// -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
//
// System.Xml.XmlNode
//
// Author:
//   Daniel Weber (daniel-weber@austin.rr.com)
//
// (C) 2001 Daniel Weber

using System;
using System.Collections;

namespace System.Xml 
{
	public abstract class XmlNode : ICloneable, IEnumerable, IXPathNavigable 
	{
		//======= Private data members ==============================================
		protected XmlNodeList _childNodes;
		protected XmlNode FOwnerNode;
		
		// ICloneable

		/// <summary>
		/// Return a clone of this node
		/// </summary>
		/// <returns></returns>
		public virtual object Clone()
		{
			// TODO - implement XmlNode.Clone() as object
			throw new NotImplementedException("object XmlNode.Clone() not implmented");
		}

		// ============ Properties ============================
		/// <summary>
		/// Get the XmlAttributeCollection representing the attributes
		///   on the node type.  Returns null if the node type is not XmlElement.
		/// </summary>
		public virtual XmlAttributeCollection Attributes 
		{
			get 
			{
				return null;
			}
		}
		/// <summary>
		///  Return the base Uniform Resource Indicator (URI) used to resolve
		///  this node, or String.Empty.
		/// </summary>
		public virtual string BaseURI 
		{
			get 
			{
				// TODO - implement XmlNode.BaseURI {get;}
				throw new NotImplementedException("XmlNode.BaseURI not implemented");

			}

		}
		/// <summary>
		/// Return all child nodes of this node.  If there are no children,
		///  return an empty XmlNodeList;
		/// </summary>
		public virtual XmlNodeList ChildNodes 
		{
			get 
			{
				if (_childNodes == null)
					_childNodes = new XmlNodeListAsArrayList();

				return _childNodes;
			}
		}
		
		/// <summary>
		/// Return first child node as XmlNode or null
		/// if the node has no children
		/// </summary>
		public virtual XmlNode FirstChild 
		{
			get
			{
				if (ChildNodes.Count == 0)
					return null;
				else
					return ChildNodes[0];
			}
		}

		/// <summary>
		///		Return true if the node has children
		/// </summary>
		public virtual bool HasChildNodes 
		{
			get 
			{
				if (_childNodes.Count == 0)
					return true;
				else
					return false;
			}
		}

		/// <summary>
		/// Get or Set the concatenated values of node and children
		/// </summary>
		public virtual string InnerText
		{
			get
			{
				// TODO - implement set InnerText()
				throw new NotImplementedException();
			}

			set 
			{
				// TODO - implement set InnerText()
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// Get/Set the XML representing just the child nodes of this node
		/// </summary>
		public virtual string InnerXml
		{
			get
			{
				// TODO - implement set InnerXml()
				throw new NotImplementedException();
			}

			set 
			{
				// TODO - implement set InnerXml()
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// Property Get - true if node is read-only
		/// </summary>
		public virtual bool IsReadOnly
		{
			get
			{
				// TODO - implement or decide to handle in subclass
				return true;
			}
		}

		/// <summary>
		/// Return the child element named [string].  Returns XmlElement
		/// Indexer for XmlNode class.
		/// </summary>
		[System.Runtime.CompilerServices.CSharp.IndexerName("Item")]
		public virtual XmlElement this [String index]
		{
			get 
			{
				// TODO - implement XmlNode.Item(int?)
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// Get the last child node, or null if there are no nodes
		/// </summary>
		public virtual XmlNode LastChild
		{
			get
			{
                if (_childNodes.Count == 0)
				 return null;
				else
				 return _childNodes.Item(_childNodes.Count - 1);
			}

		}

		/// <summary>
		/// Returns the local name of the node with qualifiers removed
		/// LocalName of ns:elementName = "elementName"
		/// </summary>
		public abstract string LocalName {get;}

		/// <summary>
		/// Get the qualified node name
		/// derived classes must implement as behavior varies
		/// by tag type.
		/// </summary>
		public abstract string Name { get; }

		/// <summary>
		/// Get the namespace URI or String.Empty if none
		/// </summary>
		public virtual string NamespaceURI
		{
			get
			{
				// TODO - implement Namespace URI, or determine abstractness
				return String.Empty;
			}
		}

