//
// System.Web.Mail.SmtpClient.cs
//
// Author(s):
//   Per Arneng <pt99par@student.bth.se>
//
//
using System;
using System.Net;
using System.IO;
using System.Text;
using System.Collections;
using System.Net.Sockets;

namespace System.Web.Mail {

    /// represents a conntection to a smtp server
    internal class SmtpClient {
	
	private string server;
	private TcpClient tcpConnection;
	private SmtpStream smtp;
	private Encoding encoding;
	
	//Initialise the variables and connect
	public SmtpClient( string server ) {
	    
	    this.server = server;
	    encoding = new ASCIIEncoding( );

	    Connect();
	}
	
	// make the actual connection
	// and HELO handshaking
	private void Connect() {
	    tcpConnection = new TcpClient( server , 25 );
	    
	    Stream stream = tcpConnection.GetStream();
	    smtp = new SmtpStream( stream );
	    
	    // read the server greeting
	    smtp.ReadResponse();
	    smtp.CheckForStatusCode( 220 );
	   
	    // write the HELO command to the server
	    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." );
	    }
	    
	    	    
	    // 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 ) );

	}
	
	// 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
	    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 = "text/plain";
		
	    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( "application/octet-stream; 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 = new FileStream( fileInfo.FullName  , FileMode.Open );
		
		// 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();
	
	}
	
		
    }

}