#!/usr/bin/env python
# encoding: utf-8
"""
format_tracker_mail.py

This program takes an email message in standard input and resends it using the given From and To addresses.  An SMTP server must be specified on the command line.  Keep in mind that the input is not validated in any way.  This program requires an X-Mailer header to be set on its outgoing mail so it will not forward messages previously sent by itself.
"""

import sys
import getopt
import email
from email.MIMEText import MIMEText
from email.MIMEMultipart import MIMEMultipart
import smtplib
import re

class TrackerMessage:
    
    def __init__(self, messageBody):
        self.newCommenter = None
        self.parseMessage(messageBody)
        
    def parseMessage(self, messageBody):
        firstLineMatch = re.search(r"^.*", messageBody)
        if firstLineMatch: self.firstLine = firstLineMatch.group()
        categoryMatch = re.search(r"^>*Category: (.*)(?=\n>*Group:)", messageBody, (re.M|re.S))
        if categoryMatch: self.category = categoryMatch.group(1).strip()
        statusMatch = re.search(r"^>*Status: (.*)(?=\n>*Resolution:)", messageBody, (re.M|re.S))
        if statusMatch: self.status = statusMatch.group(1).strip()
        submitterMatch = re.search(r"^>*Submitted By: (.*)(?=\n>*Assigned to:)", messageBody, (re.M|re.S))
        if submitterMatch: self.submitter = submitterMatch.group(1).strip()
        summaryMatch = re.search(r"^>*Summary: (.*)(?=\n>*Initial Comment:)", messageBody, (re.M|re.S))
        if summaryMatch: self.summary = summaryMatch.group(1).strip()
        initialCommentMatch = re.search(r"^>*Initial Comment:\n(.*?)(?=\n----------------------------------------------------------------------\n)", messageBody, (re.M|re.S))
        if initialCommentMatch: self.initialComment = initialCommentMatch.group(1).strip()
        newCommentMatch = re.search(r"^>Comment By: (.*?)\nDate: (.*?)\n\nMessage:.*?user_id=.*?\n\n(.*?)(?=\n----------------------------------------------------------------------\n)", messageBody, (re.M|re.S))
        if newCommentMatch:
            self.newCommenter = newCommentMatch.group(1)
            self.newCommentDate = newCommentMatch.group(2)
            self.newComment = newCommentMatch.group(3)
    
    def parseLine(self, line):
        pass
        
    def __getitem__(self, item):
        return getattr(self, item, "")
        
    def __str__(self):
        if (self.newCommenter):
            return """New comment on tracker for:
%(firstLine)s
Summary: %(summary)s

Comment by: %(newCommenter)s
Date: %(newCommentDate)s

%(newComment)s

----------------------------------------------------------------------
Category: %(category)s
Status: %(status)s
Submitted By: %(submitter)s
Initial Comment:
%(initialComment)s

***You can respond to this email with comments or suggestions by hitting the reply button.***
            
""" % (self)
        else:
            return """%(firstLine)s
Category: %(category)s
Status: %(status)s
Submitted By: %(submitter)s

Summary: %(summary)s

Initial Comment:
%(initialComment)s

***You can respond to this email with comments or suggestions by hitting the reply button.***
""" % (self)
        

    
def processMessage(aFile, xmailer, toReplace=None, fromReplace=None, replyReplace=None):
    msg = email.message_from_file(aFile)
    if msg["X-Mailer"] == xmailer: return None # prevent infinite mail loops
    if (msg.is_multipart()):
        newmsg = MIMEMultipart()
        for item in msg.get_payload():
            newmsg.attach(item)
    else:
        tm = TrackerMessage(msg.get_payload())
        text = str(tm)
        newmsg = MIMEText(text)
    newmsg["Subject"] = msg["Subject"]
    newmsg["X-Mailer"] = xmailer
    if toReplace: newmsg["To"] = toReplace
    else: newmsg["To"] = msg["To"]
    if fromReplace: newmsg["From"] = fromReplace
    else: newmsg["From"] = msg["From"]
    if replyReplace: newmsg["Reply-To"] = replyReplace
    else: newmsg["Reply-To"] = msg["Reply-To"]
    return newmsg
        

def sendMessage(msg, smtp):
    server = smtplib.SMTP(smtp)
    server.sendmail(msg["From"], [msg["To"].split(",")], msg.as_string())
    server.close()


class Usage(Exception):
    def __init__(self, msg):
        self.msg = msg


def main(argv=None):
    toReplace = None
    fromReplace = None
    replyReplace = None
    smtp = None
    xmailer = None
    if argv is None:
        argv = sys.argv
    try:
        try:
            opts, args = getopt.getopt(argv[1:], "", ["from=", "to=", "reply=", "smtp=", "xmailer="])
        except getopt.error, msg:
            raise Usage(msg)
    
        # option processing
        for option, value in opts:
            if option == "--to":
                toReplace = value
            if option == "--from":
                fromReplace = value
            if option == "--reply":
                replyReplace = value
            if option == "--smtp":
                smtp = value
            if option == "--xmailer":
                xmailer = value
        if not smtp: raise Usage("SMTP not specified")
        if not xmailer: raise Usage("X-Mailer not specified")
        
    except Usage, err:
        print >> sys.stderr, sys.argv[0].split("/")[-1] + ": " + str(err.msg)
        return 2
    
    msg = processMessage(sys.stdin, xmailer, toReplace, fromReplace, replyReplace)
    if msg: sendMessage(msg, smtp)


if __name__ == "__main__":
    sys.exit(main())