#
# Copyright (c) 2001 Bizar Software Pty Ltd (http://www.bizarsoftware.com.au/)
# This module is free software, and you may redistribute it and/or modify
# under the same terms as Python, so long as this copyright message and
# disclaimer are retained in their original form.
#
# IN NO EVENT SHALL BIZAR SOFTWARE PTY LTD BE LIABLE TO ANY PARTY FOR
# DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
# OUT OF THE USE OF THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# BIZAR SOFTWARE PTY LTD SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
# BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE.  THE CODE PROVIDED HEREUNDER IS ON AN "AS IS"
# BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
# SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
# 
'''
An e-mail gateway for Roundup.

Incoming messages are examined for multiple parts:
 . In a multipart/mixed message or part, each subpart is extracted and
   examined. The text/plain subparts are assembled to form the textual
   body of the message, to be stored in the file associated with a "msg"
   class node. Any parts of other types are each stored in separate files
   and given "file" class nodes that are linked to the "msg" node. 
 . In a multipart/alternative message or part, we look for a text/plain
   subpart and ignore the other parts.

Summary
-------
The "summary" property on message nodes is taken from the first non-quoting
section in the message body. The message body is divided into sections by
blank lines. Sections where the second and all subsequent lines begin with
a ">" or "|" character are considered "quoting sections". The first line of
the first non-quoting section becomes the summary of the message. 

Addresses
---------
All of the addresses in the To: and Cc: headers of the incoming message are
looked up among the user nodes, and the corresponding users are placed in
the "recipients" property on the new "msg" node. The address in the From:
header similarly determines the "author" property of the new "msg"
node. The default handling for addresses that don't have corresponding
users is to create new users with no passwords and a username equal to the
address. (The web interface does not permit logins for users with no
passwords.) If we prefer to reject mail from outside sources, we can simply
register an auditor on the "user" class that prevents the creation of user
nodes with no passwords. 

Actions
-------
The subject line of the incoming message is examined to determine whether
the message is an attempt to create a new item or to discuss an existing
item. A designator enclosed in square brackets is sought as the first thing
on the subject line (after skipping any "Fwd:" or "Re:" prefixes). 

If an item designator (class name and id number) is found there, the newly
created "msg" node is added to the "messages" property for that item, and
any new "file" nodes are added to the "files" property for the item. 

If just an item class name is found there, we attempt to create a new item
of that class with its "messages" property initialized to contain the new
"msg" node and its "files" property initialized to contain any new "file"
nodes. 

Triggers
--------
Both cases may trigger detectors (in the first case we are calling the
set() method to add the message to the item's spool; in the second case we
are calling the create() method to create a new node). If an auditor raises
an exception, the original message is bounced back to the sender with the
explanatory message given in the exception. 

$Id: mailgw.py,v 1.27 2001-10-30 11:26:10 richard Exp $
'''


import string, re, os, mimetools, cStringIO, smtplib, socket, binascii, quopri
import traceback
import hyperdb, date, password

class MailUsageError(ValueError):
    pass

class Message(mimetools.Message):
    ''' subclass mimetools.Message so we can retrieve the parts of the
        message...
    '''
    def getPart(self):
        ''' Get a single part of a multipart message and return it as a new
            Message instance.
        '''
        boundary = self.getparam('boundary')
        mid, end = '--'+boundary, '--'+boundary+'--'
        s = cStringIO.StringIO()
        while 1:
            line = self.fp.readline()
            if not line:
                break
            if line.strip() in (mid, end):
                break
            s.write(line)
        if not s.getvalue().strip():
            return None
        s.seek(0)
        return Message(s)

subject_re = re.compile(r'(?P<refwd>\s*\W?\s*(fwd|re)\s*\W?\s*)*'
    r'\s*(\[(?P<classname>[^\d]+)(?P<nodeid>\d+)?\])'
    r'\s*(?P<title>[^\[]+)(\[(?P<args>.+?)\])?', re.I)

class MailGW:
    def __init__(self, db):
        self.db = db

    def main(self, fp):
        ''' fp - the file from which to read the Message.

