package ca.uhn.fhir.util;

/*-
 * #%L
 * HAPI FHIR - Core Library
 * %%
 * Copyright (C) 2014 - 2021 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%
 */

import ca.uhn.fhir.context.BaseRuntimeChildDefinition;
import ca.uhn.fhir.context.BaseRuntimeElementDefinition;
import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.context.FhirVersionEnum;
import ca.uhn.fhir.context.RuntimeResourceDefinition;
import org.hl7.fhir.instance.model.api.IBase;
import org.hl7.fhir.instance.model.api.IBaseBinary;
import org.hl7.fhir.instance.model.api.IBaseReference;
import org.hl7.fhir.instance.model.api.IPrimitiveType;

import java.util.List;

public class BinaryUtil {

	private BinaryUtil() {
		// non instantiable
	}

	/**
	 * Fetches the base64Binary value of Binary.data (or Binary.content on versions of
	 * FHIR before R4), creating it if it does not already exist.
	 */
	@SuppressWarnings("unchecked")
	public static IPrimitiveType<byte[]> getOrCreateData(FhirContext theContext, IBaseBinary theBinary) {
		String elementName = "content";
		if (theContext.getVersion().getVersion().isEqualOrNewerThan(FhirVersionEnum.R4)) {
			elementName = "data";
		}

		BaseRuntimeChildDefinition entryChild = AttachmentUtil.getChild(theContext, theBinary, elementName);
		List<IBase> entries = entryChild.getAccessor().getValues(theBinary);
		return entries
			.stream()
			.map(t -> (IPrimitiveType<byte[]>) t)
			.findFirst()
			.orElseGet(() -> {
				IPrimitiveType<byte[]> binary = AttachmentUtil.newPrimitive(theContext, "base64Binary", null);
				entryChild.getMutator().setValue(theBinary, binary);
				return binary;
			});
	}


	public static IBaseReference getSecurityContext(FhirContext theCtx, IBaseBinary theBinary) {
		RuntimeResourceDefinition def = theCtx.getResourceDefinition("Binary");
		BaseRuntimeChildDefinition child = def.getChildByName("securityContext");
		IBaseReference retVal = null;
		if (child != null) {
			List<IBase> values = child.getAccessor().getValues(theBinary);
			if (values.size() > 0) {
				retVal = (IBaseReference) values.get(0);
			}
		}
		return retVal;
	}

	public static IBaseBinary newBinary(FhirContext theCtx) {
		return (IBaseBinary) theCtx.getResourceDefinition("Binary").newInstance();
	}

	public static void setSecurityContext(FhirContext theCtx, IBaseBinary theBinary, String theSecurityContext) {
		RuntimeResourceDefinition def = theCtx.getResourceDefinition("Binary");
		BaseRuntimeChildDefinition child = def.getChildByName("securityContext");

		BaseRuntimeElementDefinition<?> referenceDef = theCtx.getElementDefinition("reference");
		IBaseReference reference = (IBaseReference) referenceDef.newInstance();
		child.getMutator().addValue(theBinary, reference);

		reference.setReference(theSecurityContext);
	}

	public static void setData(FhirContext theCtx, IBaseBinary theBinary, byte[] theBytes, String theContentType) {
		getOrCreateData(theCtx, theBinary).setValue(theBytes);

		String elementName = "contentType";
		BaseRuntimeChildDefinition entryChild = AttachmentUtil.getChild(theCtx, theBinary, elementName);
		List<IBase> entries = entryChild.getAccessor().getValues(theBinary);
		IPrimitiveType<String> contentTypeElement = entries
			.stream()
			.map(t -> (IPrimitiveType<String>) t)
			.findFirst()
			.orElseGet(() -> {
				IPrimitiveType<String> stringType = AttachmentUtil.newPrimitive(theCtx, "code", null);
				entryChild.getMutator().setValue(theBinary, stringType);
				return stringType;
			});
		contentTypeElement.setValue(theContentType);

	}
}
