package org.opendaylight.groupbasedpolicy.neutron.mapper.mapping;

import static com.google.common.base.Preconditions.checkNotNull;

import java.util.ArrayList;
import java.util.List;

import org.opendaylight.controller.md.sal.binding.api.DataBroker;
import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
import org.opendaylight.controller.md.sal.binding.api.ReadTransaction;
import org.opendaylight.controller.md.sal.binding.api.ReadWriteTransaction;
import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
import org.opendaylight.groupbasedpolicy.neutron.mapper.util.DataStoreHelper;
import org.opendaylight.groupbasedpolicy.neutron.mapper.util.IidFactory;
import org.opendaylight.groupbasedpolicy.neutron.mapper.util.MappingUtils;
import org.opendaylight.groupbasedpolicy.neutron.mapper.util.MappingUtils.ForwardingCtx;
import org.opendaylight.groupbasedpolicy.neutron.mapper.util.NeutronUtils;
import org.opendaylight.groupbasedpolicy.neutron.mapper.util.Utils;
import org.opendaylight.neutron.spi.INeutronPortCRUD;
import org.opendaylight.neutron.spi.INeutronRouterAware;
import org.opendaylight.neutron.spi.INeutronSubnetCRUD;
import org.opendaylight.neutron.spi.NeutronCRUDInterfaces;
import org.opendaylight.neutron.spi.NeutronPort;
import org.opendaylight.neutron.spi.NeutronRouter;
import org.opendaylight.neutron.spi.NeutronRouter_Interface;
import org.opendaylight.neutron.spi.NeutronSecurityRule;
import org.opendaylight.neutron.spi.NeutronSubnet;
import org.opendaylight.neutron.spi.Neutron_IPs;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpPrefix;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.Description;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.EndpointGroupId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.L2FloodDomainId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.L3ContextId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.Name;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.SubnetId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.TenantId;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.EndpointService;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.UnregisterEndpointInputBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.unregister.endpoint.input.L3;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.unregister.endpoint.input.L3Builder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.neutron.mapper.rev150223.mappings.network.mappings.NetworkMapping;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.EndpointGroup;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.L2BridgeDomain;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.L2BridgeDomainBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.L3Context;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.L3ContextBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.Subnet;
import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.SubnetBuilder;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Optional;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;

public class NeutronRouterAware implements INeutronRouterAware {

    private static final Logger LOG = LoggerFactory.getLogger(NeutronRouterAware.class);
    private static final NeutronRouterAware INSTANCE = new NeutronRouterAware();
    private static DataBroker dataProvider;
    private static EndpointService epService;

    private NeutronRouterAware() {
        if (NeutronRouterAware.INSTANCE != null) {
            throw new IllegalStateException("Already instantiated");
        }
    }

    public static NeutronRouterAware getInstance() {
        return NeutronRouterAware.INSTANCE;
    }

    public static void init(DataBroker dataProvider, EndpointService epService) {
        NeutronRouterAware.dataProvider = checkNotNull(dataProvider);
        NeutronRouterAware.epService = checkNotNull(epService);
    }

    @Override
    public int canCreateRouter(NeutronRouter router) {
        LOG.trace("canCreateRouter - {}", router);
        // nothing to consider
        return StatusCode.OK;
    }

    @Override
    public void neutronRouterCreated(NeutronRouter router) {
        LOG.trace("neutronRouterCreated - {}", router);
        // TODO Li msunal external gateway
    }

    @Override
    public int canUpdateRouter(NeutronRouter delta, NeutronRouter original) {
        LOG.trace("canUpdateRouter - delta: {} original: {}", delta, original);
        // TODO Li msunal external gateway
        return StatusCode.OK;
    }

    @Override
    public void neutronRouterUpdated(NeutronRouter router) {
        LOG.trace("neutronRouterUpdated - {}", router);
        // TODO Li msunal external gateway
    }

    @Override
    public int canDeleteRouter(NeutronRouter router) {
        LOG.trace("canDeleteRouter - {}", router);
        // nothing to consider
        return StatusCode.OK;
    }

    @Override
    public void neutronRouterDeleted(NeutronRouter router) {
        LOG.trace("neutronRouterDeleted - {}", router);
        ReadWriteTransaction rwTx = dataProvider.newReadWriteTransaction();
        TenantId tenantId = new TenantId(Utils.normalizeUuid(router.getTenantID()));
        Optional<EndpointGroup> potentialEpg = DataStoreHelper.removeIfExists(LogicalDatastoreType.CONFIGURATION,
                IidFactory.endpointGroupIid(tenantId, MappingUtils.EPG_ROUTER_ID), rwTx);
        if (!potentialEpg.isPresent()) {
            LOG.warn("Illegal state - Endpoint group {} does not exist.", MappingUtils.EPG_ROUTER_ID.getValue());
            rwTx.cancel();
            return;
        }
        DataStoreHelper.submitToDs(rwTx);
    }

