/*
 * Copyright (c) 2016 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.netvirt.dhcpservice;

import static org.opendaylight.genius.infra.Datastore.CONFIGURATION;

import com.google.common.base.Optional;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.ExecutionException;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.inject.Inject;
import javax.inject.Singleton;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.genius.datastoreutils.AsyncClusteredDataTreeChangeListenerBase;
import org.opendaylight.genius.infra.ManagedNewTransactionRunner;
import org.opendaylight.genius.infra.ManagedNewTransactionRunnerImpl;
import org.opendaylight.genius.mdsalutil.MDSALUtil;
import org.opendaylight.genius.mdsalutil.NwConstants;
import org.opendaylight.infrautils.utils.concurrent.ListenableFutures;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddress;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.InterfacesState;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces.rev140508.interfaces.state.Interface;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.yang.types.rev130715.Uuid;
import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeConnectorId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.Subnetmaps;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.subnetmaps.Subnetmap;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.subnetmaps.SubnetmapBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.subnetmaps.SubnetmapKey;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.ports.rev150712.ports.attributes.ports.Port;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.rev150712.Neutron;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.subnets.rev150712.subnets.attributes.Subnets;
import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.subnets.rev150712.subnets.attributes.subnets.Subnet;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.dhcpservice.config.rev150710.DhcpserviceConfig;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.opendaylight.yangtools.yang.common.Uint64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Singleton
public class DhcpSubnetListener extends AsyncClusteredDataTreeChangeListenerBase<Subnet, DhcpSubnetListener> {
    private static final Logger LOG = LoggerFactory.getLogger(DhcpSubnetListener.class);

    private final DataBroker dataBroker;
    private final ManagedNewTransactionRunner txRunner;
    private final DhcpManager dhcpManager;
    private final DhcpExternalTunnelManager dhcpExternalTunnelManager;
    private final DhcpserviceConfig config;

    @Inject
    public DhcpSubnetListener(final DhcpManager dhcpManager, final DhcpExternalTunnelManager
            dhcpExternalTunnelManager, final DataBroker broker, final DhcpserviceConfig config) {
        super(Subnet.class, DhcpSubnetListener.class);
        this.dhcpManager = dhcpManager;
        this.dataBroker = broker;
        this.txRunner = new ManagedNewTransactionRunnerImpl(broker);
        this.dhcpExternalTunnelManager = dhcpExternalTunnelManager;
        this.config = config;
    }

    @PostConstruct
    public void init() {
        if (config.isControllerDhcpEnabled()) {
            registerListener(LogicalDatastoreType.CONFIGURATION, dataBroker);
        }
    }

    @Override
    protected void add(InstanceIdentifier<Subnet> identifier, Subnet add) {

    }

    @Override
    protected void remove(InstanceIdentifier<Subnet> identifier, Subnet del) {

    }

    @Override
    protected InstanceIdentifier<Subnet> getWildCardPath() {
        return InstanceIdentifier.create(Neutron.class).child(Subnets.class).child(Subnet.class);
    }

    @Override
    protected void update(InstanceIdentifier<Subnet> identifier, Subnet original, Subnet update) {
        LOG.trace("DhcpSubnetListener Update : Original dhcpstatus: {}, Updated dhcpstatus {}", original.isEnableDhcp(),
                update.isEnableDhcp());

        if (!Objects.equals(original.isEnableDhcp(), update.isEnableDhcp())) {
            // write api to get port list
            SubnetmapBuilder subnetmapBuilder = getSubnetMapBuilder(dataBroker, update.getUuid());
            List<Uuid> portList = subnetmapBuilder.getPortList();
            List<Uuid> directPortList = subnetmapBuilder.getDirectPortList();

            if (update.isEnableDhcp()) {
                if (null != portList) {
                    //Install Entries for neutron ports
                    installNeutronPortEntries(portList);
                }
                if (null != directPortList) {
                    //install Entries for direct ports
                    installDirectPortEntries(directPortList);
                }
            } else {
                if (null != portList) {
                    //UnInstall Entries for neutron ports
                    uninstallNeutronPortEntries(portList);
                }
                if (null != directPortList) {
                    //Uninstall Entries for direct ports
                    uninstallDirectPortEntries(directPortList);
                }
            }
        }
    }

