/*
 * Copyright 2015 Open Networking Laboratory
 *
 * 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.onosproject.incubator.net.intf.impl;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
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.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.apache.felix.scr.annotations.Service;
import org.onlab.packet.IpAddress;
import org.onlab.packet.VlanId;
import org.onosproject.incubator.net.config.basics.ConfigException;
import org.onosproject.incubator.net.config.basics.InterfaceConfig;
import org.onosproject.incubator.net.intf.Interface;
import org.onosproject.incubator.net.intf.InterfaceAdminService;
import org.onosproject.incubator.net.intf.InterfaceService;
import org.onosproject.net.ConnectPoint;
import org.onosproject.net.config.NetworkConfigEvent;
import org.onosproject.net.config.NetworkConfigListener;
import org.onosproject.net.config.NetworkConfigService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;

import static java.util.stream.Collectors.collectingAndThen;
import static java.util.stream.Collectors.toSet;

/**
 * Manages the inventory of interfaces in the system.
 */
@Service
@Component(immediate = true)
public class InterfaceManager implements InterfaceService,
        InterfaceAdminService {

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

    private static final Class<ConnectPoint> SUBJECT_CLASS = ConnectPoint.class;
    private static final Class<InterfaceConfig> CONFIG_CLASS = InterfaceConfig.class;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected NetworkConfigService configService;

    private final InternalConfigListener listener = new InternalConfigListener();

    private final Map<ConnectPoint, Set<Interface>> interfaces = Maps.newConcurrentMap();

    @Activate
    public void activate() {
        configService.addListener(listener);

        // TODO address concurrency issues here
        for (ConnectPoint subject : configService.getSubjects(SUBJECT_CLASS, CONFIG_CLASS)) {
            InterfaceConfig config = configService.getConfig(subject, CONFIG_CLASS);

            if (config != null) {
                updateInterfaces(config);
            }
        }

        log.info("Started");
    }

    @Deactivate
    public void deactivate() {
        configService.removeListener(listener);

        log.info("Stopped");
    }

    @Override
    public Set<Interface> getInterfaces() {
        return interfaces.values()
                .stream()
                .flatMap(set -> set.stream())
                .collect(collectingAndThen(toSet(), ImmutableSet::copyOf));
    }

    @Override
    public Set<Interface> getInterfacesByPort(ConnectPoint port) {
        Set<Interface> intfs = interfaces.get(port);
        if (intfs == null) {
            return Collections.emptySet();
        }
        return ImmutableSet.copyOf(intfs);
    }

    @Override
    public Set<Interface> getInterfacesByIp(IpAddress ip) {
        return interfaces.values()
                .stream()
                .flatMap(set -> set.stream())
                .filter(intf -> intf.ipAddresses()
                        .stream()
                        .anyMatch(ia -> ia.ipAddress().equals(ip)))
                .collect(collectingAndThen(toSet(), ImmutableSet::copyOf));
    }

    @Override
    public Interface getMatchingInterface(IpAddress ip) {
        Optional<Interface> match = interfaces.values()
                .stream()
                .flatMap(set -> set.stream())
                .filter(intf -> intf.ipAddresses()
                        .stream()
                        .anyMatch(intfIp -> intfIp.subnetAddress().contains(ip)))
                .findFirst();

        if (match.isPresent()) {
            return match.get();
        }

        return null;
    }

    @Override
    public Set<Interface> getInterfacesByVlan(VlanId vlan) {
        return interfaces.values()
                .stream()
                .flatMap(set -> set.stream())
                .filter(intf -> intf.vlan().equals(vlan))
                .collect(collectingAndThen(toSet(), ImmutableSet::copyOf));
    }

    private void updateInterfaces(InterfaceConfig intfConfig) {
        try {
            interfaces.put(intfConfig.subject(), Sets.newHashSet(intfConfig.getInterfaces()));
        } catch (ConfigException e) {
            log.error("Error in interface config", e);
        }
    }

    private void removeInterfaces(ConnectPoint port) {
        interfaces.remove(port);
    }

    @Override
    public void add(Interface intf) {
        addInternal(intf);

        InterfaceConfig config =
                configService.addConfig(intf.connectPoint(), CONFIG_CLASS);

        config.addInterface(intf);

        configService.applyConfig(intf.connectPoint(), CONFIG_CLASS, config.node());
    }

    private void addInternal(Interface intf) {
        interfaces.compute(intf.connectPoint(), (cp, current) -> {
            if (current == null) {
                return Sets.newHashSet(intf);
            }

            Iterator<Interface> it = current.iterator();
            while (it.hasNext()) {
                Interface i = it.next();
                if (i.name().equals(intf.name())) {
                    it.remove();
                    break;
                }
            }

            current.add(intf);
            return current;
        });
    }

    @Override
    public boolean remove(ConnectPoint connectPoint, String name) {
        boolean success = removeInternal(name, connectPoint);

        InterfaceConfig config = configService.addConfig(connectPoint, CONFIG_CLASS);
        config.removeInterface(name);

        try {
            if (config.getInterfaces().isEmpty()) {
                configService.removeConfig(connectPoint, CONFIG_CLASS);
            } else {
                configService.applyConfig(connectPoint, CONFIG_CLASS, config.node());
            }
        } catch (ConfigException e) {
            log.error("Error reading interfaces JSON", e);
        }

        return success;
    }

    public boolean removeInternal(String name, ConnectPoint connectPoint) {
        AtomicBoolean removed = new AtomicBoolean(false);

        interfaces.compute(connectPoint, (cp, current) -> {
            if (current == null) {
                return null;
            }

            Iterator<Interface> it = current.iterator();
            while (it.hasNext()) {
                Interface i = it.next();
                if (i.name().equals(name)) {
                    it.remove();
                    removed.set(true);
                    break;
                }
            }

            if (current.isEmpty()) {
                return null;
            } else {
                return current;
            }
        });

        return removed.get();
    }

    /**
     * Listener for network config events.
     */
    private class InternalConfigListener implements NetworkConfigListener {

        @Override
        public void event(NetworkConfigEvent event) {
            switch (event.type()) {
            case CONFIG_ADDED:
            case CONFIG_UPDATED:
                if (event.configClass() == InterfaceConfig.class) {
                    InterfaceConfig config =
                            configService.getConfig((ConnectPoint) event.subject(), InterfaceConfig.class);
                    updateInterfaces(config);
                }
                break;
            case CONFIG_REMOVED:
                if (event.configClass() == InterfaceConfig.class) {
                    removeInterfaces((ConnectPoint) event.subject());
                }
                break;
            case CONFIG_REGISTERED:
            case CONFIG_UNREGISTERED:
            default:
                break;
            }
        }
    }
}