#!/usr/bin/python
"""
Jutda Helpdesk - A Django powered ticket tracker for small enterprise.

(c) Copyright 2008 Jutda. All Rights Reserved. See LICENSE for details.

scripts/get_email.py - Designed to be run from cron, this script checks the
                       POP and IMAP boxes, or a local mailbox directory,
                       defined for the queues within a
                       helpdesk, creating tickets from the new messages (or
                       adding to existing tickets if needed)
"""

import email
import imaplib
import mimetypes
import poplib
import re
import socket
from os import listdir, unlink
from os.path import isfile, join

from datetime import timedelta
from email.header import decode_header
from email.utils import parseaddr, collapse_rfc2231_value
from optparse import make_option

from email_reply_parser import EmailReplyParser

from django import VERSION
from django.core.files.base import ContentFile
from django.core.management.base import BaseCommand
from django.db.models import Q
from django.utils.translation import ugettext as _
from django.utils import six
from helpdesk import settings

try:
    from django.utils import timezone
except ImportError:
    from datetime import datetime as timezone

from helpdesk.lib import send_templated_mail, safe_template_context
from helpdesk.models import Queue, Ticket, FollowUp, Attachment, IgnoreEmail

import logging
from time import ctime


class Command(BaseCommand):
    def __init__(self):
        BaseCommand.__init__(self)

        # Django 1.7 uses different way to specify options than 1.8+
        if VERSION < (1, 8):
            self.option_list += (
            make_option(
                '--quiet',
                default=False,
                action='store_true',
                dest='quiet',
                help='Hide details about each queue/message as they are processed'),
            )

    help = 'Process django-helpdesk queues and process e-mails via POP3/IMAP or from a local mailbox directory as required, feeding them into the helpdesk.'

    def add_arguments(self, parser):
        parser.add_argument(
            '--quiet',
            action='store_true',
            dest='quiet',
            default=False,
            help='Hide details about each queue/message as they are processed',
        )

    def handle(self, *args, **options):
        quiet = options.get('quiet', False)
        process_email(quiet=quiet)


def process_email(quiet=False):
    for q in Queue.objects.filter(
            email_box_type__isnull=False,
            allow_email_submission=True):

        logger = logging.getLogger('django.helpdesk.queue.' + q.slug)
        if not q.logging_type or q.logging_type == 'none':
            logging.disable(logging.CRITICAL) #disable all messages
        elif q.logging_type == 'info':
            logger.setLevel(logging.INFO)
        elif q.logging_type == 'warn':
            logger.setLevel(logging.WARN)
        elif q.logging_type == 'error':
            logger.setLevel(logging.ERROR)
        elif q.logging_type == 'crit':
            logger.setLevel(logging.CRITICAL)
        elif q.logging_type == 'debug':
            logger.setLevel(logging.DEBUG)
        if quiet:
            logger.propagate = False # do not propagate to root logger that would log to console
        logdir = q.logging_dir or '/var/log/helpdesk/'
        handler = logging.FileHandler(logdir + q.slug + '_get_email.log')
        logger.addHandler(handler)

        if not q.email_box_last_check:
            q.email_box_last_check = timezone.now()-timedelta(minutes=30)

        if not q.email_box_interval:
            q.email_box_interval = 0


        queue_time_delta = timedelta(minutes=q.email_box_interval)

        if (q.email_box_last_check + queue_time_delta) > timezone.now():
            continue

        process_queue(q, logger=logger)

        q.email_box_last_check = timezone.now()
        q.save()


def process_queue(q, logger):
    logger.info("***** %s: Begin processing mail for django-helpdesk" % ctime())

    if q.socks_proxy_type and q.socks_proxy_host and q.socks_proxy_port:
        try:
            import socks
        except ImportError:
            logger.error("Queue has been configured with proxy settings, but no socks library was installed. Try to install PySocks via pypi.")
            raise ImportError("Queue has been configured with proxy settings, but no socks library was installed. Try to install PySocks via pypi.")

