using System;
using System.IO;
using System.Text;
using System.Xml;
using System.Xml.Serialization;

namespace Xml.Utility
{
    public static class XmlUtil
    {
        /// <summary>
        /// 将一个对象序列化为XML字符串
        /// </summary>
        /// <param name="o">要序列化的对象</param>
        /// <param name="encoding">编码方式</param>
        /// <returns>序列化产生的XML字符串</returns>
        public static string XmlSerialize(object o, Encoding encoding)
        {
            if (o == null)
            {
                throw new ArgumentNullException("o");
            }

            if (encoding == null)
            {
                throw new ArgumentNullException("encoding");
            }
          
            using (MemoryStream stream = new MemoryStream())
            {
                XmlSerializer serializer = new XmlSerializer(o.GetType());

                XmlWriterSettings settings = new XmlWriterSettings();
                settings.Indent = true;
                settings.NewLineChars = "\r\n";
                settings.Encoding = encoding;
                settings.IndentChars = "  ";
                settings.OmitXmlDeclaration = true;

                using (XmlWriter writer = XmlWriter.Create(stream, settings))
                {
                    //Create our own namespaces for the output
                    XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
                    //Add an empty namespace and empty value
                    ns.Add("", "");
                    serializer.Serialize(writer, o, ns);
                    writer.Close();
                }

                stream.Position = 0;
                using (StreamReader reader = new StreamReader(stream, encoding))
                {
                    return reader.ReadToEnd();
                }
            }
        }

        /// <summary>
        /// 从XML字符串中反序列化对象
        /// </summary>
        /// <typeparam name="T">结果对象类型</typeparam>
        /// <param name="s">包含对象的XML字符串</param>
        /// <param name="encoding">编码方式</param>
        /// <returns>反序列化得到的对象</returns>
        public static T XmlDeserialize<T>(string s, Encoding encoding)
        {
            if (string.IsNullOrEmpty(s))
                throw new ArgumentNullException("s");
            if (encoding == null)
                throw new ArgumentNullException("encoding");

            XmlSerializer mySerializer = new XmlSerializer(typeof(T));
            using (MemoryStream ms = new MemoryStream(encoding.GetBytes(s)))
            {
                using (StreamReader sr = new StreamReader(ms, encoding))
                {
                    return (T)mySerializer.Deserialize(sr);
                }
            }
        }

        /// <summary>
        /// 将一个对象按XML序列化的方式写入到一个文件
        /// </summary>
        /// <param name="o">要序列化的对象</param>
        /// <param name="path">保存文件路径</param>
        /// <param name="encoding">编码方式</param>
        public static void XmlSerializeToFile(object o, string path, Encoding encoding)
        {
            if (string.IsNullOrEmpty(path))
            {
                throw new ArgumentNullException("path");
            }

            if (o == null)
            {
                throw new ArgumentNullException("o");
            }

            if (encoding == null)
            {
                throw new ArgumentNullException("encoding");
            }

            using (FileStream file = new FileStream(path, FileMode.Create, FileAccess.Write))
            {
                XmlSerializer serializer = new XmlSerializer(o.GetType());

                XmlWriterSettings settings = new XmlWriterSettings();
                settings.Indent = true;
                settings.NewLineChars = "\r\n";
                settings.Encoding = encoding;
                settings.IndentChars = "    ";

                using (XmlWriter writer = XmlWriter.Create(file, settings))
                {
                    serializer.Serialize(writer, o);
                    writer.Close();
                }
            }
        }

        /// <summary>
        /// 读入一个文件，并按XML的方式反序列化对象。
        /// </summary>
        /// <typeparam name="T">结果对象类型</typeparam>
        /// <param name="path">文件路径</param>
        /// <param name="encoding">编码方式</param>
        /// <returns>反序列化得到的对象</returns>
        public static T XmlDeserializeFromFile<T>(string path, Encoding encoding)
        {
            if (string.IsNullOrEmpty(path))
                throw new ArgumentNullException("path");
            if (encoding == null)
                throw new ArgumentNullException("encoding");

            string xml = File.ReadAllText(path, encoding);
            return XmlDeserialize<T>(xml, encoding);
        }
    }
}