/*
 * Copyright © 2016 AT&T 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.transportpce.pce.constraints;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.stream.Collectors;
import org.opendaylight.mdsal.common.api.LogicalDatastoreType;
import org.opendaylight.transportpce.common.Timeouts;
import org.opendaylight.transportpce.common.network.NetworkTransactionService;
import org.opendaylight.yang.gen.v1.http.org.opendaylight.transportpce.pce.rev190624.PathComputationRequestInput;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.pathdescription.rev171017.PathDescription;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.pathdescription.rev171017.path.description.atoz.direction.AToZ;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.pathdescription.rev171017.pce.resource.resource.resource.Link;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.pathdescription.rev171017.pce.resource.resource.resource.Node;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.RoutingConstraintsSp.PceMetric;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.CoRoutingOrGeneral;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.CoRouting;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.General;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.general.Diversity;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.general.Exclude;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.general.Include;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.general.Latency;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.constraints.sp.co.routing.or.general.general.include_.OrderedHops;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.diversity.existing.service.contraints.sp.ExistingServiceApplicability;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.ordered.constraints.sp.hop.type.HopType;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.routing.constraints.sp.HardConstraints;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints.rev171017.routing.constraints.sp.SoftConstraints;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.servicepath.rev171017.ServicePathList;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.servicepath.rev171017.service.path.list.ServicePaths;
import org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.servicepath.rev171017.service.path.list.ServicePathsKey;
import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class PceConstraintsCalc {
    /* Logging. */
    private static final Logger LOG = LoggerFactory.getLogger(PceConstraintsCalc.class);

    private PceConstraints pceHardConstraints = new PceConstraints();
    private PceConstraints pceSoftConstraints = new PceConstraints();
    private PceMetric pceMetrics = PceMetric.HopCount;
    private NetworkTransactionService networkTransactionService;

    public PceConstraintsCalc(PathComputationRequestInput input, NetworkTransactionService networkTransactionService) {
        LOG.debug("In PceconstraintsCalc start");

        pceMetrics = input.getPceMetric();

        this.networkTransactionService = networkTransactionService;

        // TODO. for now metrics are set into hard structure
        LOG.info("In PceConstraintsCalc: read PceMetric {}", pceMetrics.toString());
        pceHardConstraints.setPceMetrics(pceMetrics);

        calcHardconstraints(input);
        calcSoftconstraints(input);
    }

    private void calcHardconstraints(PathComputationRequestInput input) {
        HardConstraints servicePathHardConstraints = input.getHardConstraints();
        if (servicePathHardConstraints == null) {
            LOG.info("In calcHardconstraints: no hard constraints.");
            return;
        }

        CoRoutingOrGeneral coRoutingOrGeneral = servicePathHardConstraints.getCoRoutingOrGeneral();
        readconstraints(coRoutingOrGeneral, pceHardConstraints);

    }

    private void calcSoftconstraints(PathComputationRequestInput input) {
        SoftConstraints servicePathSoftConstraints = input.getSoftConstraints();
        if (servicePathSoftConstraints == null) {
            LOG.info("In calcSoftconstraints: no soft constraints.");
            return;
        }

        CoRoutingOrGeneral coRoutingOrGeneral = servicePathSoftConstraints.getCoRoutingOrGeneral();
        readconstraints(coRoutingOrGeneral, pceSoftConstraints);

    }

    private void readconstraints(CoRoutingOrGeneral coRoutingOrGeneral, PceConstraints constraints) {
        LOG.debug("In readconstraints start");

        if (coRoutingOrGeneral == null) {
            LOG.info("In readHardconstraints: no CoRoutingOrGeneral constraints.");
            return;
        }

        General tmpGeneral = null;
        CoRouting tmpCoRouting = null;

        if (coRoutingOrGeneral instanceof General) {
            LOG.info("In readconstraints General {}", coRoutingOrGeneral.toString());
            tmpGeneral = (General) coRoutingOrGeneral;
            readGeneralContrains(tmpGeneral, constraints);
            return;
        }

        if (coRoutingOrGeneral instanceof CoRouting) {
            LOG.info("In readconstraints CoRouting {}", coRoutingOrGeneral.toString());
            tmpCoRouting = (CoRouting) coRoutingOrGeneral;
            readCoRoutingContrains(tmpCoRouting, constraints);
            return;
        }

        return;

    }

    private void readGeneralContrains(General tmpGeneral, PceConstraints constraints) {
        LOG.debug("In readGeneralContrains start");

        if (tmpGeneral == null) {
            LOG.info("In readGeneralContrains: no General constraints.");
            return;
        }

