/*
 * @(#)WidgetRegister.java
 *
 * Copyright 2009 Instituto Superior Tecnico
 * Founding Authors: Paulo Abrantes
 * 
 *      https://fenix-ashes.ist.utl.pt/
 * 
 *   This file is part of the Dashboard Module.
 *
 *   The Dashboard Module is free software: you can
 *   redistribute it and/or modify it under the terms of the GNU Lesser General
 *   Public License as published by the Free Software Foundation, either version 
 *   3 of the License, or (at your option) any later version.
 *
 *   The Dashboard Module 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 Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with the Dashboard Module. If not, see <http://www.gnu.org/licenses/>.
 * 
 */
package module.dashBoard;

import java.util.Comparator;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

import module.dashBoard.domain.DashBoardPanel;
import module.dashBoard.widgets.WidgetController;
import pt.ist.bennu.core.domain.User;
import pt.ist.bennu.core.util.BundleUtil;

/**
 * 
 * @author João Neves
 * @author Paulo Abrantes
 * 
 */
public class WidgetRegister {

    public static WidgetAditionPredicate ALWAYS_ADD_PREDICATE = new WidgetAditionPredicate() {

        @Override
        public boolean canBeAdded(DashBoardPanel panel, User userAdding) {
            return true;
        }

    };

    public static Comparator<Class<? extends WidgetController>> WIDGET_NAME_COMPARATOR =
            new Comparator<Class<? extends WidgetController>>() {

                @Override
                public int compare(Class<? extends WidgetController> o1, Class<? extends WidgetController> o2) {
                    return BundleUtil.getLocalizedNamedFroClass(o1).compareTo(BundleUtil.getLocalizedNamedFroClass(o2));
                }

            };

    private static Set<WidgetControllerHolder> availableWidgets = new HashSet<WidgetControllerHolder>();

    public static Set<Class<? extends WidgetController>> getAvailableWidgets(DashBoardPanel panel, User userAdding) {

        Set<Class<? extends WidgetController>> widgetControllers =
                new TreeSet<Class<? extends WidgetController>>(WIDGET_NAME_COMPARATOR);
        for (WidgetControllerHolder holder : availableWidgets) {
            if (holder.canBeAdded(panel, userAdding)) {
                widgetControllers.add(holder.getController());
            }
        }
        return widgetControllers;
    }

    public static void registerWidget(Class<? extends WidgetController> widgetClass) {
        availableWidgets.add(new WidgetControllerHolder(widgetClass, ALWAYS_ADD_PREDICATE));
    }

    public static void registerWidget(Class<? extends WidgetController> widgetClass, WidgetAditionPredicate predicate) {
        availableWidgets.add(new WidgetControllerHolder(widgetClass, predicate));
    }

    public static interface WidgetAditionPredicate {
        public boolean canBeAdded(DashBoardPanel panel, User userAdding);
    }

    private static class WidgetControllerHolder {
        private final Class<? extends WidgetController> controller;
        private final WidgetAditionPredicate predicate;

        public WidgetControllerHolder(Class<? extends WidgetController> controller, WidgetAditionPredicate predicate) {
            this.controller = controller;
            this.predicate = predicate;
        }

        public boolean canBeAdded(DashBoardPanel panel, User userAdding) {
            return predicate.canBeAdded(panel, userAdding);
        }

        public Class<? extends WidgetController> getController() {
            return controller;
        }

        /*
         * (non-Javadoc) Delegating equals and hashCode to class, since we want
         * the class to be the identity of this object. This way only one
         * instance of each class controller is allowed to be in the
         * availableWidgets set at a time.
         */
        @Override
        public boolean equals(Object obj) {
            return controller.equals(obj);
        }

        @Override
        public int hashCode() {
            return controller.hashCode();
        }
    }
}