using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml.Serialization;
using System.Text.RegularExpressions;
using System.Collections;
using System.Collections.Concurrent;

namespace Bowin.Common.XML
{
    public class XmlHelper
    {
        private static Regex rgxRoot = new Regex("<(\\w+?)[ >]", RegexOptions.Compiled);
        private static Regex rgxCid = new Regex("RE\\w+", RegexOptions.IgnoreCase);
        private static ConcurrentDictionary<string, XmlSerializer> cache = new ConcurrentDictionary<string, XmlSerializer>();

        // <summary>
        /// XML序列化成实体类
        /// </summary>
        /// <typeparam name="T">序列化的实体类</typeparam>
        /// <param name="strBody">XML格式的字符串</param>
        /// <returns>返回序列化后的类</returns>
        public static T Parse<T>(string strBody)
        {
            string rootTagName = GetRoot(strBody);
            string strCommand = GetCommand(strBody);
            XmlSerializer serizaier = cache[strCommand];

            if (serizaier == null)
            {
                XmlAttributes rootAttrs = new XmlAttributes();
                rootAttrs.XmlRoot = new XmlRootAttribute(rootTagName);
                XmlAttributeOverrides attrOvrs = new XmlAttributeOverrides();
                attrOvrs.Add(typeof(T), rootAttrs);

                serizaier = new XmlSerializer(typeof(T), attrOvrs);
                //serizaier = new XmlSerializer(typeof(T));

                if (!cache.ContainsKey(strCommand))
                {
                    cache[strCommand] = serizaier;
                }
            }

            object obj = null;
            using (Stream stream = new MemoryStream(Encoding.GetEncoding("GB2312").GetBytes(strBody)))
            {
                obj = serizaier.Deserialize(stream);
            }

            return (T)obj;
        }

        /// <summary>
        /// 取得消息命令头
        /// </summary>
        /// <param name="strXml">要检查的XML字符串</param>
        /// <returns>返回找到的命令头</returns>
        private static string GetCommand(string strXml)
        {
            Match match = rgxCid.Match(strXml);
            if (match.Success)
                return match.Groups[0].ToString();
            else
                throw new Exception("Invalid XML response format!");
        }

        /// <summary>
        /// 获取XML根节点名称
        /// </summary>
        /// <param name="strBody"></param>
        /// <returns></returns>
        private static string GetRoot(string strBody)
        {
            Match match = rgxRoot.Match(strBody);
            if (match.Success)
                return match.Groups[1].ToString();
            else
                throw new Exception("Invalid XML response format!");
        }
    }
}