.log(" Assigning new engine to "+appid);
            try
            {
                if( props == null )
                {
                    props = PropertyReader.loadWebAppProps( context );
                }

                engine = new WikiEngine( context, appid, props );
                context.setAttribute( ATTR_WIKIENGINE, engine );
            }
            catch( Exception e )
            {
                context.log( "ERROR: Failed to create a Wiki engine: "+e.getMessage() );
                log.error( "ERROR: Failed to create a Wiki engine, stacktrace follows " , e);
                throw new InternalWikiException( "No wiki engine, check logs." , e);
            }

        }

        return engine;
    }


    /**
     *  Instantiate the WikiEngine using a given set of properties.
     *  Use this constructor for testing purposes only.
     *
     *  @param properties A set of properties to use to initialize this WikiEngine.
     *  @throws WikiException If the initialization fails.
     */
    public WikiEngine( Properties properties )
        throws WikiException
    {
        initialize( properties );
    }

    /**
     *  Instantiate using this method when you're running as a servlet and
     *  WikiEngine will figure out where to look for the property
     *  file.
     *  Do not use this method - use WikiEngine.getInstance() instead.
     *
     *  @param context A ServletContext.
     *  @param appid   An Application ID.  This application is an unique random string which
     *                 is used to recognize this WikiEngine.
     *  @param props   The WikiEngine configuration.
     *  @throws WikiException If the WikiEngine construction fails.
     */
    protected WikiEngine( ServletContext context, String appid, Properties props )
        throws WikiException
    {
        super();
        m_servletContext = context;
        m_appid          = appid;

        // Stash the WikiEngine in the servlet context
        if ( context != null )
        {
            context.setAttribute( ATTR_WIKIENGINE,  this );
            m_rootPath = context.getRealPath("/");
        }

        try
        {
            //
            //  Note: May be null, if JSPWiki has been deployed in a WAR file.
            //
            initialize( props );
            log.info("Root path for this Wiki is: '"+m_rootPath+"'");
        }
        catch( Exception e )
        {
            String msg = Release.APPNAME+": Unable to load and setup properties from jspwiki.properties. "+e.getMessage();
            if ( context != null )
            {
                context.log( msg );
            }
            throw new WikiException( msg, e );
        }
    }

    /**
     *  Does all the real initialization.
     */
    private void initialize( Properties props )
        throws WikiException
    {
        m_startTime  = new Date();
        m_properties = props;

        //
        //  Initialize log4j.  However, make sure that we don't initialize it multiple times.
        //  By default we load the log4j config statements from jspwiki.properties, unless
        //  the property jspwiki.use.external.logconfig=true, in that case we let log4j figure out the
        //  logging configuration.
        //
        if( !c_configured )
        {
            String useExternalLogConfig = TextUtil.getStringProperty(props,"jspwiki.use.external.logconfig","false");
            if( useExternalLogConfig == null || useExternalLogConfig.equals("false"))
            {
                PropertyConfigurator.configure( props );
            }
            c_configured = true;
        }

        log.info("*******************************************");
        log.info(Release.APPNAME+" "+Release.getVersionString()+" starting. Whee!");

        fireEvent( WikiEngineEvent.INITIALIZING ); // begin initialization

        log.debug("Java version: "+System.getProperty("java.runtime.version"));
        log.debug("Java vendor: "+System.getProperty("java.vm.vendor"));
        log.debug("OS: "+System.getProperty("os.name")+" "+System.getProperty("os.version")+" "+System.getProperty("os.arch"));
        log.debug("Default server locale: "+Locale.getDefault());
        log.debug("Default server timezone: "+TimeZone.getDefault().getDisplayName(true, TimeZone.LONG));

        if( m_servletContext != null )
        {
            log.info("Servlet container: "+m_servletContext.getServerInfo() );
            if( m_servletContext.getMajorVersion() < 2 ||
                (m_servletContext.getMajorVersion() == 2 && m_servletContext.getMinorVersion() < 4) )
            {
                throw new InternalWikiException("I require a container which supports at least version 2.4 of Servlet specification");
            }
        }

        log.debug("Configuring WikiEngine...");

        //  Initializes the CommandResolver
        m_commandResolver  = new CommandResolver( this, props );

        //
        //  Create and find the default working directory.
        //
        m_workDir = TextUtil.getStringProperty( props, PROP_WORKDIR, null );

        if( m_workDir == null ) {
            m_workDir = System.getProperty("java.io.tmpdir", ".");
            m_workDir += File.separator+Release.APPNAME+"-"+m_appid;
        }

        try {
            File f = new File( m_workDir );
            f.mkdirs();

            //
            //  A bunch of sanity checks
            //
            if( !f.exists() ) throw new WikiException("Work directory does not exist: "+m_workDir);
            if( !f.canRead() ) throw new WikiException("No permission to read work directory: "+m_workDir);
            if( !f.canWrite() ) throw new WikiException("No permission to write to work directory: "+m_workDir);
            if( !f.isDirectory() ) throw new WikiException("jspwiki.workDir does not point to a directory: "+m_workDir);
        } catch( SecurityException e ) {
            log.fatal( "Unable to find or create the working directory: "+m_workDir, e );
            throw new IllegalArgumentException( "Unable to find or create the working dir: " + m_workDir, e );
        }

        log.info("JSPWiki working directory is '"+m_workDir+"'");

        m_saveUserInfo   = TextUtil.getBooleanProperty( props, PROP_STOREUSERNAME, m_saveUserInfo );
        m_useUTF8        = StandardCharsets.UTF_8.name().equals( TextUtil.getStringProperty( props, PROP_ENCODING, StandardCharsets.ISO_8859_1.name() ) );
        m_beautifyTitle  = TextUtil.getBooleanProperty( props, PROP_BEAUTIFYTITLE, m_beautifyTitle );
        m_templateDir    = TextUtil.getStringProperty( props, PROP_TEMPLATEDIR, "default" );
        enforceValidTemplateDirectory();
        m_frontPage      = TextUtil.getStringProperty( props, PROP_FRONTPAGE,   "Main" );

        //
        //  Initialize the important modules.  Any exception thrown by the
        //  managers means that we will not start up.
        //

        // FIXME: This part of the code is getting unwieldy.  We must think
        //        of a better way to do the startup-sequence.
        try
        {
            Class< ? > urlclass = ClassUtil.findClass( "org.apache.wiki.url",
                                                       TextUtil.getStringProperty( props, PROP_URLCONSTRUCTOR, "DefaultURLConstructor" ) );
            m_urlConstructor = (URLConstructor) urlclass.getDeclaredConstructor().newInstance();
            m_urlConstructor.initialize( this, props );

            m_pageManager           = ClassUtil.getMappedObject( PageManager.class.getName(), this, props );
            m_pluginManager         = ClassUtil.getMappedObject( PluginManager.class.getName(), this, props );
            m_differenceManager     = ClassUtil.getMappedObject( DifferenceManager.class.getName(), this, props );
            m_attachmentManager     = ClassUtil.getMappedObject( AttachmentManager.class.getName(), this, props );
            m_variableManager       = ClassUtil.getMappedObject( VariableManager.class.getName(), props );
            m_renderingManager      = ClassUtil.getMappedObject( RenderingManager.class.getName() );
            m_searchManager         = ClassUtil.getMappedObject( SearchManager.class.getName(), this, props );
            m_authenticationManager = ClassUtil.getMappedObject( AuthenticationManager.class.getName() );
            m_authorizationManager  = ClassUtil.getMappedObject( AuthorizationManager.class.getName() );
            m_userManager           = ClassUtil.getMappedObject( UserManager.class.getName() );
            m_groupManager          = ClassUtil.getMappedObject( GroupManager.class.getName() );
            m_editorManager         = ClassUtil.getMappedObject( EditorManager.class.getName(), this );
            m_editorManager.initialize( props );

            m_progressManager   = new ProgressManager();

