/*
 * Copyright 2016-present Open Networking Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.opencord.cordmcast;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Modified;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.glassfish.jersey.client.ClientConfig;
import org.glassfish.jersey.client.ClientProperties;
import org.glassfish.jersey.client.authentication.HttpAuthenticationFeature;
import org.onlab.packet.Ethernet;
import org.onlab.packet.IpAddress;
import org.onlab.packet.VlanId;
import org.onosproject.cfg.ComponentConfigService;
import org.onosproject.codec.CodecService;
import org.onosproject.codec.JsonCodec;

import org.onosproject.core.ApplicationId;
import org.onosproject.core.CoreService;
import org.onosproject.net.ConnectPoint;
import org.onosproject.net.DeviceId;
import org.onosproject.net.PortNumber;
import org.onosproject.net.config.ConfigFactory;
import org.onosproject.net.config.NetworkConfigEvent;
import org.onosproject.net.config.NetworkConfigListener;
import org.onosproject.net.config.NetworkConfigRegistry;
import org.onosproject.net.config.basics.SubjectFactories;
import org.onosproject.net.flow.DefaultTrafficSelector;
import org.onosproject.net.flow.DefaultTrafficTreatment;
import org.onosproject.net.flow.FlowRuleService;
import org.onosproject.net.flow.TrafficSelector;
import org.onosproject.net.flowobjective.DefaultForwardingObjective;
import org.onosproject.net.flowobjective.DefaultNextObjective;
import org.onosproject.net.flowobjective.FlowObjectiveService;
import org.onosproject.net.flowobjective.ForwardingObjective;
import org.onosproject.net.flowobjective.NextObjective;
import org.onosproject.net.flowobjective.Objective;
import org.onosproject.net.flowobjective.ObjectiveContext;
import org.onosproject.net.flowobjective.ObjectiveError;
import org.onosproject.net.mcast.McastEvent;
import org.onosproject.net.mcast.McastListener;
import org.onosproject.net.mcast.McastRoute;
import org.onosproject.net.mcast.McastRouteInfo;
import org.onosproject.net.mcast.MulticastRouteService;
import org.onosproject.rest.AbstractWebResource;
import org.opencord.cordconfig.access.AccessAgentData;
import org.opencord.cordconfig.access.AccessDeviceData;
import org.opencord.cordconfig.CordConfigService;
import org.osgi.service.component.ComponentContext;
import org.slf4j.Logger;
import org.onosproject.net.config.basics.McastConfig;

import javax.ws.rs.ProcessingException;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Entity;
import javax.ws.rs.client.Invocation;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MediaType;
import java.io.IOException;
import java.util.Dictionary;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Properties;
import java.util.concurrent.atomic.AtomicBoolean;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Strings.isNullOrEmpty;
import static com.google.common.net.MediaType.JSON_UTF_8;
import static org.onlab.util.Tools.get;
import static org.slf4j.LoggerFactory.getLogger;

/**
 * CORD multicast provisioning application. Operates by listening to
 * events on the multicast rib and provisioning groups to program multicast
 * flows on the dataplane.
 */
@Component(immediate = true)
public class CordMcast {
    private static final String APP_NAME = "org.opencord.cordmcast";

    private final Logger log = getLogger(getClass());

    private static final int DEFAULT_REST_TIMEOUT_MS = 1000;
    private static final int DEFAULT_PRIORITY = 500;
    private static final short DEFAULT_MCAST_VLAN = 4000;
    private static final String DEFAULT_SYNC_HOST = "";
    private static final String DEFAULT_USER = "karaf";
    private static final String DEFAULT_PASSWORD = "karaf";
    private static final boolean DEFAULT_VLAN_ENABLED = true;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected MulticastRouteService mcastService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected FlowObjectiveService flowObjectiveService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected CoreService coreService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected CodecService codecService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected ComponentConfigService componentConfigService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected CordConfigService cordConfigService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected NetworkConfigRegistry networkConfig;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected FlowRuleService flowRuleService;

    protected McastListener listener = new InternalMulticastListener();
    private InternalNetworkConfigListener configListener =
            new InternalNetworkConfigListener();

    //TODO: move this to a ec map
    private Map<NextKey, Integer> groups = Maps.newConcurrentMap();

    private ApplicationId appId;
    private ApplicationId coreAppId;
    private int mcastVlan = DEFAULT_MCAST_VLAN;

    @Property(name = "vlanEnabled", boolValue = DEFAULT_VLAN_ENABLED,
            label = "Use vlan for multicast traffic?")
    private boolean vlanEnabled = DEFAULT_VLAN_ENABLED;

    @Property(name = "priority", intValue = DEFAULT_PRIORITY,
            label = "Priority for multicast rules")
    private int priority = DEFAULT_PRIORITY;

