package ca.uhn.fhir.model.view;
   
   /*
    * #%L
    * HAPI FHIR - Core Library
    * %%
    * Copyright (C) 2014 University Health Network
    * %%
    * 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 java.util.List;
  
  import ca.uhn.fhir.context.BaseRuntimeChildDefinition;
  import ca.uhn.fhir.context.BaseRuntimeElementCompositeDefinition;
  import ca.uhn.fhir.context.ConfigurationException;
  import ca.uhn.fhir.context.FhirContext;
  import ca.uhn.fhir.context.RuntimeChildDeclaredExtensionDefinition;
  import ca.uhn.fhir.context.RuntimeResourceDefinition;
  import ca.uhn.fhir.model.api.BaseElement;
  import ca.uhn.fhir.model.api.ExtensionDt;
  import ca.uhn.fhir.model.api.IElement;
  import ca.uhn.fhir.model.api.IResource;
  
  public class ViewGenerator {
  
  	private FhirContext myCtx;
  
  	public ViewGenerator(FhirContext theFhirContext) {
  		myCtx=theFhirContext;
  	}
  
  	public <T extends IResource> T newView(IResource theResource, Class<T> theTargetType) {
  		Class<? extends IResource> sourceType = theResource.getClass();
  		RuntimeResourceDefinition sourceDef = myCtx.getResourceDefinition(theResource);
  		RuntimeResourceDefinition targetDef = myCtx.getResourceDefinition(theTargetType);
  
  		if (sourceType.equals(theTargetType)) {
  			@SuppressWarnings("unchecked")
  			T resource = (T) theResource;
  			return resource;
  		}
  
  		T retVal;
  		try {
  			retVal = theTargetType.newInstance();
  		} catch (InstantiationException e) {
  			throw new ConfigurationException("Failed to instantiate " + theTargetType, e);
  		} catch (IllegalAccessException e) {
  			throw new ConfigurationException("Failed to instantiate " + theTargetType, e);
  		}
  
  		copyChildren(sourceDef, (BaseElement) theResource, targetDef, (BaseElement) retVal);
  
  		return retVal;
  	}
  
  	private void copyChildren(BaseRuntimeElementCompositeDefinition<?> theSourceDef, BaseElement theSource, BaseRuntimeElementCompositeDefinition<?> theTargetDef, BaseElement theTarget) {
  		if (!theSource.isEmpty()) {
  			List<BaseRuntimeChildDefinition> targetChildren = theTargetDef.getChildren();
  			for (BaseRuntimeChildDefinition nextChild : targetChildren) {
  
  				String elementName = nextChild.getElementName();
  				if (nextChild.getValidChildNames().size() > 1) {
  					elementName = nextChild.getValidChildNames().iterator().next();
  				}
  				
  				BaseRuntimeChildDefinition sourceChildEquivalent = theSourceDef.getChildByNameOrThrowDataFormatException(elementName);
  				if (sourceChildEquivalent == null) {
  					continue;
  				}
  
  				List<? extends IElement> sourceValues = sourceChildEquivalent.getAccessor().getValues(theSource);
  				for (IElement nextElement : sourceValues) {
  					nextChild.getMutator().addValue(theTarget, nextElement);
  				}
  			}
  			
  			List<RuntimeChildDeclaredExtensionDefinition> targetExts = theTargetDef.getExtensions();
  			for (RuntimeChildDeclaredExtensionDefinition nextExt : targetExts) {
  				String url = nextExt.getExtensionUrl();
  				
  				RuntimeChildDeclaredExtensionDefinition sourceDeclaredExt = theSourceDef.getDeclaredExtension(url);
  				if (sourceDeclaredExt == null) {
  					
  					for (ExtensionDt next : theSource.getAllUndeclaredExtensions()) {
  						if (next.getUrlAsString().equals(url)) {
  							nextExt.getMutator().addValue(theTarget, next.getValue());
 						}
 					}
 					
 				} else {
 					
 					List<? extends IElement> values = sourceDeclaredExt.getAccessor().getValues(theSource);
 					for (IElement nextElement : values) {
 						nextExt.getMutator().addValue(theTarget, nextElement);
 					}
 					
 				}
 				
 			}
 			
 			
 		}
 	}
 }