		/// <summary>
		/// Get the node immediatelly following this node, or null
		/// </summary>
		public virtual XmlNode NextSibling 
		{
			get
			{
				// TODO - implement NextSibling
				throw new NotImplementedException();
			}
		}

		public virtual XmlNodeType NodeType 
		{
			get
			{
				return XmlNodeType.None;
			}
		}

		/// <summary>
		/// Return the string representing this node and all it's children
		/// </summary>
		public virtual string OuterXml
		{
			get
			{
				// TODO - implement OuterXml {get;}
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// Return owning document.
		/// If this nodeType is a document, return null
		/// </summary>
		public virtual XmlDocument OwnerDocument
		{
			get
			{
				// TODO - implement OwnerDocument {get;}
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// Returns the parent node, or null
		/// Return value depends on superclass node type
		/// </summary>
		public virtual XmlNode ParentNode
		{
			get
			{
				// TODO - implement ParentNode[get;}
				throw new NotImplementedException();
			}
		}
		
		/// <summary>
		/// set/get the namespace prefix for this node, or 
		/// string.empty if it does not exist
		/// </summary>
		public virtual string Prefix 
		{
			get
			{
				// TODO - implement Prefix {get;}
				throw new NotImplementedException();
			}
			
			set
			{
				// TODO - implement Prefix {set;}
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// The preceding XmlNode or null
		/// </summary>
		public virtual XmlNode PreviousSibling {
			get
			{
				// TODO - implement PreviousSibling {get;}
				throw new NotImplementedException();
			}
		}

		/// <summary>
		/// Get/Set the value for this node
		/// </summary>
		public virtual string Value 
		{
			get
			{
				// TODO - implement Value {get;}
				throw new NotImplementedException();
			}
			
			set
			{
				// TODO - implement Value {set;}
				throw new NotImplementedException();
			}
		}

		//======= Methods ==========================
		/// <summary>
		/// Appends the specified node to the end of the child node list
		/// </summary>
		/// <param name="newChild"></param>
		/// <returns></returns>
		public virtual XmlNode AppendChild (XmlNode newChild)
		{
			// TODO - implement AppendChild ();
			throw new NotImplementedException();
		}

		/// <summary>
		/// Return a clone of the node
		/// </summary>
		/// <param name="deep">Make copy of all children</param>
		/// <returns>Cloned node</returns>
		public abstract XmlNode CloneNode( bool deep);

		/// <summary>
		/// Return an XPathNavigator for navigating this node
		/// </summary>
		/// <returns></returns>
		public XPathNavigator CreateNavigator()
		{
			// TODO - implement CreateNavigator()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Return true if self = obj || self.outerXml == obj.outerXml
		/// </summary>
		/// <param name="obj"></param>
		/// <returns></returns>
		public virtual bool Equals(object obj)
		{
			// TODO - implement Equals(obj)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Return true if objA = objB || objA.outXml == objB.outerXml
		/// </summary>
		/// <param name="objA"></param>
		/// <param name="objB"></param>
		/// <returns></returns>
		public static bool Equals(object objA, object objB)
		{
			// TODO - implement equals(objA, objB)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Provide support for "for each" 
		/// </summary>
		/// <returns></returns>
		public IEnumerator GetEnumerator()
		{
			// TODO - implement GetEnumerator()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Return a hash value for this node
		/// </summary>
		/// <returns></returns>
		public virtual int GetHashCode()
		{
			// TODO - implement GetHashCode()
			throw new NotImplementedException();
		}
		
		/// <summary>
		/// Look up the closest namespace for this node that is in scope for the given prefix
		/// </summary>
		/// <param name="prefix"></param>
		/// <returns>Namespace URI</returns>
		public virtual string GetNamespaceOfPrefix(string prefix)
		{
			// TODO - implement GetNamespaceOfPrefix()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Get the closest xmlns declaration for the given namespace URI that is in scope.
		/// Returns the prefix defined in that declaration.
		/// </summary>
		/// <param name="namespaceURI"></param>
		/// <returns></returns>
		public virtual string GetPrefixOfNamespace(string namespaceURI)
		{
			// TODO - implement GetPrefixOfNamespace
			throw new NotImplementedException();
		}
		
