//
// DataObject.cs - DataObject implementation for XML Signature
// http://www.w3.org/2000/09/xmldsig#Object
//
// Author:
//	Sebastien Pouliot (spouliot@motus.com)
//
// (C) 2002 Motus Technologies Inc. (http://www.motus.com)
//

using System.Security.Cryptography;
using System.Text;
using System.Xml;

namespace System.Security.Cryptography.Xml {

// XmlElement part of the signature
// Note: Looks like KeyInfoNode (but the later is XmlElement inside KeyInfo)
// required for "enveloping signatures"
public class DataObject {

	private string id;
	private string mimeType;
	private string encoding;
	private string data;
	private XmlDocument doc;

	static private string xmldsig = "http://www.w3.org/2000/09/xmldsig#";

	public DataObject () 
	{
		Build (null, null, null, null);
	}

	public DataObject (string id, string mimeType, string encoding, XmlElement data) 
	{
		if (data == null)
			throw new ArgumentNullException ("data");

		Build (id, mimeType, encoding, data);
	}

	private void Build (string id, string mimeType, string encoding, XmlElement data) 
	{
		StringBuilder sb = new StringBuilder ();
		sb.Append ("<Object ");
		if (id != null) {
			this.id = id;
			sb.Append ("Id=\"");
			sb.Append (id);
			sb.Append ("\" ");
		}
		if (mimeType != null) {
			this.mimeType = mimeType;
			sb.Append ("MimeType=\"");
			sb.Append (mimeType);
			sb.Append ("\" ");
		}
		if (encoding != null) {
			this.encoding = encoding;
			sb.Append ("Encoding=\"");
			sb.Append (encoding);
			sb.Append ("\" ");
		}
		sb.Append ("xmlns=\"http://www.w3.org/2000/09/xmldsig#\" />");
		
		doc = new XmlDocument ();
		doc.LoadXml (sb.ToString ());
		if (data != null) {
			XmlNodeList xnl = doc.GetElementsByTagName ("Object");
			XmlNode newNode = doc.ImportNode (data, true);
			xnl[0].AppendChild (newNode);
		}
	}

	// why is data a XmlNodeList instead of a XmlElement ?
	public XmlNodeList Data {
		get { 
			XmlNodeList xnl = doc.GetElementsByTagName ("Object");
			return xnl[0].ChildNodes;
		}
		set {
			if (value == null)
				throw new ArgumentNullException ("value");

			Build (id, mimeType, encoding, null);
			XmlNodeList xnl = doc.GetElementsByTagName ("Object");
			if ((xnl != null) && (xnl.Count > 0)) {
				foreach (XmlNode xn in value) {
					XmlNode newNode = doc.ImportNode (xn, true);
					xnl[0].AppendChild (newNode);
				}
			}
		}
	}

	// default to null - no encoding
	public string Encoding {
		get { return encoding; }
		set { encoding = value;	}
	}

	// default to null
	public string Id {
		get { return id; }
		set { id = value; }
	}

	// default to null
	public string MimeType {
		get { return mimeType; }
		set { mimeType = value; }
	}

	public XmlElement GetXml () 
	{
		if ((doc.DocumentElement.LocalName == "Object") && (doc.DocumentElement.NamespaceURI == "http://www.w3.org/2000/09/xmldsig#")) {
			// recreate all attributes in order
			XmlAttribute xa = null;
			doc.DocumentElement.Attributes.RemoveAll ();
			if (id != null) {
				xa = doc.CreateAttribute ("Id");
				xa.Value = id;
				doc.DocumentElement.Attributes.Append (xa);
			}
			if (mimeType != null) {
				xa = doc.CreateAttribute ("MimeType");
				xa.Value = mimeType;
				doc.DocumentElement.Attributes.Append (xa);
			}
			if (encoding != null) {
				xa = doc.CreateAttribute ("Encoding");
				xa.Value = encoding;
				doc.DocumentElement.Attributes.Append (xa);
			}
			xa = doc.CreateAttribute ("xmlns");
			xa.Value = xmldsig;
			doc.DocumentElement.Attributes.Append (xa);
		}
		return doc.DocumentElement;
	}

	public void LoadXml (XmlElement value) 
	{
		if (value == null)
			throw new ArgumentNullException ("value");

		if ((value.LocalName == "Object") && (value.NamespaceURI == "http://www.w3.org/2000/09/xmldsig#")) {
			doc.LoadXml (value.OuterXml);
			XmlAttribute xa = value.Attributes ["Id"];
			id = ((xa != null) ? xa.InnerText : null);
			xa = value.Attributes ["MimeType"];
			mimeType = ((xa != null) ? xa.InnerText : null);
			xa = value.Attributes ["Encoding"];
			encoding = ((xa != null) ? xa.InnerText : null);
		}
		else
			doc.LoadXml (value.OuterXml);
	}
}

}