/*
    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.ui;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.wiki.api.core.Context;
import org.apache.wiki.api.core.ContextEnum;
import org.apache.wiki.api.core.Engine;
import org.apache.wiki.api.exceptions.NoSuchVariableException;
import org.apache.wiki.modules.BaseModuleManager;
import org.apache.wiki.modules.WikiModuleInfo;
import org.apache.wiki.preferences.Preferences;
import org.apache.wiki.util.XmlUtil;
import org.apache.wiki.variables.VariableManager;
import org.jdom2.Element;

import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;


/**
 *  Defines an editor manager.  An editor can be added by adding a suitable JSP file under templates/default/editors
 *  If you want your editor to include any scripts or something, you can simply request it by adding the following in your
 *  {@code ini/jspwiki_module.xml}:
 *
 *  <pre>
 *  &lt;modules>
 *   &lt;editor name="myeditor">
 *       &lt;author>Janne Jalkanen&lt;/author>
 *       &lt;script>foo.js&lt;/script>
 *       &lt;stylesheet>foo.css&lt;/stylesheet>
 *       &lt;path>editors/myeditor.jsp&lt;/path>
 *   &lt;/editor>
 *  &lt;/modules>
 *  </pre>
 *
 *  @since 2.4
 */
public class DefaultEditorManager extends BaseModuleManager implements EditorManager {

    private Map< String, WikiEditorInfo > m_editors;

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

    public DefaultEditorManager( final Engine engine ) {
        super( engine );
    }

    /**
     * {@inheritDoc}
     *
     * Initializes the EditorManager.  It also registers any editors it can find.
     */
    @Override
    public void initialize( final Engine engine, final Properties props ) {
        registerEditors();
    }

    /** This method goes through the jspwiki_module.xml files and hunts for editors. Any editors found are put in the registry. */
    private void registerEditors() {
        log.info( "Registering editor modules" );
        m_editors = new HashMap<>();

        // Register all editors which have created a resource containing its properties. Get all resources of all modules
        final List< Element > editors = XmlUtil.parse( PLUGIN_RESOURCE_LOCATION, "/modules/editor" );
        for( final Element pluginEl : editors ) {
            final String name = pluginEl.getAttributeValue( "name" );
            final WikiEditorInfo info = WikiEditorInfo.newInstance( name, pluginEl );

            if( checkCompatibility( info ) ) {
                m_editors.put( name, info );
                log.debug( "Registered editor " + name );
            } else {
                log.info( "Editor '" + name + "' not compatible with this version of JSPWiki." );
            }
        }
    }

    /** {@inheritDoc} */
    @Override
    public String getEditorName( final Context context ) {
        if( context.getRequestContext().equals( ContextEnum.PAGE_PREVIEW.getRequestContext() ) ) {
            return EDITOR_PREVIEW;
        }

        // User has set an editor in preferences
        String editor = Preferences.getPreference( context, PARA_EDITOR );

        /* FIXME: actual default 'editor' property is read by the Preferences class */
        if( editor == null ) {
            // or use the default editor in jspwiki.properties
            try {
                editor = m_engine.getManager( VariableManager.class ).getValue( context, PROP_EDITORTYPE );
            } catch( final NoSuchVariableException e ) {} // This is fine
        }

        if( editor != null ) {
            final String[] editorlist = getEditorList();
            editor = editor.trim();
            for( final String s : editorlist ) {
                if( s.equalsIgnoreCase( editor ) ) {
                    return s;
                }
            }
        }

        return EDITOR_PLAIN;
    }

    /** {@inheritDoc} */
    @Override
    public String[] getEditorList() {
        final String[] editors = new String[ m_editors.size() ];
        final Set< String > keys = m_editors.keySet();

        return keys.toArray( editors );
    }

    /** {@inheritDoc} */
    @Override
    public String getEditorPath( final Context context ) {
        final String editor = getEditorName( context );
        final WikiEditorInfo ed = m_editors.get( editor );
        final String path;
        if( ed != null ) {
            path = ed.getPath();
        } else {
            path = "editors/"+editor+".jsp";
        }

        return path;
    }

    /**  Contains info about an editor. */
    private static final class WikiEditorInfo extends WikiModuleInfo {
        private String m_path;

        static WikiEditorInfo newInstance( final String name, final Element el ) {
            if( name == null || name.isEmpty() ) {
                return null;
            }
            final WikiEditorInfo info = new WikiEditorInfo( name );
            info.initializeFromXML( el );
            return info;
        }

        /** {@inheritDoc} */
        @Override
        protected void initializeFromXML( final Element el ) {
            super.initializeFromXML( el );
            m_path = el.getChildText("path");
        }

        private WikiEditorInfo( final String name ) {
            super( name );
        }

        public String getPath() {
            return m_path;
        }
    }

    /** {@inheritDoc} */
    @Override
    public Collection< WikiModuleInfo > modules() {
        return modules( m_editors.values().iterator() );
    }

    /** {@inheritDoc} */
    @Override
    public WikiEditorInfo getModuleInfo( final String moduleName ) {
        return m_editors.get( moduleName );
    }

}