        Latency latency = tmpGeneral.getLatency();
        if (latency != null) {
            constraints.setMaxLatency(latency.getMaxLatency());
            LOG.info("In readGeneralContrains: read latency {}", latency.toString());
        }

        Exclude exclude = tmpGeneral.getExclude();
        List<String> elementsToExclude = null;
        if (exclude != null) {
            elementsToExclude = exclude.getNodeId();
            if (elementsToExclude != null) {
                constraints.setExcludeSupNodes(elementsToExclude);
            }

            elementsToExclude = exclude.getSRLG();
            if (elementsToExclude != null) {
                List<Long> srlgToExclude = new ArrayList<Long>();
                for (String str : elementsToExclude) {
                    srlgToExclude.add(Long.parseLong(str));
                }
                constraints.setExcludeSRLG(srlgToExclude);
            }

            elementsToExclude = exclude.getClli();
            if (elementsToExclude != null) {
                constraints.setExcludeCLLI(elementsToExclude);
            }
        }

        Include include = tmpGeneral.getInclude();
        if (include != null) {
            List<OrderedHops> listHops = include.getOrderedHops();
            if (listHops != null) {
                readIncludeNodes(listHops, constraints);
            }
            LOG.debug("in readGeneralContrains INCLUDE {} ", include.toString());
        }

        Diversity diversity = tmpGeneral.getDiversity();
        PceConstraints.ResourceType rt = PceConstraints.ResourceType.NONE;
        if (diversity != null) {
            ExistingServiceApplicability temp = diversity.getExistingServiceApplicability();
            if (temp == null) {
                return;
            }
            if (temp.isNode()) {
                rt = PceConstraints.ResourceType.NODE;
            }
            if (temp.isSrlg()) {
                rt = PceConstraints.ResourceType.SRLG;
            }
            if (temp.isClli()) {
                rt = PceConstraints.ResourceType.CLLI;
            }
            LOG.info("in readGeneralContrains {} list is :{}", rt, diversity.toString());
            readDiversity(diversity.getExistingService(), constraints, rt);
        }

    }

    private void readIncludeNodes(List<OrderedHops> listHops, PceConstraints constraints) {
        for (int i = 0; i < listHops.size(); i++) {
            HopType hoptype = listHops.get(i).getHopType().getHopType();

            String hopt = hoptype.implementedInterface().getSimpleName();
            LOG.info("in readIncludeNodes next hop to include {}", hopt);
            switch (hopt) {
                case "Node":
                    org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints
                            .rev171017.ordered.constraints.sp.hop.type.hop.type.Node
                            node = (org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing
                            .constraints.rev171017.ordered.constraints.sp.hop.type.hop.type.Node) hoptype;
                    constraints.setListToInclude(constraints.new ResourcePair(PceConstraints.ResourceType.NODE,
                            node.getNodeId()));
                    break;
                case "SRLG":
                    org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints
                            .rev171017.ordered.constraints.sp.hop.type.hop.type.SRLG
                            srlg = (org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing
                            .constraints.rev171017.ordered.constraints.sp.hop.type.hop.type.SRLG) hoptype;
                    constraints.setListToInclude(constraints.new ResourcePair(PceConstraints.ResourceType.SRLG,
                            srlg.getSRLG()));
                    break;
                case "Clli":
                    org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing.constraints
                            .rev171017.ordered.constraints.sp.hop.type.hop.type.Clli
                            clli = (org.opendaylight.yang.gen.v1.http.org.transportpce.b.c._interface.routing
                            .constraints.rev171017.ordered.constraints.sp.hop.type.hop.type.Clli) hoptype;
                    constraints.setListToInclude(constraints.new ResourcePair(PceConstraints.ResourceType.CLLI,
                            clli.getClli()));
                    break;
                default:
                    LOG.error("in readIncludeNodes unsupported include type {}", hopt);
            }
        }
    }

    private void readDiversity(List<String> srvList, PceConstraints constraints, PceConstraints.ResourceType rt) {

