// OCSPRef.cs
//
// XAdES Starter Kit for Microsoft .NET 3.5 (and above)
// 2010 Microsoft France
// Published under the CECILL-B Free Software license agreement.
// (http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.txt)
// 
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
// WHETHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
// WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. 
// THE ENTIRE RISK OF USE OR RESULTS IN CONNECTION WITH THE USE OF THIS CODE 
// AND INFORMATION REMAINS WITH THE USER.

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

namespace Microsoft.Xades
{
    /// <summary>
    /// This class identifies one OCSP response
    /// </summary>
    public class OCSPRef
    {
        #region Private variables
        private OCSPIdentifier ocspIdentifier;
        private DigestAlgAndValueType digestAlgAndValue;
        #endregion

        #region Public properties
        /// <summary>
        /// Identification of one OCSP response
        /// </summary>
        public OCSPIdentifier OCSPIdentifier
        {
            get
            {
                return this.ocspIdentifier;
            }
            set
            {
                this.ocspIdentifier = value;
            }
        }

        /// <summary>
        /// The digest computed on the DER encoded OCSP response, since it may be
        /// needed to differentiate between two OCSP responses by the same server
        /// with their "ProducedAt" fields within the same second
        /// </summary>
        public DigestAlgAndValueType CertDigest
        {
            get
            {
                return this.digestAlgAndValue;
            }
            set
            {
                this.digestAlgAndValue = value;
            }
        }
        #endregion

        #region Constructors
        /// <summary>
        /// Default constructor
        /// </summary>
        public OCSPRef()
        {
            this.ocspIdentifier = new OCSPIdentifier();
            this.digestAlgAndValue = new DigestAlgAndValueType("DigestAlgAndValue");
        }
        #endregion

        #region Public methods
        /// <summary>
        /// Check to see if something has changed in this instance and needs to be serialized
        /// </summary>
        /// <returns>Flag indicating if a member needs serialization</returns>
        public bool HasChanged()
        {
            bool retVal = false;

            if (this.ocspIdentifier != null && this.ocspIdentifier.HasChanged())
            {
                retVal = true;
            }

            if (this.digestAlgAndValue != null && this.digestAlgAndValue.HasChanged())
            {
                retVal = true;
            }

            return retVal;
        }

        /// <summary>
        /// Load state from an XML element
        /// </summary>
        /// <param name="xmlElement">XML element containing new state</param>
        public void LoadXml(System.Xml.XmlElement xmlElement)
        {
            XmlNamespaceManager xmlNamespaceManager;
            XmlNodeList xmlNodeList;

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

            xmlNamespaceManager = new XmlNamespaceManager(xmlElement.OwnerDocument.NameTable);
            xmlNamespaceManager.AddNamespace("xsd", XadesSignedXml.XadesNamespaceUri);

            xmlNodeList = xmlElement.SelectNodes("xsd:OCSPIdentifier", xmlNamespaceManager);
            if (xmlNodeList.Count == 0)
            {
                throw new CryptographicException("OCSPIdentifier missing");
            }
            this.ocspIdentifier = new OCSPIdentifier();
            this.ocspIdentifier.LoadXml((XmlElement)xmlNodeList.Item(0));

            xmlNodeList = xmlElement.SelectNodes("xsd:DigestAlgAndValue", xmlNamespaceManager);
            if (xmlNodeList.Count == 0)
            {
                this.digestAlgAndValue = null;
            }
            else
            {
                this.digestAlgAndValue = new DigestAlgAndValueType("DigestAlgAndValue");
                this.digestAlgAndValue.LoadXml((XmlElement)xmlNodeList.Item(0));
            }
        }

        /// <summary>
        /// Returns the XML representation of the this object
        /// </summary>
        /// <returns>XML element containing the state of this object</returns>
        public XmlElement GetXml()
        {
            XmlDocument creationXmlDocument;
            XmlElement retVal;

            creationXmlDocument = new XmlDocument();
            retVal = creationXmlDocument.CreateElement("xades", "OCSPRef", XadesSignedXml.XadesNamespaceUri);

            if (this.ocspIdentifier != null && this.ocspIdentifier.HasChanged())
            {
                retVal.AppendChild(creationXmlDocument.ImportNode(this.ocspIdentifier.GetXml(), true));
            }
            else
            {
                throw new CryptographicException("OCSPIdentifier element missing in OCSPRef");
            }

            if (this.digestAlgAndValue != null && this.digestAlgAndValue.HasChanged())
            {
                retVal.AppendChild(creationXmlDocument.ImportNode(this.digestAlgAndValue.GetXml(), true));
            }

            return retVal;
        }
        #endregion
    }
}