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//   Copyright 2012,2013 Vaughn Vernon
//
//   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 io.dddspring.common.port.adapter.notification;

import io.dddspring.common.domain.model.DomainEvent;
import io.dddspring.common.event.EventStore;
import io.dddspring.common.event.StoredEvent;
import io.dddspring.common.notification.*;
import io.dddspring.common.port.adapter.messaging.rabbitmq.ConnectionSettings;
import io.dddspring.common.port.adapter.messaging.rabbitmq.Exchange;
import io.dddspring.common.port.adapter.messaging.rabbitmq.MessageParameters;
import io.dddspring.common.port.adapter.messaging.rabbitmq.MessageProducer;

import java.util.ArrayList;
import java.util.List;

public class RabbitMQNotificationPublisher implements NotificationPublisher {

    private EventStore eventStore;

    private String exchangeName;

    private PublishedNotificationTrackerStore publishedNotificationTrackerStore;

    public RabbitMQNotificationPublisher(
            EventStore anEventStore,
            PublishedNotificationTrackerStore aPublishedNotificationTrackerStore,
            Object aMessagingLocator) {

        super();

        this.setEventStore(anEventStore);
        this.setExchangeName((String) aMessagingLocator);
        this.setPublishedNotificationTrackerStore(aPublishedNotificationTrackerStore);



    }

    @Override
    public void publishNotifications() {
        PublishedNotificationTracker publishedNotificationTracker =
                this.publishedNotificationTrackerStore().publishedNotificationTracker();//通过类型获取该类型所有需要发布的消息

        List notifications =
            this.listUnpublishedNotifications(
                    publishedNotificationTracker.mostRecentPublishedNotificationId());

        MessageProducer messageProducer = this.messageProducer();

        try {
            for (Notification notification : notifications) {
                this.publish(notification, messageProducer);
            }

            this.publishedNotificationTrackerStore()
                .trackMostRecentPublishedNotification(
                    publishedNotificationTracker,
                    notifications);
        } finally {
            messageProducer.close();
        }
    }

    @Override
    public boolean internalOnlyTestConfirmation() {
        throw new UnsupportedOperationException("Not supported by production implementation. 不可用于生产环境");
    }

    private EventStore eventStore() {
        return this.eventStore;
    }

    private void setEventStore(EventStore anEventStore) {
        this.eventStore = anEventStore;
    }

    private String exchangeName() {
        return this.exchangeName;
    }

    private void setExchangeName(String anExchangeName) {
        this.exchangeName = anExchangeName;
    }

    private List listUnpublishedNotifications(
            long aMostRecentPublishedMessageId) {
        List storedEvents =
            this.eventStore().allStoredEventsSince(aMostRecentPublishedMessageId);//从eventstore中获取跟踪器设置的指定条数

        List notifications =
            this.notificationsFrom(storedEvents);

        return notifications;
    }

    private MessageProducer messageProducer() {

        // creates my exchange if non-existing
        Exchange exchange =
            Exchange.fanOutInstance(
                    ConnectionSettings.instance(),
                    this.exchangeName(),
                    true);

        // create a message producer used to forward events
        MessageProducer messageProducer = MessageProducer.instance(exchange);

        return messageProducer;
    }

    private List notificationsFrom(List aStoredEvents) {
        List notifications =
            new ArrayList(aStoredEvents.size());

        for (StoredEvent storedEvent : aStoredEvents) {
            DomainEvent domainEvent = storedEvent.toDomainEvent();

            Notification notification =
                new Notification(storedEvent.eventId(), domainEvent);

            notifications.add(notification);
        }

        return notifications;
    }

    private void publish(
            Notification aNotification,
            MessageProducer aMessageProducer) {

        MessageParameters messageParameters =
            MessageParameters.durableTextParameters(
                    aNotification.typeName(),
                    Long.toString(aNotification.notificationId()),
                    aNotification.occurredOn());

        String notification =
            NotificationSerializer
                .instance()
                .serialize(aNotification);

        aMessageProducer.send(notification, messageParameters);
    }

    private PublishedNotificationTrackerStore publishedNotificationTrackerStore() {
        return publishedNotificationTrackerStore;
    }

    private void setPublishedNotificationTrackerStore(PublishedNotificationTrackerStore publishedNotificationTrackerStore) {
        this.publishedNotificationTrackerStore = publishedNotificationTrackerStore;
    }
}