    private void installNeutronPortEntries(List<Uuid> portList) {
        LOG.trace("DhcpSubnetListener installNeutronPortEntries : portList: {}", portList);
        for (Uuid portIntf : portList) {
            NodeConnectorId nodeConnectorId = getNodeConnectorIdForPortIntf(portIntf);
            Uint64 dpId = DhcpServiceUtils.getDpnIdFromNodeConnectorId(nodeConnectorId);
            String interfaceName = portIntf.getValue();
            Port port = dhcpManager.getNeutronPort(interfaceName);
            String vmMacAddress = port.getMacAddress().getValue();
            //check whether any changes have happened
            LOG.trace("DhcpSubnetListener installNeutronPortEntries dpId: {} vmMacAddress : {}", dpId, vmMacAddress);
            //Bind the dhcp service when enabled
            ListenableFutures.addErrorLogging(txRunner.callWithNewWriteOnlyTransactionAndSubmit(CONFIGURATION,
                tx -> DhcpServiceUtils.bindDhcpService(interfaceName, NwConstants.DHCP_TABLE, tx)), LOG,
                "Error writing to the datastore");
            //install the entries
            ListenableFutures.addErrorLogging(txRunner.callWithNewReadWriteTransactionAndSubmit(CONFIGURATION,
                tx -> dhcpManager.installDhcpEntries(dpId, vmMacAddress, tx)), LOG,
                "Error writing to the datastore");
        }
    }

    private void uninstallNeutronPortEntries(List<Uuid> portList) {
        LOG.trace("DhcpSubnetListener uninstallNeutronPortEntries : portList: {}", portList);
        for (Uuid portIntf : portList) {
            NodeConnectorId nodeConnectorId = getNodeConnectorIdForPortIntf(portIntf);
            Uint64 dpId = DhcpServiceUtils.getDpnIdFromNodeConnectorId(nodeConnectorId);
            String interfaceName = portIntf.getValue();
            Port port = dhcpManager.getNeutronPort(interfaceName);
            String vmMacAddress = port.getMacAddress().getValue();
            //check whether any changes have happened
            LOG.trace("DhcpSubnetListener uninstallNeutronPortEntries dpId: {} vmMacAddress : {}",
                    dpId, vmMacAddress);
            //Unbind the dhcp service when disabled
            ListenableFutures.addErrorLogging(txRunner.callWithNewWriteOnlyTransactionAndSubmit(CONFIGURATION,
                tx -> DhcpServiceUtils.unbindDhcpService(interfaceName, tx)), LOG,
                "Error writing to the datastore");

            //uninstall the entries
            ListenableFutures.addErrorLogging(txRunner.callWithNewReadWriteTransactionAndSubmit(CONFIGURATION,
                tx -> dhcpManager.unInstallDhcpEntries(dpId, vmMacAddress, tx)), LOG,
                "Error writing to the datastore");
        }
    }

    private void installDirectPortEntries(List<Uuid> directPortList) {
        LOG.trace("DhcpSubnetListener installDirectPortEntries : directPortList: {}", directPortList);
        for (Uuid portIntf : directPortList) {
            Port port = dhcpManager.getNeutronPort(portIntf.getValue());
            String vmMacAddress = port.getMacAddress().getValue();
            Uuid networkId = port.getNetworkId();
            //install the entries on designated dpnId
            List<Uint64> listOfDpns = DhcpServiceUtils.getListOfDpns(dataBroker);
            IpAddress tunnelIp = dhcpExternalTunnelManager.getTunnelIpBasedOnElan(networkId.getValue(), vmMacAddress);
            if (null == tunnelIp) {
                LOG.warn("DhcpSubnetListener installDirectPortEntries tunnelIP is null for  port {}", portIntf);
                continue;
            }
            Uint64 designatedDpnId =
                    dhcpExternalTunnelManager.readDesignatedSwitchesForExternalTunnel(tunnelIp, networkId.getValue());
            LOG.trace("CR-DHCP DhcpSubnetListener update Install DIRECT vmMacAddress: {} tunnelIp: {} "
                    + "designatedDpnId : {} ListOf Dpn: {}",
                    vmMacAddress, tunnelIp, designatedDpnId, listOfDpns);
            dhcpExternalTunnelManager.installDhcpFlowsForVms(tunnelIp, networkId.getValue(), listOfDpns,
                    designatedDpnId, vmMacAddress);

