/*
 * #%L
 * HAPI FHIR JPA 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.dao;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.i18n.Msg;
import ca.uhn.fhir.interceptor.api.HookParams;
import ca.uhn.fhir.interceptor.api.IInterceptorBroadcaster;
import ca.uhn.fhir.interceptor.api.Pointcut;
import ca.uhn.fhir.jpa.api.config.JpaStorageSettings;
import ca.uhn.fhir.jpa.api.svc.IIdHelperService;
import ca.uhn.fhir.jpa.dao.search.ExtendedHSearchClauseBuilder;
import ca.uhn.fhir.jpa.dao.search.ExtendedHSearchIndexExtractor;
import ca.uhn.fhir.jpa.dao.search.ExtendedHSearchResourceProjection;
import ca.uhn.fhir.jpa.dao.search.ExtendedHSearchSearchBuilder;
import ca.uhn.fhir.jpa.dao.search.IHSearchSortHelper;
import ca.uhn.fhir.jpa.dao.search.LastNOperation;
import ca.uhn.fhir.jpa.dao.search.SearchScrollQueryExecutorAdaptor;
import ca.uhn.fhir.jpa.model.dao.JpaPid;
import ca.uhn.fhir.jpa.model.entity.ResourceTable;
import ca.uhn.fhir.jpa.model.search.ExtendedHSearchBuilderConsumeAdvancedQueryClausesParams;
import ca.uhn.fhir.jpa.model.search.ExtendedHSearchIndexData;
import ca.uhn.fhir.jpa.model.search.StorageProcessingMessage;
import ca.uhn.fhir.jpa.search.autocomplete.ValueSetAutocompleteOptions;
import ca.uhn.fhir.jpa.search.autocomplete.ValueSetAutocompleteSearch;
import ca.uhn.fhir.jpa.search.builder.ISearchQueryExecutor;
import ca.uhn.fhir.jpa.search.builder.SearchBuilder;
import ca.uhn.fhir.jpa.search.builder.SearchQueryExecutors;
import ca.uhn.fhir.jpa.searchparam.SearchParameterMap;
import ca.uhn.fhir.jpa.searchparam.extractor.ISearchParamExtractor;
import ca.uhn.fhir.jpa.searchparam.extractor.ResourceIndexedSearchParams;
import ca.uhn.fhir.model.api.IQueryParameterType;
import ca.uhn.fhir.parser.IParser;
import ca.uhn.fhir.rest.api.Constants;
import ca.uhn.fhir.rest.api.server.RequestDetails;
import ca.uhn.fhir.rest.api.server.storage.IResourcePersistentId;
import ca.uhn.fhir.rest.server.servlet.ServletRequestDetails;
import ca.uhn.fhir.rest.server.util.CompositeInterceptorBroadcaster;
import ca.uhn.fhir.rest.server.util.ISearchParamRegistry;
import ca.uhn.fhir.rest.server.util.ResourceSearchParams;
import com.google.common.collect.Ordering;
import jakarta.annotation.Nonnull;
import jakarta.persistence.EntityManager;
import jakarta.persistence.PersistenceContext;
import jakarta.persistence.PersistenceContextType;
import org.hibernate.search.backend.elasticsearch.ElasticsearchExtension;
import org.hibernate.search.engine.search.predicate.dsl.PredicateFinalStep;
import org.hibernate.search.engine.search.predicate.dsl.SearchPredicateFactory;
import org.hibernate.search.engine.search.projection.dsl.CompositeProjectionOptionsStep;
import org.hibernate.search.engine.search.projection.dsl.SearchProjectionFactory;
import org.hibernate.search.engine.search.query.dsl.SearchQueryOptionsStep;
import org.hibernate.search.mapper.orm.Search;
import org.hibernate.search.mapper.orm.common.EntityReference;
import org.hibernate.search.mapper.orm.search.loading.dsl.SearchLoadingOptionsStep;
import org.hibernate.search.mapper.orm.session.SearchSession;
import org.hibernate.search.mapper.orm.work.SearchIndexingPlan;
import org.hibernate.search.util.common.SearchException;
import org.hl7.fhir.instance.model.api.IBaseResource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.transaction.support.TransactionTemplate;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Spliterators;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import static ca.uhn.fhir.rest.server.BasePagingProvider.DEFAULT_MAX_PAGE_SIZE;
import static org.apache.commons.lang3.StringUtils.isNotBlank;