        proxy_type = {
            'socks4': socks.SOCKS4,
            'socks5': socks.SOCKS5,
        }.get(q.socks_proxy_type)

        socks.set_default_proxy(proxy_type=proxy_type, addr=q.socks_proxy_host, port=q.socks_proxy_port)
        socket.socket = socks.socksocket
    else:
        if six.PY2:
            socket.socket = socket._socketobject
        elif six.PY3:
            import _socket
            socket.socket = _socket.socket

    email_box_type = settings.QUEUE_EMAIL_BOX_TYPE if settings.QUEUE_EMAIL_BOX_TYPE else q.email_box_type

    if email_box_type == 'pop3':

        if q.email_box_ssl or settings.QUEUE_EMAIL_BOX_SSL:
            if not q.email_box_port: q.email_box_port = 995
            server = poplib.POP3_SSL(q.email_box_host or settings.QUEUE_EMAIL_BOX_HOST, int(q.email_box_port))
        else:
            if not q.email_box_port: q.email_box_port = 110
            server = poplib.POP3(q.email_box_host or settings.QUEUE_EMAIL_BOX_HOST, int(q.email_box_port))

        logger.info("Attempting POP3 server login")

        server.getwelcome()
        server.user(q.email_box_user or settings.QUEUE_EMAIL_BOX_USER)
        server.pass_(q.email_box_pass or settings.QUEUE_EMAIL_BOX_PASSWORD)


        messagesInfo = server.list()[1]
        logger.info("Received %s messages from POP3 server" % str(len(messagesInfo)))

        for msg in messagesInfo:
            msgNum = msg.split(" ")[0]
            msgSize = msg.split(" ")[1]
            logger.info("Processing message %s" % str(msgNum))

            full_message = "\n".join(server.retr(msgNum)[1])
            ticket = ticket_from_message(message=full_message, queue=q)

            if ticket:
                server.dele(msgNum)
                logger.info("Successfully processed message %s, deleted from POP3 server" % str(msgNum))
            else:
                logger.warn("Message %s was not successfully processed, and will be left on POP3 server" % str(msgNum))

        server.quit()

    elif email_box_type == 'imap':
        if q.email_box_ssl or settings.QUEUE_EMAIL_BOX_SSL:
            if not q.email_box_port: q.email_box_port = 993
            server = imaplib.IMAP4_SSL(q.email_box_host or settings.QUEUE_EMAIL_BOX_HOST, int(q.email_box_port))
        else:
            if not q.email_box_port: q.email_box_port = 143
            server = imaplib.IMAP4(q.email_box_host or settings.QUEUE_EMAIL_BOX_HOST, int(q.email_box_port))

        logger.info("Attempting IMAP server login")

        server.login(q.email_box_user or settings.QUEUE_EMAIL_BOX_USER, q.email_box_pass or settings.QUEUE_EMAIL_BOX_PASSWORD)
        server.select(q.email_box_imap_folder)

        status, data = server.search(None, 'NOT', 'DELETED')
        if data:
            msgnums = data[0].split()
            logger.info("Received %s messages from IMAP server" % str(len(msgnums)))
            for num in msgnums:
                logger.info("Processing message %s" % str(num))
                status, data = server.fetch(num, '(RFC822)')
                ticket = ticket_from_message(message=data[0][1], queue=q)
                if ticket:
                    server.store(num, '+FLAGS', '\\Deleted')
                    logger.info("Successfully processed message %s, deleted from IMAP server" % str(msgNum))
                else:
                    logger.warn("Message %s was not successfully processed, and will be left on IMAP server" % str(msgNum))

        server.expunge()
        server.close()
        server.logout()

