package ca.uhn.fhir.jpa.subscription.channel.subscription;

/*-
 * #%L
 * HAPI FHIR Subscription Server
 * %%
 * Copyright (C) 2014 - 2021 Smile CDR, Inc.
 * %%
 * 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.
 * #L%
 */

import ca.uhn.fhir.jpa.subscription.channel.api.IChannelReceiver;
import org.apache.commons.lang3.Validate;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.SubscribableChannel;
import org.springframework.messaging.support.AbstractSubscribableChannel;
import org.springframework.messaging.support.ChannelInterceptor;

import java.util.Set;

public class BroadcastingSubscribableChannelWrapper extends AbstractSubscribableChannel implements IChannelReceiver {

    private final IChannelReceiver myWrappedChannel;
    private final MessageHandler myHandler;

    public BroadcastingSubscribableChannelWrapper(IChannelReceiver theChannel) {
        myHandler = message -> send(message);
        theChannel.subscribe(myHandler);
        myWrappedChannel = theChannel;
    }

    public SubscribableChannel getWrappedChannel() {
        return myWrappedChannel;
    }

    @Override
    protected boolean sendInternal(Message<?> theMessage, long timeout) {
        Set<MessageHandler> subscribers = getSubscribers();
        Validate.isTrue(subscribers.size() > 0, "Channel has zero subscribers");
        for (MessageHandler next : subscribers) {
            next.handleMessage(theMessage);
        }
        return true;
    }

    @Override
    public void destroy() throws Exception {
        myWrappedChannel.destroy();
        myWrappedChannel.unsubscribe(myHandler);
    }

    @Override
    public void addInterceptor(ChannelInterceptor interceptor) {
        super.addInterceptor(interceptor);
        myWrappedChannel.addInterceptor(interceptor);
    }


    @Override
    public String getName() {
        return myWrappedChannel.getName();
    }
}