public class FulltextSearchSvcImpl implements IFulltextSearchSvc {
        private static final org.slf4j.Logger ourLog = org.slf4j.LoggerFactory.getLogger(FulltextSearchSvcImpl.class);
        private static final int DEFAULT_MAX_NON_PAGED_SIZE = 500;
        private final ExtendedHSearchSearchBuilder myAdvancedIndexQueryBuilder = new ExtendedHSearchSearchBuilder();

        @Autowired
        ISearchParamExtractor mySearchParamExtractor;

        @Autowired
        IIdHelperService myIdHelperService;

        @PersistenceContext(type = PersistenceContextType.TRANSACTION)
        private EntityManager myEntityManager;

        @Autowired
        private PlatformTransactionManager myTxManager;

        @Autowired
        private FhirContext myFhirContext;

        @Autowired
        private ISearchParamRegistry mySearchParamRegistry;

        @Autowired
        private JpaStorageSettings myStorageSettings;

        @Autowired
        private IHSearchSortHelper myExtendedFulltextSortHelper;

        @Autowired(required = false)
        private IHSearchEventListener myHSearchEventListener;

        @Autowired
        private IInterceptorBroadcaster myInterceptorBroadcaster;

        private Boolean ourDisabled;

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

        @Override
        public ExtendedHSearchIndexData extractLuceneIndexData(
                        IBaseResource theResource, ResourceIndexedSearchParams theNewParams) {
                String resourceType = myFhirContext.getResourceType(theResource);
                ResourceSearchParams activeSearchParams = mySearchParamRegistry.getActiveSearchParams(
                                resourceType, ISearchParamRegistry.SearchParamLookupContextEnum.SEARCH);
                ExtendedHSearchIndexExtractor extractor = new ExtendedHSearchIndexExtractor(
                                myStorageSettings, myFhirContext, activeSearchParams, mySearchParamExtractor);
                return extractor.extract(theResource, theNewParams);
        }

        @Override
        public boolean canUseHibernateSearch(String theResourceType, SearchParameterMap myParams) {
                boolean requiresHibernateSearchAccess = myParams.containsKey(Constants.PARAM_CONTENT)
                                || myParams.containsKey(Constants.PARAM_TEXT)
                                || myParams.isLastN();
                // we have to use it - _text and _content searches only use hibernate
                if (requiresHibernateSearchAccess) {
                        return true;
                }

                // if the registry has not been initialized
                // we cannot use HibernateSearch because it
                // will, internally, trigger a new search
                // when it refreshes the search parameters
                // (which will cause an infinite loop)
                if (!mySearchParamRegistry.isInitialized()) {
                        return false;
                }

                return myStorageSettings.isAdvancedHSearchIndexing()
                                && myAdvancedIndexQueryBuilder.canUseHibernateSearch(theResourceType, myParams, mySearchParamRegistry);
        }

        @Override
        public void reindex(ResourceTable theEntity) {
                validateHibernateSearchIsEnabled();

                SearchIndexingPlan plan = getSearchSession().indexingPlan();
                plan.addOrUpdate(theEntity);
        }

        @Override
        public ISearchQueryExecutor searchNotScrolled(
                        String theResourceName,
                        SearchParameterMap theParams,
                        Integer theMaxResultsToFetch,
                        RequestDetails theRequestDetails) {
                validateHibernateSearchIsEnabled();

                return doSearch(theResourceName, theParams, null, theMaxResultsToFetch, theRequestDetails);
        }

