/*
 * Copyright 2017-present 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.grpc.ctl;

import com.google.common.collect.ImmutableSet;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
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.Service;
import org.onosproject.grpc.api.GrpcChannelId;
import org.onosproject.grpc.api.GrpcController;
import org.onosproject.grpc.api.GrpcObserverHandler;
import org.onosproject.grpc.api.GrpcStreamObserverId;
import org.onosproject.net.DeviceId;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Default implementation of the GrpcController.
 */
@Component(immediate = true)
@Service
public class GrpcControllerImpl implements GrpcController {

    public static final Logger log = LoggerFactory
            .getLogger(GrpcControllerImpl.class);

    private Map<GrpcStreamObserverId, GrpcObserverHandler> observers;
    private Map<GrpcChannelId, ManagedChannel> channels;
    private Map<GrpcChannelId, ManagedChannelBuilder<?>> channelBuilders;

    @Activate
    public void activate() {
        observers = new ConcurrentHashMap<>();
        channels = new ConcurrentHashMap<>();
        channelBuilders = new ConcurrentHashMap<>();
        log.info("Started");
    }

    @Deactivate
    public void deactivate() {
        channels.values().forEach(ManagedChannel::shutdown);
        observers.clear();
        channels.clear();
        channelBuilders.clear();
        log.info("Stopped");
    }

    @Override
    public void addObserver(GrpcStreamObserverId observerId, GrpcObserverHandler grpcObserverHandler) {
        grpcObserverHandler.bindObserver(channels.get(observerId.serviceId().channelId()));
        observers.put(observerId, grpcObserverHandler);
    }

    @Override
    public void removeObserver(GrpcStreamObserverId observerId) {
        observers.get(observerId).removeObserver();
        observers.remove(observerId);
    }

    @Override
    public Optional<GrpcObserverHandler> getObserverManager(GrpcStreamObserverId observerId) {
        return Optional.ofNullable(observers.get(observerId));
    }

    @Override
    public ManagedChannel connectChannel(GrpcChannelId channelId, ManagedChannelBuilder<?> channelBuilder) {
        ManagedChannel channel = channelBuilder.build();

        channel.getState(true);
        channelBuilders.put(channelId, channelBuilder);
        channels.put(channelId, channel);
        return channel;
    }

    @Override
    public void disconnectChannel(GrpcChannelId channelId) {
        channels.get(channelId).shutdown();
        channels.remove(channelId);
        channelBuilders.remove(channelId);
    }

    @Override
    public Map<GrpcChannelId, ManagedChannel> getChannels() {
        return channels;
    }

    @Override
    public Collection<ManagedChannel> getChannels(final DeviceId deviceId) {
        final Set<ManagedChannel> deviceChannels = new HashSet<>();
        channels.forEach((k, v) -> {
            if (k.deviceId().equals(deviceId)) {
                deviceChannels.add(v);
            }
        });

        return ImmutableSet.copyOf(deviceChannels);
    }

    @Override
    public Optional<ManagedChannel> getChannel(GrpcChannelId channelId) {
        return Optional.ofNullable(channels.get(channelId));
    }
}