/**
    * Copyright © 2018 spring-data-dynamodb (https://github.com/derjust/spring-data-dynamodb)
    *
    * 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.socialsignin.spring.data.dynamodb.repository.support;
  
  import org.springframework.data.repository.core.support.AbstractEntityInformation;
  import org.springframework.lang.NonNull;
  import org.springframework.util.Assert;
  import org.springframework.util.ReflectionUtils;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Field;
  import java.lang.reflect.Method;
  
  /**
   * {@link org.springframework.data.repository.core.EntityInformation}
   * implementation that inspects getters for an annotation and invokes this
   * getter's value to retrieve the id.
   *
   * @author Michael Lavelle
   * @author Sebastian Just
   */
  public class FieldAndGetterReflectionEntityInformation<T, ID> extends AbstractEntityInformation<T, ID> {
  
  	protected Method method;
  	private Field field;
  
  	/**
  	 * Creates a new {@link FieldAndGetterReflectionEntityInformation} inspecting
  	 * the given domain class for a getter carrying the given annotation.
  	 *
  	 * @param domainClass
  	 *            must not be {@literal null}.
  	 * @param annotation
  	 *            must not be {@literal null}.
  	 */
  	public FieldAndGetterReflectionEntityInformation(@NonNull Class<T> domainClass,
  			@NonNull final Class<? extends Annotation> annotation) {
  
  		super(domainClass);
  		Assert.notNull(annotation, "annotation must not be null!");
  
  		ReflectionUtils.doWithMethods(domainClass, (method) -> {
  			if (method.getAnnotation(annotation) != null) {
  				this.method = method;
  				return;
  			}
  		});
  
  		if (method == null) {
  			field = null;
  			ReflectionUtils.doWithFields(domainClass, (field) -> {
  				if (field.getAnnotation(annotation) != null) {
  					this.field = field;
  					return;
  				}
  			});
  		}
  
  		Assert.isTrue(this.method != null || this.field != null,
  				String.format("No field or method annotated with %s found!", annotation.toString()));
  		Assert.isTrue(this.method == null || this.field == null,
  				String.format("Both field and method annotated with %s found!", annotation.toString()));
  
  		if (method != null) {
  			ReflectionUtils.makeAccessible(method);
  		}
  	}
  
  	/*
  	 * (non-Javadoc)
  	 *
  	 * @see org.springframework.data.repository.core.EntityInformation#getId(java
  	 * .lang.Object)
  	 */
  	@Override
  	@SuppressWarnings("unchecked")
  	public ID getId(T entity) {
  		if (method != null) {
  			return entity == null ? null : (ID) ReflectionUtils.invokeMethod(method, entity);
  		} else {
  			return entity == null ? null : (ID) ReflectionUtils.getField(field, entity);
  		}
  	}
  
  	/*
  	 * (non-Javadoc)
 	 *
 	 * @see org.springframework.data.repository.core.EntityInformation#getIdType()
 	 */
 	@Override
 	@SuppressWarnings("unchecked")
 	public Class<ID> getIdType() {
 		return (Class<ID>) (method != null ? method.getReturnType() : field.getType());
 	}
 }