    @Property(name = "syncHost", value = DEFAULT_SYNC_HOST,
            label = "host:port to synchronize routes to")
    private String syncHost = null;

    @Property(name = "username", value = DEFAULT_USER,
            label = "Username for REST password authentication")
    private String user = DEFAULT_USER;

    @Property(name = "password", value = DEFAULT_PASSWORD,
            label = "Password for REST authentication")
    private String password = DEFAULT_PASSWORD;

    private String fabricOnosUrl;
    private static final Class<McastConfig> CORD_MCAST_CONFIG_CLASS =
            McastConfig.class;

    private ConfigFactory<ApplicationId, McastConfig> cordMcastConfigFactory =
            new ConfigFactory<ApplicationId, McastConfig>(
                    SubjectFactories.APP_SUBJECT_FACTORY, CORD_MCAST_CONFIG_CLASS, "multicast") {
                @Override
                public McastConfig createConfig() {
                    return new McastConfig();
                }
            };

    @Activate
    public void activate(ComponentContext context) {
        componentConfigService.registerProperties(getClass());
        modified(context);

        appId = coreService.registerApplication(APP_NAME);
        coreAppId = coreService.registerApplication(CoreService.CORE_APP_NAME);

        clearRemoteRoutes();
        networkConfig.registerConfigFactory(cordMcastConfigFactory);
        networkConfig.addListener(configListener);
        mcastService.addListener(listener);

        mcastService.getRoutes().stream()
                .map(r -> new ImmutablePair<>(r, mcastService.fetchSinks(r)))
                .filter(pair -> pair.getRight() != null && !pair.getRight().isEmpty())
                .forEach(pair -> pair.getRight().forEach(sink -> provisionGroup(pair.getLeft(),
                        sink)));

        McastConfig config = networkConfig.getConfig(coreAppId, CORD_MCAST_CONFIG_CLASS);
        if (config != null) {
            mcastVlan = config.egressVlan().toShort();
        }

        log.info("Started");
    }

    @Deactivate
    public void deactivate() {
        componentConfigService.unregisterProperties(getClass(), false);
        mcastService.removeListener(listener);
        networkConfig.removeListener(configListener);
        networkConfig.unregisterConfigFactory(cordMcastConfigFactory);
        clearGroups();
        log.info("Stopped");
    }

    public void clearGroups() {
        groups.keySet().forEach(d -> {
            flowObjectiveService.next(d.getDevice(), nextObject(groups.get(d), PortNumber.ANY, NextType.Remove));
        });
        flowRuleService.removeFlowRulesById(appId);
        groups.clear();
    }

    @Modified
    public void modified(ComponentContext context) {
        Dictionary<?, ?> properties = context != null ? context.getProperties() : new Properties();

        try {
            String s = get(properties, "username");
            user = isNullOrEmpty(s) ? DEFAULT_USER : s.trim();

            s = get(properties, "password");
            password = isNullOrEmpty(s) ? DEFAULT_PASSWORD : s.trim();

            s = get(properties, "vlanEnabled");
            vlanEnabled = isNullOrEmpty(s) ? DEFAULT_VLAN_ENABLED : Boolean.parseBoolean(s.trim());

            s = get(properties, "priority");
            priority = isNullOrEmpty(s) ? DEFAULT_PRIORITY : Integer.parseInt(s.trim());

            s = get(properties, "syncHost");
            syncHost = isNullOrEmpty(s) ? null : s.trim();
        } catch (Exception e) {
            user = DEFAULT_USER;
            password = DEFAULT_PASSWORD;
            syncHost = null;
            mcastVlan = DEFAULT_MCAST_VLAN;
            vlanEnabled = false;
            priority = DEFAULT_PRIORITY;
        }
        fabricOnosUrl = createRemoteUrl(syncHost);
    }

    private static String createRemoteUrl(String remoteHost) {
        return "http://" + remoteHost + "/onos/v1/mcast";
    }

    private class InternalMulticastListener implements McastListener {
        @Override
        public void event(McastEvent event) {
            McastRouteInfo info = event.subject();
            switch (event.type()) {
                case ROUTE_ADDED:
                    break;
                case ROUTE_REMOVED:
                    break;
                case SOURCE_ADDED:
                    break;
                case SINK_ADDED:
                    if (!info.sink().isPresent()) {
                        log.warn("No sink given after sink added event: {}", info);
                        return;
                    }
                    provisionGroup(info.route(), info.sink().get());
                    break;
                case SINK_REMOVED:
                    unprovisionGroup(event.subject());
                    break;
                default:
                    log.warn("Unknown mcast event {}", event.type());
            }
        }
    }

    private enum NextType { AddNew, AddToExisting, Remove, RemoveFromExisting };


    private NextObjective nextObject(Integer id, PortNumber port, NextType nextType) {
        DefaultNextObjective.Builder build = DefaultNextObjective.builder()
                .fromApp(appId)
                .addTreatment(DefaultTrafficTreatment.builder().setOutput(port).build())
                .withType(NextObjective.Type.BROADCAST)
                .withId(id);
        ObjectiveContext content = new ObjectiveContext() {
            @Override
            public void onSuccess(Objective objective) {
                //TODO: change to debug
                log.info("Next Objective {} installed", objective.id());
            }