    @Override
    public int canAttachInterface(NeutronRouter router, NeutronRouter_Interface routerInterface) {
        LOG.trace("canAttachInterface - router: {} interface: {}", router, routerInterface);
        try (ReadOnlyTransaction rTx = dataProvider.newReadOnlyTransaction()) {
            L3ContextId l3ContextIdFromRouterId = new L3ContextId(router.getID());
            TenantId tenantId = new TenantId(Utils.normalizeUuid(router.getTenantID()));
            SubnetId subnetId = new SubnetId(routerInterface.getSubnetUUID());
            Optional<Subnet> potentialSubnet = DataStoreHelper.readFromDs(LogicalDatastoreType.CONFIGURATION,
                    IidFactory.subnetIid(tenantId, subnetId), rTx);
            if (!potentialSubnet.isPresent()) {
                LOG.warn("Illegal state - subnet {} does not exist.", subnetId.getValue());
                return StatusCode.NOT_FOUND;
            }
            Subnet subnet = potentialSubnet.get();
            L2FloodDomainId l2FdId = new L2FloodDomainId(subnet.getParent().getValue());
            ForwardingCtx fwCtx = MappingUtils.createForwardingContext(tenantId, l2FdId, rTx);
            if (fwCtx.getL3Context() != null && fwCtx.getL3Context().equals(l3ContextIdFromRouterId)) {
                // TODO Be msunal
                LOG.warn("Illegal state - Neutron mapper does not support multiple router interfaces in the same subnet yet.");
                return StatusCode.FORBIDDEN;
            }
            return StatusCode.OK;
        }
    }

    @Override
    public void neutronRouterInterfaceAttached(NeutronRouter router, NeutronRouter_Interface routerInterface) {
        LOG.trace("neutronRouterInterfaceAttached - router: {} interface: {}", router, routerInterface);
        INeutronPortCRUD portInterface = NeutronCRUDInterfaces.getINeutronPortCRUD(this);
        if (portInterface == null) {
            LOG.warn("Illegal state - No provider for {}", INeutronPortCRUD.class.getName());
            return;
        }

        INeutronSubnetCRUD subnetInterface = NeutronCRUDInterfaces.getINeutronSubnetCRUD(this);
        if (subnetInterface == null) {
            LOG.warn("Illegal state - No provider for {}", INeutronSubnetCRUD.class.getName());
            return;
        }

        ReadWriteTransaction rwTx = dataProvider.newReadWriteTransaction();
        TenantId tenantId = new TenantId(Utils.normalizeUuid(router.getTenantID()));
        L3ContextId l3ContextIdFromRouterId = new L3ContextId(router.getID());
        InstanceIdentifier<L3Context> l3ContextIidForRouterId = IidFactory.l3ContextIid(tenantId,
                l3ContextIdFromRouterId);
        Optional<L3Context> potentialL3ContextForRouter = DataStoreHelper.readFromDs(
                LogicalDatastoreType.CONFIGURATION, l3ContextIidForRouterId, rwTx);
        // add L3 context if missing
        if (!potentialL3ContextForRouter.isPresent()) {
            Name l3ContextName = null;
            if (!Strings.isNullOrEmpty(router.getName())) {
                l3ContextName = new Name(router.getName());
            }
            L3Context l3Context = new L3ContextBuilder().setId(l3ContextIdFromRouterId)
                    .setName(l3ContextName)
                    .setDescription(new Description(MappingUtils.NEUTRON_ROUTER__ + router.getID()))
                    .build();
            rwTx.put(LogicalDatastoreType.CONFIGURATION, l3ContextIidForRouterId, l3Context);
        }

        SubnetId subnetId = new SubnetId(routerInterface.getSubnetUUID());
        Optional<Subnet> potentialSubnet = DataStoreHelper.readFromDs(LogicalDatastoreType.CONFIGURATION,
                IidFactory.subnetIid(tenantId, subnetId), rwTx);
        if (!potentialSubnet.isPresent()) {
            LOG.warn("Illegal state - subnet {} does not exist.", subnetId.getValue());
            rwTx.cancel();
            return;
        }

        // Based on Neutron Northbound - Port representing router interface
        // contains exactly on
        // fixed IP
        NeutronPort routerPort = portInterface.getPort(routerInterface.getPortUUID());
        // TODO: Li alagalah: Add gateways and prefixes instead of
        // VirtualRouterID
        Subnet subnet = new SubnetBuilder(potentialSubnet.get()).setVirtualRouterIp(
                Utils.createIpAddress(routerPort.getFixedIPs().get(0).getIpAddress())).build();
        rwTx.put(LogicalDatastoreType.CONFIGURATION, IidFactory.subnetIid(tenantId, subnetId), subnet);
        if (subnet.getParent() == null) {
            LOG.warn("Illegal state - subnet {} does not have a parent.", subnetId.getValue());
            rwTx.cancel();
            return;
        }