        List<String> elementsToExclude = new ArrayList<String>();
        LOG.info("in readDiversity {}", srvList.toString());

        for (String srv : srvList) {
            Optional<PathDescription> service = getPathDescriptionFromDatastore(srv);
            if (service.isPresent()) {
                LOG.info("in readDiversity service list {}", service.toString());
                switch (rt) {
                    case NODE:
                        elementsToExclude
                                .addAll(getAToZNodeList(service.get()));
                        LOG.info("readDiversity NODE : {}", elementsToExclude);
                        if (elementsToExclude != null) {
                            constraints.setExcludeNodes(elementsToExclude);
                        }
                        break;
                    case SRLG:
                        elementsToExclude
                                .addAll(getSRLGList(service.get()));
                        LOG.info("readDiversity SRLG : {}", elementsToExclude);
                        if (elementsToExclude != null) {
                            constraints.setExcludeSrlgLinks(elementsToExclude);
                        }
                        break;
                    case CLLI:
                        /// Retrieve nodes into dedicated CLLI list
                        /// during node validation check their CLLI and build CLLI exclude list
                        elementsToExclude
                                .addAll(getAToZNodeList(service.get()));
                        LOG.info("readDiversity CLLI : {}", elementsToExclude);
                        if (elementsToExclude != null) {
                            constraints.setExcludeClliNodes(elementsToExclude);
                        }
                        break;
                    default:
                        LOG.info("in readDiversity unsupported divercity type", rt);
                }

            } else {
                LOG.info("in readDiversity srv={} is not present", srv);
            }
        }

    }

    private List<String> getAToZNodeList(PathDescription pathDescription) {
        List<AToZ> aendToZList = pathDescription.getAToZDirection().getAToZ();
        return aendToZList.stream().filter(aToZ -> {
            if (aToZ.getResource() == null || aToZ.getResource().getResource() == null) {
                LOG.warn("Diversity constraint: Resource of AToZ node {} is null! Skipping this node!", aToZ.getId());
                return false;
            }
            return aToZ.getResource().getResource() instanceof Node;
        }).filter(aToZ -> {
            Node node = (Node) aToZ.getResource().getResource();
            if (node.getNodeId() == null) {
                LOG.warn("Node in AToZ node {} contains null! Skipping this node!", aToZ.getId());
                return false;
            }
            return true;
        }).map(aToZ -> {
            Node node = ((Node) aToZ.getResource().getResource());
            return node.getNodeId().toString();
        }).collect(Collectors.toList());
    }

    private List<String> getSRLGList(PathDescription pathDescription) {
        List<AToZ> aendToZList = pathDescription.getAToZDirection().getAToZ();
        return aendToZList.stream().filter(aToZ -> {
            if (aToZ.getResource() == null
                    || aToZ.getResource().getResource() == null) {
                LOG.warn("Diversity constraint: Resource of AToZ {} is null! Skipping this resource!", aToZ.getId());
                return false;
            }
            return aToZ.getResource().getResource() instanceof Link;
        }).filter(aToZ -> {
            Link link = (Link) aToZ.getResource().getResource();
            if (link.getLinkId() == null) {
                LOG.warn("Link in AToZ link {} contains null! Skipping this link!", aToZ.getId());
                return false;
            }
            return true;
        }).map(aToZ -> {
            return ((Link) aToZ.getResource().getResource()).getLinkId();
        }).collect(Collectors.toList());
    }

    private Optional<PathDescription> getPathDescriptionFromDatastore(String serviceName) {
        Optional<PathDescription> result = Optional.empty();
        InstanceIdentifier<ServicePaths> pathDescriptionIID = InstanceIdentifier.create(ServicePathList.class)
                .child(ServicePaths.class, new ServicePathsKey(serviceName));
        try {
            LOG.info("PCE diversity constraints: Getting path description for service {}", serviceName);
            ServicePaths servicePaths =
                networkTransactionService.read(LogicalDatastoreType.CONFIGURATION, pathDescriptionIID)
                    .get(Timeouts.DATASTORE_READ, TimeUnit.MILLISECONDS).get();
            if (servicePaths != null) {
                PathDescription path = servicePaths.getPathDescription();
                if (path != null) {
                    result = Optional.of(path);
                }
            }
        } catch (InterruptedException | ExecutionException | TimeoutException e) {
            LOG.warn(
                "PCE diversity constraints: Exception while getting path description from datastore {} for service {}!",
                pathDescriptionIID,serviceName, e);
            return result;
        }
        return result;
    }

    private void readCoRoutingContrains(CoRouting tmpcoRouting, PceConstraints constraints) {
        LOG.info("In readCoRoutingContrains start");

        if (tmpcoRouting == null) {
            LOG.info("In readCoRoutingContrains: no General constraints.");
            return;
        }

    }

    public PceConstraints getPceHardConstraints() {
        return pceHardConstraints;
    }

    public PceConstraints getPceSoftConstraints() {
        return pceSoftConstraints;
    }

    public PceMetric getPceMetrics() {
        return pceMetrics;
    }

}