/*
 * Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
 *
 * 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 com.hazelcast.internal.partition.impl;

import com.hazelcast.core.MigrationEvent;
import com.hazelcast.core.MigrationListener;
import com.hazelcast.instance.MemberImpl;
import com.hazelcast.instance.Node;
import com.hazelcast.internal.cluster.impl.ClusterServiceImpl;
import com.hazelcast.internal.partition.MigrationInfo;
import com.hazelcast.logging.ILogger;
import com.hazelcast.partition.PartitionLostEvent;
import com.hazelcast.partition.PartitionLostListener;
import com.hazelcast.spi.EventRegistration;
import com.hazelcast.spi.EventService;
import com.hazelcast.spi.PartitionAwareService;
import com.hazelcast.spi.impl.NodeEngineImpl;
import com.hazelcast.spi.partition.IPartitionLostEvent;

import java.util.Collection;

import static com.hazelcast.internal.partition.InternalPartitionService.MIGRATION_EVENT_TOPIC;
import static com.hazelcast.internal.partition.InternalPartitionService.PARTITION_LOST_EVENT_TOPIC;
import static com.hazelcast.spi.ExecutionService.SYSTEM_EXECUTOR;
import static com.hazelcast.spi.partition.IPartitionService.SERVICE_NAME;

/**
 * Maintains registration of partition-system related listeners and dispatches corresponding events.
 */
public class PartitionEventManager {

    private final Node node;
    private final NodeEngineImpl nodeEngine;

    public PartitionEventManager(Node node) {
        this.node = node;
        this.nodeEngine = node.nodeEngine;
    }

    /** Sends a {@link MigrationEvent} to the registered event listeners. */
    void sendMigrationEvent(final MigrationInfo migrationInfo, final MigrationEvent.MigrationStatus status) {
        if (migrationInfo.getSourceCurrentReplicaIndex() != 0
                && migrationInfo.getDestinationNewReplicaIndex() != 0) {
            // only fire events for 0th replica migrations
            return;
        }

        ClusterServiceImpl clusterService = node.getClusterService();
        MemberImpl current = clusterService.getMember(migrationInfo.getSource());
        MemberImpl newOwner = clusterService.getMember(migrationInfo.getDestination());
        MigrationEvent event = new MigrationEvent(migrationInfo.getPartitionId(), current, newOwner, status);
        EventService eventService = nodeEngine.getEventService();
        Collection<EventRegistration> registrations = eventService.getRegistrations(SERVICE_NAME, MIGRATION_EVENT_TOPIC);
        eventService.publishEvent(SERVICE_NAME, registrations, event, event.getPartitionId());
    }

    public String addMigrationListener(MigrationListener listener) {
        if (listener == null) {
            throw new NullPointerException("listener can't be null");
        }

        final MigrationListenerAdapter adapter = new MigrationListenerAdapter(listener);

        EventService eventService = nodeEngine.getEventService();
        EventRegistration registration = eventService.registerListener(SERVICE_NAME, MIGRATION_EVENT_TOPIC, adapter);
        return registration.getId();
    }

    public boolean removeMigrationListener(String registrationId) {
        if (registrationId == null) {
            throw new NullPointerException("registrationId can't be null");
        }

        EventService eventService = nodeEngine.getEventService();
        return eventService.deregisterListener(SERVICE_NAME, MIGRATION_EVENT_TOPIC, registrationId);
    }

    public String addPartitionLostListener(PartitionLostListener listener) {
        if (listener == null) {
            throw new NullPointerException("listener can't be null");
        }

        final PartitionLostListenerAdapter adapter = new PartitionLostListenerAdapter(listener);

        EventService eventService = nodeEngine.getEventService();
        EventRegistration registration = eventService.registerListener(SERVICE_NAME, PARTITION_LOST_EVENT_TOPIC, adapter);
        return registration.getId();
    }

    public String addLocalPartitionLostListener(PartitionLostListener listener) {
        if (listener == null) {
            throw new NullPointerException("listener can't be null");
        }

        final PartitionLostListenerAdapter adapter = new PartitionLostListenerAdapter(listener);

        EventService eventService = nodeEngine.getEventService();
        EventRegistration registration =
                eventService.registerLocalListener(SERVICE_NAME, PARTITION_LOST_EVENT_TOPIC, adapter);
        return registration.getId();
    }

    public boolean removePartitionLostListener(String registrationId) {
        if (registrationId == null) {
            throw new NullPointerException("registrationId can't be null");
        }

        EventService eventService = nodeEngine.getEventService();
        return eventService.deregisterListener(SERVICE_NAME, PARTITION_LOST_EVENT_TOPIC, registrationId);
    }

    public void onPartitionLost(IPartitionLostEvent event) {
        final PartitionLostEvent partitionLostEvent = new PartitionLostEvent(event.getPartitionId(), event.getLostReplicaIndex(),
                event.getEventSource());
        final EventService eventService = nodeEngine.getEventService();
        final Collection<EventRegistration> registrations = eventService
                .getRegistrations(SERVICE_NAME, PARTITION_LOST_EVENT_TOPIC);
        eventService.publishEvent(SERVICE_NAME, registrations, partitionLostEvent, event.getPartitionId());
    }

    public void sendPartitionLostEvent(int partitionId, int lostReplicaIndex) {
        final IPartitionLostEvent event = new IPartitionLostEvent(partitionId, lostReplicaIndex,
                nodeEngine.getThisAddress());
        final InternalPartitionLostEventPublisher publisher = new InternalPartitionLostEventPublisher(nodeEngine, event);
        nodeEngine.getExecutionService().execute(SYSTEM_EXECUTOR, publisher);
    }

    /** Task which notifies all {@link PartitionAwareService}s that replicas have been lost. */
    private static class InternalPartitionLostEventPublisher
            implements Runnable {

        private final NodeEngineImpl nodeEngine;

        private final IPartitionLostEvent event;

        InternalPartitionLostEventPublisher(NodeEngineImpl nodeEngine, IPartitionLostEvent event) {
            this.nodeEngine = nodeEngine;
            this.event = event;
        }

        @Override
        public void run() {
            for (PartitionAwareService service : nodeEngine.getServices(PartitionAwareService.class)) {
                try {
                    service.onPartitionLost(event);
                } catch (Exception e) {
                    final ILogger logger = nodeEngine.getLogger(InternalPartitionLostEventPublisher.class);
                    logger.warning("Handling partitionLostEvent failed. Service: " + service.getClass() + " Event: " + event, e);
                }
            }
        }

        public IPartitionLostEvent getEvent() {
            return event;
        }
    }

}