        Read a message from fp and then call handle_message() with the
        result. This method's job is to make that call and handle any
        errors in a sane manner. It should be replaced if you wish to
        handle errors in a different manner.
        '''
        # ok, figure the subject, author, recipients and content-type
        message = Message(fp)
        m = []
        try:
            self.handle_message(message)
        except MailUsageError, value:
            # bounce the message back to the sender with the usage message
            fulldoc = '\n'.join(string.split(__doc__, '\n')[2:])
            sendto = [message.getaddrlist('from')[0][1]]
            m = ['Subject: Failed issue tracker submission', '']
            m.append(str(value))
            m.append('\n\nMail Gateway Help\n=================')
            m.append(fulldoc)
        except:
            # bounce the message back to the sender with the error message
            sendto = [message.getaddrlist('from')[0][1]]
            m = ['Subject: failed issue tracker submission']
            m.append('')
            # TODO as attachments?
            m.append('----  traceback of failure  ----')
            s = cStringIO.StringIO()
            import traceback
            traceback.print_exc(None, s)
            m.append(s.getvalue())
            m.append('---- failed message follows ----')
            try:
                fp.seek(0)
            except:
                pass
            m.append(fp.read())
        if m:
            try:
                smtp = smtplib.SMTP(self.MAILHOST)
                smtp.sendmail(self.ADMIN_EMAIL, sendto, '\n'.join(m))
            except socket.error, value:
                return "Couldn't send confirmation email: mailhost %s"%value
            except smtplib.SMTPException, value:
                return "Couldn't send confirmation email: %s"%value

    def handle_message(self, message):
        ''' message - a Message instance

        Parse the message as per the module docstring.
        '''
        # handle the subject line
        subject = message.getheader('subject', '')
        m = subject_re.match(subject)
        if not m:
            raise MailUsageError, '''
The message you sent to roundup did not contain a properly formed subject
line. The subject must contain a class name or designator to indicate the
"topic" of the message. For example:
    Subject: [issue] This is a new issue
      - this will create a new issue in the tracker with the title "This is
        a new issue".
    Subject: [issue1234] This is a followup to issue 1234
      - this will append the message's contents to the existing issue 1234
        in the tracker.

Subject was: "%s"
'''%subject
        classname = m.group('classname')
        nodeid = m.group('nodeid')
        title = m.group('title').strip()
        subject_args = m.group('args')
        try:
            cl = self.db.getclass(classname)
        except KeyError:
            raise MailUsageError, '''
The class name you identified in the subject line ("%s") does not exist in the
database.

Valid class names are: %s
Subject was: "%s"
'''%(classname, ', '.join(self.db.getclasses()), subject)

        # If there's no nodeid, check to see if this is a followup and
        # maybe someone's responded to the initial mail that created an
        # entry. Try to find the matching nodes with the same title, and
        # use the _last_ one matched (since that'll _usually_ be the most
        # recent...)
        if not nodeid and m.group('refwd'):
            l = cl.stringFind(title=title)
            if l:
                nodeid = l[-1]

        # start of the props
        properties = cl.getprops()
        props = {}

        # handle the args
        args = m.group('args')
        if args:
            for prop in string.split(args, ';'):
                try:
                    key, value = prop.split('=')
                except ValueError, message:
                    raise MailUsageError, '''
Subject argument list not of form [arg=value,value,...;arg=value,value...]
   (specific exception message was "%s")

Subject was: "%s"
'''%(message, subject)
                try:
                    type =  properties[key]
                except KeyError:
                    raise MailUsageError, '''
Subject argument list refers to an invalid property: "%s"

Subject was: "%s"
'''%(key, subject)
                if isinstance(type, hyperdb.String):
                    props[key] = value 
                if isinstance(type, hyperdb.Password):
                    props[key] = password.Password(value)
                elif isinstance(type, hyperdb.Date):
                    props[key] = date.Date(value)
                elif isinstance(type, hyperdb.Interval):
                    props[key] = date.Interval(value)
                elif isinstance(type, hyperdb.Link):
                    props[key] = value
                elif isinstance(type, hyperdb.Multilink):
                    props[key] = value.split(',')

        #
        # handle the users
        #
        author = self.db.uidFromAddress(message.getaddrlist('from')[0])
        recipients = []
        tracker_email = self.ISSUE_TRACKER_EMAIL.lower()
        for recipient in message.getaddrlist('to') + message.getaddrlist('cc'):
            if recipient[1].strip().lower() == tracker_email:
                continue
            recipients.append(self.db.uidFromAddress(recipient))

        # now handle the body - find the message
        content_type =  message.gettype()
        attachments = []
        if content_type == 'multipart/mixed':
            # skip over the intro to the first boundary
            part = message.getPart()
            content = None
            while 1:
                # get the next part
                part = message.getPart()
                if part is None:
                    break
                # parse it
                subtype = part.gettype()
                if subtype == 'text/plain' and not content:
                    # add all text/plain parts to the message content
                    if content is None:
                        content = part.fp.read()
                    else:
                        content = content + part.fp.read()

                elif subtype == 'message/rfc822':
                    # handle message/rfc822 specially - the name should be
                    # the subject of the actual e-mail embedded here
                    i = part.fp.tell()
                    mailmess = Message(part.fp)
                    name = mailmess.getheader('subject')
                    part.fp.seek(i)
                    attachments.append((name, 'message/rfc822', part.fp.read()))

