/**
 * 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.openflowplugin.openflow.md.core.sal;

import java.math.BigInteger;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.InetSocketAddress;

import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.sal.binding.api.BindingAwareBroker.ProviderContext;
import org.opendaylight.controller.sal.binding.api.NotificationProviderService;
import org.opendaylight.openflowplugin.api.openflow.md.ModelDrivenSwitch;
import org.opendaylight.openflowplugin.api.openflow.md.core.NotificationQueueWrapper;
import org.opendaylight.openflowplugin.openflow.md.core.session.OFSessionUtil;
import org.opendaylight.openflowplugin.api.openflow.md.core.session.SessionContext;
import org.opendaylight.openflowplugin.api.openflow.md.core.session.SessionListener;
import org.opendaylight.openflowplugin.api.openflow.md.core.session.SessionManager;
import org.opendaylight.openflowplugin.api.openflow.md.core.session.SwitchSessionKeyOF;
import org.opendaylight.openflowplugin.openflow.md.lldp.LLDPSpeaker;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpAddress;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Address;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv6Address;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNodeUpdated;
import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNodeUpdatedBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeRef;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeRemoved;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeRemovedBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeUpdated;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeUpdatedBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.NodeKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.protocol.rev130731.GetFeaturesOutput;
import org.opendaylight.yangtools.concepts.CompositeObjectRegistration;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier.InstanceIdentifierBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * session and inventory listener implementation
 */
public class SalRegistrationManager implements SessionListener, AutoCloseable {

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

    private ProviderContext providerContext;

    private NotificationProviderService publishService;

    private DataBroker dataService;

    private SwitchFeaturesUtil swFeaturesUtil;

    public SalRegistrationManager() {
        swFeaturesUtil = SwitchFeaturesUtil.getInstance();
    }

    public NotificationProviderService getPublishService() {
        return publishService;
    }

    public void setPublishService(NotificationProviderService publishService) {
        this.publishService = publishService;
    }

    public ProviderContext getProviderContext() {
        return providerContext;
    }

    public void onSessionInitiated(ProviderContext session) {
        LOG.debug("onSessionInitiated");
        this.providerContext = session;
        this.publishService = session.getSALService(NotificationProviderService.class);
        this.dataService = session.getSALService(DataBroker.class);
        // We register as listener for Session Manager
        getSessionManager().registerSessionListener(this);
        getSessionManager().setNotificationProviderService(publishService);
        getSessionManager().setDataBroker(dataService);
        LOG.debug("SalRegistrationManager initialized");
    }

    @Override
    public void onSessionAdded(SwitchSessionKeyOF sessionKey, SessionContext context) {
        GetFeaturesOutput features = context.getFeatures();
        BigInteger datapathId = features.getDatapathId();
        InstanceIdentifier<Node> identifier = identifierFromDatapathId(datapathId);
        NodeRef nodeRef = new NodeRef(identifier);
        NodeId nodeId = nodeIdFromDatapathId(datapathId);
        ModelDrivenSwitchImpl ofSwitch = new ModelDrivenSwitchImpl(nodeId, identifier, context);
        LLDPSpeaker.getInstance().addModelDrivenSwitch(identifier, ofSwitch);
        CompositeObjectRegistration<ModelDrivenSwitch> registration = ofSwitch.register(providerContext);
        context.setProviderRegistration(registration);

        LOG.debug("ModelDrivenSwitch for {} registered to MD-SAL.", datapathId.toString());

        NotificationQueueWrapper wrappedNotification = new NotificationQueueWrapper(
                nodeAdded(ofSwitch, features, nodeRef), 
                context.getFeatures().getVersion());
        context.getNotificationEnqueuer().enqueueNotification(wrappedNotification);
    }

    @Override
    public void onSessionRemoved(SessionContext context) {
        GetFeaturesOutput features = context.getFeatures();
        BigInteger datapathId = features.getDatapathId();
        InstanceIdentifier<Node> identifier = identifierFromDatapathId(datapathId);
        NodeRef nodeRef = new NodeRef(identifier);
        NodeRemoved nodeRemoved = nodeRemoved(nodeRef);
        LLDPSpeaker.getInstance().removeModelDrivenSwitch(identifier);
        if (context.isValid()) {
            CompositeObjectRegistration<ModelDrivenSwitch> registration = context.getProviderRegistration();
            registration.close();
        }

        LOG.debug("ModelDrivenSwitch for {} unregistered from MD-SAL.", datapathId.toString());
        
        NotificationQueueWrapper wrappedNotification = new NotificationQueueWrapper(
                nodeRemoved, context.getFeatures().getVersion());
        context.getNotificationEnqueuer().enqueueNotification(wrappedNotification);
    }

    private NodeUpdated nodeAdded(ModelDrivenSwitch sw, GetFeaturesOutput features, NodeRef nodeRef) {
        NodeUpdatedBuilder builder = new NodeUpdatedBuilder();
        builder.setId(sw.getNodeId());
        builder.setNodeRef(nodeRef);

        FlowCapableNodeUpdatedBuilder builder2 = new FlowCapableNodeUpdatedBuilder();
        builder2.setIpAddress(getIpAddressOf(sw));
        builder2.setSwitchFeatures(swFeaturesUtil.buildSwitchFeatures(features));
        builder.addAugmentation(FlowCapableNodeUpdated.class, builder2.build());

        return builder.build();
    }

    private IpAddress getIpAddressOf(ModelDrivenSwitch sw) {
        SessionContext sessionContext = sw.getSessionContext();
        if (!sessionContext.isValid()) {
            LOG.warn("IP address of the node {} cannot be obtained. Session is not valid.", sw.getNodeId());
            return null;
        }
        InetSocketAddress remoteAddress = sessionContext.getPrimaryConductor().getConnectionAdapter()
                .getRemoteAddress();
        if (remoteAddress == null) {
            LOG.warn("IP address of the node {} cannot be obtained. No connection with switch.", sw.getNodeId());
            return null;
        }
        return resolveIpAddress(remoteAddress.getAddress());
    }

    private static IpAddress resolveIpAddress(InetAddress address) {
        String hostAddress = address.getHostAddress();
        if (address instanceof Inet4Address) {
            return new IpAddress(new Ipv4Address(hostAddress));
        }
        if (address instanceof Inet6Address) {
            return new IpAddress(new Ipv6Address(hostAddress));
        }
        throw new IllegalArgumentException("Unsupported IP address type!");
    }

    private NodeRemoved nodeRemoved(NodeRef nodeRef) {
        NodeRemovedBuilder builder = new NodeRemovedBuilder();
        builder.setNodeRef(nodeRef);
        return builder.build();
    }

    public static InstanceIdentifier<Node> identifierFromDatapathId(BigInteger datapathId) {
        NodeKey nodeKey = nodeKeyFromDatapathId(datapathId);
        InstanceIdentifierBuilder<Node> builder = InstanceIdentifier.builder(Nodes.class).child(Node.class, nodeKey);
        return builder.toInstance();
    }

    public static NodeKey nodeKeyFromDatapathId(BigInteger datapathId) {
        return new NodeKey(nodeIdFromDatapathId(datapathId));
    }

    public static NodeId nodeIdFromDatapathId(BigInteger datapathId) {
        // FIXME: Convert to textual representation of datapathID
        String current = datapathId.toString();
        return new NodeId("openflow:" + current);
    }

    public SessionManager getSessionManager() {
        return OFSessionUtil.getSessionManager();
    }

    @Override
    public void close() {
        LOG.debug("close");
        dataService = null;
        providerContext = null;
        publishService = null;
    }
}