/*
 * Copyright (c) 2015 Ericsson India Global Services Pvt Ltd. 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.vpnservice.interfacemgr;

import com.google.common.util.concurrent.FutureCallback;
import org.opendaylight.yang.gen.v1.urn.opendaylight.vpnservice.interfacemgr.rev150331.BaseIds;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.node.NodeConnectorKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.node.NodeConnector;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.NodeKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeConnectorId;
import org.opendaylight.vpnservice.AbstractDataChangeListener;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.DataChangeListener;
import org.opendaylight.yangtools.concepts.ListenerRegistration;
import org.opendaylight.yangtools.yang.binding.DataObject;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier.InstanceIdentifierBuilder;
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.AsyncDataBroker.DataChangeScope;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.Interfaces;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.Interface;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.InterfaceKey;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Optional;

public class InterfaceManager extends AbstractDataChangeListener<Interface> implements AutoCloseable{
    private static final Logger LOG = LoggerFactory.getLogger(InterfaceManager.class);
    private ListenerRegistration<DataChangeListener> listenerRegistration;
    private final DataBroker broker;

    private static final FutureCallback<Void> DEFAULT_CALLBACK =
                    new FutureCallback<Void>() {
                        public void onSuccess(Void result) {
                            LOG.debug("Success in Datastore write operation");
                        }

                        public void onFailure(Throwable error) {
                            LOG.error("Error in Datastore write operation", error);
                        };
                    };

    public InterfaceManager(final DataBroker db) {
        super(Interface.class);
        broker = db;
        registerListener(db);
    }

    @Override
    public void close() throws Exception {
        if (listenerRegistration != null) {
            try {
                listenerRegistration.close();
            } catch (final Exception e) {
                LOG.error("Error when cleaning up DataChangeListener.", e);
            }
            listenerRegistration = null;
        }
        LOG.info("Interface Manager Closed");
    }
    
    private void registerListener(final DataBroker db) {
        try {
            listenerRegistration = db.registerDataChangeListener(LogicalDatastoreType.CONFIGURATION,
                    getWildCardPath(), InterfaceManager.this, DataChangeScope.SUBTREE);
        } catch (final Exception e) {
            LOG.error("InterfaceManager DataChange listener registration fail!", e);
            throw new IllegalStateException("InterfaceManager registration Listener failed.", e);
        }
    }

    @Override
    protected void add(final InstanceIdentifier<Interface> identifier,
            final Interface imgrInterface) {
        LOG.trace("key: " + identifier + ", value=" + imgrInterface );
        addInterface(identifier, imgrInterface);
    }

    private InstanceIdentifier<Interface> buildId(final InstanceIdentifier<Interface> identifier) {
        //TODO Make this generic and move to AbstractDataChangeListener or Utils.
        final InterfaceKey key = identifier.firstKeyOf(Interface.class, InterfaceKey.class);
        String interfaceName = key.getName();
        InstanceIdentifierBuilder<Interface> idBuilder = 
                InstanceIdentifier.builder(Interfaces.class).child(Interface.class, new InterfaceKey(interfaceName));
        InstanceIdentifier<Interface> id = idBuilder.build();
        return id;
    }

    private void addInterface(final InstanceIdentifier<Interface> identifier,
                              final Interface imgrInterface) {
        InstanceIdentifier<Interface> id = buildId(identifier);
        Optional<Interface> port = read(LogicalDatastoreType.CONFIGURATION, id);
        if(port.isPresent()) {
            Interface interf = port.get();
            NodeConnector nodeConn = getNodeConnectorFromInterface(interf);
            updateInterfaceState(identifier, imgrInterface, interf);
            /* TODO:
             *  1. Get interface-id from id manager
             *  2. Update interface-state with following:
             *    admin-status = set to enable value
             *    oper-status = Down [?]
             *    if-index = interface-id
             *    
             * FIXME:
             *  1. Get operational data from node-connector-id?
             *
             */
        }
    }

    private void updateInterfaceState(InstanceIdentifier<Interface> identifier, Interface imgrInterface,
                    Interface interf) {
        // TODO Update InterfaceState
        
    }

    private NodeConnector getNodeConnectorFromInterface(Interface interf) {
        NodeConnectorId ncId = interf.getAugmentation(BaseIds.class).getOfPortId();
        NodeId nodeId = new NodeId(ncId.getValue().substring(0,ncId.getValue().lastIndexOf(":")));
        InstanceIdentifier<NodeConnector> ncIdentifier = InstanceIdentifier.builder(Nodes.class)
                        .child(Node.class, new NodeKey(nodeId))
                        .child(NodeConnector.class, new NodeConnectorKey(ncId)).build();

        Optional<NodeConnector> nc = read(LogicalDatastoreType.OPERATIONAL, ncIdentifier);
        if(nc.isPresent()) {
            NodeConnector nodeConn = nc.get();
            LOG.trace("nodeConnector: {}",nodeConn);
            return nodeConn;
        }
        return null;
    }

    private void delInterface(final InstanceIdentifier<Interface> identifier,
                              final Interface del) {
        InstanceIdentifier<Interface> id = buildId(identifier);
        Optional<Interface> port = read(LogicalDatastoreType.CONFIGURATION, id);
        if(port.isPresent()) {
            Interface interf = port.get();
            // TODO: Update operational data
        }
    }

    private void updateInterface(final InstanceIdentifier<Interface> identifier,
                              final Interface original, final Interface udpate) {
        InstanceIdentifier<Interface> id = buildId(identifier);
        Optional<Interface> port = read(LogicalDatastoreType.CONFIGURATION, id);
        if(port.isPresent()) {
            Interface interf = port.get();
            //TODO: Update operational data
        }
    }

    private <T extends DataObject> Optional<T> read(LogicalDatastoreType datastoreType,
            InstanceIdentifier<T> path) {

        ReadOnlyTransaction tx = broker.newReadOnlyTransaction();

        Optional<T> result = Optional.absent();
        try {
            result = tx.read(datastoreType, path).get();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        return result;
    }

    private InstanceIdentifier<Interface> getWildCardPath() {
        return InstanceIdentifier.create(Interfaces.class).child(Interface.class);
    }

    @Override
    protected void remove(InstanceIdentifier<Interface> identifier, Interface del) {
        LOG.trace("key: " + identifier + ", value=" + del );
        delInterface(identifier, del);
    }

    @Override
    protected void update(InstanceIdentifier<Interface> identifier, Interface original, Interface update) {
        LOG.trace("key: " + identifier + ", original=" + original + ", update=" + update );
        updateInterface(identifier, original, update);
        
    }

}