        @Transactional
        @Override
        public ISearchQueryExecutor searchScrolled(
                        String theResourceType, SearchParameterMap theParams, RequestDetails theRequestDetails) {
                validateHibernateSearchIsEnabled();

                SearchQueryOptionsStep<?, Long, SearchLoadingOptionsStep, ?, ?> searchQueryOptionsStep =
                                getSearchQueryOptionsStep(theResourceType, theParams, null);
                logQuery(searchQueryOptionsStep, theRequestDetails);

                return new SearchScrollQueryExecutorAdaptor(searchQueryOptionsStep.scroll(SearchBuilder.getMaximumPageSize()));
        }

        // keep this in sync with supportsSomeOf();
        @SuppressWarnings("rawtypes")
        private ISearchQueryExecutor doSearch(
                        String theResourceType,
                        SearchParameterMap theParams,
                        IResourcePersistentId theReferencingPid,
                        Integer theMaxResultsToFetch,
                        RequestDetails theRequestDetails) {

                int offset = theParams.getOffset() == null ? 0 : theParams.getOffset();
                int count = getMaxFetchSize(theParams, theMaxResultsToFetch);

                // perform an offset search instead of a scroll one, which doesn't allow for offset
                SearchQueryOptionsStep<?, Long, SearchLoadingOptionsStep, ?, ?> searchQueryOptionsStep =
                                getSearchQueryOptionsStep(theResourceType, theParams, theReferencingPid);
                logQuery(searchQueryOptionsStep, theRequestDetails);
                List<Long> longs = searchQueryOptionsStep.fetchHits(offset, count);

                // indicate param was already processed, otherwise queries DB to process it
                theParams.setOffset(null);
                return SearchQueryExecutors.from(longs);
        }

        private int getMaxFetchSize(SearchParameterMap theParams, Integer theMax) {
                if (theMax != null) {
                        return theMax;
                }

                // todo mb we should really pass this in.
                if (theParams.getCount() != null) {
                        return theParams.getCount();
                }

                return DEFAULT_MAX_NON_PAGED_SIZE;
        }

        @SuppressWarnings("rawtypes")
        private SearchQueryOptionsStep<?, Long, SearchLoadingOptionsStep, ?, ?> getSearchQueryOptionsStep(
                        String theResourceType, SearchParameterMap theParams, IResourcePersistentId theReferencingPid) {

                dispatchEvent(IHSearchEventListener.HSearchEventType.SEARCH);
                var query = getSearchSession()
                                .search(ResourceTable.class)
                                // The document id is the PK which is pid.  We use this instead of _myId to avoid fetching the doc body.
                                .select(
                                                // adapt the String docRef.id() to the Long that it really is.
                                                f -> f.composite(docRef -> Long.valueOf(docRef.id()), f.documentReference()))
                                .where(f -> buildWhereClause(f, theResourceType, theParams, theReferencingPid));

                if (theParams.getSort() != null) {
                        query.sort(f -> myExtendedFulltextSortHelper.getSortClauses(f, theParams.getSort(), theResourceType));

                        // indicate parameter was processed
                        theParams.setSort(null);
                }

                return query;
        }

        @SuppressWarnings("rawtypes")
        private PredicateFinalStep buildWhereClause(
                        SearchPredicateFactory f,
                        String theResourceType,
                        SearchParameterMap theParams,
                        IResourcePersistentId theReferencingPid) {
                return f.bool(b -> {
                        ExtendedHSearchClauseBuilder builder =
                                        new ExtendedHSearchClauseBuilder(myFhirContext, myStorageSettings, b, f);

