//
// System.Web.Mail.SmtpClient.cs
//
// Author(s):
//   Per Arneng <pt99par@student.bth.se>
//   Sanjay Gupta <gsanjay@novell.com>
//   (C) 2004, Novell, Inc. (http://www.novell.com)
//

//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Net;
using System.IO;
using System.Text;
using System.Collections;
using System.Net.Sockets;
using System.Security.Permissions;
using System.Reflection;

namespace System.Web.Mail {

    /// represents a conntection to a smtp server
    internal class SmtpClient {
	
	private string server;
	private TcpClient tcpConnection;
	private SmtpStream smtp;
 	private string username;
 	private string password;
 	private int port = 25;
 	private bool usessl = false;
 	private short authenticate = 1;  	
        
    //Initialise the variables and connect
	public SmtpClient( string server ) {
	    
	    this.server = server;
	    Connect();
	}
	
	// make the actual connection
	// and HELO handshaking
	private void Connect() {
	    tcpConnection = new TcpClient( server , port );
	    
	    NetworkStream stream = tcpConnection.GetStream();
	    smtp = new SmtpStream( stream );
	}
	    	    
	private void ChangeToSSLSocket( ) {
#if TARGET_JVM
		java.lang.Class c = vmw.common.TypeUtils.ToClass( smtp.Stream );
		java.lang.reflect.Method m = c.getMethod("ChangeToSSLSocket", null);
		m.invoke(smtp.Stream, new object[]{});
#else
		// Load Mono.Security.dll
		Assembly a;
		try {
			a = Assembly.Load(Consts.AssemblyMono_Security);
		}
		catch(System.IO.FileNotFoundException) {
			throw new SmtpException( "Cannot load Mono.Security.dll" );
		}
		Type tSslClientStream = a.GetType("Mono.Security.Protocol.Tls.SslClientStream");
		object[] consArgs = new object[4];
		consArgs[0] = smtp.Stream;
		consArgs[1] = server;
		consArgs[2] = true;
		Type tSecurityProtocolType = a.GetType("Mono.Security.Protocol.Tls.SecurityProtocolType");
		int nSsl3Val = (int) Enum.Parse(tSecurityProtocolType, "Ssl3");
		int nTlsVal = (int) Enum.Parse(tSecurityProtocolType, "Tls");
		consArgs[3] = Enum.ToObject(tSecurityProtocolType, nSsl3Val | nTlsVal);

		object objSslClientStream = 
			Activator.CreateInstance(tSslClientStream, consArgs); 

		if (objSslClientStream != null)
			smtp = new SmtpStream( (Stream)objSslClientStream );
#endif
	}
		
	private void ReadFields(MailMessageWrapper msg)
	{
		string tmp;
		username = msg.Fields.Data["http://schemas.microsoft.com/cdo/configuration/sendusername"];
		password = msg.Fields.Data["http://schemas.microsoft.com/cdo/configuration/sendpassword"]; 
		tmp = msg.Fields.Data["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"]; 
		if (tmp != null)
			authenticate = short.Parse(tmp);
		tmp = msg.Fields.Data["http://schemas.microsoft.com/cdo/configuration/smtpusessl"]; 	
		if (tmp != null)
			usessl = bool.Parse(tmp);
		tmp = msg.Fields.Data["http://schemas.microsoft.com/cdo/configuration/smtpserverport"]; 
		if (tmp != null)
			port = int.Parse(tmp);
	}

	private void StartSend(MailMessageWrapper msg)
	{
		ReadFields(msg);
		
		// read the server greeting
		smtp.ReadResponse();
		smtp.CheckForStatusCode( 220 );

		if (usessl || (username != null && password != null && authenticate != 1)) 
		{
			smtp.WriteEhlo( Dns.GetHostName() );

			if (usessl) {
				bool isSSL = smtp.WriteStartTLS();
				if (isSSL)
					ChangeToSSLSocket();
			}

			if (username != null && password != null && authenticate != 1) 
			{
				smtp.WriteAuthLogin();
				if (smtp.LastResponse.StatusCode == 334) 
				{
					smtp.WriteLine(Convert.ToBase64String(Encoding.ASCII.GetBytes(username)));
					smtp.ReadResponse();
					smtp.CheckForStatusCode(334);
					smtp.WriteLine(Convert.ToBase64String(Encoding.ASCII.GetBytes(password)));
					smtp.ReadResponse();
					smtp.CheckForStatusCode(235);
				}
			}
		}
		else 
		{
			smtp.WriteHelo( Dns.GetHostName() );
		}
	}
	
	public void Send( MailMessageWrapper msg ) {
	    
	    if( msg.From == null ) {
		throw new SmtpException( "From property must be set." );
	    }

	    if( msg.To == null ) {
		if( msg.To.Count < 1 ) throw new SmtpException( "Atleast one recipient must be set." );
	    }
	    
	    StartSend (msg);
	    // start with a reset incase old data
	    // is present at the server in this session
	    smtp.WriteRset();
	    
	    // write the mail from command
	    smtp.WriteMailFrom( msg.From.Address );
	    