        }
    }

    private void uninstallDirectPortEntries(List<Uuid> directPortList) {
        LOG.trace("DhcpSubnetListener uninstallDirectPortEntries : directPortList: {}", directPortList);
        for (Uuid portIntf : directPortList) {
            Port port = dhcpManager.getNeutronPort(portIntf.getValue());
            String vmMacAddress = port.getMacAddress().getValue();
            Uuid networkId = port.getNetworkId();
            List<Uint64> listOfDpns = DhcpServiceUtils.getListOfDpns(dataBroker);
            LOG.trace("DhcpSubnetListener uninstallDirectPortEntries  vmMacAddress: {} networkId: {} ListOf Dpn: {}",
                    vmMacAddress, networkId, listOfDpns);
            dhcpExternalTunnelManager.unInstallDhcpFlowsForVms(networkId.getValue(), listOfDpns, vmMacAddress);
        }
    }


    private NodeConnectorId getNodeConnectorIdForPortIntf(Uuid interfaceName) {
        LOG.trace("DhcpSubnetListener getNodeConnectorIdForPortIntf  interfaceName: {}", interfaceName);
        NodeConnectorId nodeConnectorId = null;
        InstanceIdentifier.InstanceIdentifierBuilder<Interface> idBuilder =
                InstanceIdentifier.builder(InterfacesState.class)
                        .child(Interface.class,
                                new org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.interfaces
                                        .rev140508.interfaces.state.InterfaceKey(interfaceName.getValue()));

        InstanceIdentifier<Interface> ifStateId = idBuilder.build();

        Optional<Interface> ifStateOptional = MDSALUtil.read(LogicalDatastoreType.OPERATIONAL, ifStateId, dataBroker);
        Interface interfaceState = null;
        if (ifStateOptional.isPresent()) {
            interfaceState = ifStateOptional.get();
        }
        if (interfaceState != null) {
            List<String> ofportIds = interfaceState.getLowerLayerIf();
            nodeConnectorId = new NodeConnectorId(ofportIds.get(0));
            LOG.trace(
                    "DhcpSubnetListener getNodeConnectorIdForPortIntf returned nodeConnectorId {} for the interface {}",
                    nodeConnectorId.getValue(), interfaceName);
        }
        return nodeConnectorId;
    }

    private SubnetmapBuilder getSubnetMapBuilder(DataBroker broker, Uuid subnetId) {
        SubnetmapBuilder builder = null ;
        InstanceIdentifier<Subnetmap> id = InstanceIdentifier.builder(Subnetmaps.class)
                .child(Subnetmap.class, new SubnetmapKey(subnetId)).build();
        ReadOnlyTransaction tx = broker.newReadOnlyTransaction();

        Optional<Subnetmap> sn ;
        try {
            sn = tx.read(LogicalDatastoreType.CONFIGURATION, id).get();
        } catch (InterruptedException | ExecutionException e) {
            throw new RuntimeException(e);
        } finally {
            tx.close();
        }

        if (sn.isPresent()) {
            builder = new SubnetmapBuilder(sn.get());
        } else {
            builder = new SubnetmapBuilder().withKey(new SubnetmapKey(subnetId)).setId(subnetId);
        }
        return builder;
    }

    @Override
    @PreDestroy
    public void close() {
        super.close();
        LOG.info("DhcpSubnetListener Closed");
    }

    @Override
    protected DhcpSubnetListener getDataTreeChangeListener() {
        return DhcpSubnetListener.this;
    }
}