/**
 * Copyright © 2015-2018 ODM All rights reserved.
 */
package com.thinkgem.jeesite.common.utils;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.TimeZone;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.JsonParser.Feature;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.util.JSONPObject;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

/**
 * 简单封装Jackson，实现JSON String<->Java Object的Mapper.
 * 封装不同的输出风格, 使用不同的builder函数创建实例.
 * @author ThinkGem
 * @version 2013-11-15
 */
public class JsonUtil extends ObjectMapper {

	private static final long serialVersionUID = 1L;

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

	private static JsonUtil mapper;

	
	//将该标记放在属性上，如果该属性为NULL则不参与序列化 
	//如果放在类上边,那对这个类的全部属性起作用 
	//Include.Include.ALWAYS 默认 
	//Include.NON_DEFAULT 属性为默认值不序列化 
	//Include.NON_EMPTY 属性为 空（“”） 或者为 NULL 都不序列化 
	//Include.NON_NULL 属性为NULL 不序列化 


	public JsonUtil() {
		this(Include.ALWAYS);
	}

	public JsonUtil(Include include) {
		// 设置输出时包含属性的风格
		if (include != null) {
			this.setSerializationInclusion(include);
		}
		// 允许单引号、允许不带引号的字段名称
		this.enableSimple();
		// 设置输入时忽略在JSON字符串中存在但Java对象实际没有的属性
		this.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        // 空值处理为空串
		this.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>(){
			@Override
			public void serialize(Object value, JsonGenerator jgen,
					SerializerProvider provider) throws IOException,
					JsonProcessingException {
				jgen.writeString("");
			}
        });
		// 设置时区
		this.setTimeZone(TimeZone.getDefault());//getTimeZone("GMT+8:00")
	}

	/**
	 * 创建只输出非Null且非Empty(如List.isEmpty)的属性到Json字符串的Mapper,建议在外部接口中使用.
	 */
	public static JsonUtil getInstance() {
		if (mapper == null){
			mapper = new JsonUtil().enableSimple();
		}
		return mapper;
	}

	/**
	 * 创建只输出初始值被改变的属性到Json字符串的Mapper, 最节约的存储方式，建议在内部接口中使用。
	 */
	public static JsonUtil nonDefaultMapper() {
		if (mapper == null){
			mapper = new JsonUtil(Include.ALWAYS);
		}
		return mapper;
	}
	
	/**
	 * Object可以是POJO，也可以是Collection或数组。
	 * 如果对象为Null, 返回"null".
	 * 如果集合为空集合, 返回"[]".
	 */
	public String toJson(Object object) {
		try {
			return this.writeValueAsString(object);
		} catch (IOException e) {
			logger.warn("write to json string error:" + object, e);
			return null;
		}
	}

	/**
	 * 反序列化POJO或简单Collection如List<String>.
	 * 
	 * 如果JSON字符串为Null或"null"字符串, 返回Null.
	 * 如果JSON字符串为"[]", 返回空集合.
	 * 
	 * 如需反序列化复杂Collection如List<MyBean>, 请使用fromJson(String,JavaType)
	 * @see #fromJson(String, JavaType)
	 */
	public static <T> T fromJson(String jsonString, Class<T> clazz) {
		if (StringUtils.isEmpty(jsonString)) {
			return null;
		}
		try {
			return JsonUtil.getInstance().readValue(jsonString, clazz);
		} catch (IOException e) {
			logger.warn("parse json string error:" + jsonString, e);
			return null;
		}
	}

	/**
	 * 反序列化复杂Collection如List<Bean>, 先使用函數createCollectionType构造类型,然后调用本函数.
	 * @see #createCollectionType(Class, Class...)
	 */
	@SuppressWarnings("unchecked")
	public static <T> T fromJson(String jsonString, JavaType javaType) {
		if (StringUtils.isEmpty(jsonString)) {
			return null;
		}
		try {
			JsonUtil.getInstance().configure(Feature.ALLOW_UNQUOTED_CONTROL_CHARS, true);
			JsonUtil.getInstance().configure(Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
			JsonUtil.getInstance().configure(Feature.ALLOW_SINGLE_QUOTES, true);
			JsonUtil.getInstance().configure(Feature.ALLOW_UNQUOTED_CONTROL_CHARS, true);
			//JsonUtil.getInstance().configure(Feature.INTERN_FIELD_NAMES, true);
			//JsonUtil.getInstance().configure(Feature.CANONICALIZE_FIELD_NAMES, true);
			return (T) JsonUtil.getInstance().readValue(jsonString, javaType);
		} catch (IOException e) {
			logger.warn("parse json string error:" + jsonString, e);
			return null;
		}
	}
	
