/*******************************************************************************
 * Copyright (c) 2007 IBM Corporation and Others
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Daisuke SATO - initial API and implementation
 *******************************************************************************/
package org.eclipse.actf.ai.audio.description;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Locale;

import org.eclipse.actf.ai.audio.description.impl.MetadataManager;
import org.eclipse.actf.ai.audio.description.impl.MetadataProviderImpl;
import org.eclipse.actf.ai.audio.description.views.DescriptionView;
import org.eclipse.actf.ai.navigator.IMediaControl;
import org.eclipse.actf.ai.tts.ITTSEngine;
import org.eclipse.actf.ai.voice.internal.AbstractPreferenceUIPlugin;
import org.eclipse.actf.ai.voice.internal.TTSRegistry;
import org.eclipse.actf.ai.xmlstore.IXMLInfo;
import org.eclipse.actf.ai.xmlstore.IXMLSelector;
import org.eclipse.actf.ai.xmlstore.IXMLStore;
import org.eclipse.actf.ai.xmlstore.IXMLStoreService;
import org.eclipse.actf.ai.xmlstore.XMLStorePlugin;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.osgi.framework.BundleContext;


/**
 * The activator class controls the plug-in life cycle.
 * And this provides information of audio description and TTS function to speak the description. 
 */
public class DescriptionPlugin extends AbstractPreferenceUIPlugin implements IPropertyChangeListener {

    /**
     * The plug-in ID.
     */
    public static final String PLUGIN_ID = "org.eclipse.actf.ai.audio.description";

    /**
     * The preferences ID of TTS engine for audio description.
     */
    public static final String PREF_ENGINE = "AudioDescriptionTTSEngine";

    /*
     * The shared instance.
     */
    private static DescriptionPlugin plugin;

    /*
     * The switch weather enable or disable audio description speaking.
     */
    private boolean enable = false;

    /*
     * The current active audio description manager. 
     * If the target page has no audio description then this should be null.
     */
    private IMetadataProvider activeProvider;

    /*
     * The instance of TTS engine for audio description.
     */
    private ITTSEngine engine;

    /**
     * The constructor
     */
    public DescriptionPlugin() {
        plugin = this;
    }

    /**
     * @param url The URL string which determines audio description files in the XMLStore
     * @see org.eclipse.actf.ai.xmlstore.XMLStorePlugin#getXMLStoreService
     * @return metadata information
     */
    public IMetadataProvider getMetadata(String url) {
        IXMLStoreService service = XMLStorePlugin.getDefault().getXMLStoreService();
        IXMLStore store = service.getRootStore();
        IXMLSelector selector1 = service.getSelectorWithDocElem("puits", "urn:puits");
        IXMLSelector selector2 = service.getSelectorWithIRI(url);
        store = store.specify(selector1);
        store = store.specify(selector2);
        
        ArrayList<IXMLInfo> list = new ArrayList<IXMLInfo>();
        for(Iterator<IXMLInfo> i = store.getInfoIterator(); i.hasNext();){
            list.add(i.next());
        }
        if(list.size() == 0)
            return null;
        MetadataProviderImpl provider = new MetadataProviderImpl(list);
        if (provider != null){
            provider.reload();
            provider.setLocale(Locale.getDefault());
            provider.setAlternative();
        }
        return provider;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.plugin.AbstractUIPlugin#start(org.osgi.framework.BundleContext)
     */
    @Override
    public void start(BundleContext context) throws Exception {
        super.start(context);
        initialize();
    }

    /**
     * The initializer of the plug-in.
     */
    private void initialize() {
        engine = newTTSEngine();
        DescriptionPlugin.getDefault().addPropertyChangeListener(this);
    }

    
    /**
     * @return TTS engine using the preference value
     * @see #engine
     */
    private ITTSEngine newTTSEngine() {
        ITTSEngine engine;
        String e = DescriptionPlugin.getDefault().getPreferenceStore().getString(DescriptionPlugin.PREF_ENGINE);
        
        // TODO  
        if (e.equals("org.eclipse.actf.ai.screenreader.jaws"))
            return null;
        engine = TTSRegistry.createTTSEngine(e);
        if(engine != null)
            engine.setSpeed(50);
        return engine;
    }

    /* (non-Javadoc)
     * @see org.eclipse.actf.ai.voice.internal.AbstractPreferenceUIPlugin#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
     */
    @Override
    public void propertyChange(PropertyChangeEvent event) {
        if (DescriptionPlugin.PREF_ENGINE.equals(event.getProperty())) {
            if (null != engine) {
                engine.stop();
                engine.dispose();
                engine = newTTSEngine();
            }
        }
    }

    /**
     * @return instance of TTS engine.
     */
    public ITTSEngine getTTSEngine() {
        return engine;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.plugin.AbstractUIPlugin#stop(org.osgi.framework.BundleContext)
     */
    @Override
    public void stop(BundleContext context) throws Exception {
        plugin = null;
        super.stop(context);
    }

    /**
     * Returns the shared instance
     * 
     * @return the shared instance
     */
    public static DescriptionPlugin getDefault() {
        return plugin;
    }

    
    /**
     * The instance of the view.
     */
    private DescriptionView view;

    /**
     * @param view Keep the instance of the view to share the instance.
     */
    public void setDescriptionView(DescriptionView view) {
        this.view = view;
    }

    /**
     * @return shared instance of the view.
     */
    public DescriptionView getDescriptionView() {
        return view;
    }

    /**
     * @param flag The switch to enable/disable
     * @return The status of the audio description plug-in
     * @see IMediaControl.STATUS_NOT_AVAILABLE
     * @see IMediaControl.STATUS_ON
     * @see IMediaControl.STATUS_OFF
     */
    public int setEnable(boolean flag) {
        if(!isAvailable()){
            enable = false;
            return IMediaControl.STATUS_NOT_AVAILABLE;
        }

        enable = flag;
        getDescriptionView().setEnable(enable);
        if (enable) {
            return IMediaControl.STATUS_ON;
        } else {
            return IMediaControl.STATUS_OFF;
        }
    }

    /**
     * @return The availability of the plug-in. If there is no active metadata manager then this returns false.
     * @see #setActiveMetadataProvider(MetadataManager)
     */
    public boolean isAvailable() {
        if (activeProvider == null)
            return false;
        return activeProvider.hasMetadata();
    }
    
    
    /**
     * @return The availability of TTS engine.
     */
    public boolean canSpeak() {
        return engine != null;
    }

    /**
     * @param str The string to be spoken.
     */
    public void speak(String str) {
        if(engine != null)
            engine.speak(str, ITTSEngine.TTSFLAG_FLUSH, -1);
    }

    /**
     * Toggle the enable and disable of the plug-in.
     * @return The status of the plug-in.
     * @see #setEnable(boolean)
     */
    public int toggleEnable() {
        return setEnable(!getEnable());
    }

    /**
     * @return The value of enable/disable
     */
    public boolean getEnable() {
        return enable;
    }

    /**
     * @param manager The active metadata provider to know the metadata avilability
     */
    public void setActiveMetadataProvider(IMetadataProvider provider) {
        this.activeProvider = provider;
    }
    
    /**
     * @param key The key for the resource string.
     * @return The resource string.
     */
    public static String getString(String key) {
        return Platform.getResourceString(getDefault().getBundle(), key);
    }
}