                        /*
                         * Handle _content parameter (resource body content)
                         *
                         * Posterity:
                         * We do not want the HAPI-FHIR dao's to process the
                         * _content parameter, so we remove it from the map here
                         */
                        List<List<IQueryParameterType>> contentAndTerms = theParams.remove(Constants.PARAM_CONTENT);
                        builder.addStringTextSearch(Constants.PARAM_CONTENT, contentAndTerms);

                        /*
                         * Handle _text parameter (resource narrative content)
                         *
                         * Posterity:
                         * We do not want the HAPI-FHIR dao's to process the
                         * _text parameter, so we remove it from the map here
                         */
                        List<List<IQueryParameterType>> textAndTerms = theParams.remove(Constants.PARAM_TEXT);
                        builder.addStringTextSearch(Constants.PARAM_TEXT, textAndTerms);

                        if (theReferencingPid != null) {
                                b.must(f.match().field("myResourceLinksField").matching(theReferencingPid.toString()));
                        }

                        if (isNotBlank(theResourceType)) {
                                builder.addResourceTypeClause(theResourceType);
                        }

                        /*
                         * Handle other supported parameters
                         */
                        if (myStorageSettings.isAdvancedHSearchIndexing() && theParams.getEverythingMode() == null) {
                                ExtendedHSearchBuilderConsumeAdvancedQueryClausesParams params =
                                                new ExtendedHSearchBuilderConsumeAdvancedQueryClausesParams();
                                params.setSearchParamRegistry(mySearchParamRegistry)
                                                .setResourceType(theResourceType)
                                                .setSearchParameterMap(theParams);
                                myAdvancedIndexQueryBuilder.addAndConsumeAdvancedQueryClauses(builder, params);
                        }
                        // DROP EARLY HERE IF BOOL IS EMPTY?
                });
        }

        @Nonnull
        private SearchSession getSearchSession() {
                return Search.session(myEntityManager);
        }

        @SuppressWarnings("rawtypes")
        private List<IResourcePersistentId> convertLongsToResourcePersistentIds(List<Long> theLongPids) {
                return theLongPids.stream().map(JpaPid::fromId).collect(Collectors.toList());
        }

        @Override
        @SuppressWarnings({"rawtypes", "unchecked"})
        public List<IResourcePersistentId> everything(
                        String theResourceName,
                        SearchParameterMap theParams,
                        IResourcePersistentId theReferencingPid,
                        RequestDetails theRequestDetails) {
                validateHibernateSearchIsEnabled();

                // todo mb what about max results here?
                List<IResourcePersistentId> retVal =
                                toList(doSearch(null, theParams, theReferencingPid, 10_000, theRequestDetails), 10_000);
                if (theReferencingPid != null) {
                        retVal.add(theReferencingPid);
                }
                return retVal;
        }

        private void validateHibernateSearchIsEnabled() {
                if (isDisabled()) {
                        throw new UnsupportedOperationException(Msg.code(2137) + "Hibernate search is not enabled!");
                }
        }

        @Override
        public boolean isDisabled() {
                Boolean retVal = ourDisabled;

                if (retVal == null) {
                        retVal = new TransactionTemplate(myTxManager).execute(t -> {
                                try {
                                        SearchSession searchSession = getSearchSession();
                                        searchSession.search(ResourceTable.class);
                                        return Boolean.FALSE;
                                } catch (Exception e) {
                                        ourLog.trace("FullText test failed", e);
                                        ourLog.debug(
                                                        "Hibernate Search (Lucene) appears to be disabled on this server, fulltext will be disabled");
                                        return Boolean.TRUE;
                                }
                        });
                        ourDisabled = retVal;
                }

                assert retVal != null;
                return retVal;
        }

        @Transactional()
        @Override
        @SuppressWarnings("unchecked")
        public List<IResourcePersistentId> search(
                        String theResourceName, SearchParameterMap theParams, RequestDetails theRequestDetails) {
                validateHibernateSearchIsEnabled();
                return toList(
                                doSearch(theResourceName, theParams, null, DEFAULT_MAX_NON_PAGED_SIZE, theRequestDetails),
                                DEFAULT_MAX_NON_PAGED_SIZE);
        }