            // Initialize the authentication, authorization, user and acl managers
            m_authenticationManager.initialize( this, props );
            m_authorizationManager.initialize( this, props );
            m_userManager.initialize( this, props );
            m_groupManager.initialize( this, props );
            m_aclManager = getAclManager();

            // Start the Workflow manager
            m_workflowMgr = ClassUtil.getMappedObject(WorkflowManager.class.getName());
            m_workflowMgr.initialize(this, props);
            m_tasksManager = ClassUtil.getMappedObject(TasksManager.class.getName());

            m_internationalizationManager = ClassUtil.getMappedObject(InternationalizationManager.class.getName(),this);
            m_templateManager = ClassUtil.getMappedObject(TemplateManager.class.getName(), this, props );

            // Since we want to use a page filters initilize() method
            // as a engine startup listener where we can initialize global event listeners,
            // it must be called lastly, so that all object references in the engine
            // are availabe to the initialize() method
            m_filterManager = ClassUtil.getMappedObject(FilterManager.class.getName(), this, props );

            m_adminBeanManager = ClassUtil.getMappedObject(AdminBeanManager.class.getName(),this);

            // RenderingManager depends on FilterManager events.
            m_renderingManager.initialize( this, props );

            //
            //  ReferenceManager has the side effect of loading all
            //  pages.  Therefore after this point, all page attributes
            //  are available.
            //
            //  initReferenceManager is indirectly using m_filterManager, therefore
            //  it has to be called after it was initialized.
            //
            initReferenceManager();

            //
            //  Hook the different manager routines into the system.
            //
            m_filterManager.addPageFilter(m_referenceManager, -1001 );
            m_filterManager.addPageFilter(m_searchManager, -1002 );
        }

        catch( RuntimeException e )
        {
            // RuntimeExceptions may occur here, even if they shouldn't.
            log.fatal( "Failed to start managers.", e );
            throw new WikiException( "Failed to start managers: " + e.getMessage(), e );
        }
        catch (ClassNotFoundException e)
        {
            log.fatal( "JSPWiki could not start, URLConstructor was not found: " + e.getMessage(), e );
            throw new WikiException(e.getMessage(), e );
        }
        catch (InstantiationException e)
        {
            log.fatal( "JSPWiki could not start, URLConstructor could not be instantiated: " + e.getMessage(), e );
            throw new WikiException(e.getMessage(), e );
        }
        catch (IllegalAccessException e)
        {
            log.fatal( "JSPWiki could not start, URLConstructor cannot be accessed: " + e.getMessage(), e );
            throw new WikiException(e.getMessage(), e );
        }
        catch( Exception e )
        {
            // Final catch-all for everything
            log.fatal( "JSPWiki could not start, due to an unknown exception when starting.",e );
            throw new WikiException( "Failed to start. Caused by: " + e.getMessage() +
                                     "; please check log files for better information.", e );
        }

        //
        //  Initialize the good-to-have-but-not-fatal modules.
        //
        try
        {
            if( TextUtil.getBooleanProperty( props,
                                             RSSGenerator.PROP_GENERATE_RSS,
                                             false ) )
            {
                m_rssGenerator = (RSSGenerator)ClassUtil.getMappedObject(RSSGenerator.class.getName(), this, props );
            }

            m_pageRenamer = (PageRenamer)ClassUtil.getMappedObject(PageRenamer.class.getName(), this, props );
        }
        catch( Exception e )
        {
            log.error( "Unable to start RSS generator - JSPWiki will still work, "+
                       "but there will be no RSS feed.", e );
        }

        // Start the RSS generator & generator thread
        if( m_rssGenerator != null )
        {
            m_rssFile = TextUtil.getStringProperty( props,
                    RSSGenerator.PROP_RSSFILE, "rss.rdf" );
            File rssFile=null;
            if (m_rssFile.startsWith(File.separator))
            {
                // honor absolute pathnames:
                rssFile = new File(m_rssFile );
            }
            else
            {
                // relative path names are anchored from the webapp root path:
                rssFile = new File( getRootPath(), m_rssFile );
            }
            int rssInterval = TextUtil.getIntegerProperty( props,
                    RSSGenerator.PROP_INTERVAL, 3600 );
            RSSThread rssThread = new RSSThread( this, rssFile, rssInterval );
            rssThread.start();
        }

        fireEvent( WikiEngineEvent.INITIALIZED ); // initialization complete

        log.info("WikiEngine configured.");
        m_isConfigured = true;
    }

    /**
     * Checks if the template directory specified in the wiki's properties actually exists. If it doesn't, then {@code m_templateDir} is
     * set to {@link #DEFAULT_TEMPLATE_NAME}.
     * <p>
     * This checks the existence of the <tt>ViewTemplate.jsp</tt> file, which exists in every template using {@code m_servletContext.getRealPath("/")}.
     * <p>
     * {@code m_servletContext.getRealPath("/")} can return {@code null} on certain servers/conditions (f.ex, packed wars), an extra check
     * against {@code m_servletContext.getResource} is made.
     */
    void enforceValidTemplateDirectory() {
        if( m_servletContext != null ) {
            final String viewTemplate = "templates" + File.separator + getTemplateDir() + File.separator + "ViewTemplate.jsp";
            boolean exists = new File( m_servletContext.getRealPath("/") + viewTemplate ).exists();
            if( !exists ) {
                try {
                    URL url = m_servletContext.getResource( viewTemplate );
                    exists = url != null && StringUtils.isNotEmpty( url.getFile() );
                } catch( MalformedURLException e ) {
                    exists = false;
                }
            }
            if( !exists ) {
                log.warn( getTemplateDir() + " template not found, updating WikiEngine's default template to " + DEFAULT_TEMPLATE_NAME );
                m_templateDir = DEFAULT_TEMPLATE_NAME;
            }
        }
    }

    /**
     *  Initializes the reference manager. Scans all existing WikiPages for
     *  internal links and adds them to the ReferenceManager object.
     *
     *  @throws WikiException If the reference manager initialization fails.
     */
    public void initReferenceManager() throws WikiException {
        try {
            ArrayList<WikiPage> pages = new ArrayList<>();
            pages.addAll( m_pageManager.getAllPages() );
            pages.addAll( m_attachmentManager.getAllAttachments() );

            // Build a new manager with default key lists.
            if( m_referenceManager == null )
            {
                m_referenceManager = ClassUtil.getMappedObject(ReferenceManager.class.getName(), this );
                m_referenceManager.initialize( pages );
            }

        } catch( ProviderException e ) {
            log.fatal("PageProvider is unable to list pages: ", e);
        } catch( ReflectiveOperationException | IllegalArgumentException e ) {
            throw new WikiException( "Could not instantiate ReferenceManager: " + e.getMessage(), e );
        }
    }

    /**
     *  Returns the set of properties that the WikiEngine was initialized
     *  with.  Note that this method returns a direct reference, so it's possible
     *  to manipulate the properties.  However, this is not advised unless you
     *  really know what you're doing.
     *
     *  @return The wiki properties
     */

    public Properties getWikiProperties()
    {
        return m_properties;
    }

    /**
     *  Returns the JSPWiki working directory set with "jspwiki.workDir".
     *
     *  @since 2.1.100
     *  @return The working directory.
     */
    public String getWorkDir()
    {
        return m_workDir;
    }

