/**
 * <copyright>
 * 
 * Copyright (c) 2009-2010 Thales Corporate Services S.A.S.
 * 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:
 * Thales Corporate Services S.A.S - initial API and implementation
 * 
 * </copyright>
 */

package org.eclipse.egf.pattern.ui.java.editor;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.core.runtime.preferences.IScopeContext;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.widgets.Display;
import org.osgi.service.prefs.BackingStoreException;

/**
 * @author Yahong Song - Soyatec
 * 
 */
class EclipsePreferencesAdapter implements IPreferenceStore {

    /**
     * Preference change listener. Listens for events preferences fires a
     * {@link org.eclipse.jface.util.PropertyChangeEvent} on this adapter with
     * arguments from the received event.
     */
    private class PreferenceChangeListener implements IEclipsePreferences.IPreferenceChangeListener {

        /**
         * {@inheritDoc}
         */
        public void preferenceChange(final IEclipsePreferences.PreferenceChangeEvent event) {
            if (Display.getCurrent() == null) {
                Display.getDefault().asyncExec(new Runnable() {
                    public void run() {
                        firePropertyChangeEvent(event.getKey(), event.getOldValue(), event.getNewValue());
                    }
                });
            } else {
                firePropertyChangeEvent(event.getKey(), event.getOldValue(), event.getNewValue());
            }
        }
    }

    /** Listeners on on this adapter */
    private ListenerList fListeners = new ListenerList(ListenerList.IDENTITY);

    /** Listener on the node */
    private IEclipsePreferences.IPreferenceChangeListener fListener = new PreferenceChangeListener();

    /** wrapped node */
    private final IScopeContext fContext;
    private final String fQualifier;

    /**
     * Initialize with the node to wrap
     * 
     * @param context
     *            The context to access
     */
    public EclipsePreferencesAdapter(IScopeContext context, String qualifier) {
        fContext = context;
        fQualifier = qualifier;
    }

    private IEclipsePreferences getNode() {
        return fContext.getNode(fQualifier);
    }

    /**
     * {@inheritDoc}
     */
    public void addPropertyChangeListener(IPropertyChangeListener listener) {
        if (fListeners.size() == 0)
            getNode().addPreferenceChangeListener(fListener);
        fListeners.add(listener);
    }

    /**
     * {@inheritDoc}
     */
    public void removePropertyChangeListener(IPropertyChangeListener listener) {
        fListeners.remove(listener);
        if (fListeners.size() == 0) {
            getNode().removePreferenceChangeListener(fListener);
        }
    }

    /**
     * {@inheritDoc}
     */
    public boolean contains(String name) {
        return getNode().get(name, null) != null;
    }

    /**
     * {@inheritDoc}
     */
    public void firePropertyChangeEvent(String name, Object oldValue, Object newValue) {
        PropertyChangeEvent event = new PropertyChangeEvent(this, name, oldValue, newValue);
        Object[] listeners = fListeners.getListeners();
        for (int i = 0; i < listeners.length; i++)
            ((IPropertyChangeListener) listeners[i]).propertyChange(event);
    }

    /**
     * {@inheritDoc}
     */
    public boolean getBoolean(String name) {
        return getNode().getBoolean(name, BOOLEAN_DEFAULT_DEFAULT);
    }

    /**
     * {@inheritDoc}
     */
    public boolean getDefaultBoolean(String name) {
        return BOOLEAN_DEFAULT_DEFAULT;
    }

    /**
     * {@inheritDoc}
     */
    public double getDefaultDouble(String name) {
        return DOUBLE_DEFAULT_DEFAULT;
    }

    /**
     * {@inheritDoc}
     */
    public float getDefaultFloat(String name) {
        return FLOAT_DEFAULT_DEFAULT;
    }

    /**
     * {@inheritDoc}
     */
    public int getDefaultInt(String name) {
        return INT_DEFAULT_DEFAULT;
    }

    /**
     * {@inheritDoc}
     */
    public long getDefaultLong(String name) {
        return LONG_DEFAULT_DEFAULT;
    }

    /**
     * {@inheritDoc}
     */
    public String getDefaultString(String name) {
        return STRING_DEFAULT_DEFAULT;
    }

    /**
     * {@inheritDoc}
     */
    public double getDouble(String name) {
        return getNode().getDouble(name, DOUBLE_DEFAULT_DEFAULT);
    }

    /**
     * {@inheritDoc}
     */
    public float getFloat(String name) {
        return getNode().getFloat(name, FLOAT_DEFAULT_DEFAULT);
    }

    /**
     * {@inheritDoc}
     */
    public int getInt(String name) {
        return getNode().getInt(name, INT_DEFAULT_DEFAULT);
    }

    /**
     * {@inheritDoc}
     */
    public long getLong(String name) {
        return getNode().getLong(name, LONG_DEFAULT_DEFAULT);
    }

    /**
     * {@inheritDoc}
     */
    public String getString(String name) {
        return getNode().get(name, STRING_DEFAULT_DEFAULT);
    }

    /**
     * {@inheritDoc}
     */
    public boolean isDefault(String name) {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    public boolean needsSaving() {
        try {
            return getNode().keys().length > 0;
        } catch (BackingStoreException e) {
            // ignore
        }
        return true;
    }

    /**
     * {@inheritDoc}
     */
    public void putValue(String name, String value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setDefault(String name, double value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setDefault(String name, float value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setDefault(String name, int value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setDefault(String name, long value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setDefault(String name, String defaultObject) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setDefault(String name, boolean value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setToDefault(String name) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setValue(String name, double value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setValue(String name, float value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setValue(String name, int value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setValue(String name, long value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setValue(String name, String value) {
        throw new UnsupportedOperationException();
    }

    /**
     * {@inheritDoc}
     */
    public void setValue(String name, boolean value) {
        throw new UnsupportedOperationException();
    }

}