/*
 * SimplyHTML, a word processor based on Java, HTML and CSS
 * Copyright (C) 2002 Ulrich Hilger
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU 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.lightdev.app.shtm;

import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.prefs.Preferences;

import javax.swing.Action;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenuItem;

/**
 * Base class for plug-ins of application SimplyHTML.
 *
 * <p>Defines some common methods for reuse in plug-ins. All
 * settings such as dockLocation or activation state
 * of a plug-in are stored persistently in a preferences file
 * with the help of class <code>Prefs</code>. The preferences
 * file is valid for the current user, so each user has own
 * plug-in settings.</p>
 *
 * <p>Menus are constructed with the help of class
 * <code>DynamicResource</code>. This class needs menu definitions
 * accessible in a .properties file as described in the API docs
 * of <code>DynamicResource</code>. I.e., methods of class
 * <code>AbstractPlugin</code> only work as defined herein when
 * accompanied by such .properties file accordingly.</p>
 *
 * @author Ulrich Hilger
 * @author Light Development
 * @author <a href="http://www.lightdev.com">http://www.lightdev.com</a>
 * @author <a href="mailto:info@lightdev.com">info@lightdev.com</a>
 * @author published under the terms and conditions of the
 *      GNU General Public License,
 *      for details see file gpl.txt in the distribution
 *      package of this software
 *
 * 
 *
 * @see com.lightdev.app.shtm.DynamicResource
 */
public abstract class AbstractPlugin implements SHTMLPlugin {
    /**
     * construct an AbstractPlugin
     *
     * <p>Constructor may not have parameters so that
     * java.lang.Class.newInstance can be used on it.</p>
     */
    public AbstractPlugin() {
        prefs = Preferences.userNodeForPackage(getClass());
    }

    /**
     * init the plug-in
     * this is called by the PluginManager directly after instantiating the plug-in
     */
    public void initPlugin(final SHTMLPanelImpl owner) {
        this.owner = owner;
    }

    /**
     * create the plug-in menu
     */
    protected void createPluginMenu() {
        if (pluginMenuId != null) {
            pMenu = owner.dynRes.createMenu(AbstractPlugin.textResources, pluginMenuId);
        }
    }

    /**
     * create the help menu
     */
    protected void createHelpMenu() {
        if (helpMenuId != null) {
            hMenu = owner.dynRes.createMenu(AbstractPlugin.textResources, helpMenuId);
            initHelpMenu();
        }
    }

    public void initHelpMenu() {
    }

    /**
     * create a frame for the component of this plug-in, if it
     * has a JComponent to display.
     */
    protected void createFrame() {
        if (c != null) {
            frame = new JFrame(getGUIName());
            frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
            frame.setSize(300, 400);
            frame.getContentPane().add(c);
        }
        frame.pack();
    }

    /**
     * create, show or hide frame as needed, depending
     * on a given dock location
     *
     * @param location  the dock location of the plug-in, one of
     * DOCK_LOCATION_TOP, DOCK_LOCATION_BOTTOM,
     * DOCK_LOCATION.LEFT, DOCK_LOCATION_RIGHT or DOCK_LOCATION_NONE, if the
     * component shall not dock.
     */
    protected void createFrameAsNeeded(final int location) {
        if (location == SHTMLPlugin.DOCK_LOCATION_NONE) {
            if ((frame == null) && (c != null)) {
                createFrame();
            }
            if (frame != null) {
                frame.setVisible(true);
            }
        }
        else {
            if (frame != null) {
                frame.setVisible(false);
            }
        }
    }

    /* ----------- SimplyHTML plugin interface implementation start --------- */
    /**
     * initialize the plugin
     *
     * @param owner  the owner of this plug-in
     * @param internalName  the internal name this plug-in shall have
     * @param pluginMenuId  the id of the plug-in menu in the TextResources,
     * or null if no plugin-in menu is to be created
     * @param helpMenuId  the id of the help menu for this plug-in in the
     * TextResources, or null if no help menu is to be created
     */
    public void initPlugin(final SHTMLPanel owner, final String internalName, final String pluginMenuId,
                           final String helpMenuId) {
        this.owner = (SHTMLPanelImpl) owner;
        this.internalName = internalName;
        this.pluginMenuId = pluginMenuId;
        this.helpMenuId = helpMenuId;
        try {
            if (SHTMLPanelImpl.pluginManager != null) {
                final ClassLoader plLoader = SHTMLPanelImpl.pluginManager.getPluginLoader();
                if (plLoader != null) {
                    final ResourceBundle resourceBundle = ResourceBundle.getBundle(this.getClass().getName(),
                        Locale.getDefault(), plLoader);
                    textResources = new InternalUiResources(resourceBundle);
                }
                else {
                    textResources = new InternalUiResources(ResourceBundle.getBundle(this
                        .getClass().getName(), Locale.getDefault()));
                }
            }
            else {
                textResources = new InternalUiResources(ResourceBundle.getBundle(this.getClass()
                    .getName(), Locale.getDefault()));
            }
            active = prefs.getBoolean(internalName + PREFSID_PLUGIN_ACTIVE, true);
            dockLocation = prefs.getInt(internalName + PREFSID_PLUGIN_DOCK_LOCATION, SHTMLPlugin.DOCK_LOCATION_LEFT);
            createFrameAsNeeded(dockLocation);
        }
        catch (final MissingResourceException mre) {
            Util.errMsg(null, this.getClass().getName() + ".properties not found", mre);
        }
    }