    /**
     *  Returns the current template directory.
     *
     *  @since 1.9.20
     *  @return The template directory as initialized by the engine.
     */
    public String getTemplateDir()
    {
        return m_templateDir;
    }

    /**
     *  Returns the current TemplateManager.
     *
     *  @return A TemplateManager instance.
     */
    public TemplateManager getTemplateManager()
    {
        return m_templateManager;
    }

    /**
     *  Returns the base URL, telling where this Wiki actually lives.
     *
     *  @since 1.6.1
     *  @return The Base URL.
     */
    public String getBaseURL() {
        return m_servletContext.getContextPath();
    }

    /**
     *  Returns the moment when this engine was started.
     *
     *  @since 2.0.15.
     *  @return The start time of this wiki.
     */
    public Date getStartTime()
    {
        return (Date)m_startTime.clone();
    }

    /**
     * <p>
     * Returns the basic absolute URL to a page, without any modifications. You
     * may add any parameters to this.
     * </p>
     * <p>
     * Since 2.3.90 it is safe to call this method with <code>null</code>
     * pageName, in which case it will default to the front page.
     * </p>
     * @since 2.0.3
     * @param pageName The name of the page.  May be null, in which case defaults to the front page.
     * @return An absolute URL to the page.
     */
    public String getViewURL( String pageName ) {
        if( pageName == null ) {
            pageName = getFrontPage();
        }
        return getURLConstructor().makeURL( WikiContext.VIEW, pageName, "absolute".equals( PROP_REFSTYLE ), null );
    }

    /**
     *  Returns an URL if a WikiContext is not available.
     *
     *  @param context The WikiContext (VIEW, EDIT, etc...)
     *  @param pageName Name of the page, as usual
     *  @param params List of parameters. May be null, if no parameters.
     *  @param absolute If true, will generate an absolute URL regardless of properties setting.
     *  @return An URL (absolute or relative).
     */
    public String getURL( final String context, String pageName, final String params, final boolean absolute ) {
        if( pageName == null ) {
            pageName = getFrontPage();
        }
        return m_urlConstructor.makeURL( context, pageName, absolute, params );
    }

    /**
     *  Returns the default front page, if no page is used.
     *
     *  @return The front page name.
     */

    public String getFrontPage()
    {
        return m_frontPage;
    }

    /**
     *  Returns the ServletContext that this particular WikiEngine was
     *  initialized with.  <B>It may return null</B>, if the WikiEngine is not
     *  running inside a servlet container!
     *
     *  @since 1.7.10
     *  @return ServletContext of the WikiEngine, or null.
     */

    public ServletContext getServletContext()
    {
        return m_servletContext;
    }

    /**
     *  Returns the query string (the portion after the question mark).
     *
     *  @param request The HTTP request to parse.
     *  @return The query string.  If the query string is null,
     *          returns an empty string.
     *
     *  @since 2.1.3
     */
    public String safeGetQueryString( final HttpServletRequest request ) {
        if (request == null) {
            return "";
        }

        String res = request.getQueryString();
        if( res != null ) {
            res = new String( res.getBytes( StandardCharsets.ISO_8859_1 ), getContentEncoding() );

            //
            // Ensure that the 'page=xyz' attribute is removed
            // FIXME: Is it really the mandate of this routine to do that?
            //
            final int pos1 = res.indexOf("page=");
            if( pos1 >= 0 ) {
                String tmpRes = res.substring( 0, pos1 );
                final int pos2 = res.indexOf( "&",pos1 ) + 1;
                if ( ( pos2 > 0 ) && ( pos2 < res.length() ) ) {
                    tmpRes = tmpRes + res.substring(pos2);
                }
                res = tmpRes;
            }
        }

        return res;
    }

    /**
     *  Returns an URL to some other Wiki that we know.
     *
     *  @param  wikiName The name of the other wiki.
     *  @return null, if no such reference was found.
     */
    public String getInterWikiURL( String wikiName )
    {
        return TextUtil.getStringProperty(m_properties,PROP_INTERWIKIREF+wikiName,null);
    }

    /**
     *  Returns a collection of all supported InterWiki links.
     *
     *  @return A Collection of Strings.
     */
    public Collection< String > getAllInterWikiLinks()
    {
        ArrayList< String > list = new ArrayList< >();

        for( Enumeration< ? > i = m_properties.propertyNames(); i.hasMoreElements(); )
        {
            String prop = ( String )i.nextElement();

            if( prop.startsWith( PROP_INTERWIKIREF ) )
            {
                list.add( prop.substring( prop.lastIndexOf( "." ) + 1 ) );
            }
        }

        return list;
    }

    /**
     *  Returns a collection of all image types that get inlined.
     *
     *  @return A Collection of Strings with a regexp pattern.
     */
    public Collection< String > getAllInlinedImagePatterns()
    {
        Properties props    = getWikiProperties();
        ArrayList<String>  ptrnlist = new ArrayList<>();

        for( Enumeration< ? > e = props.propertyNames(); e.hasMoreElements(); )
        {
            String name = ( String )e.nextElement();

            if( name.startsWith( PROP_INLINEIMAGEPTRN ) )
            {
                String ptrn = TextUtil.getStringProperty( props, name, null );

                ptrnlist.add( ptrn );
            }
        }

        if( ptrnlist.size() == 0 )
        {
            ptrnlist.add( DEFAULT_INLINEPATTERN );
        }

        return ptrnlist;
    }

    /**
     *  <p>If the page is a special page, then returns a direct URL
     *  to that page.  Otherwise returns <code>null</code>.
     *  This method delegates requests to
     *  {@link org.apache.wiki.ui.CommandResolver#getSpecialPageReference(String)}.
     *  </p>
     *  <p>
     *  Special pages are defined in jspwiki.properties using the jspwiki.specialPage
     *  setting.  They're typically used to give Wiki page names to e.g. custom JSP
     *  pages.
     *  </p>
     *
     *  @param original The page to check
     *  @return A reference to the page, or null, if there's no special page.
     */
    public String getSpecialPageReference( String original )
    {
        return m_commandResolver.getSpecialPageReference( original );
    }

    /**
     *  Returns the name of the application.
     *
     *  @return A string describing the name of this application.
     */

    // FIXME: Should use servlet context as a default instead of a constant.
    public String getApplicationName()
    {
        String appName = TextUtil.getStringProperty(m_properties,PROP_APPNAME,Release.APPNAME);

        return MarkupParser.cleanLink( appName );
    }

    /**
     *  Beautifies the title of the page by appending spaces in suitable
     *  places, if the user has so decreed in the properties when constructing
     *  this WikiEngine.  However, attachment names are only beautified by
     *  the name.
     *
     *  @param title The title to beautify
     *  @return A beautified title (or, if beautification is off,
     *          returns the title without modification)
     *  @since 1.7.11
     */
    public String beautifyTitle( String title )
    {
        if( m_beautifyTitle )
        {
            try
            {
                Attachment att = m_attachmentManager.getAttachmentInfo(title);

                if(att == null)
                {
                    return TextUtil.beautifyString( title );
                }

