/*
 * Copyright 2022 the original author or authors.
 *
 *  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.
 */
package org.openehealth.ipf.commons.ihe.fhir.support;

import ca.uhn.fhir.rest.api.server.RequestDetails;
import ca.uhn.fhir.rest.server.RestfulServer;
import ca.uhn.fhir.rest.server.provider.ServerCapabilityStatementProvider;
import org.hl7.fhir.instance.model.api.IBaseConformance;
import org.hl7.fhir.r4.model.CapabilityStatement;

import jakarta.servlet.http.HttpServletRequest;

/**
 * ServerCapabilityStatementProvider that defends against NPE when no resource
 * providers are present.
 *
 * @author Christian Ohr
 */
public class NullsafeServerCapabilityStatementProvider extends ServerCapabilityStatementProvider {

    private final RestfulServer fhirServer;

    public NullsafeServerCapabilityStatementProvider(RestfulServer fhirServer) {
        super(fhirServer);
        this.fhirServer = fhirServer;
        this.fhirServer.setServerConformanceProvider(this);
    }

    @Override
    public IBaseConformance getServerConformance(HttpServletRequest theRequest, RequestDetails theRequestDetails) {
        if (fhirServer.getResourceProviders().isEmpty() && fhirServer.getPlainProviders().isEmpty()){
            return new CapabilityStatement();
        } else {
            return super.getServerConformance(theRequest, theRequestDetails);
        }
    }
}