		/// <summary>
		/// Get the type of the current node
		/// </summary>
		/// <returns></returns>
		public Type GetType()
		{
			// TODO - implement GetType()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Insert newChild directlly after the reference node
		/// </summary>
		/// <param name="newChild"></param>
		/// <param name="refChild"></param>
		/// <returns></returns>
		public virtual XmlNode InsertAfter(XmlNode newChild, XmlNode refChild)
		{
			// TODO - implement InsertAfter();
			throw new NotImplementedException();
		}
		
		/// <summary>
		/// Insert newChild directly before the reference node.
		/// </summary>
		/// <param name="newChild"></param>
		/// <param name="refChild"></param>
		/// <returns></returns>
		public virtual XmlNode InsertBefore(XmlNode newChild, XmlNode refChild)
		{
			// TODO - implement InsertBefore()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Put all nodes under this node in "normal" form
		/// Whatever that means...
		/// </summary>
		public virtual void Normalize()
		{
			// TODO - Implement Normalize()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Add the specified child to the beginning of the child node list
		/// </summary>
		/// <param name="newChild">Node to add</param>
		/// <returns>The node added</returns>
		public virtual XmlNode PrependChild(XmlNode newChild)
		{
			//TODO - implement PrependChild(newChild)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Remove all children and attributes
		/// </summary>
		public virtual void RemoveAll()
		{
			// TODO - implement RemoveAll()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Remove specified child node
		/// </summary>
		/// <param name="oldChild"></param>
		/// <returns>Removed node</returns>
		public virtual XmlNode RemoveChild(XmlNode oldChild)
		{
			// TODO - implement RemoveChild(oldChild)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Select a list of nodes matching the xpath
		/// </summary>
		/// <param name="xpath"></param>
		/// <returns>matching nodes</returns>
		public XmlNodeList SelectNodes( string xpath)
		{
			// TODO - imlement SelectNodes(xpath)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Select a list of nodes matching the xpath.  Any prefixes are resolved
		/// using the passed namespace manager
		/// </summary>
		/// <param name="xpath"></param>
		/// <param name="nsmgr"></param>
		/// <returns></returns>
		public XmlNodeList SelectNodes(string xpath, XmlNamespaceManager nsmgr)
		{
			// TODO - implement SelectNodes(xpath, nsmgr)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Selects the first node that matches xpath
		/// </summary>
		/// <param name="?"></param>
		/// <returns></returns>
		public XmlNode SelectSingleNode(string xpatch)
		{
			// TODO - implement SelectSingeNode(xpath)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Returns the first node that matches xpath
		/// Uses the passed namespace manager to resolve namespace URI's
		/// </summary>
		/// <param name="xpath"></param>
		/// <param name="nsmgr"></param>
		/// <returns></returns>
		public XmlNode SelectSingleNode(string xpath, XmlNamespaceManager nsmgr)
		{
			// Implement SelectSingleNode(xpath, nsmgr)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Tests if the DOM implementation supports the passed feature
		/// </summary>
		/// <param name="feature"></param>
		/// <param name="version"></param>
		/// <returns></returns>
		public virtual bool Supports(string feature, string version)
		{
			//TODO - implement Supports(feature, version)
			throw new NotImplementedException();
		}

		/// <summary>
		/// Returns a string representation of the current node and it's children
		/// </summary>
		/// <returns></returns>
		public virtual string ToString()
		{
			// TODO - implement ToString()
			throw new NotImplementedException();
		}

		/// <summary>
		/// Saves all children of the current node to the passed writer
		/// </summary>
		/// <param name="w"></param>
		public abstract void WriteContentTo(XmlWriter w);
		
		/// <summary>
		/// Saves the current node to writer w
		/// </summary>
		/// <param name="w"></param>
		public abstract void WriteTo(XmlWriter w);

		//======= Internal methods    ===============================================
		//======= Protected methods    ==============================================

		//======= Private Methods ==================

	}	// XmlNode
}	// using namespace System.Xml