                String parent = TextUtil.beautifyString( att.getParentName() );

                return parent + "/" + att.getFileName();
            }
            catch( ProviderException e )
            {
                return title;
            }
        }

        return title;
    }

    /**
     *  Beautifies the title of the page by appending non-breaking spaces
     *  in suitable places.  This is really suitable only for HTML output,
     *  as it uses the &amp;nbsp; -character.
     *
     *  @param title The title to beautify
     *  @return A beautified title.
     *  @since 2.1.127
     */
    public String beautifyTitleNoBreak( String title )
    {
        if( m_beautifyTitle )
        {
            return TextUtil.beautifyString( title, "&nbsp;" );
        }

        return title;
    }

    /**
     *  Returns true, if the requested page (or an alias) exists.  Will consider
     *  any version as existing.  Will also consider attachments.
     *
     *  @param page WikiName of the page.
     *  @return true, if page (or attachment) exists.
     */
    public boolean pageExists( String page )
    {
        Attachment att = null;

        try
        {
            if( m_commandResolver.getSpecialPageReference(page) != null ) return true;

            if( getFinalPageName( page ) != null )
            {
                return true;
            }

            att = getAttachmentManager().getAttachmentInfo( (WikiContext)null, page );
        }
        catch( ProviderException e )
        {
            log.debug("pageExists() failed to find attachments",e);
        }

        return att != null;
    }

    /**
     *  Returns true, if the requested page (or an alias) exists with the
     *  requested version.
     *
     *  @param page Page name
     *  @param version Page version
     *  @return True, if page (or alias, or attachment) exists
     *  @throws ProviderException If the provider fails.
     */
    public boolean pageExists( String page, int version )
        throws ProviderException
    {
        if( m_commandResolver.getSpecialPageReference(page) != null ) return true;

        String finalName = getFinalPageName( page );

        boolean isThere = false;

        if( finalName != null )
        {
            //
            //  Go and check if this particular version of this page
            //  exists.
            //
            isThere = m_pageManager.pageExists( finalName, version );
        }

        if( isThere == false )
        {
            //
            //  Go check if such an attachment exists.
            //
            try
            {
                isThere = getAttachmentManager().getAttachmentInfo( (WikiContext)null, page, version ) != null;
            }
            catch( ProviderException e )
            {
                log.debug("pageExists() failed to find attachments",e);
            }
        }

        return isThere;
    }

    /**
     *  Returns true, if the requested page (or an alias) exists, with the
     *  specified version in the WikiPage.
     *
     *  @param page A WikiPage object describing the name and version.
     *  @return true, if the page (or alias, or attachment) exists.
     *  @throws ProviderException If something goes badly wrong.
     *  @since 2.0
     */
    public boolean pageExists( WikiPage page )
        throws ProviderException
    {
        if( page != null )
        {
            return pageExists( page.getName(), page.getVersion() );
        }
        return false;
    }

    /**
     *  Returns the correct page name, or null, if no such
     *  page can be found.  Aliases are considered. This
     *  method simply delegates to
     *  {@link org.apache.wiki.ui.CommandResolver#getFinalPageName(String)}.
     *  @since 2.0
     *  @param page Page name.
     *  @return The rewritten page name, or null, if the page does not exist.
     *  @throws ProviderException If something goes wrong in the backend.
     */
    public String getFinalPageName( String page )
        throws ProviderException
    {
        return m_commandResolver.getFinalPageName( page );
    }

    /**
     *  Turns a WikiName into something that can be
     *  called through using an URL.
     *
     *  @since 1.4.1
     *  @param pagename A name.  Can be actually any string.
     *  @return A properly encoded name.
     *  @see #decodeName(String)
     */
    public String encodeName( String pagename )
    {
        try
        {
            return URLEncoder.encode( pagename, m_useUTF8 ? "UTF-8" : "ISO-8859-1" );
        }
        catch( UnsupportedEncodingException e )
        {
            throw new InternalWikiException( "ISO-8859-1 not a supported encoding!?!  Your platform is borked." , e);
        }
    }

    /**
     *  Decodes a URL-encoded request back to regular life.  This properly heeds
     *  the encoding as defined in the settings file.
     *
     *  @param pagerequest The URL-encoded string to decode
     *  @return A decoded string.
     *  @see #encodeName(String)
     */
    public String decodeName( final String pagerequest ) {
        try {
            return URLDecoder.decode( pagerequest, m_useUTF8 ? "UTF-8" : "ISO-8859-1" );
        } catch( UnsupportedEncodingException e ) {
            throw new InternalWikiException("ISO-8859-1 not a supported encoding!?!  Your platform is borked.", e);
        }
    }

    /**
     *  Returns the IANA name of the character set encoding we're
     *  supposed to be using right now.
     *
     *  @since 1.5.3
     *  @return The content encoding (either UTF-8 or ISO-8859-1).
     */
    public Charset getContentEncoding() {
        if( m_useUTF8 ) {
            return StandardCharsets.UTF_8;
        }
        return StandardCharsets.ISO_8859_1;
    }

    /**
     * Returns the {@link org.apache.wiki.workflow.WorkflowManager} associated with this
     * WikiEngine. If the WIkiEngine has not been initialized, this method will return
     * <code>null</code>.
     * @return the task queue
     */
    public WorkflowManager getWorkflowManager()
    {
        return m_workflowMgr;
    }

    /**
     *  Returns the un-HTMLized text of the latest version of a page.
     *  This method also replaces the &lt; and &amp; -characters with
     *  their respective HTML entities, thus making it suitable
     *  for inclusion on an HTML page.  If you want to have the
     *  page text without any conversions, use getPureText().
     *
     *  @param page WikiName of the page to fetch.
     *  @return WikiText.
     */
    public String getText( String page )
    {
        return getText( page, WikiPageProvider.LATEST_VERSION );
    }

    /**
     *  Returns the un-HTMLized text of the given version of a page.
     *  This method also replaces the &lt; and &amp; -characters with
     *  their respective HTML entities, thus making it suitable
     *  for inclusion on an HTML page.  If you want to have the
     *  page text without any conversions, use getPureText().
     *
     *
     * @param page WikiName of the page to fetch
     * @param version  Version of the page to fetch
     * @return WikiText.
     */
    public String getText( String page, int version )
    {
        String result = getPureText( page, version );

        //
        //  Replace ampersand first, or else all quotes and stuff
        //  get replaced as well with &quot; etc.
        //
        /*
        result = TextUtil.replaceString( result, "&", "&amp;" );
        */

        result = TextUtil.replaceEntities( result );

        return result;
    }

    /**
     *  Returns the un-HTMLized text of the given version of a page in
     *  the given context.  USE THIS METHOD if you don't know what
     *  doing.
     *  <p>
     *  This method also replaces the &lt; and &amp; -characters with
     *  their respective HTML entities, thus making it suitable
     *  for inclusion on an HTML page.  If you want to have the
     *  page text without any conversions, use getPureText().
     *
     *  @since 1.9.15.
     *  @param context The WikiContext
     *  @param page    A page reference (not an attachment)
     *  @return The page content as HTMLized String.
     *  @see   #getPureText(WikiPage)
     */
    public String getText( WikiContext context, WikiPage page )
    {
        return getText( page.getName(), page.getVersion() );
    }