	    // write the rcpt to command for the To addresses
	    foreach( MailAddress addr in msg.To ) {
		smtp.WriteRcptTo( addr.Address );
	    }

	    // write the rcpt to command for the Cc addresses
	    foreach( MailAddress addr in msg.Cc ) {
		smtp.WriteRcptTo( addr.Address );
	    }

	    // write the rcpt to command for the Bcc addresses
	    foreach( MailAddress addr in msg.Bcc ) {
		smtp.WriteRcptTo( addr.Address );
	    }
	    
	    // write the data command and then
	    // send the email
	    smtp.WriteData();
		
	    if( msg.Attachments.Count == 0 ) {
		SendSinglepartMail( msg );	    
	    } else {
		
		SendMultipartMail( msg );
	    
	    }

	    // write the data end tag "."
	    smtp.WriteDataEndTag();

	}
	
	// sends a single part mail to the server
	private void SendSinglepartMail( MailMessageWrapper msg ) {
	    	    	    
	    // write the header
	    smtp.WriteHeader( msg.Header );
	    
	    // send the mail body
	    smtp.WriteBytes( msg.BodyEncoding.GetBytes( msg.Body ) );

	}

	// SECURITY-FIXME: lower assertion with imperative asserts	
	[FileIOPermission (SecurityAction.Assert, Unrestricted = true)]
	// sends a multipart mail to the server
	private void SendMultipartMail( MailMessageWrapper msg ) {
	    	    
	    // generate the boundary between attachments
	    string boundary = MailUtil.GenerateBoundary();
		
	    // set the Content-Type header to multipart/mixed
	    string bodyContentType = msg.Header.ContentType;

	    msg.Header.ContentType = 
		String.Format( "multipart/mixed;\r\n   boundary={0}" , boundary );
		
	    // write the header
	    smtp.WriteHeader( msg.Header );
		
	    // write the first part text part
	    // before the attachments
	    smtp.WriteBoundary( boundary );
		
	    MailHeader partHeader = new MailHeader();
	    partHeader.ContentType = bodyContentType;		

#if NET_1_1
		// Add all the custom headers to body part as specified in 
		//Fields property of MailMessageWrapper

        //Remove fields specific for authenticating to SMTP server.
        //Need to incorporate AUTH command in SmtpStream to handle  
        //Authorization info. Its a temporary fix for Bug no 68829.
        //Will dig some more on SMTP AUTH command, and then implement
        //Authorization. - Sanjay

        if (msg.Fields.Data ["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"] != null)
            msg.Fields.Data.Remove ("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate");
        if (msg.Fields.Data ["http://schemas.microsoft.com/cdo/configuration/sendusername"] != null)
            msg.Fields.Data.Remove ("http://schemas.microsoft.com/cdo/configuration/sendusername");
        if (msg.Fields.Data ["http://schemas.microsoft.com/cdo/configuration/sendpassword"] != null)
            msg.Fields.Data.Remove ("http://schemas.microsoft.com/cdo/configuration/sendpassword");
		partHeader.Data.Add (msg.Fields.Data);
#endif

	    smtp.WriteHeader( partHeader );
	  
	    // FIXME: probably need to use QP or Base64 on everything higher
	    // then 8-bit .. like utf-16
	    smtp.WriteBytes( msg.BodyEncoding.GetBytes( msg.Body )  );

	    smtp.WriteBoundary( boundary );

	    // now start to write the attachments
	    
	    for( int i=0; i< msg.Attachments.Count ; i++ ) {
		MailAttachment a = (MailAttachment)msg.Attachments[ i ];
			
		FileInfo fileInfo = new FileInfo( a.Filename );

		MailHeader aHeader = new MailHeader();
		
		aHeader.ContentType = 
		    String.Format (MimeTypes.GetMimeType (fileInfo.Name) + "; name=\"{0}\"",fileInfo.Name);
		
		aHeader.ContentDisposition = 
		    String.Format( "attachment; filename=\"{0}\"" , fileInfo.Name );
		
		aHeader.ContentTransferEncoding = a.Encoding.ToString();
		    		
		smtp.WriteHeader( aHeader );
		   
		// perform the actual writing of the file.
		// read from the file stream and write to the tcp stream
		FileStream ins = fileInfo.OpenRead ();
		
		// create an apropriate encoder
		IAttachmentEncoder encoder;
		if( a.Encoding == MailEncoding.UUEncode ) {
		    encoder = new UUAttachmentEncoder( 644 , fileInfo.Name  );
		} else {
		    encoder = new Base64AttachmentEncoder();
		}
		
		encoder.EncodeStream( ins , smtp.Stream );
		
		ins.Close();
		
		    
		smtp.WriteLine( "" );
		
		// if it is the last attachment write
		// the final boundary otherwise write
		// a normal one.
		if( i < (msg.Attachments.Count - 1) ) { 
		    smtp.WriteBoundary( boundary );
		} else {
		    smtp.WriteFinalBoundary( boundary );
		}
		    
	    }
	       
	}
	
	// send quit command and
	// closes the connection
	public void Close() {
	    
	    smtp.WriteQuit();
	    tcpConnection.Close();
	
	}
	
		
    }
}