        /**
         * Adapt our async interface to the legacy concrete List
         */
        @SuppressWarnings("rawtypes")
        private List<IResourcePersistentId> toList(ISearchQueryExecutor theSearchResultStream, long theMaxSize) {
                return StreamSupport.stream(Spliterators.spliteratorUnknownSize(theSearchResultStream, 0), false)
                                .map(JpaPid::fromId)
                                .limit(theMaxSize)
                                .collect(Collectors.toList());
        }

        @Transactional()
        @Override
        public IBaseResource tokenAutocompleteValueSetSearch(ValueSetAutocompleteOptions theOptions) {
                validateHibernateSearchIsEnabled();
                ensureElastic();

                ValueSetAutocompleteSearch autocomplete =
                                new ValueSetAutocompleteSearch(myFhirContext, myStorageSettings, getSearchSession());

                dispatchEvent(IHSearchEventListener.HSearchEventType.SEARCH);
                return autocomplete.search(theOptions);
        }

        /**
         * Throws an error if configured with Lucene.
         * <p>
         * Some features only work with Elasticsearch.
         * Lastn and the autocomplete search use nested aggregations which are Elasticsearch-only
         */
        private void ensureElastic() {
                try {
                        getSearchSession().scope(ResourceTable.class).aggregation().extension(ElasticsearchExtension.get());
                } catch (SearchException e) {
                        // unsupported.  we are probably running Lucene.
                        throw new IllegalStateException(
                                        Msg.code(2070) + "This operation requires Elasticsearch.  Lucene is not supported.");
                }
        }

        @Override
        @SuppressWarnings("rawtypes")
        public List<IResourcePersistentId> lastN(SearchParameterMap theParams, Integer theMaximumResults) {
                ensureElastic();
                dispatchEvent(IHSearchEventListener.HSearchEventType.SEARCH);
                List<Long> pidList = new LastNOperation(
                                                getSearchSession(), myFhirContext, myStorageSettings, mySearchParamRegistry)
                                .executeLastN(theParams, theMaximumResults);
                return convertLongsToResourcePersistentIds(pidList);
        }

        @Override
        public List<IBaseResource> getResources(Collection<Long> thePids) {
                if (thePids.isEmpty()) {
                        return Collections.emptyList();
                }

                SearchSession session = getSearchSession();
                dispatchEvent(IHSearchEventListener.HSearchEventType.SEARCH);
                List<ExtendedHSearchResourceProjection> rawResourceDataList = session.search(ResourceTable.class)
                                .select(this::buildResourceSelectClause)
                                .where(
                                                f -> f.id().matchingAny(thePids) // matches '_id' from resource index
                                                )
                                .fetchAllHits();

                // order resource projections as per thePids
                ArrayList<Long> pidList = new ArrayList<>(thePids);
                List<ExtendedHSearchResourceProjection> orderedAsPidsResourceDataList = rawResourceDataList.stream()
                                .sorted(Ordering.explicit(pidList).onResultOf(ExtendedHSearchResourceProjection::getPid))
                                .collect(Collectors.toList());

                return resourceProjectionsToResources(orderedAsPidsResourceDataList);
        }

        @Nonnull
        private List<IBaseResource> resourceProjectionsToResources(
                        List<ExtendedHSearchResourceProjection> theResourceDataList) {
                IParser parser = myFhirContext.newJsonParser();
                return theResourceDataList.stream().map(p -> p.toResource(parser)).collect(Collectors.toList());
        }

        private CompositeProjectionOptionsStep<?, ExtendedHSearchResourceProjection> buildResourceSelectClause(
                        SearchProjectionFactory<EntityReference, ResourceTable> f) {
                return f.composite(
                                ExtendedHSearchResourceProjection::new,
                                f.field("myId", Long.class),
                                f.field("myForcedId", String.class),
                                f.field("myRawResource", String.class));
        }