    /**
     *  Returns the pure text of a page, no conversions.  Use this
     *  if you are writing something that depends on the parsing
     *  of the page.  Note that you should always check for page
     *  existence through pageExists() before attempting to fetch
     *  the page contents.
     *
     *  @param page    The name of the page to fetch.
     *  @param version If WikiPageProvider.LATEST_VERSION, then uses the
     *  latest version.
     *  @return The page contents.  If the page does not exist,
     *          returns an empty string.
     */
    // FIXME: Should throw an exception on unknown page/version?
    public String getPureText( String page, int version )
    {
        String result = null;

        try
        {
            result = m_pageManager.getPageText( page, version );
        }
        catch( ProviderException e )
        {
            // FIXME
        }
        finally
        {
            if( result == null )
                result = "";
        }

        return result;
    }

    /**
     *  Returns the pure text of a page, no conversions.  Use this
     *  if you are writing something that depends on the parsing
     *  the page. Note that you should always check for page
     *  existence through pageExists() before attempting to fetch
     *  the page contents.
     *
     *  @param page A handle to the WikiPage
     *  @return String of WikiText.
     *  @since 2.1.13.
     */
    public String getPureText( WikiPage page )
    {
        return getPureText( page.getName(), page.getVersion() );
    }

    /**
     *  Returns the converted HTML of the page using a different
     *  context than the default context.
     *
     *  @param  context A WikiContext in which you wish to render this page in.
     *  @param  page WikiPage reference.
     *  @return HTML-rendered version of the page.
     */

    public String getHTML( WikiContext context, WikiPage page )
    {
        String pagedata = null;

        pagedata = getPureText( page.getName(), page.getVersion() );

        String res = textToHTML( context, pagedata );

        return res;
    }

    /**
     *  Returns the converted HTML of the page.
     *
     *  @param page WikiName of the page to convert.
     *  @return HTML-rendered version of the page.
     */
    public String getHTML( String page )
    {
        return getHTML( page, WikiPageProvider.LATEST_VERSION );
    }

    /**
     *  Returns the converted HTML of the page's specific version.
     *  The version must be a positive integer, otherwise the current
     *  version is returned.
     *
     *  @param pagename WikiName of the page to convert.
     *  @param version Version number to fetch
     *  @return HTML-rendered page text.
     */
    public String getHTML( String pagename, int version )
    {
        WikiPage page = getPage( pagename, version );

        WikiContext context = new WikiContext( this,
                                               page );
        context.setRequestContext( WikiContext.NONE );

        String res = getHTML( context, page );

        return res;
    }

    /**
     *  Converts raw page data to HTML.
     *
     *  @param pagedata Raw page data to convert to HTML
     *  @param context  The WikiContext in which the page is to be rendered
     *  @return Rendered page text
     */
    public String textToHTML( WikiContext context, String pagedata )
    {
        String result = "";

        boolean runFilters = "true".equals(m_variableManager.getValue(context,PROP_RUNFILTERS,"true"));

        StopWatch sw = new StopWatch();
        sw.start();
        try
        {
            if( runFilters )
                pagedata = m_filterManager.doPreTranslateFiltering( context, pagedata );

            result = m_renderingManager.getHTML( context, pagedata );

            if( runFilters )
                result = m_filterManager.doPostTranslateFiltering( context, result );
        }
        catch( FilterException e )
        {
            // FIXME: Don't yet know what to do
        }
        sw.stop();
        if( log.isDebugEnabled() )
            log.debug("Page "+context.getRealPage().getName()+" rendered, took "+sw );

        return result;
    }

    /**
     * Protected method that signals that the WikiEngine will be
     * shut down by the servlet container. It is called by
     * {@link WikiServlet#destroy()}. When this method is called,
     * it fires a "shutdown" WikiEngineEvent to all registered
     * listeners.
     */
    protected void shutdown()
    {
        fireEvent( WikiEngineEvent.SHUTDOWN );
        m_filterManager.destroy();
    }

    /**
     *  Reads a WikiPageful of data from a String and returns all links
     *  internal to this Wiki in a Collection.
     *
     *  @param page The WikiPage to scan
     *  @param pagedata The page contents
     *  @return a Collection of Strings
     */
    public Collection< String > scanWikiLinks( WikiPage page, String pagedata ) {
        LinkCollector localCollector = new LinkCollector();

        textToHTML( new WikiContext( this, page ),
                    pagedata,
                    localCollector,
                    null,
                    localCollector,
                    false,
                    true );

        return localCollector.getLinks();
    }

    /**
     *  Just convert WikiText to HTML.
     *
     *  @param context The WikiContext in which to do the conversion
     *  @param pagedata The data to render
     *  @param localLinkHook Is called whenever a wiki link is found
     *  @param extLinkHook   Is called whenever an external link is found
     *
     *  @return HTML-rendered page text.
     */

    public String textToHTML( WikiContext context,
                              String pagedata,
                              StringTransmutator localLinkHook,
                              StringTransmutator extLinkHook )
    {
        return textToHTML( context, pagedata, localLinkHook, extLinkHook, null, true, false );
    }

    /**
     *  Just convert WikiText to HTML.
     *
     *  @param context The WikiContext in which to do the conversion
     *  @param pagedata The data to render
     *  @param localLinkHook Is called whenever a wiki link is found
     *  @param extLinkHook   Is called whenever an external link is found
     *  @param attLinkHook   Is called whenever an attachment link is found
     *  @return HTML-rendered page text.
     */

    public String textToHTML( WikiContext context,
                              String pagedata,
                              StringTransmutator localLinkHook,
                              StringTransmutator extLinkHook,
                              StringTransmutator attLinkHook )
    {
        return textToHTML( context, pagedata, localLinkHook, extLinkHook, attLinkHook, true, false );
    }

    /**
     *  Helper method for doing the HTML translation.
     *
     *  @param context The WikiContext in which to do the conversion
     *  @param pagedata The data to render
     *  @param localLinkHook Is called whenever a wiki link is found
     *  @param extLinkHook   Is called whenever an external link is found
     *  @param parseAccessRules Parse the access rules if we encounter them
     *  @param justParse Just parses the pagedata, does not actually render.  In this case,
     *                   this methods an empty string.
     *  @return HTML-rendered page text.

     */
    private String textToHTML( WikiContext context,
                               String pagedata,
                               StringTransmutator localLinkHook,
                               StringTransmutator extLinkHook,
                               StringTransmutator attLinkHook,
                               boolean            parseAccessRules,
                               boolean            justParse )
    {
        String result = "";

        if( pagedata == null )
        {
            log.error("NULL pagedata to textToHTML()");
            return null;
        }

        boolean runFilters = "true".equals(m_variableManager.getValue(context,PROP_RUNFILTERS,"true"));

        try
        {
            StopWatch sw = new StopWatch();
            sw.start();

            if( runFilters && m_filterManager != null )
                pagedata = m_filterManager.doPreTranslateFiltering( context, pagedata );

            MarkupParser mp = m_renderingManager.getParser( context, pagedata );
            mp.addLocalLinkHook( localLinkHook );
            mp.addExternalLinkHook( extLinkHook );
            mp.addAttachmentLinkHook( attLinkHook );

            if( !parseAccessRules ) mp.disableAccessRules();

            WikiDocument doc = mp.parse();

            //
            //  In some cases it's better just to parse, not to render
            //
            if( !justParse )
            {
                result = m_renderingManager.getHTML( context, doc );

                if( runFilters && m_filterManager != null )
                    result = m_filterManager.doPostTranslateFiltering( context, result );
            }

            sw.stop();

            if( log.isDebugEnabled() )
                log.debug("Page "+context.getRealPage().getName()+" rendered, took "+sw );
        }
        catch( IOException e )
        {
            log.error( "Failed to scan page data: ", e );
        }
        catch( FilterException e )
        {
            log.error( "page filter threw exception: ", e );
            // FIXME: Don't yet know what to do
        }

        return result;
    }

    /**
     *  Updates all references for the given page.
     *
     *  @param page wiki page for which references should be updated
     */
    public void updateReferences( WikiPage page )
    {
        String pageData = getPureText( page.getName(), WikiProvider.LATEST_VERSION );

        m_referenceManager.updateReferences( page.getName(),
                                             scanWikiLinks( page, pageData ) );
    }