        L2FloodDomainId l2FdId = new L2FloodDomainId(subnet.getParent().getValue());
        ForwardingCtx fwCtx = MappingUtils.createForwardingContext(tenantId, l2FdId, rwTx);
        if (fwCtx.getL2BridgeDomain() == null) {
            LOG.warn("Illegal state - l2-flood-domain {} does not have a parent.", l2FdId.getValue());
            rwTx.cancel();
            return;
        }

        L2BridgeDomain l2BridgeDomain = new L2BridgeDomainBuilder(fwCtx.getL2BridgeDomain()).setParent(
                l3ContextIdFromRouterId).build();
        rwTx.put(LogicalDatastoreType.CONFIGURATION, IidFactory.l2BridgeDomainIid(tenantId, l2BridgeDomain.getId()),
                l2BridgeDomain);

        // create security rules for router
        List<NeutronSecurityRule> routerSecRules = createRouterSecRules(routerPort, null, rwTx);
        if (routerSecRules == null) {
            rwTx.cancel();
            return;
        }
        for (NeutronSecurityRule routerSecRule : routerSecRules) {
            boolean isRouterSecRuleAdded = NeutronSecurityRuleAware.addNeutronSecurityRule(routerSecRule, rwTx);
            if (!isRouterSecRuleAdded) {
                rwTx.cancel();
                return;
            }
        }

        List<L3> l3Eps = new ArrayList<>();
        L3ContextId oldL3ContextId = fwCtx.getL3Context().getId();
        NeutronSubnet neutronSubnet = subnetInterface.getSubnet(subnetId.getValue());
        List<NeutronPort> portsInNeutronSubnet = neutronSubnet.getPortsInSubnet();
        for (NeutronPort port : portsInNeutronSubnet) {
            boolean isPortAdded = NeutronPortAware.addNeutronPort(port, rwTx, epService);
            if (!isPortAdded) {
                rwTx.cancel();
                return;
            }
            // TODO Li msunal this has to be rewrite when OFOverlay renderer
            // will support l3-endpoints.
            Neutron_IPs firstIp = MappingUtils.getFirstIp(port.getFixedIPs());
            if (firstIp != null) {
                l3Eps.add(new L3Builder().setL3Context(oldL3ContextId)
                        .setIpAddress(Utils.createIpAddress(firstIp.getIpAddress()))
                        .build());
            }
        }

        if (!l3Eps.isEmpty()) {
            epService.unregisterEndpoint(new UnregisterEndpointInputBuilder().setL3(l3Eps).build());
        }

        DataStoreHelper.submitToDs(rwTx);
    }

    public static List<NeutronSecurityRule> createRouterSecRules(NeutronPort port, EndpointGroupId consumerEpgId,
            ReadTransaction rTx) {
        TenantId tenantId = new TenantId(Utils.normalizeUuid(port.getTenantID()));
        Neutron_IPs firstIp = MappingUtils.getFirstIp(port.getFixedIPs());
        if (firstIp == null) {
            LOG.warn("Illegal state - Router port does not have an IP address.");
            return null;
        }
        SubnetId routerSubnetId = new SubnetId(firstIp.getSubnetUUID());
        Optional<Subnet> potentialSubnet = DataStoreHelper.readFromDs(LogicalDatastoreType.CONFIGURATION,
                IidFactory.subnetIid(tenantId, routerSubnetId), rTx);
        if (!potentialSubnet.isPresent()) {
            LOG.warn("Illegal state - Subnet {} where is router port does not exist.", routerSubnetId.getValue());
            return null;
        }
        IpPrefix ipSubnet = potentialSubnet.get().getIpPrefix();
        NeutronSecurityRule routerRuleEgress = createRouterSecRule(port.getID(), tenantId, ipSubnet, consumerEpgId,
                true);
        NeutronSecurityRule routerRuleIngress = createRouterSecRule(port.getID(), tenantId, ipSubnet, consumerEpgId,
                false);
        return ImmutableList.of(routerRuleEgress, routerRuleIngress);
    }

