/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */
package org.onap.aai.serialization.queryformats.utils;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Set;

import javax.ws.rs.core.MultivaluedMap;

import org.onap.aai.serialization.queryformats.exceptions.QueryParamInjectionException;
import org.onap.aai.serialization.queryformats.params.Inject;
import org.onap.aai.serialization.queryformats.params.Setter;
import org.reflections.Reflections;

public class QueryParamInjector {

	private final Set<Class<?>> results;
	
	
	private QueryParamInjector () {
		Reflections reflections = new Reflections("org.onap.aai.serialization.queryformats.params");
		results = reflections.getTypesAnnotatedWith(Inject.class);
	}
	
	private static class Helper {
		private static final QueryParamInjector INSTANCE = new QueryParamInjector();
	}
	
	public static QueryParamInjector getInstance() {
		return Helper.INSTANCE;
	}
	
	public <T> T injectParams(T obj, MultivaluedMap<String, String> params) throws QueryParamInjectionException{
		try {
			for (Class<?> item : results) {
				if (item.isAssignableFrom(obj.getClass())) {
					String name = item.getAnnotation(Inject.class).name();
					
					if (params.containsKey(name)) {
						String value = params.getFirst(name);
						
						for (Method method : item.getMethods()) {
							if (method.isAnnotationPresent(Setter.class)) {
								Class<?>[] args = method.getParameterTypes();
								if (args.length == 1) {
									Object o = args[0].getConstructor(String.class).newInstance(value);
									method.invoke(obj, o);
								} else {
									method.invoke(obj);
								}
							}
						}
					}
				}
			}
	} catch (InstantiationException | IllegalAccessException | IllegalArgumentException
											| InvocationTargetException | NoSuchMethodException
											| SecurityException e) {
		throw new QueryParamInjectionException("issue with query params", e);
	}
		
		
		return obj;
	}
}