/*-
 * #%L
 * HAPI FHIR - Master Data Management
 * %%
 * 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.mdm.util;

import ca.uhn.fhir.mdm.api.MdmConstants;
import jakarta.annotation.Nonnull;
import org.hl7.fhir.instance.model.api.IBaseCoding;
import org.hl7.fhir.instance.model.api.IBaseResource;

import java.util.Optional;

public final class MdmResourceUtil {

        private MdmResourceUtil() {}

        /**
         * If the resource is tagged as not managed by MDM, return false. Otherwise true.
         *
         * @param theBaseResource The FHIR resource that is potentially managed by MDM.
         * @return A boolean indicating whether MDM can manage this resource.
         */
        public static boolean isMdmAllowed(IBaseResource theBaseResource) {
                return theBaseResource.getMeta().getTag(MdmConstants.SYSTEM_MDM_MANAGED, MdmConstants.CODE_NO_MDM_MANAGED)
                                == null;
        }

        /**
         * Checks for the presence of the MDM-managed tag, indicating the MDM system has ownership
         * of this golden resource's links.
         *
         * @param theBaseResource the resource to check.
         * @return a boolean indicating whether or not MDM manages this FHIR resource.
         */
        public static boolean isMdmManaged(IBaseResource theBaseResource) {
                return resourceHasTag(theBaseResource, MdmConstants.SYSTEM_MDM_MANAGED, MdmConstants.CODE_HAPI_MDM_MANAGED);
        }

        public static boolean isGoldenRecord(IBaseResource theBaseResource) {
                return resourceHasTag(
                                theBaseResource, MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS, MdmConstants.CODE_GOLDEN_RECORD);
        }

        public static boolean hasGoldenRecordSystemTag(IBaseResource theIBaseResource) {
                return resourceHasTagWithSystem(theIBaseResource, MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS);
        }

        public static boolean containsTagWithSystem(IBaseResource theBaseResource) {
                return resourceHasTagWithSystem(theBaseResource, MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS);
        }

        public static boolean isGoldenRecordRedirected(IBaseResource theBaseResource) {
                return resourceHasTag(
                                theBaseResource, MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS, MdmConstants.CODE_GOLDEN_RECORD_REDIRECTED);
        }

        private static boolean resourceHasTag(IBaseResource theBaseResource, String theSystem, String theCode) {
                if (theBaseResource == null) {
                        return false;
                }
                return theBaseResource.getMeta().getTag(theSystem, theCode) != null;
        }

        private static boolean resourceHasTagWithSystem(IBaseResource theBaseResource, @Nonnull String theSystem) {
                if (theBaseResource == null) {
                        return false;
                }
                return theBaseResource.getMeta().getTag().stream().anyMatch(tag -> theSystem.equalsIgnoreCase(tag.getSystem()));
        }

        private static Optional<? extends IBaseCoding> getTagWithSystem(
                        IBaseResource theResource, @Nonnull String theSystem) {
                return theResource.getMeta().getTag().stream()
                                .filter(tag -> theSystem.equalsIgnoreCase(tag.getSystem()))
                                .findFirst();
        }

        public static void removeTagWithSystem(IBaseResource theResource, @Nonnull String theSystem) {
                theResource.getMeta().getTag().removeIf(tag -> theSystem.equalsIgnoreCase(tag.getSystem()));
        }

        /**
         * Sets the MDM-managed tag, indicating the MDM system has ownership of this
         * Resource. No changes are made if resource is already managed by MDM.
         *
         * @param theBaseResource resource to set the tag for
         * @return Returns resource with the tag set.
         */
        public static IBaseResource setMdmManaged(IBaseResource theBaseResource) {
                return setTagOnResource(
                                theBaseResource,
                                MdmConstants.SYSTEM_MDM_MANAGED,
                                MdmConstants.CODE_HAPI_MDM_MANAGED,
                                MdmConstants.DISPLAY_HAPI_MDM_MANAGED);
        }

        public static IBaseResource setGoldenResource(IBaseResource theBaseResource) {
                return setTagOnResource(
                                theBaseResource,
                                MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS,
                                MdmConstants.CODE_GOLDEN_RECORD,
                                MdmConstants.DISPLAY_GOLDEN_RECORD);
        }

        /**
         * Sets the provided resource as 'redirected' golden resource.
         * This is done when a Golden Resource has been deprecated
         * and is no longer the primary golden resource (for example,
         * after a merge of 2 golden resources).
         */
        public static IBaseResource setGoldenResourceRedirected(IBaseResource theBaseResource) {
                return setTagOnResource(
                                theBaseResource,
                                MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS,
                                MdmConstants.CODE_GOLDEN_RECORD_REDIRECTED,
                                MdmConstants.DISPLAY_GOLDEN_REDIRECT);
        }

        /**
         * Adds the BLOCKED tag to the golden resource.
         * Because this is called *before* a resource is saved,
         * we must add a new system/code combo to it
         * @param theBaseResource
         * @return
         */
        public static IBaseResource setGoldenResourceAsBlockedResourceGoldenResource(IBaseResource theBaseResource) {
                IBaseCoding tag = theBaseResource.getMeta().addTag();
                tag.setSystem(MdmConstants.SYSTEM_GOLDEN_RECORD_STATUS);
                tag.setCode(MdmConstants.CODE_BLOCKED);
                tag.setDisplay(MdmConstants.CODE_BLOCKED_DISPLAY);
                tag.setUserSelected(false);
                tag.setVersion("1");

                return theBaseResource;
        }

        /**
         * WARNING: This code may _look_ like it replaces in place a code of a tag, but this DOES NOT ACTUALLY WORK!. In reality what will
         * happen is a secondary tag will be created with the same system. the only way to actually remove a tag from a resource
         * is by calling dao.removeTag(). This logic here is for the case where our representation of the resource still happens to contain
         * a reference to a tag, to make sure it isn't double-added.
         */
        @Nonnull
        private static IBaseResource setTagOnResource(
                        IBaseResource theGoldenResource, String theSystem, String theCode, String theDisplay) {
                Optional<? extends IBaseCoding> tagWithSystem = getTagWithSystem(theGoldenResource, theSystem);
                if (tagWithSystem.isPresent()) {
                        tagWithSystem.get().setCode(theCode);
                        tagWithSystem.get().setDisplay(theDisplay);
                } else {
                        IBaseCoding tag = theGoldenResource.getMeta().addTag();
                        tag.setSystem(theSystem);
                        tag.setCode(theCode);
                        tag.setDisplay(theDisplay);
                        tag.setUserSelected(false);
                        tag.setVersion("1");
                }
                return theGoldenResource;
        }
}