    /**
     * set the owner of this plug-in
     *
     * @param owner  the main frame of the instance of SimplyHTML creating the plug-in
     */
    public void setOwner(final SHTMLPanelImpl owner) {
        this.owner = owner;
    }

    /**
     * get the owner of this plug-in
     *
     * @return the owner of this plug-in
     */
    public SHTMLPanelImpl getOwner() {
        return owner;
    }

    /**
     * set status of plug-in and persistently store setting in
     * a preferences file
     *
     * @param isActive  indicates whether or not the plug-in shall be activated
     */
    public void setStatus(final boolean isActive) {
        active = isActive;
        prefs.putBoolean(getInternalName() + PREFSID_PLUGIN_ACTIVE, isActive);
        try {
            prefs.flush();
        }
        catch (final Exception e) {
            Util.errMsg(null, e.getMessage(), e);
        }
    }

    /**
     * set the location the component returned by getDockComponent()
     * shall be docked at. Persistently store setting in
     * a preferences file.
     *
     * @param location the dock location, one of DOCK_LOCATION_TOP, DOCK_LOCATION_BOTTOM,
     * DOCK_LOCATION.LEFT, DOCK_LOCATION_RIGHT or DOCK_LOCATION_NONE, if the
     * component shall not dock.
     */
    public void setDockLocation(final int location) {
        dockLocation = location;
        prefs.putInt(getInternalName() + PREFSID_PLUGIN_DOCK_LOCATION, location);
        try {
            prefs.flush();
        }
        catch (final Exception e) {
            Util.errMsg(null, e.getMessage(), e);
        }
        createFrameAsNeeded(location);
    }

    /**
     * get a menu of actions this plug-in provides.
     *
     * <p><code>JMenu</code> is a descendant of <code>JMenuItem</code>
     * so this method may return a single menu item up to a whole
     * structure of submenus in its return value.</p>
     *
     * @return the plug-in menu
     */
    public JMenuItem getPluginMenu() {
        return pMenu;
    }

    /**
     * get a menu item providing documentation about this
     * plug-in.
     *
     * <p><code>JMenu</code> is a descendant of <code>JMenuItem</code>
     * so this method may return a single menu item up to a whole
     * structure of submenus in its return value.</p>
     *
     * @return a menu item with help for this plug-in
     */
    public JMenuItem getHelpMenu() {
        return hMenu;
    }

    /**
     * get the name of the plug-in as it shall appear
     * on a GUI.
     *
     * @return the name of the plug-in
     */
    public String getGUIName() {
        return "AbstractPlugin";
    }

    /**
     * get the name used internally for this plug-in
     *
     * @return the internal name of this plug-in
     */
    public String getInternalName() {
        return internalName;
    }

    /**
     * get the location the component returned by getDockComponent()
     * shall be docked at.
     *
     * @return the dock location, one of DOCK_LOCATION_TOP, DOCK_LOCATION_BOTTOM,
     * DOCK_LOCATION.LEFT, DOCK_LOCATION_RIGHT or DOCK_LOCATION_NONE, if the
     * component shall not dock.
     */
    public int getDockLocation() {
        return dockLocation;
    }

    /**
     * get the component that this plug-in produces, if any
     *
     * @return the component produced by this plug-in, or null if none
     * is produced
     */
    public JComponent getComponent() {
        return c;
    }

    /**
     * get the status of the plug-in
     *
     * @return true, if activated, false if not
     */
    public boolean isActive() {
        return active;
    }

    /**
     * get a string from the resource bundle of the owner of this plug-in
     *
     * @param nm  the name of the string resource to get
     *
     * @return the string with the given name or null, if none is found
     */
    public String getOwnerResString(final String nm) {
        return Util.getResourceString(SHTMLPanelImpl.getUiResources(), nm);
    }

    /**
     * get an action from the resource bundle of the owner of this plug-in
     *
     * @param cmd  the name of the action to get
     *
     * @return the action with the given name or null, if none is found
     */
    public Action getOwnerAction(final String cmd) {
        return owner.getDynRes().getAction(cmd);
    }

    /* ----------- SimplyHTML plugin interface implementation end --------- */
    /* --------------- class fields start --------------------- */
    /** TextResources of plug-in */
    public static UIResources textResources;
    /** constant for active setting in preferences file */
    public static final String PREFSID_PLUGIN_ACTIVE = "Active";
    /** constant for dock location setting in preferences file */
    public static final String PREFSID_PLUGIN_DOCK_LOCATION = "DockLocation";
    /** the internal name of this plug-in */
    protected String internalName;
    /** the id in the ResourceFile for the menu of this plug-in */
    protected String pluginMenuId;
    /** the id in the ResourceFile for the help menu of this plug-in */
    protected String helpMenuId;
    /** the plug-in menu provided by this plug-in */
    protected JMenuItem pMenu = null;
    /** the help menu provided by this plug-in */
    protected JMenuItem hMenu = null;
    /** status of plug-in */
    protected boolean active = true;
    /** current dock location */
    protected int dockLocation = SHTMLPlugin.DOCK_LOCATION_LEFT;
    /** component of this plug-in */
    protected final JComponent c = null;
    /** JFrame for dockLocation=none */
    protected JFrame frame = null;
    /** reference for user preferences for this class */
    protected final Preferences prefs;
    /** the owner of this plug in */
    protected SHTMLPanelImpl owner;
    /* ------------- class fields end ------------------ */
}