    /**
     *  Writes the WikiText of a page into the page repository. If the <code>jspwiki.properties</code> file contains
     *  the property <code>jspwiki.approver.workflow.saveWikiPage</code> and its value resolves to a valid user,
     *  {@link org.apache.wiki.auth.authorize.Group} or {@link org.apache.wiki.auth.authorize.Role}, this method will
     *  place a {@link org.apache.wiki.workflow.Decision} in the approver's workflow inbox and throw a
     *  {@link org.apache.wiki.workflow.DecisionRequiredException}. If the submitting user is authenticated and the
     *  page save is rejected, a notification will be placed in the user's decision queue.
     *
     *  @since 2.1.28
     *  @param context The current WikiContext
     *  @param text    The Wiki markup for the page.
     *  @throws WikiException if the save operation encounters an error during the save operation. If the page-save
     *  operation requires approval, the exception will be of type {@link org.apache.wiki.workflow.DecisionRequiredException}.
     *  Individual PageFilters, such as the {@link org.apache.wiki.filters.SpamFilter} may also throw a
     *  {@link org.apache.wiki.api.exceptions.RedirectException}.
     */
    public void saveText( WikiContext context, String text ) throws WikiException {
        // Check if page data actually changed; bail if not
        WikiPage page = context.getPage();
        String oldText = getPureText( page );
        String proposedText = TextUtil.normalizePostData( text );
        if ( oldText != null && oldText.equals( proposedText ) ) {
            return;
        }

        // Check if creation of empty pages is allowed; bail if not
        boolean allowEmpty = TextUtil.getBooleanProperty( m_properties, PROP_ALLOW_CREATION_OF_EMPTY_PAGES, false );
        if ( !allowEmpty && !pageExists( page ) && text.trim().equals( "" ) ) {
            return;
        }

        // Create approval workflow for page save; add the diffed, proposed and old text versions as
        // Facts for the approver (if approval is required). If submitter is authenticated, any reject
        // messages will appear in his/her workflow inbox.
        WorkflowBuilder builder = WorkflowBuilder.getBuilder( this );
        Principal submitter = context.getCurrentUser();
        Step prepTask = m_tasksManager.buildPreSaveWikiPageTask( context, proposedText );
        Step completionTask = m_tasksManager.buildSaveWikiPageTask();
        String diffText = m_differenceManager.makeDiff( context, oldText, proposedText );
        boolean isAuthenticated = context.getWikiSession().isAuthenticated();
        Fact[] facts = new Fact[ 5 ];
        facts[ 0 ] = new Fact( WorkflowManager.WF_WP_SAVE_FACT_PAGE_NAME, page.getName() );
        facts[ 1 ] = new Fact( WorkflowManager.WF_WP_SAVE_FACT_DIFF_TEXT, diffText );
        facts[ 2 ] = new Fact( WorkflowManager.WF_WP_SAVE_FACT_PROPOSED_TEXT, proposedText );
        facts[ 3 ] = new Fact( WorkflowManager.WF_WP_SAVE_FACT_CURRENT_TEXT, oldText);
        facts[ 4 ] = new Fact( WorkflowManager.WF_WP_SAVE_FACT_IS_AUTHENTICATED, Boolean.valueOf( isAuthenticated ) );
        String rejectKey = isAuthenticated ? WorkflowManager.WF_WP_SAVE_REJECT_MESSAGE_KEY : null;
        Workflow workflow = builder.buildApprovalWorkflow( submitter,
                                                           WorkflowManager.WF_WP_SAVE_APPROVER,
                                                           prepTask,
                                                           WorkflowManager.WF_WP_SAVE_DECISION_MESSAGE_KEY,
                                                           facts,
                                                           completionTask,
                                                           rejectKey );
        m_workflowMgr.start( workflow );

        // Let callers know if the page-save requires approval
        if ( workflow.getCurrentStep() instanceof Decision ) {
            throw new DecisionRequiredException( "The page contents must be approved before they become active." );
        }
    }

    /**
     *  Returns the number of pages in this Wiki
     *  @return The total number of pages.
     */
    public int getPageCount()
    {
        return m_pageManager.getTotalPageCount();
    }

    /**
     *  Returns the provider name.
     *  @return The full class name of the current page provider.
     */

    public String getCurrentProvider()
    {
        return m_pageManager.getProvider().getClass().getName();
    }

    /**
     *  Return information about current provider.  This method just calls
     *  the corresponding PageManager method, which in turn calls the
     *  provider method.
     *
     *  @return A textual description of the current provider.
     *  @since 1.6.4
     */
    public String getCurrentProviderInfo()
    {
        return m_pageManager.getProviderDescription();
    }

    /**
     *  Returns a Collection of WikiPages, sorted in time
     *  order of last change (i.e. first object is the most
     *  recently changed).  This method also includes attachments.
     *
     *  @return Set of WikiPage objects.
     */

    // FIXME: Should really get a Date object and do proper comparisons. This is terribly wasteful.
    public Set< WikiPage > getRecentChanges()
    {
        try {
            Collection<WikiPage>   pages = m_pageManager.getAllPages();
            Collection<Attachment>  atts = m_attachmentManager.getAllAttachments();

            TreeSet<WikiPage> sortedPages = new TreeSet<>( new PageTimeComparator() );

            sortedPages.addAll( pages );
            sortedPages.addAll( atts );

            return sortedPages;
        } catch( ProviderException e ) {
            log.error( "Unable to fetch all pages: ",e);
            return null;
        }
    }

    /**
     *  Finds the corresponding WikiPage object based on the page name.  It always finds
     *  the latest version of a page.
     *
     *  @param pagereq The name of the page to look for.
     *  @return A WikiPage object, or null, if the page by the name could not be found.
     */

    public WikiPage getPage( String pagereq )
    {
        return getPage( pagereq, WikiProvider.LATEST_VERSION );
    }

    /**
     *  Finds the corresponding WikiPage object base on the page name and version.
     *
     *  @param pagereq The name of the page to look for.
     *  @param version The version number to look for.  May be WikiProvider.LATEST_VERSION,
     *  in which case it will look for the latest version (and this method then becomes
     *  the equivalent of getPage(String).
     *
     *  @return A WikiPage object, or null, if the page could not be found; or if there
     *  is no such version of the page.
     *  @since 1.6.7.
     */

    public WikiPage getPage( String pagereq, int version )
    {
        try
        {
            WikiPage p = m_pageManager.getPageInfo( pagereq, version );

            if( p == null )
            {
                p = m_attachmentManager.getAttachmentInfo( (WikiContext)null, pagereq );
            }

            return p;
        }
        catch( ProviderException e )
        {
            log.error( "Unable to fetch page info",e);
            return null;
        }
    }