                else:
                    # try name on Content-Type
                    name = part.getparam('name')
                    # this is just an attachment
                    encoding = part.getencoding()
                    if encoding == 'base64':
                        data = binascii.a2b_base64(part.fp.read())
                    elif encoding == 'quoted-printable':
                        # the quopri module wants to work with files
                        decoded = cStringIO.StringIO()
                        quopri.decode(part.fp, decoded)
                        data = decoded.getvalue()
                    elif encoding == 'uuencoded':
                        data = binascii.a2b_uu(part.fp.read())
                    attachments.append((name, part.gettype(), data))

            if content is None:
                raise MailUsageError, '''
Roundup requires the submission to be plain text. The message parser could
not find a text/plain part to use.
'''

        elif content_type[:10] == 'multipart/':
            # skip over the intro to the first boundary
            message.getPart()
            content = None
            while 1:
                # get the next part
                part = message.getPart()
                if part is None:
                    break
                # parse it
                if part.gettype() == 'text/plain' and not content:
                    # this one's our content
                    content = part.fp.read()
            if content is None:
                raise MailUsageError, '''
Roundup requires the submission to be plain text. The message parser could
not find a text/plain part to use.
'''

        elif content_type != 'text/plain':
            raise MailUsageError, '''
Roundup requires the submission to be plain text. The message parser could
not find a text/plain part to use.
'''

        else:
            content = message.fp.read()

        summary, content = parseContent(content)

        # handle the files
        files = []
        for (name, type, data) in attachments:
            files.append(self.db.file.create(type=type, name=name,
                content=data))

        # now handle the db stuff
        if nodeid:
            # If an item designator (class name and id number) is found there,
            # the newly created "msg" node is added to the "messages" property
            # for that item, and any new "file" nodes are added to the "files" 
            # property for the item. 
            message_id = self.db.msg.create(author=author,
                recipients=recipients, date=date.Date('.'), summary=summary,
                content=content, files=files)
            try:
                messages = cl.get(nodeid, 'messages')
            except IndexError:
                raise MailUsageError, '''
The node specified by the designator in the subject of your message ("%s")
does not exist.

Subject was: "%s"
'''%(nodeid, subject)
            messages.append(message_id)
            props['messages'] = messages

            # if the message is currently 'unread' or 'resolved', then set
            # it to 'chatting'
            if properties.has_key('status'):
                try:
                    # determine the id of 'unread', 'resolved' and 'chatting'
                    unread_id = self.db.status.lookup('unread')
                    resolved_id = self.db.status.lookup('resolved')
                    chatting_id = self.db.status.lookup('chatting')
                except KeyError:
                    pass
                else:
                    if (not props.has_key('status') or
                            props['status'] == unread_id or
                            props['status'] == resolved_id):
                        props['status'] = chatting_id

            cl.set(nodeid, **props)
        else:
            # If just an item class name is found there, we attempt to create a
            # new item of that class with its "messages" property initialized to
            # contain the new "msg" node and its "files" property initialized to
            # contain any new "file" nodes. 
            message_id = self.db.msg.create(author=author,
                recipients=recipients, date=date.Date('.'), summary=summary,
                content=content, files=files)
            # fill out the properties with defaults where required
            if properties.has_key('assignedto') and \
                    not props.has_key('assignedto'):
                props['assignedto'] = '1'             # "admin"
            if properties.has_key('status') and not props.has_key('status'):
                props['status'] = '1'                 # "unread"
            if properties.has_key('title') and not props.has_key('title'):
                props['title'] = title
            props['messages'] = [message_id]
            props['nosy'] = props.get('nosy', []) + recipients
            props['nosy'].append(author)
            props['nosy'].sort()
            nodeid = cl.create(**props)

def parseContent(content, blank_line=re.compile(r'[\r\n]+\s*[\r\n]+'),
        eol=re.compile(r'[\r\n]+'), signature=re.compile(r'^[>|\s]*[-_]+\s*$')):
    ''' The message body is divided into sections by blank lines.
    Sections where the second and all subsequent lines begin with a ">" or "|"
    character are considered "quoting sections". The first line of the first
    non-quoting section becomes the summary of the message. 
    '''
    # strip off leading carriage-returns / newlines
    i = 0
    for i in range(len(content)):
        if content[i] not in '\r\n':
            break
    if i > 0:
        sections = blank_line.split(content[i:])
    else:
        sections = blank_line.split(content)