            @Override
            public void onError(Objective objective, ObjectiveError error) {
                //TODO: change to debug
                log.info("Next Objective {} failed, because {}",
                        objective.id(),
                        error);
            }
        };

        switch (nextType) {
            case AddNew:
                return build.add(content);
            case AddToExisting:
                return build.addToExisting(content);
            case Remove:
                return build.remove(content);
            case RemoveFromExisting:
                return build.removeFromExisting(content);
            default:
                return null;
        }
    }

    private void unprovisionGroup(McastRouteInfo info) {

        if (info.sinks().isEmpty()) {
            removeRemoteRoute(info.route());
        }

        if (!info.sink().isPresent()) {
            log.warn("No sink given after sink removed event: {}", info);
            return;
        }
        ConnectPoint loc = info.sink().get();

        NextKey key = new NextKey(loc.deviceId(), info.route().group());
        if (groups.get(key) == null) {
            log.warn("No groups on device: {}", loc.deviceId());
            return;
        }
        flowObjectiveService.next(loc.deviceId(), nextObject(groups.get(key), loc.port(), NextType.RemoveFromExisting));
    }

    private void provisionGroup(McastRoute route, ConnectPoint sink) {
        checkNotNull(route, "Route cannot be null");
        checkNotNull(sink, "Sink cannot be null");

        Optional<AccessDeviceData> oltInfo = cordConfigService.getAccessDevice(sink.deviceId());

        if (!oltInfo.isPresent()) {
            log.warn("Unknown OLT device : {}", sink.deviceId());
            return;
        }

        final AtomicBoolean sync = new AtomicBoolean(false);
        NextKey key = new NextKey(sink.deviceId(), route.group());
        Integer nextId = groups.computeIfAbsent(key, (g) -> {
            Integer id = flowObjectiveService.allocateNextId();

            flowObjectiveService.next(sink.deviceId(), nextObject(id, sink.port(), NextType.AddNew));

            TrafficSelector.Builder mcast = DefaultTrafficSelector.builder()
                    .matchInPort(oltInfo.get().uplink())
                    .matchEthType(Ethernet.TYPE_IPV4)
                    .matchIPDst(route.group().toIpPrefix());

            if (vlanEnabled) {
                mcast.matchVlanId(VlanId.vlanId((short) mcastVlan));
            }

            ForwardingObjective fwd = DefaultForwardingObjective.builder()
                    .fromApp(appId)
                    .nextStep(id)
                    .makePermanent()
                    .withFlag(ForwardingObjective.Flag.VERSATILE)
                    .withPriority(priority)
                    .withSelector(mcast.build())
                    .add(new ObjectiveContext() {
                        @Override
                        public void onSuccess(Objective objective) {
                            //TODO: change to debug
                            log.info("Forwarding objective installed {}", objective);
                        }

                        @Override
                        public void onError(Objective objective, ObjectiveError error) {
                            //TODO: change to debug
                            log.info("Forwarding objective failed {}", objective);
                        }
                    });

            flowObjectiveService.forward(sink.deviceId(), fwd);

            sync.set(true);

            return id;
        });

        if (!sync.get()) {
            flowObjectiveService.next(sink.deviceId(), nextObject(nextId, sink.port(), NextType.AddToExisting));
        }

        addRemoteRoute(route, sink);
    }

    private void addRemoteRoute(McastRoute route, ConnectPoint inPort) {
        checkNotNull(route);
        if (syncHost == null) {
            log.warn("No host configured for synchronization; route will be dropped");
            return;
        }

        Optional<AccessAgentData> accessAgent = cordConfigService.getAccessAgent(inPort.deviceId());
        if (!accessAgent.isPresent()) {
            log.warn("No accessAgent config found for in port {}", inPort);
            return;
        }

        if (!accessAgent.get().getOltConnectPoint(inPort).isPresent()) {
            log.warn("No OLT configured for in port {}", inPort);
            return;
        }

        ConnectPoint oltConnectPoint = accessAgent.get().getOltConnectPoint(inPort).get();

        log.debug("Sending route {} to other ONOS {}", route, fabricOnosUrl);

        Invocation.Builder builder = getClientBuilder(fabricOnosUrl);

