/*
 * Copyright (c) 2020 pig4cloud Authors. 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.
 */

package com.pig4cloud.pig.common.core.util;

import lombok.experimental.UtilityClass;
import org.springframework.core.BridgeMethodResolver;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.MethodParameter;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.core.annotation.SynthesizingMethodParameter;
import org.springframework.web.method.HandlerMethod;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

/**
 * 类工具类
 *
 * @author L.cm
 */
@UtilityClass
public class ClassUtils extends org.springframework.util.ClassUtils {

	private final ParameterNameDiscoverer PARAMETERNAMEDISCOVERER = new DefaultParameterNameDiscoverer();

	/**
	 * 获取方法参数信息
	 * @param constructor 构造器
	 * @param parameterIndex 参数序号
	 * @return {MethodParameter}
	 */
	public MethodParameter getMethodParameter(Constructor<?> constructor, int parameterIndex) {
		MethodParameter methodParameter = new SynthesizingMethodParameter(constructor, parameterIndex);
		methodParameter.initParameterNameDiscovery(PARAMETERNAMEDISCOVERER);
		return methodParameter;
	}

	/**
	 * 获取方法参数信息
	 * @param method 方法
	 * @param parameterIndex 参数序号
	 * @return {MethodParameter}
	 */
	public MethodParameter getMethodParameter(Method method, int parameterIndex) {
		MethodParameter methodParameter = new SynthesizingMethodParameter(method, parameterIndex);
		methodParameter.initParameterNameDiscovery(PARAMETERNAMEDISCOVERER);
		return methodParameter;
	}

	/**
	 * 获取Annotation
	 * @param method Method
	 * @param annotationType 注解类
	 * @param <A> 泛型标记
	 * @return {Annotation}
	 */
	public <A extends Annotation> A getAnnotation(Method method, Class<A> annotationType) {
		Class<?> targetClass = method.getDeclaringClass();
		// The method may be on an interface, but we need attributes from the target
		// class.
		// If the target class is null, the method will be unchanged.
		Method specificMethod = ClassUtils.getMostSpecificMethod(method, targetClass);
		// If we are dealing with method with generic parameters, find the original
		// method.
		specificMethod = BridgeMethodResolver.findBridgedMethod(specificMethod);
		// 先找方法，再找方法上的类
		A annotation = AnnotatedElementUtils.findMergedAnnotation(specificMethod, annotationType);
		;
		if (null != annotation) {
			return annotation;
		}
		// 获取类上面的Annotation，可能包含组合注解，故采用spring的工具类
		return AnnotatedElementUtils.findMergedAnnotation(specificMethod.getDeclaringClass(), annotationType);
	}

	/**
	 * 获取Annotation
	 * @param handlerMethod HandlerMethod
	 * @param annotationType 注解类
	 * @param <A> 泛型标记
	 * @return {Annotation}
	 */
	public <A extends Annotation> A getAnnotation(HandlerMethod handlerMethod, Class<A> annotationType) {
		// 先找方法，再找方法上的类
		A annotation = handlerMethod.getMethodAnnotation(annotationType);
		if (null != annotation) {
			return annotation;
		}
		// 获取类上面的Annotation，可能包含组合注解，故采用spring的工具类
		Class<?> beanType = handlerMethod.getBeanType();
		return AnnotatedElementUtils.findMergedAnnotation(beanType, annotationType);
	}

}