    # extract out the summary from the message
    summary = ''
    l = []
    for section in sections:
        #section = section.strip()
        if not section:
            continue
        lines = eol.split(section)
        if lines[0] and lines[0][0] in '>|':
            continue
        if len(lines) > 1 and lines[1] and lines[1][0] in '>|':
            continue
        if not summary:
            summary = lines[0]
            l.append(section)
            continue
        if signature.match(lines[0]):
            break
        l.append(section)
    return summary, '\n\n'.join(l)

#
# $Log: not supported by cvs2svn $
# Revision 1.26  2001/10/30 00:54:45  richard
# Features:
#  . #467129 ] Lossage when username=e-mail-address
#  . #473123 ] Change message generation for author
#  . MailGW now moves 'resolved' to 'chatting' on receiving e-mail for an issue.
#
# Revision 1.25  2001/10/28 23:22:28  richard
# fixed bug #474749 ] Indentations lost
#
# Revision 1.24  2001/10/23 22:57:52  richard
# Fix unread->chatting auto transition, thanks Roch'e
#
# Revision 1.23  2001/10/21 04:00:20  richard
# MailGW now moves 'unread' to 'chatting' on receiving e-mail for an issue.
#
# Revision 1.22  2001/10/21 03:35:13  richard
# bug #473125: Paragraph in e-mails
#
# Revision 1.21  2001/10/21 00:53:42  richard
# bug #473130: Nosy list not set correctly
#
# Revision 1.20  2001/10/17 23:13:19  richard
# Did a fair bit of work on the admin tool. Now has an extra command "table"
# which displays node information in a tabular format. Also fixed import and
# export so they work. Removed freshen.
# Fixed quopri usage in mailgw from bug reports.
#
# Revision 1.19  2001/10/11 23:43:04  richard
# Implemented the comma-separated printing option in the admin tool.
# Fixed a typo (more of a vim-o actually :) in mailgw.
#
# Revision 1.18  2001/10/11 06:38:57  richard
# Initial cut at trying to handle people responding to CC'ed messages that
# create an issue.
#
# Revision 1.17  2001/10/09 07:25:59  richard
# Added the Password property type. See "pydoc roundup.password" for
# implementation details. Have updated some of the documentation too.
#
# Revision 1.16  2001/10/05 02:23:24  richard
#  . roundup-admin create now prompts for property info if none is supplied
#    on the command-line.
#  . hyperdb Class getprops() method may now return only the mutable
#    properties.
#  . Login now uses cookies, which makes it a whole lot more flexible. We can
#    now support anonymous user access (read-only, unless there's an
#    "anonymous" user, in which case write access is permitted). Login
#    handling has been moved into cgi_client.Client.main()
#  . The "extended" schema is now the default in roundup init.
#  . The schemas have had their page headings modified to cope with the new
#    login handling. Existing installations should copy the interfaces.py
#    file from the roundup lib directory to their instance home.
#  . Incorrectly had a Bizar Software copyright on the cgitb.py module from
#    Ping - has been removed.
#  . Fixed a whole bunch of places in the CGI interface where we should have
#    been returning Not Found instead of throwing an exception.
#  . Fixed a deviation from the spec: trying to modify the 'id' property of
#    an item now throws an exception.
#
# Revision 1.15  2001/08/30 06:01:17  richard
# Fixed missing import in mailgw :(
#
# Revision 1.14  2001/08/13 23:02:54  richard
# Make the mail parser a little more robust.
#
# Revision 1.13  2001/08/12 06:32:36  richard
# using isinstance(blah, Foo) now instead of isFooType
#
# Revision 1.12  2001/08/08 01:27:00  richard
# Added better error handling to mailgw.
#
# Revision 1.11  2001/08/08 00:08:03  richard
# oops ;)
#
# Revision 1.10  2001/08/07 00:24:42  richard
# stupid typo
#
# Revision 1.9  2001/08/07 00:15:51  richard
# Added the copyright/license notice to (nearly) all files at request of
# Bizar Software.
#
# Revision 1.8  2001/08/05 07:06:07  richard
# removed some print statements
#
# Revision 1.7  2001/08/03 07:18:22  richard
# Implemented correct mail splitting (was taking a shortcut). Added unit
# tests. Also snips signatures now too.
#
# Revision 1.6  2001/08/01 04:24:21  richard
# mailgw was assuming certain properties existed on the issues being created.
#
# Revision 1.5  2001/07/29 07:01:39  richard
# Added vim command to all source so that we don't get no steenkin' tabs :)
#
# Revision 1.4  2001/07/28 06:43:02  richard
# Multipart message class has the getPart method now. Added some tests for it.
#
# Revision 1.3  2001/07/28 00:34:34  richard
# Fixed some non-string node ids.
#
# Revision 1.2  2001/07/22 12:09:32  richard
# Final commit of Grande Splite
#
#
# vim: set filetype=python ts=4 sw=4 et si