        @Override
        public long count(String theResourceName, SearchParameterMap theParams) {
                SearchQueryOptionsStep<?, Long, SearchLoadingOptionsStep, ?, ?> queryOptionsStep =
                                getSearchQueryOptionsStep(theResourceName, theParams, null);

                return queryOptionsStep.fetchTotalHitCount();
        }

        @Override
        @Transactional(readOnly = true)
        public List<IBaseResource> searchForResources(
                        String theResourceType, SearchParameterMap theParams, RequestDetails theRequestDetails) {
                int offset = 0;
                int limit = theParams.getCount() == null ? DEFAULT_MAX_PAGE_SIZE : theParams.getCount();

                if (theParams.getOffset() != null && theParams.getOffset() != 0) {
                        offset = theParams.getOffset();
                        // indicate param was already processed, otherwise queries DB to process it
                        theParams.setOffset(null);
                }

                dispatchEvent(IHSearchEventListener.HSearchEventType.SEARCH);

                var query = getSearchSession()
                                .search(ResourceTable.class)
                                .select(this::buildResourceSelectClause)
                                .where(f -> buildWhereClause(f, theResourceType, theParams, null));

                if (theParams.getSort() != null) {
                        query.sort(f -> myExtendedFulltextSortHelper.getSortClauses(f, theParams.getSort(), theResourceType));
                }

                logQuery(query, theRequestDetails);
                List<ExtendedHSearchResourceProjection> extendedLuceneResourceProjections = query.fetchHits(offset, limit);

                return resourceProjectionsToResources(extendedLuceneResourceProjections);
        }

        /**
         * Fire the JPA_PERFTRACE_INFO hook if it is enabled
         * @param theQuery the query to log
         * @param theRequestDetails the request details
         */
        @SuppressWarnings("rawtypes")
        private void logQuery(SearchQueryOptionsStep theQuery, RequestDetails theRequestDetails) {
                if (CompositeInterceptorBroadcaster.hasHooks(
                                Pointcut.JPA_PERFTRACE_INFO, myInterceptorBroadcaster, theRequestDetails)) {
                        StorageProcessingMessage storageProcessingMessage = new StorageProcessingMessage();
                        String queryString = theQuery.toQuery().queryString();
                        storageProcessingMessage.setMessage(queryString);
                        HookParams params = new HookParams()
                                        .add(RequestDetails.class, theRequestDetails)
                                        .addIfMatchesType(ServletRequestDetails.class, theRequestDetails)
                                        .add(StorageProcessingMessage.class, storageProcessingMessage);
                        CompositeInterceptorBroadcaster.doCallHooks(
                                        myInterceptorBroadcaster, theRequestDetails, Pointcut.JPA_PERFTRACE_INFO, params);
                }
        }

        @Override
        public boolean supportsAllOf(SearchParameterMap theParams) {
                return myAdvancedIndexQueryBuilder.isSupportsAllOf(theParams);
        }

        @Override
        public boolean supportsAllSortTerms(String theResourceType, SearchParameterMap theParams) {
                return myExtendedFulltextSortHelper.supportsAllSortTerms(theResourceType, theParams);
        }

        private void dispatchEvent(IHSearchEventListener.HSearchEventType theEventType) {
                if (myHSearchEventListener != null) {
                        myHSearchEventListener.hsearchEvent(theEventType);
                }
        }

        @Override
        public void deleteIndexedDocumentsByTypeAndId(Class theClazz, List<Object> theGivenIds) {
                SearchSession session = Search.session(myEntityManager);
                SearchIndexingPlan indexingPlan = session.indexingPlan();
                for (Object givenId : theGivenIds) {
                        indexingPlan.purge(theClazz, givenId, null);
                }
                indexingPlan.process();
                indexingPlan.execute();
        }
}