// TimeStamp.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.Collections;
using System.Security.Cryptography;
using System.Xml;

namespace Microsoft.Xades
{
    /// <summary>
    /// This class contains timestamp information
    /// </summary>
    public class TimeStamp
    {
        #region Private variables
        private string tagName;
        private HashDataInfoCollection hashDataInfoCollection;
        private EncapsulatedPKIData encapsulatedTimeStamp;
        private XMLTimeStamp xmlTimeStamp;
        #endregion

        #region Public properties
        /// <summary>
        /// The name of the element when serializing
        /// </summary>
        public string TagName
        {
            get
            {
                return this.tagName;
            }
            set
            {
                this.tagName = value;
            }
        }

        /// <summary>
        /// A collection of hash data infos
        /// </summary>
        public HashDataInfoCollection HashDataInfoCollection
        {
            get
            {
                return this.hashDataInfoCollection;
            }
            set
            {
                this.hashDataInfoCollection = value;
            }
        }

        /// <summary>
        /// The time-stamp generated by a TSA encoded as an ASN.1 data
        /// object
        /// </summary>
        public EncapsulatedPKIData EncapsulatedTimeStamp
        {
            get
            {
                return this.encapsulatedTimeStamp;
            }
            set
            {
                this.encapsulatedTimeStamp = value;
                if (this.encapsulatedTimeStamp != null)
                {
                    this.xmlTimeStamp = null;
                }
            }
        }

        /// <summary>
        /// The time-stamp generated by a TSA encoded as a generic XML
        /// timestamp
        /// </summary>
        public XMLTimeStamp XMLTimeStamp
        {
            get
            {
                return this.xmlTimeStamp;
            }
            set
            {
                this.xmlTimeStamp = value;
                if (this.xmlTimeStamp != null)
                {
                    this.encapsulatedTimeStamp = null;
                }
            }
        }
        #endregion

        #region Constructors
        /// <summary>
        /// Default constructor
        /// </summary>
        public TimeStamp()
        {
            this.hashDataInfoCollection = new HashDataInfoCollection();
            this.encapsulatedTimeStamp = new EncapsulatedPKIData("EncapsulatedTimeStamp");
            this.xmlTimeStamp = null;
        }

        /// <summary>
        /// Constructor with TagName
        /// </summary>
        /// <param name="tagName">Name of the tag when serializing with GetXml</param>
        public TimeStamp(string tagName) : this()
        {
            this.tagName = tagName;
        }
        #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.hashDataInfoCollection.Count > 0)
            {
                retVal = true;
            }

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

            if (this.xmlTimeStamp != null && this.xmlTimeStamp.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;
            IEnumerator enumerator;
            XmlElement iterationXmlElement;
            HashDataInfo newHashDataInfo;

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

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

            this.hashDataInfoCollection.Clear();
            xmlNodeList = xmlElement.SelectNodes("xsd:HashDataInfo", xmlNamespaceManager);
            enumerator = xmlNodeList.GetEnumerator();
            try
            {
                while (enumerator.MoveNext())
                {
                    iterationXmlElement = enumerator.Current as XmlElement;
                    if (iterationXmlElement != null)
                    {
                        newHashDataInfo = new HashDataInfo();
                        newHashDataInfo.LoadXml(iterationXmlElement);
                        this.hashDataInfoCollection.Add(newHashDataInfo);
                    }
                }
            }
            finally
            {
                IDisposable disposable = enumerator as IDisposable;
                if (disposable != null)
                {
                    disposable.Dispose();
                }
            }

            xmlNodeList = xmlElement.SelectNodes("xsd:EncapsulatedTimeStamp", xmlNamespaceManager);
            if (xmlNodeList.Count != 0)
            {
                this.encapsulatedTimeStamp = new EncapsulatedPKIData("EncapsulatedTimeStamp");
                this.encapsulatedTimeStamp.LoadXml((XmlElement)xmlNodeList.Item(0));
                this.xmlTimeStamp = null;
            }
            else
            {
                xmlNodeList = xmlElement.SelectNodes("xsd:XMLTimeStamp", xmlNamespaceManager);
                if (xmlNodeList.Count != 0)
                {
                    this.xmlTimeStamp = new XMLTimeStamp();
                    this.xmlTimeStamp.LoadXml((XmlElement)xmlNodeList.Item(0));
                    this.encapsulatedTimeStamp = null;

                }
                else
                {
                    throw new CryptographicException("EncapsulatedTimeStamp or XMLTimeStamp missing");
                }
            }
        }

        /// <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", this.tagName, XadesSignedXml.XadesNamespaceUri);

            if (this.hashDataInfoCollection.Count > 0)
            {
                foreach (HashDataInfo hashDataInfo in this.hashDataInfoCollection)
                {
                    if (hashDataInfo.HasChanged())
                    {
                        retVal.AppendChild(creationXmlDocument.ImportNode(hashDataInfo.GetXml(), true));
                    }
                }
            }
            else
            {
                throw new CryptographicException("HashDataInfoCollection is empty.  TimeStamp needs at least one HashDataInfo element");
            }

            if (this.encapsulatedTimeStamp != null && this.encapsulatedTimeStamp.HasChanged())
            {
                retVal.AppendChild(creationXmlDocument.ImportNode(this.encapsulatedTimeStamp.GetXml(), true));
            }
            else
            {
                if (this.xmlTimeStamp != null && this.xmlTimeStamp.HasChanged())
                {
                    retVal.AppendChild(creationXmlDocument.ImportNode(this.xmlTimeStamp.GetXml(), true));
                }
                else
                {
                    throw new CryptographicException("EncapsulatedTimeStamp or XMLTimeStamp element missing");
                }
            }

            return retVal;
        }
        #endregion
    }
}