/*
 * 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.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutionException;

import org.opendaylight.bgpcep.topology.TopologyReference;
import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
import org.opendaylight.controller.md.sal.common.api.data.DataChangeEvent;
import org.opendaylight.controller.md.sal.common.api.data.DataModification;
import org.opendaylight.controller.sal.binding.api.data.DataChangeListener;
import org.opendaylight.controller.sal.binding.api.data.DataModificationTransaction;
import org.opendaylight.controller.sal.binding.api.data.DataProviderService;
import org.opendaylight.protocol.bgp.rib.RibReference;
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.bgp.rib.rib.LocRib;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.Tables;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.TablesKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.AddressFamily;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.SubsequentAddressFamily;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.NetworkTopology;
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;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.TopologyBuilder;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.TopologyKey;
import org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.topology.TopologyTypes;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.common.RpcResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.JdkFutureAdapters;

public abstract class AbstractTopologyBuilder<T extends Route> implements AutoCloseable, DataChangeListener, LocRIBListener,
TopologyReference {
	private static final Logger LOG = LoggerFactory.getLogger(AbstractTopologyBuilder.class);
	private final RibReference locRibReference;
	private final InstanceIdentifier<Topology> topology;
	private final DataProviderService dataProvider;
	private final Class<T> idClass;

	protected AbstractTopologyBuilder(final DataProviderService dataProvider, final RibReference locRibReference, final TopologyId topologyId, final TopologyTypes types, final Class<T> idClass) {
		this.dataProvider = Preconditions.checkNotNull(dataProvider);
		this.locRibReference = Preconditions.checkNotNull(locRibReference);
		this.idClass = Preconditions.checkNotNull(idClass);

		final TopologyKey tk = new TopologyKey(Preconditions.checkNotNull(topologyId));
		this.topology = InstanceIdentifier.builder(NetworkTopology.class).child(Topology.class, tk).toInstance();

		LOG.debug("Initiating topology builder from {} at {}", locRibReference, this.topology);

		DataModificationTransaction t = dataProvider.beginTransaction();
		Object o = t.readOperationalData(this.topology);
		Preconditions.checkState(o == null, "Data provider conflict detected on object {}", this.topology);

		t.putOperationalData(this.topology, new TopologyBuilder().setKey(tk).setServerProvided(Boolean.TRUE).setTopologyTypes(types).build());
		Futures.addCallback(JdkFutureAdapters.listenInPoolThread(t.commit()), new FutureCallback<RpcResult<TransactionStatus>>() {
			@Override
			public void onSuccess(final RpcResult<TransactionStatus> result) {
				LOG.trace("Change committed successfully");
			}

			@Override
			public void onFailure(final Throwable t) {
				LOG.error("Failed to initiate topology {} by listener {}", AbstractTopologyBuilder.this.topology, AbstractTopologyBuilder.this, t);
			}
		});
	}

	public final InstanceIdentifier<Tables> tableInstanceIdentifier(final Class<? extends AddressFamily> afi, final Class<? extends SubsequentAddressFamily> safi) {
		return this.locRibReference.getInstanceIdentifier().builder().child(LocRib.class).child(Tables.class, new TablesKey(afi, safi)).toInstance();
	}

	protected abstract void createObject(DataModification<InstanceIdentifier<?>, DataObject> trans, InstanceIdentifier<T> id, T value);

	protected abstract void removeObject(DataModification<InstanceIdentifier<?>, DataObject> trans, InstanceIdentifier<T> id, T value);

	public final DataProviderService getDataProvider() {
		return this.dataProvider;
	}

	@Override
	public final InstanceIdentifier<Topology> getInstanceIdentifier() {
		return this.topology;
	}

	private void addIdentifier(final InstanceIdentifier<?> i, final String set, final Set<InstanceIdentifier<T>> out) {
		final InstanceIdentifier<T> id = i.firstIdentifierOf(this.idClass);
		if (id != null) {
			out.add(id);
		} else {
			LOG.debug("Identifier {} in {} set does not contain listening class {}, ignoring it", i, set, this.idClass);
		}
	}

	@Override
	public final void onLocRIBChange(final DataModification<InstanceIdentifier<?>, DataObject> trans,
			final DataChangeEvent<InstanceIdentifier<?>, DataObject> event) {
		LOG.debug("Received data change {} event with transaction {}", event, trans);

		final Set<InstanceIdentifier<T>> ids = new HashSet<>();
		for (final InstanceIdentifier<?> i : event.getRemovedOperationalData()) {
			addIdentifier(i, "remove", ids);
		}
		for (final InstanceIdentifier<?> i : event.getUpdatedOperationalData().keySet()) {
			addIdentifier(i, "update", ids);
		}
		for (final InstanceIdentifier<?> i : event.getCreatedOperationalData().keySet()) {
			addIdentifier(i, "create", ids);
		}

		final Map<InstanceIdentifier<?>, DataObject> o = event.getOriginalOperationalData();
		final Map<InstanceIdentifier<?>, DataObject> n = event.getUpdatedOperationalData();
		for (final InstanceIdentifier<T> i : ids) {
			final T oldValue = this.idClass.cast(o.get(i));
			final T newValue = this.idClass.cast(n.get(i));

			LOG.debug("Updating object {} value {} -> {}", i, oldValue, newValue);
			if (oldValue != null) {
				removeObject(trans, i, oldValue);
			}
			if (newValue != null) {
				createObject(trans, i, newValue);
			}
		}

		Futures.addCallback(JdkFutureAdapters.listenInPoolThread(trans.commit()), new FutureCallback<RpcResult<TransactionStatus>>() {
			@Override
			public void onSuccess(final RpcResult<TransactionStatus> result) {
				LOG.trace("Change committed successfully");
			}

			@Override
			public void onFailure(final Throwable t) {
				LOG.error("Failed to propagate change by listener {}", AbstractTopologyBuilder.this);
			}
		});
	}

	@Override
	public final void close() throws InterruptedException, ExecutionException {
		LOG.info("Shutting down builder for {}", getInstanceIdentifier());
		final DataModificationTransaction trans = this.dataProvider.beginTransaction();
		trans.removeOperationalData(getInstanceIdentifier());
		trans.commit().get();
	}

	@Override
	public final void onDataChanged(final DataChangeEvent<InstanceIdentifier<?>, DataObject> change) {
		final DataModificationTransaction trans = this.dataProvider.beginTransaction();

		try {
			onLocRIBChange(trans, change);
		} catch (final RuntimeException e) {
			LOG.warn("Data change {} was not completely propagated to listener {}", change, this, e);
			return;
		}

		switch (trans.getStatus()) {
		case COMMITED:
		case SUBMITED:
			break;
		case NEW:
			LOG.warn("Data change {} transaction {} was not committed by builder {}", change, trans, this);
			break;
		case CANCELED:
		case FAILED:
			LOG.error("Data change {} transaction {} failed to commit", change, trans);
			break;
		}
	}
}