/*
 * Copyright (c) 2013 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.bgpcep.bgp.topology.provider;

import java.util.ArrayList;

import org.opendaylight.controller.md.sal.common.api.data.DataModification;
import org.opendaylight.controller.sal.binding.api.data.DataProviderService;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpPrefix;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.Route;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.route.Attributes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.CNextHop;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.Ipv4NextHopCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.Ipv6NextHopCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.ipv4.next.hop._case.Ipv4NextHop;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.next.hop.c.next.hop.ipv6.next.hop._case.Ipv6NextHop;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.NodeId;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.TopologyId;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.topology.Node;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.topology.NodeKey;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.Node1;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.Node1Builder;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.igp.node.attributes.IgpNodeAttributesBuilder;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.igp.node.attributes.igp.node.attributes.Prefix;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.igp.node.attributes.igp.node.attributes.PrefixBuilder;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.igp.node.attributes.igp.node.attributes.PrefixKey;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 */
abstract class AbstractReachabilityTopologyBuilder<T extends Route> extends AbstractTopologyBuilder<T> {
	private static final Logger LOG = LoggerFactory.getLogger(AbstractReachabilityTopologyBuilder.class);

	protected AbstractReachabilityTopologyBuilder(final DataProviderService dataProvider, final TopologyId topologyId,
			final Class<T> idClass) {
		super(dataProvider, topologyId, idClass);
	}

	private NodeId advertizingNode(final Attributes attrs) {
		final CNextHop nh = attrs.getCNextHop();
		if (nh instanceof Ipv4NextHopCase) {
			final Ipv4NextHop ipv4 = ((Ipv4NextHopCase) nh).getIpv4NextHop();

			return new NodeId(ipv4.getGlobal().getValue());
		} else if (nh instanceof Ipv6NextHopCase) {
			final Ipv6NextHop ipv6 = ((Ipv6NextHopCase) nh).getIpv6NextHop();

			return new NodeId(ipv6.getGlobal().getValue());
		} else {
			LOG.warn("Unhandled next hop class {}", nh.getImplementedInterface());
			return null;
		}
	}

	private InstanceIdentifier<Node1> nodeInstanceId(final NodeId ni) {
		return InstanceIdentifier.builder(getInstanceIdentifier()).child(Node.class, new NodeKey(ni)).augmentation(Node1.class).toInstance();
	}

	private InstanceIdentifier<Node1> ensureNodePresent(final DataModification<InstanceIdentifier<?>, DataObject> trans, final NodeId ni) {
		final InstanceIdentifier<Node1> nii = nodeInstanceId(ni);

		if (trans.readOperationalData(nii) == null) {
			LOG.debug("Create a new node at {}", nii);
			trans.putOperationalData(
					nii,
					new Node1Builder().setIgpNodeAttributes(new IgpNodeAttributesBuilder().setPrefix(new ArrayList<Prefix>()).build()).build());
		}

		return nii;
	}

	private void removeEmptyNode(final DataModification<InstanceIdentifier<?>, DataObject> trans, final InstanceIdentifier<Node1> nii) {
		final Node1 node = (Node1) trans.readOperationalData(nii);
		if (node != null && node.getIgpNodeAttributes().getPrefix().isEmpty()) {
			trans.removeOperationalData(nii);
		}
	}

	protected abstract Attributes getAttributes(final T value);

	protected abstract IpPrefix getPrefix(final T value);

	@Override
	protected final void createObject(final DataModification<InstanceIdentifier<?>, DataObject> trans, final InstanceIdentifier<T> id,
			final T value) {
		final NodeId ni = advertizingNode(getAttributes(value));
		final InstanceIdentifier<Node1> nii = ensureNodePresent(trans, ni);

		final IpPrefix prefix = getPrefix(value);
		final PrefixKey pk = new PrefixKey(prefix);

		trans.putOperationalData(
				InstanceIdentifier.builder(nii).child(
						org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.igp.node.attributes.IgpNodeAttributes.class).child(
						Prefix.class, pk).toInstance(), new PrefixBuilder().setKey(pk).setPrefix(prefix).build());
	}

	@Override
	protected final void removeObject(final DataModification<InstanceIdentifier<?>, DataObject> trans, final InstanceIdentifier<T> id,
			final T value) {
		final NodeId ni = advertizingNode(getAttributes(value));
		final InstanceIdentifier<Node1> nii = nodeInstanceId(ni);

		final IpPrefix prefix = getPrefix(value);
		final PrefixKey pk = new PrefixKey(prefix);

		trans.removeOperationalData(InstanceIdentifier.builder(nii).child(
				org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.nt.l3.unicast.igp.topology.rev131021.igp.node.attributes.IgpNodeAttributes.class).child(
				Prefix.class, pk).toInstance());

		removeEmptyNode(trans, nii);
	}

}