/**
 * Copyright (c) 2005-2009 springside.org.cn
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * 
 * $Id: ReflectionUtils.java,v 1.2 2009/12/02 02:09:22 kingapex Exp $
 */
package com.enation.eop.sdk.utils;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.commons.beanutils.PropertyUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

/**
 * 反射的Util函数集合.
 * 
 * 提供访问私有变量,获取泛型类型Class,提取集合中元素的属性,转换字符串到对象等Util函数.
 * 
 * @author calvin
 */
public class ReflectionUtils {

	private static Logger logger = LoggerFactory.getLogger(ReflectionUtils.class);

	/**
	 * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
	 */
	public static Object getFieldValue(final Object object, final String fieldName) {
		Field field = getDeclaredField(object, fieldName);

		if (field == null)
			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]");

		makeAccessible(field);

		Object result = null;
		try {
			result = field.get(object);
		} catch (IllegalAccessException e) {
			logger.error("不可能抛出的异常{}", e.getMessage());
		}
		return result;
	}

	/**
	 * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
	 */
	public static void setFieldValue(final Object object, final String fieldName, final Object value) {
		Field field = getDeclaredField(object, fieldName);

		if (field == null)
			throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]");

		makeAccessible(field);

		try {
			field.set(object, value);
		} catch (IllegalAccessException e) {
			logger.error("不可能抛出的异常:{}", e.getMessage());
		}
	}

	/**
	 * 直接调用对象方法, 无视private/protected修饰符.
	 */
	public static Object invokeMethod(final Object object, final String methodName, final Class<?>[] parameterTypes,
			final Object[] parameters) {
		Method method = getDeclaredMethod(object, methodName, parameterTypes);
		if (method == null)
			throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + object + "]");

		method.setAccessible(true);

		try {
			return method.invoke(object, parameters);
		} catch (Exception e) {
			throw convertReflectionExceptionToUnchecked(e);
		}
	}

	/**
	 * 循环向上转型, 获取对象的DeclaredField.
	 * 
	 * 如向上转型到Object仍无法找到, 返回null.
	 */
	protected static Field getDeclaredField(final Object object, final String fieldName) {
		Assert.notNull(object, "object不能为空");
		Assert.hasText(fieldName, "fieldName");
		for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
				.getSuperclass()) {
			try {
				return superClass.getDeclaredField(fieldName);
			} catch (NoSuchFieldException e) {
				// Field不在当前类定义,继续向上转型
			}
		}
		return null;
	}

	/**
	 * 强行设置Field可访问.
	 */
	protected static void makeAccessible(final Field field) {
		if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
			field.setAccessible(true);
		}
	}

	/**
	 * 循环向上转型,获取对象的DeclaredMethod.
	 * 
	 * 如向上转型到Object仍无法找到, 返回null.
	 */
	protected static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes) {
		Assert.notNull(object, "object不能为空");

		for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
				.getSuperclass()) {
			try {
				return superClass.getDeclaredMethod(methodName, parameterTypes);
			} catch (NoSuchMethodException e) {
				// Method不在当前类定义,继续向上转型
			}
		}
		return null;
	}

	/**
	 * 通过反射,获得Class定义中声明的父类的泛型参数的类型.
	 * 如无法找到, 返回Object.class.
	 * eg.
	 * public UserDao extends HibernateDao<User>
	 *
	 * @param clazz The class to introspect
	 * @return the first generic declaration, or Object.class if cannot be determined
	 */
	@SuppressWarnings("unchecked")
	public static <T> Class<T> getSuperClassGenricType(final Class clazz) {
		return getSuperClassGenricType(clazz, 0);
	}

	/**
	 * 通过反射,获得定义Class时声明的父类的泛型参数的类型.
	 * 如无法找到, 返回Object.class.
	 * 
	 * 如public UserDao extends HibernateDao<User,Long>
	 *
	 * @param clazz clazz The class to introspect
	 * @param index the Index of the generic ddeclaration,start from 0.
	 * @return the index generic declaration, or Object.class if cannot be determined
	 */
	@SuppressWarnings("unchecked")
	public static Class getSuperClassGenricType(final Class clazz, final int index) {

		Type genType = clazz.getGenericSuperclass();
	 
		if (!(genType instanceof ParameterizedType)) {
			logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
			return Object.class;
		}

		Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

		if (index >= params.length || index < 0) {
			logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
					+ params.length);
			return Object.class;
		}
		if (!(params[index] instanceof Class)) {
			logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
			return Object.class;
		}

		return (Class) params[index];
	}


	public static Class getInterfaceClassGenricType(final Class clazz, final int index) {

		Type[] genTypes = clazz.getGenericInterfaces();
		if(genTypes==null || genTypes.length==0 ){
			logger.warn(clazz.getSimpleName() + "'s not impl interface ");
			return Object.class;
		}
		
		
		if (!(genTypes[0] instanceof ParameterizedType)) {
			logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
			return Object.class;
		}

		Type[] params = ((ParameterizedType) genTypes[0]).getActualTypeArguments();
	
		if (index >= params.length || index < 0) {
			logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
					+ params.length);
			return Object.class;
		}
		if (!(params[index] instanceof Class)) {
			logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
			return Object.class;
		}

		return (Class) params[index];
	}
	
	/**
	 * 提取集合中的对象的属性(通过getter函数), 组合成List.
	 * 
	 * @param collection 来源集合.
	 * @param propertyName 要提取的属性名.
	 */
	@SuppressWarnings("unchecked")
	public static List convertElementPropertyToList(final Collection collection, final String propertyName) {
		List list = new ArrayList();

		try {
			for (Object obj : collection) {
				list.add(PropertyUtils.getProperty(obj, propertyName));
			}
		} catch (Exception e) {
			throw convertReflectionExceptionToUnchecked(e);
		}

		return list;
	}

	/**
	 * 提取集合中的对象的属性(通过getter函数), 组合成由分割符分隔的字符串.
	 * 
	 * @param collection 来源集合.
	 * @param propertyName 要提取的属性名.
	 * @param separator 分隔符.
	 */
//	@SuppressWarnings("unchecked")
//	public static String convertElementPropertyToString(final Collection collection, final String propertyName,
//			final String separator) {
//		List list = convertElementPropertyToList(collection, propertyName);
//		return StringUtils.join(list, separator);
//	}

	/**
	 * 转换字符串类型到clazz的property类型的值.
	 * 
	 * @param value 待转换的字符串
	 * @param clazz 提供类型信息的Class
	 * @param propertyName 提供类型信息的Class的属性.
	 */
//	public static Object convertValue(Object value, Class<?> toType) {
//		try {
//			DateConverter dc = new DateConverter();
//			dc.setUseLocaleFormat(true);
//			dc.setPatterns(new String[] { "yyyy-MM-dd", "yyyy-MM-dd HH:mm:ss" });
//			ConvertUtils.register(dc, Date.class);
//			return ConvertUtils.convert(value, toType);
//		} catch (Exception e) {
//			throw convertReflectionExceptionToUnchecked(e);
//		}
//	}

	/**
	 * 将反射时的checked exception转换为unchecked exception.
	 */
	public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
		if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
				|| e instanceof NoSuchMethodException)
			return new IllegalArgumentException("Reflection Exception.", e);
		else if (e instanceof InvocationTargetException)
			return new RuntimeException("Reflection Exception.", ((InvocationTargetException) e).getTargetException());
		else if (e instanceof RuntimeException) {
			return (RuntimeException) e;
		}
		return new RuntimeException("Unexpected Checked Exception.", e);
	}
}
