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/**
 * Copyright (C) 2016 - 2030 youtongluan.
 *
 * 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.yx.util.kit;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Objects;

import org.yx.bean.Loader;
import org.yx.exception.SumkException;

/**
 * 支持子类，但不支持属性的嵌套解析
 */

public class BeanConverter {
	private static final String JAVA_PRE = "java";

	private static final int NOT_PARSE = Modifier.STATIC | Modifier.TRANSIENT | Modifier.FINAL;

	private Map, Field[]> cache = Collections
			.synchronizedMap(new LinkedHashMap, Field[]>(32, 0.75f, true) {
				private static final long serialVersionUID = 1L;

				@Override
				protected boolean removeEldestEntry(Entry, Field[]> eldest) {
					return this.size() > 500;
				}

			});

	private Field[] parseFields(Class clz) {
		List list = new ArrayList<>();
		Class tempClz = clz;
		while (tempClz != null && tempClz != Object.class) {

			Field[] fs = cache.get(tempClz);
			if (fs != null) {
				Collections.addAll(list, fs);
				break;
			}
			fs = tempClz.getDeclaredFields();
			for (Field f : fs) {
				if ((f.getModifiers() & NOT_PARSE) != 0) {
					continue;
				}
				f.setAccessible(true);
				list.add(f);
			}
			tempClz = tempClz.getSuperclass();
		}
		return list.toArray(new Field[list.size()]);
	}

	public Field[] getFields(Class clz) {
		Field[] fields = cache.get(clz);
		if (fields != null) {
			return fields;
		}
		fields = this.parseFields(clz);
		String clzName = clz.getName();
		if (clzName.startsWith(JAVA_PRE) || clzName.contains("$")) {
			return fields;
		}
		Field[] f2 = cache.putIfAbsent(clz, fields);
		return f2 != null ? f2 : fields;
	}

	/**
	 * 根据field转为map。不会对属性内部的字段再做解析
	 * 
	 * @param bean
	 *            用于转化的pojo对象。
	 * @param keepNull
	 *            如果为true，那么它就会保留null字段
	 * @return 返回map对象，不为null。
	 */
	@SuppressWarnings("unchecked")
	public Map beanToMap(Object bean, boolean keepNull) {
		if (bean == null) {
			return Collections.emptyMap();
		}
		if (Map.class.isInstance(bean)) {
			return (Map) bean;
		}
		try {
			Field[] fields = getFields(bean.getClass());
			Map map = new HashMap<>();
			for (Field f : fields) {
				Object v = f.get(bean);
				if (v == null && !keepNull) {
					continue;
				}
				map.putIfAbsent(f.getName(), v);
			}
			return map;
		} catch (Exception e) {
			throw new SumkException(35432540, "beanToMap to map failed, because of " + e.getMessage(), e);
		}
	}

	/**
	 * 根据map的内容填充bean的属性。只转义第一层的key。

	 * 对大小写和下划线不敏感
	 * 
	 * @param map
	 *            原始map
	 * @param bean
	 *            目标对象，它的属性会被填充进来
	 * @return 返回目标对象
	 */
	@SuppressWarnings("unchecked")
	public  T fillBeanIgnoreCaseAndUnderLine(Map map, T bean) {
		if (map == null || bean == null || map.isEmpty()) {
			return bean;
		}
		if (Map.class.isInstance(bean)) {
			Map.class.cast(bean).putAll(map);
			return bean;
		}
		Map tmp = new HashMap<>();
		map.forEach((k, v) -> {
			if (k == null || v == null) {
				return;
			}
			tmp.put(k.toLowerCase().replace("_", ""), v);
		});
		map = tmp;
		Field[] fields = getFields(bean.getClass());
		try {
			for (Field f : fields) {
				String fName = f.getName().toLowerCase().replace("_", "");
				if (map.containsKey(fName)) {
					f.set(bean, map.get(fName));
				}
			}
		} catch (Exception e) {
			throw new SumkException(35432541, "fillBean failed, because of " + e.getMessage(), e);
		}
		return bean;
	}

	/**
	 * 根据map的内容填充bean的属性。只转义第一层的key。

	 * 
	 * @param map
	 *            原始map
	 * @param bean
	 *            目标对象，它的属性会被填充进来
	 * @return 返回目标对象
	 */
	@SuppressWarnings("unchecked")
	public  T fillBean(Map map, T bean) {
		if (map == null || bean == null || map.isEmpty()) {
			return bean;
		}
		if (Map.class.isInstance(bean)) {
			Map.class.cast(bean).putAll(map);
			return bean;
		}
		Field[] fields = getFields(bean.getClass());
		try {
			for (Field f : fields) {
				if (map.containsKey(f.getName())) {
					f.set(bean, map.get(f.getName()));
				}
			}
		} catch (Exception e) {
			throw new SumkException(35432541, "fillBean failed, because of " + e.getMessage(), e);
		}
		return bean;
	}

	public  T copyFields(Object src, T dest) {
		if (src == null || dest == null) {
			return dest;
		}
		Class srcClz = src.getClass();
		if (!srcClz.isInstance(dest)) {
			throw new SumkException(35432543, dest.getClass().getName() + " cannot convert to " + srcClz.getName());
		}
		Field[] fields = getFields(srcClz);
		try {
			for (Field f : fields) {
				f.set(dest, f.get(src));
			}
		} catch (Exception e) {
			throw new SumkException(35432542, "copyFields failed, because of " + e.getMessage(), e);
		}
		return dest;
	}

	public Object clone(Object src) {
		if (src == null) {
			return null;
		}
		Object dest;
		try {
			dest = Loader.newInstance(src.getClass());
		} catch (Exception e) {
			throw new SumkException(35432545, "clone failed, because of " + e.getMessage(), e);
		}
		return this.copyFields(src, dest);
	}

	public Map, Field[]> getCache() {
		return cache;
	}

	public void setCache(Map, Field[]> threadSaftMap) {
		this.cache = Objects.requireNonNull(threadSaftMap);
	}
}