/*-
 * #%L
 * HAPI FHIR Subscription Server
 * %%
 * Copyright (C) 2014 - 2024 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%
 */
package ca.uhn.fhir.jpa.subscription.submit.interceptor;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.interceptor.api.Hook;
import ca.uhn.fhir.interceptor.api.HookParams;
import ca.uhn.fhir.interceptor.api.IInterceptorBroadcaster;
import ca.uhn.fhir.interceptor.api.Interceptor;
import ca.uhn.fhir.interceptor.api.Pointcut;
import ca.uhn.fhir.interceptor.model.RequestPartitionId;
import ca.uhn.fhir.jpa.model.config.SubscriptionSettings;
import ca.uhn.fhir.jpa.model.entity.IPersistedResourceModifiedMessage;
import ca.uhn.fhir.jpa.partition.IRequestPartitionHelperSvc;
import ca.uhn.fhir.jpa.subscription.match.matcher.matching.IResourceModifiedConsumer;
import ca.uhn.fhir.jpa.subscription.model.ResourceModifiedMessage;
import ca.uhn.fhir.rest.api.server.RequestDetails;
import ca.uhn.fhir.rest.server.messaging.BaseResourceMessage;
import ca.uhn.fhir.rest.server.util.CompositeInterceptorBroadcaster;
import ca.uhn.fhir.subscription.api.IResourceModifiedMessagePersistenceSvc;
import org.hl7.fhir.instance.model.api.IBaseResource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.MessageDeliveryException;

import static java.util.Objects.isNull;
import static org.apache.commons.lang3.StringUtils.isBlank;

/**
 *
 * This interceptor is responsible for submitting operations on resources to the subscription pipeline.
 *
 */
@Interceptor
public class SubscriptionMatcherInterceptor {
        private static final Logger ourLog = LoggerFactory.getLogger(SubscriptionMatcherInterceptor.class);

        @Autowired
        private FhirContext myFhirContext;

        @Autowired
        private IInterceptorBroadcaster myInterceptorBroadcaster;

        @Autowired
        private SubscriptionSettings mySubscriptionSettings;

        @Autowired
        private IRequestPartitionHelperSvc myRequestPartitionHelperSvc;

        @Autowired
        private IResourceModifiedMessagePersistenceSvc myResourceModifiedMessagePersistenceSvc;

        @Autowired
        private IResourceModifiedConsumer myResourceModifiedConsumer;

        /**
         * Constructor
         */
        public SubscriptionMatcherInterceptor() {
                super();
        }

        @Hook(Pointcut.STORAGE_PRECOMMIT_RESOURCE_CREATED)
        public void resourceCreated(IBaseResource theResource, RequestDetails theRequest) {

                processResourceModifiedEvent(theResource, ResourceModifiedMessage.OperationTypeEnum.CREATE, theRequest);
        }

        @Hook(Pointcut.STORAGE_PRECOMMIT_RESOURCE_DELETED)
        public void resourceDeleted(IBaseResource theResource, RequestDetails theRequest) {

                processResourceModifiedEvent(theResource, ResourceModifiedMessage.OperationTypeEnum.DELETE, theRequest);
        }

        @Hook(Pointcut.STORAGE_PRECOMMIT_RESOURCE_UPDATED)
        public void resourceUpdated(IBaseResource theOldResource, IBaseResource theNewResource, RequestDetails theRequest) {
                boolean dontTriggerSubscriptionWhenVersionsAreTheSame =
                                !mySubscriptionSettings.isTriggerSubscriptionsForNonVersioningChanges();
                boolean resourceVersionsAreTheSame = isSameResourceVersion(theOldResource, theNewResource);

                if (dontTriggerSubscriptionWhenVersionsAreTheSame && resourceVersionsAreTheSame) {
                        return;
                }

                processResourceModifiedEvent(theNewResource, ResourceModifiedMessage.OperationTypeEnum.UPDATE, theRequest);
        }

        /**
         * This is an internal API - Use with caution!
         *
         * This method will create a {@link ResourceModifiedMessage}, persist it and arrange for its delivery to the
         * subscription pipeline after the resource was committed.  The message is persisted to provide asynchronous submission
         * in the event where submission would fail.
         */
        protected void processResourceModifiedEvent(
                        IBaseResource theNewResource,
                        ResourceModifiedMessage.OperationTypeEnum theOperationType,
                        RequestDetails theRequest) {

                ResourceModifiedMessage msg = createResourceModifiedMessage(theNewResource, theOperationType, theRequest);

                // Interceptor call: SUBSCRIPTION_RESOURCE_MODIFIED
                IInterceptorBroadcaster compositeBroadcaster =
                                CompositeInterceptorBroadcaster.newCompositeBroadcaster(myInterceptorBroadcaster, theRequest);
                if (compositeBroadcaster.hasHooks(Pointcut.SUBSCRIPTION_RESOURCE_MODIFIED)) {
                        HookParams params = new HookParams().add(ResourceModifiedMessage.class, msg);
                        boolean outcome = compositeBroadcaster.callHooks(Pointcut.SUBSCRIPTION_RESOURCE_MODIFIED, params);

                        if (!outcome) {
                                return;
                        }
                }

                processResourceModifiedMessage(msg);
        }

        protected void processResourceModifiedMessage(ResourceModifiedMessage theResourceModifiedMessage) {
                // Persist the message for async submission to the processing pipeline.
                // see {@link AsyncResourceModifiedProcessingSchedulerSvc}
                // If enabled in {@link JpaStorageSettings} the subscription will be handled immediately.

                if (mySubscriptionSettings.isSubscriptionChangeQueuedImmediately()
                                && theResourceModifiedMessage.hasPayloadType(myFhirContext, "Subscription")) {
                        try {
                                myResourceModifiedConsumer.submitResourceModified(theResourceModifiedMessage);
                                return;
                        } catch (MessageDeliveryException exception) {
                                String payloadId = theResourceModifiedMessage.getPayloadId();
                                String subscriptionId = theResourceModifiedMessage.getSubscriptionId();
                                ourLog.error(
                                                "Channel submission failed for resource with id {} matching subscription with id {}.  Further attempts will be performed at later time.",
                                                payloadId,
                                                subscriptionId,
                                                exception);
                        }
                }

                IPersistedResourceModifiedMessage persistedResourceModifiedMessage =
                                myResourceModifiedMessagePersistenceSvc.persist(theResourceModifiedMessage);
        }

        protected ResourceModifiedMessage createResourceModifiedMessage(
                        IBaseResource theNewResource,
                        BaseResourceMessage.OperationTypeEnum theOperationType,
                        RequestDetails theRequest) {
                // Even though the resource is being written, the subscription will be interacting with it by effectively
                // "reading" it so we set the RequestPartitionId as a read request
                RequestPartitionId requestPartitionId = myRequestPartitionHelperSvc.determineReadPartitionForRequestForRead(
                                theRequest, theNewResource.getIdElement());
                return new ResourceModifiedMessage(
                                myFhirContext, theNewResource, theOperationType, theRequest, requestPartitionId);
        }

        private boolean isSameResourceVersion(IBaseResource theOldResource, IBaseResource theNewResource) {
                if (isNull(theOldResource) || isNull(theNewResource)) {
                        return false;
                }

                String oldVersion = theOldResource.getIdElement().getVersionIdPart();
                String newVersion = theNewResource.getIdElement().getVersionIdPart();

                if (isBlank(oldVersion) || isBlank(newVersion)) {
                        return false;
                }

                return oldVersion.equals(newVersion);
        }

        public void setFhirContext(FhirContext theCtx) {
                myFhirContext = theCtx;
        }
}