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


namespace GroundZero.KeyCodes
{
	/// <summary>
	/// AyaNova .net key reader and validator
	/// </summary>
	public class KeyReader
	{

		private bool _IsValid;
		private string _RegisteredTo;
		private int _ScheduleableUsers;
		private bool _FeatureWebInterface;
		private object _Expires;
		private bool _FeatureQuickBooksInterface;
		private string _status;
		private DateTime _Generated;
		private DateTime _InstallableUntil;
		private bool _Installable;
		private double _SchemaVersion;
	


		

		public string RegisteredTo
		{
			get
			{
				return _RegisteredTo;
			}
			
		}

		public string Status
		{
			get
			{
				return _status;
			}
			
		}

		public int ScheduleableUsers
		{
			get
			{
				return _ScheduleableUsers;
			}
			
		}

		public bool FeatureWebInterface
		{
			get
			{
				return _FeatureWebInterface;
			}
			
		}

		

		public bool FeatureQuickBooksInterface
		{
			get
			{
				return _FeatureQuickBooksInterface;
			}
			
		}

		public bool IsValid
		{
			get
			{
				return _IsValid;
			}
			
		}

		public DateTime Generated
		{
			get
			{
				return _Generated;
			}
			
		}

		
		public object Expires
		{
			get
			{				
				return _Expires;
			}
			
		}

		public DateTime InstallableUntil
		{
			get
			{
				return _InstallableUntil;
			}
			
		}

		public bool Installable
		{
			get
			{
				return _Installable;
			}
			
		}

		public double SchemaVersion
		{
			get
			{
				return _SchemaVersion;
			}
			
		}

		
		public KeyReader(string Key)
		{
			_IsValid=false;
			_FeatureWebInterface=false;
			_FeatureQuickBooksInterface=false;
			
			_Installable=false;

			//Ensure we have a key and strip out any unnecessary text
			int nStart=Key.IndexOf("<?xml version=\"1.0\" encoding=\"utf-16\" standalone=\"yes\"?>");
			int nEnd=Key.IndexOf("</AyaNovaLicenseKey>");
			if(nEnd==-1 || nStart==-1 || nEnd<nStart)
			{
				_IsValid=false;
				_status="Error: could not find license XML in text.";
				
				return;

			}
		   Key=Key.Substring(nStart,(nEnd+("</AyaNovaLicenseKey>".Length))-nStart);


			//validate key signature then get settings within key
			// Get the XML content from the embedded XML public key.
			Stream s = null;
			string xmlkey = string.Empty;
			try
			{

				//				System.Reflection.Assembly ass=System.Reflection.Assembly.GetExecutingAssembly();
				//				string [] items=ass.GetManifestResourceNames();
				//				foreach(string ss in items)
				//				{
				//					string xy=ss;
				//					string ab=xy;
				//
				//				}



				s = typeof(KeyReader).Assembly.GetManifestResourceStream(
					"Generator.pubkey.xml");

				// Read-in the XML content.
				StreamReader reader = new StreamReader(s);
				xmlkey = reader.ReadToEnd();
				reader.Close();
			}
			catch (Exception ex)
			{
				_IsValid=false;
				_status="Error: could not import public key. " + ex.Message + "\r\n" + ex.InnerException;
				
				return;
			}

			// Create an RSA crypto service provider from the embedded
			// XML document resource (the public key).
			RSACryptoServiceProvider csp = new RSACryptoServiceProvider();
			csp.FromXmlString(xmlkey);

			// Load the signed XML license file.
			XmlDocument xmldoc = new XmlDocument();
			try
			{
				xmldoc.LoadXml(Key);
			}
			catch(Exception ex)
			{
				_IsValid=false;
				_status="Error: exception in LoadXml:\r\n." + ex.Message + "\r\n" + ex.InnerException;
				return;
				
			}

			// Create the signed XML object.
			SignedXml sxml = new SignedXml(xmldoc);

			try
			{
				// Get the XML Signature node and load it into the signed XML object.
				XmlNode dsig = xmldoc.GetElementsByTagName("Signature",
					SignedXml.XmlDsigNamespaceUrl)[0];
				sxml.LoadXml((XmlElement)dsig);
			}
			catch(Exception ex)
			{
				_IsValid=false;
				_status="Error: no signature found." + ex.Message + "\r\n" + ex.InnerException;
				return;
				
				
			}

			// Verify the signature.
			if (!sxml.CheckSignature(csp))
			{
				_IsValid=false;
				_status="Error: Signature not valid, key has been tampered with.";
				return;
					
			}

			_IsValid=true;

			
  
			try
			{
				
				_SchemaVersion=XmlConvert.ToDouble(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/SchemaVersion").InnerText);
				_RegisteredTo=xmldoc.SelectSingleNode("/AyaNovaLicenseKey/RegisteredTo").InnerText;
				_ScheduleableUsers=XmlConvert.ToInt32(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/TotalScheduleableUsers").InnerText);
				_Generated=XmlConvert.ToDateTime(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/Created").InnerText);
				_InstallableUntil=XmlConvert.ToDateTime(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/InstallableUntil").InnerText);
				
				if(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/Expires")!=null)
					_Expires=XmlConvert.ToDateTime(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/Expires").InnerText);
				else
					_Expires=null;
				_FeatureQuickBooksInterface=XmlConvert.ToBoolean(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/FeatureQuickBooksInterface").InnerText);
				_FeatureWebInterface=XmlConvert.ToBoolean(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/FeatureWebBrowserInterface").InnerText);
				if(System.DateTime.Now > _InstallableUntil)
				{
					_Installable=false;
					_status="Error: Installation key has expired.";
					return;
					
				}

				_Installable=true;

				//FUTURE: Here is an example of new items in a hypothetical future schema version...
//				if(_SchemaVersion>1.1)
//				{
//					_FeatureNew=XmlConvert.ToBoolean(xmldoc.SelectSingleNode("/AyaNovaLicenseKey/FeatureNew").InnerText);
//				}
//				
//				if(_SchemaVersion>1.2)
//				{
//				}

				// ETC

			}
			catch(Exception ex)
			{
				_IsValid=false;
				_status="Error: Signature not valid - exception processing fields:\r\n." + ex.Message + "\r\n" + ex.InnerException;
				return;
				
			}

		}



		

	}
}