From ff7e89e6eef5a6d05f4f573f06394561b10f9091 Mon Sep 17 00:00:00 2001
From: Pawel Mankowski <pawelman@gmail.com>
Date: Sat, 18 Feb 2023 18:19:44 -0500
Subject: [PATCH] [HIE-2] make CR request for patients matching identifiers
 returned by ihe-pix CR endpoint

---
 .../api/impl/FhirCRPatientServiceImpl.java    | 54 +++++++++++--------
 .../providers/FhirCRConstants.java            |  1 +
 2 files changed, 34 insertions(+), 21 deletions(-)

diff --git a/api/src/main/java/org/openmrs/module/clientregistry/api/impl/FhirCRPatientServiceImpl.java b/api/src/main/java/org/openmrs/module/clientregistry/api/impl/FhirCRPatientServiceImpl.java
index c8f64ac..6f91773 100644
--- a/api/src/main/java/org/openmrs/module/clientregistry/api/impl/FhirCRPatientServiceImpl.java
+++ b/api/src/main/java/org/openmrs/module/clientregistry/api/impl/FhirCRPatientServiceImpl.java
@@ -1,11 +1,15 @@
 package org.openmrs.module.clientregistry.api.impl;
 
 import ca.uhn.fhir.rest.client.api.IGenericClient;
+import ca.uhn.fhir.rest.gclient.IOperationUntypedWithInputAndPartialOutput;
 import ca.uhn.fhir.rest.gclient.IQuery;
+import ca.uhn.fhir.rest.gclient.StringClientParam;
+import ca.uhn.fhir.rest.param.StringOrListParam;
+import ca.uhn.fhir.rest.param.StringParam;
+import ca.uhn.fhir.rest.param.TokenParam;
+import ca.uhn.fhir.rest.param.UriOrListParam;
 import org.hl7.fhir.instance.model.api.IBaseBundle;
-import org.hl7.fhir.r4.model.Bundle;
-import org.hl7.fhir.r4.model.Parameters;
-import org.hl7.fhir.r4.model.Patient;
+import org.hl7.fhir.r4.model.*;
 import org.openmrs.module.clientregistry.ClientRegistryConfig;
 import org.openmrs.module.clientregistry.api.CRPatientService;
 import org.openmrs.module.clientregistry.providers.FhirCRConstants;
@@ -14,7 +18,9 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
+import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
 
 @Component
@@ -27,34 +33,40 @@ public class FhirCRPatientServiceImpl implements CRPatientService {
 	private ClientRegistryConfig config;
 	
 	/**
-	 * Constructs a $ihe-pix fhir client call to an external Client Registry returning any patients
-	 * that match the given source identifier/system and target systems.
+	 * Get patient identifiers from an external client registry's $ihe-pix implementation. Use the
+	 * returned identifiers to then request a matching Patient bundle from the client registry.
 	 */
 	@Override
 	public List<Patient> getCRPatients(String sourceIdentifier, String sourceIdentifierSystem, List<String> targetSystems) {
-
-
-		Parameters betterCrRequest = fhirClient
+		// construct request to external FHIR $ihe-pix endpoint
+		IOperationUntypedWithInputAndPartialOutput<Parameters> identifiersRequest = fhirClient
 				.operation()
 				.onType(FhirConstants.PATIENT)
 				.named(FhirCRConstants.IHE_PIX_OPERATION)
-				.withNoParameters(Parameters.class)
-				.execute();
-
-		// construct and send request to external client registry
-		IQuery<IBaseBundle> crRequest = fhirClient
-		        .search()
-		        .byUrl(
-		            String.format("%s/%s", config.getClientRegistryServerUrl(), config.getClientRegistryGetPatientEndpoint()))
-		        .where(
-		            FhirCRConstants.SOURCE_IDENTIFIER_PARAM.exactly().systemAndIdentifier(sourceIdentifierSystem,
-		                sourceIdentifier));
+				.withSearchParameter(Parameters.class, FhirCRConstants.SOURCE_IDENTIFIER, new TokenParam(sourceIdentifierSystem, sourceIdentifier));
 
 		if (!targetSystems.isEmpty()) {
-			crRequest.and(FhirCRConstants.TARGET_SYSTEM_PARAM.matches().values(targetSystems));
+			identifiersRequest.andSearchParameter(FhirCRConstants.TARGET_SYSTEM, new StringParam(String.join(",", targetSystems)));
+		}
+
+		Parameters crMatchingParams = identifiersRequest.useHttpGet().execute();
+		List<String> crIdentifiers = crMatchingParams.getParameter().stream()
+				.filter(param -> Objects.equals(param.getName(), "targetId"))
+				.map(param -> param.getValue().toString())
+				.collect(Collectors.toList());
+
+		if (crIdentifiers.isEmpty()) {
+			return Collections.emptyList();
 		}
+
+		// construct and send request to external client registry
+		Bundle patientBundle = fhirClient
+				.search()
+				.forResource(Patient.class)
+				.where(new StringClientParam(Patient.SP_RES_ID).matches().values(crIdentifiers))
+				.returnBundle(Bundle.class)
+				.execute();
 		
-		Bundle patientBundle = crRequest.returnBundle(Bundle.class).execute();
 		return parseCRPatientSearchResults(patientBundle);
 	}
 	
diff --git a/api/src/main/java/org/openmrs/module/clientregistry/providers/FhirCRConstants.java b/api/src/main/java/org/openmrs/module/clientregistry/providers/FhirCRConstants.java
index 3ec4eea..66c7286 100644
--- a/api/src/main/java/org/openmrs/module/clientregistry/providers/FhirCRConstants.java
+++ b/api/src/main/java/org/openmrs/module/clientregistry/providers/FhirCRConstants.java
@@ -4,6 +4,7 @@
 import ca.uhn.fhir.rest.gclient.StringClientParam;
 import ca.uhn.fhir.rest.gclient.TokenClientParam;
 import ca.uhn.fhir.rest.gclient.UriClientParam;
+import ca.uhn.fhir.rest.param.StringOrListParam;
 
 public class FhirCRConstants {