    private static NeutronSecurityRule createRouterSecRule(String ruleUuid, TenantId tenantId, IpPrefix ipSubnet,
            EndpointGroupId consumerEpgId, boolean isEgress) {
        NeutronSecurityRule dhcpSecRule = new NeutronSecurityRule();
        dhcpSecRule.setSecurityRuleGroupID(MappingUtils.EPG_ROUTER_ID.getValue());
        dhcpSecRule.setSecurityRuleTenantID(tenantId.getValue());
        dhcpSecRule.setSecurityRuleRemoteIpPrefix(Utils.getStringIpPrefix(ipSubnet));
        if (isEgress) {
            dhcpSecRule.setSecurityRuleUUID(NeutronUtils.EGRESS + "__" + ruleUuid);
            dhcpSecRule.setSecurityRuleDirection(NeutronUtils.EGRESS);
        } else {
            dhcpSecRule.setSecurityRuleUUID(NeutronUtils.INGRESS + "__" + ruleUuid);
            dhcpSecRule.setSecurityRuleDirection(NeutronUtils.INGRESS);
        }
        if (ipSubnet.getIpv4Prefix() != null) {
            dhcpSecRule.setSecurityRuleEthertype(NeutronUtils.IPv4);
        } else {
            dhcpSecRule.setSecurityRuleEthertype(NeutronUtils.IPv6);
        }
        return dhcpSecRule;
    }

    @Override
    public int canDetachInterface(NeutronRouter router, NeutronRouter_Interface routerInterface) {
        LOG.trace("canDetachInterface - router: {} interface: {}", router, routerInterface);
        // nothing to consider
        return StatusCode.OK;
    }

    @Override
    public void neutronRouterInterfaceDetached(NeutronRouter router, NeutronRouter_Interface routerInterface) {
        LOG.trace("neutronRouterInterfaceDetached - router: {} interface: {}", router, routerInterface);
        INeutronSubnetCRUD subnetInterface = NeutronCRUDInterfaces.getINeutronSubnetCRUD(this);
        if (subnetInterface == null) {
            LOG.warn("Illegal state - No provider for {}", INeutronSubnetCRUD.class.getName());
            return;
        }

        ReadWriteTransaction rwTx = dataProvider.newReadWriteTransaction();
        TenantId tenantId = new TenantId(Utils.normalizeUuid(router.getTenantID()));
        L3ContextId l3ContextId = new L3ContextId(router.getID());
        SubnetId subnetId = new SubnetId(routerInterface.getSubnetUUID());
        InstanceIdentifier<L3Context> l3ContextIid = IidFactory.l3ContextIid(tenantId, l3ContextId);
        DataStoreHelper.removeIfExists(LogicalDatastoreType.CONFIGURATION,
                IidFactory.l3ContextIid(tenantId, l3ContextId), rwTx);

        Optional<Subnet> potentialSubnet = DataStoreHelper.readFromDs(LogicalDatastoreType.CONFIGURATION,
                IidFactory.subnetIid(tenantId, subnetId), rwTx);
        if (!potentialSubnet.isPresent()) {
            LOG.warn("Illegal state - subnet {} does not exist.", subnetId.getValue());
            rwTx.cancel();
            return;
        }

        Subnet subnet = new SubnetBuilder(potentialSubnet.get()).setVirtualRouterIp(null).build();
        rwTx.put(LogicalDatastoreType.CONFIGURATION, IidFactory.subnetIid(tenantId, subnetId), subnet);

        L2FloodDomainId l2FdId = new L2FloodDomainId(subnet.getParent().getValue());
        ForwardingCtx fwCtx = MappingUtils.createForwardingContext(tenantId, l2FdId, rwTx);
        if (fwCtx.getL2BridgeDomain() == null) {
            LOG.warn("Illegal state - l2-flood-domain {} does not have a parent.", l2FdId.getValue());
            rwTx.cancel();
            return;
        }

        Optional<NetworkMapping> potentialNetworkMapping = DataStoreHelper.readFromDs(LogicalDatastoreType.OPERATIONAL,
                IidFactory.networkMappingIid(l2FdId), rwTx);
        if (!potentialNetworkMapping.isPresent()) {
            LOG.warn("Illegal state - network-mapping {} does not exist.", l2FdId.getValue());
            rwTx.cancel();
            return;
        }

        L2BridgeDomain l2BridgeDomain = new L2BridgeDomainBuilder(fwCtx.getL2BridgeDomain()).setParent(
                potentialNetworkMapping.get().getL3ContextId()).build();
        rwTx.put(LogicalDatastoreType.CONFIGURATION, IidFactory.l2BridgeDomainIid(tenantId, l2BridgeDomain.getId()),
                l2BridgeDomain);

        NeutronSubnet neutronSubnet = subnetInterface.getSubnet(subnetId.getValue());
        List<NeutronPort> portsInNeutronSubnet = neutronSubnet.getPortsInSubnet();
        for (NeutronPort port : portsInNeutronSubnet) {
            boolean isPortAdded = NeutronPortAware.addNeutronPort(port, rwTx, epService);
            if (!isPortAdded) {
                rwTx.cancel();
                return;
            }
        }
    }

}