/*
 * Copyright (c) 2014 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.ovsdb.southbound;

import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.rev150105.OvsdbBridgeAttributes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.rev150105.OvsdbNodeAugmentation;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.rev150105.OvsdbNodeRef;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.topology.Node;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.CheckedFuture;

public class SouthboundUtil {

    private static final Logger LOG = LoggerFactory.getLogger(SouthboundUtil.class);


    public static Optional<OvsdbNodeAugmentation> getManagingNode(DataBroker db,OvsdbBridgeAttributes mn) {
        Preconditions.checkNotNull(mn);
        try {
            OvsdbNodeRef ref = mn.getManagedBy();
            if(ref != null && ref.getValue() != null) {
                ReadOnlyTransaction transaction = db.newReadOnlyTransaction();
                @SuppressWarnings("unchecked") // Note: erasure makes this safe in combination with the typecheck below
                InstanceIdentifier<Node> path = (InstanceIdentifier<Node>) ref.getValue();
                CheckedFuture<Optional<Node>, ReadFailedException> nf = transaction.read(LogicalDatastoreType.OPERATIONAL, path);
                transaction.close();
                Optional<Node> optional = nf.get();
                if(optional != null && optional.isPresent() && optional.get() instanceof Node) {
                    OvsdbNodeAugmentation ovsdbNode = optional.get().getAugmentation(OvsdbNodeAugmentation.class);
                    if(ovsdbNode !=null) {
                        return Optional.of(ovsdbNode);
                    } else {
                        LOG.warn("OvsdbManagedNode {} claims to be managed by {} but that OvsdbNode does not exist",mn,ref.getValue());
                        return Optional.absent();
                    }
                } else {
                    LOG.warn("Mysteriously got back a thing which is *not* a topology Node: {}",optional);
                    return Optional.absent();
                }
            } else {
                LOG.warn("Cannot find client for OvsdbManagedNode without a specified ManagedBy {}",mn);
                return Optional.absent();
            }
         } catch (Exception e) {
             LOG.warn("Failed to get OvsdbNode that manages OvsdbManagedNode {}",mn, e);
             return Optional.absent();
         }
    }
}