    elif email_box_type == 'local':
        mail_dir = q.email_box_local_dir or '/var/lib/mail/helpdesk/'
        mail = [join(mail_dir, f) for f in listdir(mail_dir) if isfile(join(mail_dir, f))]
        logger.info("Found %s messages in local mailbox directory" % str(len(mail)))
        for m in mail:
            logger.info("Processing message %s" % str(m))
            f = open(m, 'r')
            ticket = ticket_from_message(message=f.read(), queue=q, logger=logger)
            if ticket:
                logger.info("Successfully processed message %s, ticket/comment created." % str(m))
                try:
                    #unlink(m) #delete message file if ticket was successful
                    logger.info("Successfully deleted message %s." % str(m))
                except:
                    logger.error("Unable to delete message %s." % str(m))
            else:
                logger.warn("Message %s was not successfully processed, and will be left in local directory" % str(m))


def decodeUnknown(charset, string):
    if six.PY2:
        if not charset:
            try:
                return string.decode('utf-8','ignore')
            except:
                return string.decode('iso8859-1','ignore')
        return unicode(string, charset)
    elif six.PY3:
        if type(string) is not str:
            if not charset:
                try:
                    return str(string,encoding='utf-8',errors='replace')
                except:
                    return str(string,encoding='iso8859-1',errors='replace')
            return str(string,encoding=charset)
        return string

def decode_mail_headers(string):
    decoded = decode_header(string)
    if six.PY2:
        return u' '.join([unicode(msg, charset or 'utf-8') for msg, charset in decoded])
    elif six.PY3:
        return u' '.join([str(msg,encoding=charset,errors='replace') if charset else str(msg) for msg, charset in decoded])

def ticket_from_message(message, queue, logger):
    # 'message' must be an RFC822 formatted message.
    msg = message
    message = email.message_from_string(msg)
    subject = message.get('subject', _('Created from e-mail'))
    subject = decode_mail_headers(decodeUnknown(message.get_charset(), subject))
    subject = subject.replace("Re: ", "").replace("Fw: ", "").replace("RE: ", "").replace("FW: ", "").replace("Automatic reply: ", "").strip()

    sender = message.get('from', _('Unknown Sender'))
    sender = decode_mail_headers(decodeUnknown(message.get_charset(), sender))

    sender_email = parseaddr(sender)[1]

    body_plain, body_html = '', ''

    for ignore in IgnoreEmail.objects.filter(Q(queues=queue) | Q(queues__isnull=True)):
        if ignore.test(sender_email):
            if ignore.keep_in_mailbox:
                # By returning 'False' the message will be kept in the mailbox,
                # and the 'True' will cause the message to be deleted.
                return False
            return True

    matchobj = re.match(r".*\["+queue.slug+"-(?P<id>\d+)\]", subject)
    if matchobj:
        # This is a reply or forward.
        ticket = matchobj.group('id')
        logger.info("Matched tracking ID %s-%s" % (queue.slug, ticket))
    else:
        logger.info("No tracking ID matched.")
        ticket = None

    counter = 0
    files = []

    for part in message.walk():
        if part.get_content_maintype() == 'multipart':
            continue

        name = part.get_param("name")
        if name:
            name = collapse_rfc2231_value(name)

        if part.get_content_maintype() == 'text' and name == None:
            if part.get_content_subtype() == 'plain':
                body_plain = EmailReplyParser.parse_reply(decodeUnknown(part.get_content_charset(), part.get_payload(decode=True)))
                logger.debug("Discovered plain text MIME part")
            else:
                body_html = part.get_payload(decode=True)
                logger.debug("Discovered HTML MIME part")
        else:
            if not name:
                ext = mimetypes.guess_extension(part.get_content_type())
                name = "part-%i%s" % (counter, ext)

            files.append({
                'filename': name,
                'content': part.get_payload(decode=True),
                'type': part.get_content_type()},
                )
            logger.debug("Found MIME attachment %s" % name)

        counter += 1

    if body_plain:
        body = body_plain
    else:
        body = _('No plain-text email body available. Please see attachment "email_html_body.html".')

