/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright (c) 2003-2007 by AG-Software 											 *
 * All Rights Reserved.																 *
 * Contact information for AG-Software is available at http://www.ag-software.de	 *
 *																					 *
 * Licence:																			 *
 * The agsXMPP SDK is released under a dual licence									 *
 * agsXMPP can be used under either of two licences									 *
 * 																					 *
 * A commercial licence which is probably the most appropriate for commercial 		 *
 * corporate use and closed source projects. 										 *
 *																					 *
 * The GNU Public License (GPL) is probably most appropriate for inclusion in		 *
 * other open source projects.														 *
 *																					 *
 * See README.html for details.														 *
 *																					 *
 * For general enquiries visit our website at:										 *
 * http://www.ag-software.de														 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/* --------------------------------------------------------------------------
 * Copyrights
 * 
 * Portions created by or assigned to Cursive Systems, Inc. are 
 * Copyright (c) 2002-2005 Cursive Systems, Inc.  All Rights Reserved.  Contact
 * information for Cursive Systems, Inc. is available at
 * http://www.cursive.net/.
 *
 * License
 * 
 * Jabber-Net can be used under either JOSL or the GPL.  
 * See LICENSE.txt for details.
 * --------------------------------------------------------------------------*/
using System.Collections;

namespace agsXMPP.Xml.xpnet
{
    /// <summary>
    /// Namespace stack.
    /// </summary>
    public class NS
    {
        private Stack m_stack = new Stack();
        
        /// <summary>
        /// Create a new stack, primed with xmlns and xml as prefixes.
        /// </summary>
        public NS()
        {
            PushScope();
            AddNamespace("xmlns", "http://www.w3.org/2000/xmlns/");
            AddNamespace("xml", "http://www.w3.org/XML/1998/namespace");
        }
        
        /// <summary>
        /// Declare a new scope, typically at the start of each element
        /// </summary>
        public void PushScope()
        {
            m_stack.Push(new Hashtable());
        }

        /// <summary>
        /// Pop the current scope off the stack.  Typically at the end of each element.
        /// </summary>
        public void PopScope()
        {
            m_stack.Pop();
        }

        /// <summary>
        /// Add a namespace to the current scope.
        /// </summary>
        /// <param name="prefix"></param>
        /// <param name="uri"></param>
        public void AddNamespace(string prefix, string uri)
        {
            ((Hashtable)m_stack.Peek()).Add(prefix, uri);
        }

        /// <summary>
        /// Lookup a prefix to find a namespace.  Searches down the stack, starting at the current scope.
        /// </summary>
        /// <param name="prefix"></param>
        /// <returns></returns>
        public string LookupNamespace(string prefix)
        {
            foreach (Hashtable ht in m_stack)
            {
				if ((ht.Count > 0) && (ht.ContainsKey(prefix)))
                    return (string)ht[prefix];
            }
            return "";
        }

        /// <summary>
        /// The current default namespace.
        /// </summary>
        public string DefaultNamespace
        {
            get { return LookupNamespace(string.Empty); }
        }
		        
        /// <summary>
        /// Debug output only.
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder();
            
            foreach (Hashtable ht in m_stack)
            {
                sb.Append("---\n");
                foreach (string k in ht.Keys)
                {
                    sb.Append(string.Format("{0}={1}\n", k, ht[k]));
                }
            }
            return sb.ToString();
        }

		public void Clear()
		{			
#if !CF
		    m_stack.Clear();
#else
			while (m_stack.Count > 0)
			    m_stack.Pop();
#endif
		}
    }
}