using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.Serialization;
using System.Xml;

namespace Volian.CSLA.Library
{
	[Serializable()]
	class XMLProperties
	{
		#region Constructors
		public XMLProperties()
		{
			_XmlContents = new XmlDocument();
			_XmlContents.LoadXml("<config/>");
		}
		public XMLProperties(string xml)
		{
			_XmlContents = new XmlDocument();
			_XmlContents.LoadXml(xml);
		}
		#endregion
		#region BusinessMethods
		[NonSerialized]
		XmlDocument _XmlContents;
		public XmlDocument XmlContents
		{
			get { return _XmlContents; }
		}
		private XmlNode GetGroup(string group)
		{
			XmlNodeList xl = _XmlContents.DocumentElement.SelectNodes(string.Format("//{0}", group));
			switch (xl.Count)
			{
				case 0: // No nodes found
					return null;
				case 1: // Found the node
					XmlNode xn = xl[0];
					if (xn.GetType() == typeof(XmlElement)) return xn;
					throw new XmlPropertiesException("Retrieved {0} while looking for XmlElement //{1}", xn.GetType().ToString(), group);
				default: // Found more than 1 node
					throw new XmlPropertiesException("Found more than one node //{0}", group);
			}
		}
		private XmlAttribute GetItem(XmlNode xx, string item)
		{
			XmlNodeList xl = xx.SelectNodes(string.Format("@{0}", item));
			switch (xl.Count)
			{
				case 0: // No nodes found
					return null;
				case 1: // Found the node
					XmlNode xn = xl[0];
					if (xn.GetType() == typeof(XmlAttribute)) return (XmlAttribute)xn;
					throw new XmlPropertiesException("Retrieved {0} while looking for XmlAttribute @{1}", xn.GetType().ToString(), item);
				default: // Found more than 1 node
					throw new XmlPropertiesException("Found more than one node @{0}", item);
			}
		}
		public string this[string group, string item]
		{
			get
			{
				XmlNode xn = GetGroup(group);
				if (xn == null) return string.Empty;
				XmlNode xa = GetItem(xn, item);
				if (xa == null) return string.Empty;
				return xa.InnerText;
			}
			set
			{
				if (value == null) value = string.Empty;
				XmlNode xn = GetGroup(group);
				if (xn == null)
				{
					if (value != string.Empty)// Add Group and Item
					{
						xn = _XmlContents.DocumentElement.AppendChild(_XmlContents.CreateElement(group));
						XmlAttribute xa = xn.Attributes.Append(_XmlContents.CreateAttribute(item));
						xa.Value = value;
					}
				}
				else
				{
					XmlAttribute xa = GetItem(xn, item);
					if (xa == null)
					{
						if (value != string.Empty) // Add Item
						{
							xa = xn.Attributes.Append(_XmlContents.CreateAttribute(item));
							xa.Value = value;
						}
					}
					else
					{
						if (value != string.Empty) // Add Item
						{
							xa.Value = value;
						}
						else
						{
							xn.Attributes.Remove(xa);
							if (xn.Attributes.Count == 0)
								_XmlContents.DocumentElement.RemoveChild(xn);
						}
					}
				}
			}
		}
		public override string ToString()
		{
			return _XmlContents.OuterXml;
		}
		#endregion
		#region XmlPropertiesException
		public class XmlPropertiesException : Exception
		{
			public XmlPropertiesException() : base() { ;}
			public XmlPropertiesException(string message) : base(message) { ;}
			public XmlPropertiesException(string messageFormat,params  object [] args) : base(string.Format(messageFormat,args)) { ;}
			public XmlPropertiesException(SerializationInfo info, StreamingContext context) : base(info, context) { ;}
			public XmlPropertiesException(string message,Exception innerException) : base(message, innerException) { ;}
		}
		#endregion
	}
}