    if body_html:
        files.append({
            'filename': _("email_html_body.html"),
            'content': body_html,
            'type': 'text/html',
        })

    now = timezone.now()

    if ticket:
        try:
            t = Ticket.objects.get(id=ticket)
            new = False
            logger.info("Found existing ticket with Tracking ID %s-%s" % (t.queue.slug, t.id))
        except Ticket.DoesNotExist:
            logger.info("Tracking ID %s-%s not associated with existing ticket. Creating new ticket." % (queue.slug, ticket))
            ticket = None

    priority = 3

    smtp_priority = message.get('priority', '')
    smtp_importance = message.get('importance', '')

    high_priority_types = ('high', 'important', '1', 'urgent')

    if smtp_priority in high_priority_types or smtp_importance in high_priority_types:
        priority = 2

    if ticket == None:
        t = Ticket(
            title=subject,
            queue=queue,
            submitter_email=sender_email,
            created=now,
            description=body,
            priority=priority,
        )
        t.save()
        new = True
        update = ''
        logger.debug("Created new ticket %s-%s" % (t.queue.slug, t.id))

    elif t.status == Ticket.CLOSED_STATUS:
        t.status = Ticket.REOPENED_STATUS
        t.save()

    f = FollowUp(
        ticket = t,
        title = _('E-Mail Received from %(sender_email)s' % {'sender_email': sender_email}),
        date = timezone.now(),
        public = True,
        comment = body,
    )

    if t.status == Ticket.REOPENED_STATUS:
        f.new_status = Ticket.REOPENED_STATUS
        f.title = _('Ticket Re-Opened by E-Mail Received from %(sender_email)s' % {'sender_email': sender_email})

    f.save()
    logger.debug("Created new FollowUp for Ticket")

    if six.PY2:
        logger.info(("[%s-%s] %s" % (t.queue.slug, t.id, t.title,)).encode('ascii', 'replace'))
    elif six.PY3:
        logger.info("[%s-%s] %s" % (t.queue.slug, t.id, t.title,))

    for file in files:
        if file['content']:
            if six.PY2:
                filename = file['filename'].encode('ascii', 'replace').replace(' ', '_')
            elif six.PY3:
                filename = file['filename'].replace(' ', '_')
            filename = re.sub('[^a-zA-Z0-9._-]+', '', filename)
            logger.info("Found attachment '%s'" % filename)
            a = Attachment(
                followup=f,
                filename=filename,
                mime_type=file['type'],
                size=len(file['content']),
                )
            a.file.save(filename, ContentFile(file['content']), save=False)
            a.save()
            logger.info("Attachment '%s' successfully added to ticket." % filename)


    context = safe_template_context(t)

    if new:

        if sender_email:
            send_templated_mail(
                'newticket_submitter',
                context,
                recipients=sender_email,
                sender=queue.from_address,
                fail_silently=True,
                )

        if queue.new_ticket_cc:
            send_templated_mail(
                'newticket_cc',
                context,
                recipients=queue.new_ticket_cc,
                sender=queue.from_address,
                fail_silently=True,
                )

        if queue.updated_ticket_cc and queue.updated_ticket_cc != queue.new_ticket_cc:
            send_templated_mail(
                'newticket_cc',
                context,
                recipients=queue.updated_ticket_cc,
                sender=queue.from_address,
                fail_silently=True,
                )

    else:
        context.update(comment=f.comment)

        if t.status == Ticket.REOPENED_STATUS:
            update = _(' (Reopened)')
        else:
            update = _(' (Updated)')

        if t.assigned_to:
            send_templated_mail(
                'updated_owner',
                context,
                recipients=t.assigned_to.email,
                sender=queue.from_address,
                fail_silently=True,
                )

        if queue.updated_ticket_cc:
            send_templated_mail(
                'updated_cc',
                context,
                recipients=queue.updated_ticket_cc,
                sender=queue.from_address,
                fail_silently=True,
                )

    return t


if __name__ == '__main__':
    process_email()