    /**
     *  Returns a Collection of WikiPages containing the version history of a page.
     *
     *  @param page Name of the page to look for
     *  @return an ordered List of WikiPages, each corresponding to a different revision of the page.
     */
    public List< ? extends WikiPage > getVersionHistory( String page ) {
        List< ? extends WikiPage > c = null;

        try {
            c = m_pageManager.getVersionHistory( page );

            if( c == null ) {
                c = m_attachmentManager.getVersionHistory( page );
            }
        } catch( ProviderException e ) {
            log.error( "FIXME", e );
        }

        return c;
    }

    /**
     *  Returns a diff of two versions of a page.
     *  <p>
     *  Note that the API was changed in 2.6 to provide a WikiContext object!
     *
     *  @param context The WikiContext of the page you wish to get a diff from
     *  @param version1 Version number of the old page.  If WikiPageProvider.LATEST_VERSION (-1), then uses current page.
     *  @param version2 Version number of the new page.  If WikiPageProvider.LATEST_VERSION (-1), then uses current page.
     *
     *  @return A HTML-ized difference between two pages.  If there is no difference, returns an empty string.
     */
    public String getDiff( WikiContext context, int version1, int version2 )
    {
        String page = context.getPage().getName();
        String page1 = getPureText( page, version1 );
        String page2 = getPureText( page, version2 );

        // Kludge to make diffs for new pages to work this way.

        if( version1 == WikiPageProvider.LATEST_VERSION )
        {
            page1 = "";
        }

        String diff  = m_differenceManager.makeDiff( context, page1, page2 );

        return diff;
    }

    /**
     *  Returns this object's ReferenceManager.
     *  @return The current ReferenceManager instance.
     *
     *  @since 1.6.1
     */
    public ReferenceManager getReferenceManager()
    {
        return m_referenceManager;
    }

    /**
     *  Returns the current rendering manager for this wiki application.
     *
     *  @since 2.3.27
     * @return A RenderingManager object.
     */
    public RenderingManager getRenderingManager()
    {
        return m_renderingManager;
    }

    /**
     *  Returns the current plugin manager.
     *
     *  In 2.10 the PluginManager will be returned instead of the generic
     *
     *  @since 1.6.1
     *  @return The current PluginManager instance
     */
    @SuppressWarnings("unchecked")
    public < T extends PluginManager > T getPluginManager()
    {
        return (T)m_pluginManager;
    }

    /**
     *  Returns the current variable manager.
     *  @return The current VariableManager.
     */

    public VariableManager getVariableManager()
    {
        return m_variableManager;
    }

    /**
     *  Shortcut to getVariableManager().getValue(). However, this method does not
     *  throw a NoSuchVariableException, but returns null in case the variable does
     *  not exist.
     *
     *  @param context WikiContext to look the variable in
     *  @param name Name of the variable to look for
     *  @return Variable value, or null, if there is no such variable.
     *  @since 2.2
     */
    public String getVariable( WikiContext context, String name ) {
        try {
            return m_variableManager.getValue( context, name );
        } catch( NoSuchVariableException e ) {
            return null;
        }
    }

    /**
     *  Throws an exception if a property is not found.
     *
     *  @param props A set of properties to search the key in.
     *  @param key   The key to look for.
     *  @return The required property
     *
     *  @throws NoRequiredPropertyException If the search key is not in the property set.
     *  @since 2.0.26 (on TextUtils, moved To WikiEngine on 2.11.0-M1)
     */
    public String getRequiredProperty( Properties props, String key ) throws NoRequiredPropertyException {
        String value = TextUtil.getStringProperty( props, key, null );
        if( value == null ) {
            throw new NoRequiredPropertyException( "Required property not found", key );
        }
        return value;
    }

    /**
     *  Returns the current PageManager which is responsible for storing
     *  and managing WikiPages.
     *
     *  @return The current PageManager instance.
     */
    public PageManager getPageManager()
    {
        return m_pageManager;
    }

    /**
     * Returns the CommandResolver for this wiki engine.
     * @return the resolver
     */
    public CommandResolver getCommandResolver()
    {
        return m_commandResolver;
    }

    /**
     *  Returns the current AttachmentManager, which is responsible for
     *  storing and managing attachments.
     *
     *  @since 1.9.31.
     *  @return The current AttachmentManager instance
     */
    public AttachmentManager getAttachmentManager()
    {
        return m_attachmentManager;
    }

    /**
     *  Returns the currently used authorization manager.
     *
     *  @return The current AuthorizationManager instance
     */
    public AuthorizationManager getAuthorizationManager()
    {
        return m_authorizationManager;
    }

    /**
     *  Returns the currently used authentication manager.
     *
     *  @return The current AuthenticationManager instance.
     */
    public AuthenticationManager getAuthenticationManager()
    {
        return m_authenticationManager;
    }

    /**
     *  Returns the manager responsible for the filters.
     *  @since 2.1.88
     *  @return The current FilterManager instance
     */
    @SuppressWarnings("unchecked")
    public < T extends FilterManager > T getFilterManager()
    {
        return (T)m_filterManager;
    }

    /**
     *  Returns the manager responsible for searching the Wiki.
     *  @since 2.2.21
     *  @return The current SearchManager instance
     */
    public SearchManager getSearchManager()
    {
        return m_searchManager;
    }

    /**
     *  Returns the progress manager we're using
     *  @return A ProgressManager
     *  @since 2.6
     */
    public ProgressManager getProgressManager()
    {
        return m_progressManager;
    }

    /**
     *  Figure out to which page we are really going to.  Considers
     *  special page names from the jspwiki.properties, and possible aliases.
     *  This method delgates requests to
     *  {@link org.apache.wiki.WikiContext#getRedirectURL()}.
     *  @param context The Wiki Context in which the request is being made.
     *  @return A complete URL to the new page to redirect to
     *  @since 2.2
     */

    public String getRedirectURL( final WikiContext context )
    {
        return context.getRedirectURL();
    }

    /**
     *  Shortcut to create a WikiContext from a supplied HTTP request,
     *  using a default wiki context.
     *  @param request the HTTP request
     *  @param requestContext the default context to use
     *  @return a new WikiContext object.
     *
     *  @see org.apache.wiki.ui.CommandResolver
     *  @see org.apache.wiki.ui.Command
     *  @since 2.1.15.
     */
    // FIXME: We need to have a version which takes a fixed page name as well, or check it elsewhere.
    public WikiContext createContext( final HttpServletRequest request, final String requestContext ) {
        if( !m_isConfigured ) {
            throw new InternalWikiException( "WikiEngine has not been properly started.  It is likely that the configuration is faulty.  Please check all logs for the possible reason." );
        }

        // Build the wiki context
        final Command command = m_commandResolver.findCommand( request, requestContext );
        return new WikiContext( this, request, command );
    }

    /**
     *  Deletes a page or an attachment completely, including all versions.  If the page
     *  does not exist, does nothing.
     *
     * @param pageName The name of the page.
     * @throws ProviderException If something goes wrong.
     */
    public void deletePage( final String pageName ) throws ProviderException {
        final WikiPage p = getPage( pageName );
        if( p != null ) {
            if( p instanceof Attachment ) {
                m_attachmentManager.deleteAttachment( ( Attachment )p );
            } else {
                final Collection< String > refTo = m_referenceManager.findRefersTo( pageName );
                // May return null, if the page does not exist or has not been indexed yet.

                if( m_attachmentManager.hasAttachments( p ) ) {
                    final List< Attachment > attachments = m_attachmentManager.listAttachments( p );
                    for( final Attachment attachment : attachments ) {
                        if( refTo != null ) {
                            refTo.remove( attachment.getName() );
                        }

                        m_attachmentManager.deleteAttachment( attachment );
                    }
                }
                m_pageManager.deletePage( p );
                firePageEvent( WikiPageEvent.PAGE_DELETED, pageName );
            }
        }
    }