        ObjectNode json = codecService.getCodec(McastRoute.class)
                .encode(route, new AbstractWebResource());

        try {
            builder.post(Entity.json(json.toString()));

            builder = getClientBuilder(fabricOnosUrl + "/sinks/" + route.group() + "/" + route.source());
            ObjectMapper mapper = new ObjectMapper();
            ObjectNode obj = mapper.createObjectNode();
            obj.putArray("sinks").add(oltConnectPoint.deviceId() + "/" + oltConnectPoint.port());

            builder.post(Entity.json(obj.toString()));
        } catch (ProcessingException e) {
            log.warn("Unable to send route to remote controller: {}", e.getMessage());
        }
    }

    private void removeRemoteRoute(McastRoute route) {
        if (syncHost == null) {
            log.warn("No host configured for synchronization; route will be dropped");
            return;
        }

        log.debug("Removing route {} from other ONOS {}", route, fabricOnosUrl);

        Invocation.Builder builder = getClientBuilder(fabricOnosUrl)
                .property(ClientProperties.SUPPRESS_HTTP_COMPLIANCE_VALIDATION, true);

        ObjectNode json = codecService.getCodec(McastRoute.class)
                .encode(route, new AbstractWebResource());

        builder.method("DELETE", Entity.entity(json.asText(),
                MediaType.APPLICATION_OCTET_STREAM));
    }

    private void clearRemoteRoutes() {
        if (syncHost == null) {
            log.warn("No host configured for synchronization");
            return;
        }

        log.debug("Clearing remote multicast routes from {}", fabricOnosUrl);

        Invocation.Builder builder = getClientBuilder(fabricOnosUrl);
        List<McastRoute> mcastRoutes = Lists.newArrayList();

        try {
            String response = builder
                    .accept(MediaType.APPLICATION_JSON_TYPE)
                    .get(String.class);

            JsonCodec<McastRoute> routeCodec = codecService.getCodec(McastRoute.class);
            ObjectMapper mapper = new ObjectMapper();


            ObjectNode node = (ObjectNode) mapper.readTree(response);
            ArrayNode list = (ArrayNode) node.path("routes");

            list.forEach(n -> mcastRoutes.add(
                    routeCodec.decode((ObjectNode) n, new AbstractWebResource())));

        } catch (IOException | ProcessingException e) {
            log.warn("Error clearing remote routes", e);
        }

        mcastRoutes.forEach(this::removeRemoteRoute);
    }

    private Invocation.Builder getClientBuilder(String uri) {
        ClientConfig config = new ClientConfig();
        Client client = ClientBuilder.newClient(config);

        client.property(ClientProperties.CONNECT_TIMEOUT, DEFAULT_REST_TIMEOUT_MS);
        client.property(ClientProperties.READ_TIMEOUT,    DEFAULT_REST_TIMEOUT_MS);
        client.register(HttpAuthenticationFeature.basic(user, password));

        WebTarget wt = client.target(uri);
        return wt.request(JSON_UTF_8.toString());
    }

    private class InternalNetworkConfigListener implements NetworkConfigListener {
        @Override
        public void event(NetworkConfigEvent event) {
            switch (event.type()) {

                case CONFIG_ADDED:
                case CONFIG_UPDATED:
                    if (event.configClass().equals(CORD_MCAST_CONFIG_CLASS)) {
                        McastConfig config = networkConfig.getConfig(coreAppId, CORD_MCAST_CONFIG_CLASS);
                        if (config != null) {
                            //TODO: Simply remove flows/groups, hosts will response period query
                            // and re-sent IGMP report, so the flows can be rebuild.
                            // However, better to remove and re-add mcast flow rules here
                            if (mcastVlan != config.egressVlan().toShort() && vlanEnabled) {
                                clearGroups();
                            }
                            mcastVlan = config.egressVlan().toShort();
                        }
                    }
                    break;
                case CONFIG_REGISTERED:
                case CONFIG_UNREGISTERED:
                case CONFIG_REMOVED:
                    break;
                default:
                    break;
            }
        }
    }

    private class NextKey {
        private DeviceId device;
        private IpAddress group;
        public NextKey(DeviceId deviceId, IpAddress groupAddress) {
            device = deviceId;
            group = groupAddress;
        }

        public DeviceId getDevice() {
            return device;
        }

        public int hashCode() {
            return com.google.common.base.Objects.hashCode(new Object[]{this.device, this.group});
        }

        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            } else if (!(obj instanceof NextKey)) {
                return false;
            } else {
                NextKey that = (NextKey) obj;
                return this.getClass() == that.getClass() &&
                        Objects.equals(this.device, that.device) &&
                        Objects.equals(this.group, that.group);
            }
        }
    }
}