	public static Map jsonToMap(String jsonString) {
		return fromJson(jsonString,  Map.class);
	}
	
	public static Map ObjectToMap(String jsonString) {
		return fromJson(jsonString,  Map.class);
	}

	public static List ObjectToList(String jsonString) {
		return fromJson(jsonString,  List.class);
	}
	/**
	 * 構造泛型的Collection Type如:
	 * ArrayList<MyBean>, 则调用constructCollectionType(ArrayList.class,MyBean.class)
	 * HashMap<String,MyBean>, 则调用(HashMap.class,String.class, MyBean.class)
	 */
	public JavaType createCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
		return this.getTypeFactory().constructParametricType(collectionClass, elementClasses);
	}

	/**
	 * 當JSON裡只含有Bean的部分屬性時，更新一個已存在Bean，只覆蓋該部分的屬性.
	 */
	@SuppressWarnings("unchecked")
	public <T> T update(String jsonString, T object) {
		try {
			return (T) this.readerForUpdating(object).readValue(jsonString);
		} catch (JsonProcessingException e) {
			logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
		} catch (IOException e) {
			logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
		}
		return null;
	}

	/**
	 * 輸出JSONP格式數據.
	 */
	public String toJsonP(String functionName, Object object) {
		return toJson(new JSONPObject(functionName, object));
	}

	/**
	 * 設定是否使用Enum的toString函數來讀寫Enum,
	 * 為False時時使用Enum的name()函數來讀寫Enum, 默認為False.
	 * 注意本函數一定要在Mapper創建後, 所有的讀寫動作之前調用.
	 */
	public JsonUtil enableEnumUseToString() {
		this.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
		this.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
		return this;
	}


	/**
	 * 允许单引号
	 * 允许不带引号的字段名称
	 */
	public JsonUtil enableSimple() {
		this.configure(Feature.ALLOW_SINGLE_QUOTES, true);
		this.configure(Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
		return this;
	}
	
	/**
	 * 取出Mapper做进一步的设置或使用其他序列化API.
	 */
	public ObjectMapper getMapper() {
		return this;
	}

	/**
	 * 对象转换为JSON字符串
	 * @param object
	 * @return
	 */
	public static String toJsonStringnotnull(Object object){
		return JsonUtil.getInstance().toJson(object);
	}
	/**
	 * 对象转换为JSON字符串
	 * @param object
	 * @return
	 */
	public static String toJsonString(Object object){
		return JsonUtil.getInstance().toJson(object);
	}
	/**
	 * JSON字符串转换为对象
	 * @param jsonString
	 * @param clazz
	 * @return
	 */
	public static Object fromJsonString(String jsonString, Class<?> clazz){
		return JsonUtil.getInstance().fromJson(jsonString, clazz);
	}
	
	/**
	 * 测试
	 */
	public static void main(String[] args) {
		List<Map<String, Object>> list = Lists.newArrayList();
		Map<String, Object> map = Maps.newHashMap();
		map.put("id", 1);
		map.put("pId", -1);
		map.put("name", "根节点");
		list.add(map);
		map = Maps.newHashMap();
		map.put("id", 2);
		map.put("pId", 1);
		map.put("name", "你好");
		map.put("open", true);
		list.add(map);
		map = Maps.newHashMap();
		map.put("id", null);
		map.put("pId", null);
		map.put("name", "而俄国人");
		map.put("open", true);
		list.add(map);
		String json = JsonUtil.getInstance().toJson(list);
		System.out.println(json);
	}
	public static Map ObjectoMap(Object obj) {
		return fromJson( toJsonString(obj),Map.class);
	}
}