    /**
     *  Deletes a specific version of a page or an attachment.
     *
     *  @param page The page object.
     *  @throws ProviderException If something goes wrong.
     */
    public void deleteVersion( final WikiPage page ) throws ProviderException {
        if( page instanceof Attachment ) {
            m_attachmentManager.deleteVersion( (Attachment) page );
        } else {
            m_pageManager.deleteVersion( page );
        }
    }

    /**
     *  Returns the URL of the global RSS file.  May be null, if the
     *  RSS file generation is not operational.
     *  @since 1.7.10
     *  @return The global RSS url
     */
    public String getGlobalRSSURL()
    {
        if( m_rssGenerator != null && m_rssGenerator.isEnabled() )
        {
            return getBaseURL()+ "/" + m_rssFile;
        }

        return null;
    }

    /**
     *  Returns the root path.  The root path is where the WikiEngine is
     *  located in the file system.
     *
     *  @since 2.2
     *  @return A path to where the Wiki is installed in the local filesystem.
     */
    public String getRootPath()
    {
        return m_rootPath;
    }

    /**
     * @since 2.2.6
     * @return the URL constructor
     */
    public URLConstructor getURLConstructor()
    {
        return m_urlConstructor;
    }

    /**
     * Returns the RSSGenerator. If the property <code>jspwiki.rss.generate</code>
     * has not been set to <code>true</code>, this method will return <code>null</code>,
     * <em>and callers should check for this value.</em>
     * @since 2.1.165
     * @return the RSS generator
     */
    public RSSGenerator getRSSGenerator()
    {
        return m_rssGenerator;
    }

    /**
     * Renames, or moves, a wiki page. Can also alter referring wiki
     * links to point to the renamed page.
     *
     * @param context           The context during which this rename takes
     *                          place.
     * @param renameFrom        Name of the source page.
     * @param renameTo          Name of the destination page.
     * @param changeReferrers   If true, then changes any referring links
     *                          to point to the renamed page.
     *
     * @return The name of the page that the source was renamed to.
     *
     * @throws WikiException    In the case of an error, such as the destination
     *                          page already existing.
     */
    public String renamePage( WikiContext context,
                              String renameFrom,
                              String renameTo,
                              boolean changeReferrers)
        throws WikiException
    {
        String newPageName = m_pageRenamer.renamePage(context, renameFrom, renameTo, changeReferrers);
        firePageRenameEvent(renameFrom, newPageName);
        return newPageName;
    }

    /**
     *  Returns the PageRenamer employed by this WikiEngine.
     *  @since 2.5.141
     *  @return The current PageRenamer instance.
     */
    public PageRenamer getPageRenamer()
    {
        return m_pageRenamer;
    }

    /**
     *  Returns the UserManager employed by this WikiEngine.
     *  @since 2.3
     *  @return The current UserManager instance.
     */
    public UserManager getUserManager()
    {
        return m_userManager;
    }

    /**
     *  Returns the TasksManager employed by this WikiEngine.
     *  @return The current TasksManager instance.
     */
    public TasksManager getTasksManager()
    {
        return m_tasksManager;
    }

    /**
     *  Returns the GroupManager employed by this WikiEngine.
     *  @since 2.3
     *  @return The current GroupManager instance
     */
    public GroupManager getGroupManager()
    {
        return m_groupManager;
    }

    /**
     *  Returns the current {@link AdminBeanManager}.
     *
     *  @return The current {@link AdminBeanManager}.
     *  @since  2.6
     */
    public AdminBeanManager getAdminBeanManager() {
        return m_adminBeanManager;
    }

    /**
     *  Returns the AclManager employed by this WikiEngine.
     *  The AclManager is lazily initialized.
     *  <p>
     *  The AclManager implementing class may be set by the
     *  System property {@link #PROP_ACL_MANAGER_IMPL}.
     *  </p>
     *
     * @since 2.3
     * @return The current AclManager.
     */
    public AclManager getAclManager()
    {
        if( m_aclManager == null )
        {
            try
            {
                String s = m_properties.getProperty( PROP_ACL_MANAGER_IMPL, ClassUtil.getMappedClass( AclManager.class.getName() ).getName() );
                m_aclManager = ClassUtil.getMappedObject(s); // TODO: I am not sure whether this is the right call
                m_aclManager.initialize( this, m_properties );
            }
            catch ( ReflectiveOperationException | IllegalArgumentException e )
            {
                log.fatal( "unable to instantiate class for AclManager: " + e.getMessage() );
                throw new InternalWikiException( "Cannot instantiate AclManager, please check logs.", e );
            }
        }
        return m_aclManager;
    }

    /**
     *  Returns the DifferenceManager so that texts can be compared.
     *  @return the difference manager
     */
    public DifferenceManager getDifferenceManager()
    {
        return m_differenceManager;
    }

    /**
     *  Returns the current EditorManager instance.
     *
     *  @return The current EditorManager.
     */
    public EditorManager getEditorManager()
    {
        return m_editorManager;
    }

    /**
     *  Returns the current i18n manager.
     *
     *  @return The current Intertan... Interante... Internatatializ... Whatever.
     */
    public InternationalizationManager getInternationalizationManager()
    {
        return m_internationalizationManager;
    }

    /**
     * Registers a WikiEventListener with this instance.
     * @param listener the event listener
     */
    public final synchronized void addWikiEventListener( WikiEventListener listener )
    {
        WikiEventManager.addWikiEventListener( this, listener );
    }

    /**
     * Un-registers a WikiEventListener with this instance.
     * @param listener the event listener
     */
    public final synchronized void removeWikiEventListener( WikiEventListener listener )
    {
        WikiEventManager.removeWikiEventListener( this, listener );
    }

    /**
     * Fires a WikiEngineEvent to all registered listeners.
     * @param type  the event type
     */
    protected final void fireEvent( int type )
    {
        if ( WikiEventManager.isListening(this) )
        {
            WikiEventManager.fireEvent(this,new WikiEngineEvent(this,type));
        }
    }

    /**
     * Fires a WikiPageEvent to all registered listeners.
     * @param type  the event type
     */
    protected final void firePageEvent( int type, String pageName )
    {
        if ( WikiEventManager.isListening(this) )
        {
            WikiEventManager.fireEvent(this,new WikiPageEvent(this,type,pageName));
        }
    }

    /**
     * Fires a WikiPageRenameEvent to all registered listeners.
     * @param oldName the former page name
     * @param newName the new page name
     */
    protected final void firePageRenameEvent(String oldName, String newName )
    {
        if ( WikiEventManager.isListening(this) )
        {
            WikiEventManager.fireEvent(this,new WikiPageRenameEvent(this,oldName,newName));
        }
    }

    /**
     * Adds an attribute to the engine for the duration of this engine.  The
     * value is not persisted.
     *
     * @since 2.4.91
     * @param key the attribute name
     * @param value the value
     */
    public void setAttribute( String key, Object value )
    {
        m_attributes.put( key, value );
    }

    /**
     *  Gets an attribute from the engine.
     *
     *  @param key the attribute name
     *  @return the value
     */
    public Object getAttribute( String key )
    {
        return m_attributes.get( key );
    }

    /**
     *  Removes an attribute.
     *
     *  @param key The key of the attribute to remove.
     *  @return The previous attribute, if it existed.
     */
    public Object removeAttribute( String key )
    {
        return m_attributes.remove( key );
    }

    /**
     *  Returns a WatchDog for current thread.
     *
     *  @return The current thread WatchDog.
     *  @since 2.4.92
     */
    public WatchDog getCurrentWatchDog()
    {
        return WatchDog.getCurrentWatchDog(this);
    }

}