"""

Simple module to ease the task of sending out a simple email
message with MIME attachments from Python.

The code is based on ideas from:
  http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52243
and
  http://sourceforge.net/snippet/detail.php?type=snippet&id=100444

Prabhu Ramachandran <prabhu@aero.iitm.ernet.in>

"""

import sys, os, time
import smtplib, MimeWriter, base64, StringIO, mimetypes

class MailMsgError(Exception):
    pass

class MailMsg:    
    """Simple class that makes it easy to send a multipart email
    message with text and base 64 encoded attachments.  """
    def __init__(self, from_=None, subject='No Subject'):
        """ The constructor.
         Arguments:

            from_   -- The From header.  Defaults to None.
        
            subject -- The subject header of the email. Defaults to
                       'No Subject'
        """
        self.finished = 0
        self.msg = StringIO.StringIO()
        self.writer = MimeWriter.MimeWriter(self.msg)

        if from_:
            self.writer.addheader('From', from_)
        t_str = time.strftime ("%a %b %e %H:%M:%S %Z %Y", time.localtime())
        self.writer.addheader('Date', t_str)
        self.writer.addheader('Subject', subject)
        self.writer.addheader('MIME-Version', '1.0')
        body = self.writer.startmultipartbody('mixed')
        body.write("This is a multi-part message in MIME format.\n")

    def addText(self, txt):
        """When passed an argument containing the text adds a
        text/plain body to the message containing the text.

        Arguments:

          txt -- text to be sent.
        """        
        part = self.writer.nextpart()
        body = part.startbody('text/plain')
        body.write(txt + '\n')

    def addHtml(self, html_txt):        
        """When passed an argument containing the text adds a
        text/html body to the message containing the text.

        Arguments:

          html_txt -- HTML text to be attached.
        """        
        part = self.writer.nextpart()
        part.addheader("Content-Transfer-Encoding","8bit")
        body  = part.startbody("text/html", [("charset","iso-8859-1")])
        body.write(html_txt + "\n")
        
    def addAttachment(self, file_name):
        """ Encodes file pointed to by the passed file name using
        base64 encoding and attaches a mime body with the contents of
        the file.

        Arguments:

           file_name -- Name of file to be attached.
        """        
        if not os.path.isfile(file_name):
            msg = "Specified file %s does not exist!"%file_name
            raise MailMsgError, msg
        
        type = mimetypes.guess_type(file_name)
        if type[0] is None:
            msg = "Sorry unable to determine mime type of file: "\
                  "%s"%file_name
            raise MailMsgError, msg
        
        part = self.writer.nextpart()
        part.addheader('Content-Transfer-Encoding', 'base64')
        hdr = "%s; name=%s"%(type[0], os.path.basename(file_name))
        body = part.startbody(hdr)
        base64.encode(open(file_name, 'rb'), body)

    def finish(self):        
        """Finish the email.  This function must be called before you
        can send the message out."""        
        self.writer.lastpart()
        self.finished = 1
        
    def mail(self, from_addr, to_addrs, host='localhost', port=0,
             mail_options=[], rcpt_options=[]):
        """This command sends the message out using SMTP.
        
        The arguments are:
            - from_addr    : The address sending this mail.            
            - to_addrs     : A list of addresses to send this mail to.
                             A bare string will be treated as a list
                             with 1 address.                             
            - host         : The SMTP host to connect to - defaults
                             to localhost.
            - port         : The port where the mailer is listening -
                             defaults to 0 (which should work).            
            - mail_options : List of ESMTP options (such as 8bitmime) for
                             the mail command.
            - rcpt_options : List of ESMTP options (such as DSN commands)
                             for all the rcpt commands.
        """        
        if not self.finished:
            self.finish()
           
        smtp = smtplib.SMTP(host, port)
        smtp.sendmail(from_addr, to_addrs, self.msg.getvalue(),
                     mail_options, rcpt_options)
        smtp.quit()