/**
 * Copyright (c) 2005-2011 by Appcelerator, Inc. All Rights Reserved.
 * Licensed under the terms of the Eclipse Public License (EPL).
 * Please see the license.txt included with this distribution for details.
 * Any modifications to this file must keep this entire header intact.
 */
package org.python.pydev.navigator.filters;

import java.lang.ref.WeakReference;
import java.util.List;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.jface.viewers.Viewer;
import org.python.pydev.core.docutils.StringUtils;
import org.python.pydev.navigator.actions.PySetupCustomFilters;
import org.python.pydev.navigator.properties.StringMatcherSimple;
import org.python.pydev.plugin.PydevPlugin;

/**
 * Will filter out any resource that matches a filter that the user specified.
 *
 * @author Fabio
 */
public class CustomFilters extends AbstractFilter {

    /**
     * This property listener will just store a weak reference to the custom filter that actually needs the values
     * (so that it is not kept alive by registering itself in the preferences).
     *
     * @author Fabio
     */
    private static class PropertyListener implements IPropertyChangeListener {

        private WeakReference<CustomFilters> weakCustomFilter;

        public PropertyListener(CustomFilters customFilter) {
            weakCustomFilter = new WeakReference<CustomFilters>(customFilter);
            IPreferenceStore prefs = PydevPlugin.getDefault().getPreferenceStore();
            prefs.addPropertyChangeListener(this);
        }

        public void propertyChange(PropertyChangeEvent event) {
            CustomFilters customFilters = weakCustomFilter.get();
            if (customFilters == null) {
                IPreferenceStore prefs = PydevPlugin.getDefault().getPreferenceStore();
                prefs.removePropertyChangeListener(this);
            } else {
                String property = event.getProperty();
                if (property.equals(PySetupCustomFilters.CUSTOM_FILTERS_PREFERENCE_NAME)) {
                    customFilters.update((String) event.getNewValue());
                }
            }
        }

    }

    /**
     * Update the initial filters and register a listener for it.
     */
    public CustomFilters() {
        IPreferenceStore prefs = PydevPlugin.getDefault().getPreferenceStore();
        update(prefs.getString(PySetupCustomFilters.CUSTOM_FILTERS_PREFERENCE_NAME));
        new PropertyListener(this); //this is the listener that will update this filter
    }

    /**
     * Filter things out based on the filter.
     */
    @Override
    public boolean select(Viewer viewer, Object parentElement, Object element) {
        String name = getName(element);
        return filterName(name);
    }

    protected boolean filterName(String name) {
        if (name == null) {
            return true;
        }
        StringMatcherSimple[] temp = filters;
        for (int i = 0; i < temp.length; i++) {
            if (temp[i].match(name)) {
                return false;
            }
        }
        return true;
    }

    /**
     * Holds the filters available.
     */
    private StringMatcherSimple[] filters;

    public void update(String customFilters) {
        List<String> splittedCustomFilters = StringUtils.splitAndRemoveEmptyTrimmed(customFilters, ',');
        StringMatcherSimple[] temp = new StringMatcherSimple[splittedCustomFilters.size()];
        for (int i = 0; i < temp.length; i++) {
            temp[i] = new StringMatcherSimple(splittedCustomFilters.get(i).trim());
        }
        filters = temp;
    }

}