/*
 * 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.controller.remote.rpc;


import akka.actor.ActorRef;
import com.google.common.base.Preconditions;
import org.opendaylight.controller.md.sal.common.api.routing.RouteChange;
import org.opendaylight.controller.md.sal.common.api.routing.RouteChangeListener;
import org.opendaylight.controller.remote.rpc.registry.RpcRegistry;
import org.opendaylight.controller.sal.connector.api.RpcRouter;
import org.opendaylight.controller.sal.core.api.RpcRoutingContext;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public class RoutedRpcListener implements RouteChangeListener<RpcRoutingContext, YangInstanceIdentifier>{
  private static final Logger LOG = LoggerFactory.getLogger(RoutedRpcListener.class);
  private final ActorRef rpcRegistry;

  public RoutedRpcListener(ActorRef rpcRegistry) {
    Preconditions.checkNotNull(rpcRegistry, "rpc registry actor should not be null");

    this.rpcRegistry = rpcRegistry;
  }

  @Override
  public void onRouteChange(RouteChange<RpcRoutingContext, YangInstanceIdentifier> routeChange) {
    Map<RpcRoutingContext, Set<YangInstanceIdentifier>> announcements = routeChange.getAnnouncements();
    if(announcements != null && announcements.size() > 0){
      announce(getRouteIdentifiers(announcements));
    }

    Map<RpcRoutingContext, Set<YangInstanceIdentifier>> removals = routeChange.getRemovals();
    if(removals != null && removals.size() > 0 ) {
      remove(getRouteIdentifiers(removals));
    }
  }

  /**
   *
   * @param announcements
   */
  private void announce(Set<RpcRouter.RouteIdentifier<?, ?, ?>> announcements) {
    if(LOG.isDebugEnabled()) {
        LOG.debug("Announcing [{}]", announcements);
    }
    RpcRegistry.Messages.AddOrUpdateRoutes addRpcMsg = new RpcRegistry.Messages.AddOrUpdateRoutes(new ArrayList<>(announcements));
    rpcRegistry.tell(addRpcMsg, ActorRef.noSender());
  }

  /**
   *
   * @param removals
   */
  private void remove(Set<RpcRouter.RouteIdentifier<?, ?, ?>> removals){
    if(LOG.isDebugEnabled()) {
        LOG.debug("Removing [{}]", removals);
    }
    RpcRegistry.Messages.RemoveRoutes removeRpcMsg = new RpcRegistry.Messages.RemoveRoutes(new ArrayList<>(removals));
    rpcRegistry.tell(removeRpcMsg, ActorRef.noSender());
  }

  /**
   *
   * @param changes
   * @return
   */
  private Set<RpcRouter.RouteIdentifier<?, ?, ?>> getRouteIdentifiers(Map<RpcRoutingContext, Set<YangInstanceIdentifier>> changes) {
    RouteIdentifierImpl routeId = null;
    Set<RpcRouter.RouteIdentifier<?, ?, ?>> routeIdSet = new HashSet<>();

    for (RpcRoutingContext context : changes.keySet()){
      for (YangInstanceIdentifier instanceId : changes.get(context)){
        routeId = new RouteIdentifierImpl(null, context.getRpc(), instanceId);
        routeIdSet.add(routeId);
      }
    }
    return routeIdSet;
  }
}