/*
 * Copyright (c) 2015 Cisco Systems, Inc. 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
 */
package org.opendaylight.openflowplugin.applications.notification.supplier.impl;

import com.google.common.base.Preconditions;
import java.util.Collection;
import org.opendaylight.mdsal.binding.api.DataBroker;
import org.opendaylight.mdsal.binding.api.DataObjectModification;
import org.opendaylight.mdsal.binding.api.DataTreeModification;
import org.opendaylight.mdsal.binding.api.NotificationPublishService;
import org.opendaylight.openflowplugin.applications.notification.supplier.NotificationSupplierForItemRoot;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.binding.Notification;

/**
 * Class is package protected abstract implementation for all Root Items
 * Notification Suppliers.
 *
 * @param <O> - data tree item Object
 * @param <C> - Create notification
 * @param <D> - Delete notification
 */
public abstract class AbstractNotificationSupplierForItemRoot<O extends DataObject, C extends Notification, D extends
        Notification> extends AbstractNotificationSupplierBase<O> implements NotificationSupplierForItemRoot<O, C, D> {

    private final NotificationPublishService notificationProviderService;

    /**
     * Default constructor for all Root Item Notification Supplier implementation.
     *
     * @param notificationProviderService - notification publisher
     * @param db                          - DataBroker for DataTreeChangeListener registration
     * @param clazz                       - Statistics Notification Class
     */
    public AbstractNotificationSupplierForItemRoot(final NotificationPublishService notificationProviderService,
                                                   final DataBroker db, final Class<O> clazz) {
        super(db, clazz);
        this.notificationProviderService = Preconditions.checkNotNull(notificationProviderService);
    }

    @Override
    public void onDataTreeChanged(Collection<DataTreeModification<O>> changes) {

        Preconditions.checkNotNull(changes, "Changes may not be null!");

        for (DataTreeModification<O> change : changes) {
            final InstanceIdentifier<O> key = change.getRootPath().getRootIdentifier();
            final DataObjectModification<O> mod = change.getRootNode();
            switch (mod.getModificationType()) {
                case DELETE:
                    remove(key, mod.getDataBefore());
                    break;
                case SUBTREE_MODIFIED:
                    update(key, mod.getDataBefore(), mod.getDataAfter());
                    break;
                case WRITE:
                    if (mod.getDataBefore() == null) {
                        add(key, mod.getDataAfter());
                    } else {
                        update(key, mod.getDataBefore(), mod.getDataAfter());
                    }
                    break;
                default:
                    throw new IllegalArgumentException("Unhandled modification type " + mod.getModificationType());
            }
        }
    }


    public void add(InstanceIdentifier<O> identifier, O add) {
        putNotification(createNotification(add, identifier));
    }

    public void remove(InstanceIdentifier<O> identifier, O del) {
        putNotification(deleteNotification(identifier.firstIdentifierOf(clazz)));
    }

    public void update(InstanceIdentifier<O> identifier, O before, O after) {
        //EMPTY NO-OP
    }

    private void putNotification(Notification notif) {
        if (notif != null) {
            try {
                notificationProviderService.putNotification(notif);
            } catch (InterruptedException e) {
                throw new IllegalStateException("Interrupted while publishing " + notif, e);
            }
        }
    }
}