"""News to mail gateway script. Copyright 2000 Cosimo Alfarano

Author: Cosimo Alfarano
Date: June 11 2000

news2mail.py - (C) 2000 by Cosimo Alfarano <Alfarano@Students.CS.UniBo.It>
You can use this software under the terms of the GPL. If we meet some day,
and you think this stuff is worth it, you can buy me a beer in return.

Thanks to md for this useful formula. Beer is beer.

Gets news article and sends it via SMTP.

class news2mail is hopefully conform to rfc822.

normal (what pygs does) operations flow is:
1) reads from stdin NNTP article (readfile)
2) divide headers and body (parsearticle)
3) merges NNTP and SMTP heads into a unique heads
4) adds, renames and removes some heads
5) sorts remaining headers starting at top with Received: From: To: Subject:
    Date:, normal headers ending with X-* and Resent-* headers.

"""
from __future__ import absolute_import
from __future__ import print_function
from collections import OrderedDict
import email
from mail2news import VERSION, DESC
import smtplib
from socket import gethostbyaddr, gethostname
import sys
import time


# logging.basicConfig(level=logging.DEBUG)
class news2mail(object):
    """news to mail gateway class"""

    def __init__(self, verbose=False):
        self.wlfile = None
        self.logfile = None
        self.verbose = verbose

        self.sender = ''
        self.rcpt = ''
        self.envelope = ''

        self.smtpserver = 'localhost'

        self.hostname = gethostbyaddr(gethostname())[0]

        self.heads_dict = {}
        self.article, self.headers, self.body = [], [], []
        self.message = self.__addheads(email.message_from_file(sys.stdin))

    def __addheads(self, msg):
        """add new header like X-Gateway: Received:
        """

        msg['X-Gateway'] = 'pyg {0} {1}'.format(VERSION, DESC)

        # to make Received: header
        t = time.ctime(time.time())

        if time.daylight:
            tzone = time.tzname[1]
        else:
            tzone = time.tzname[0]

        # An example from debian-italian:
        # Received: from murphy.debian.org (murphy.debian.org [216.234.231.6])
        #        by smv04.iname.net (8.9.3/8.9.1SMV2) with SMTP id JAA26407
        #        for <kame.primo@innocent.com> sent by
        #        <debian-italian-request@lists.debian.org

        tmp = 'from GATEWAY by ' + self.hostname + \
            ' with pyg' + \
            '\n\tfor <' + self.rcpt + '> ; ' + \
            t + ' (' + tzone + ')\n'

        msg['Received'] = tmp

        return msg

    def __renameheads(self):
        """remove headers like Xref: Path: Lines:
           rename headers such as Newsgroups: to X-Newsgroups:

        headers renamed are useless or not rfc 822 copliant
        """
        try:
            if 'Newsgroups' in self.message:
                self.message['X-Newsgroups'] = \
                    self.message['Newsgroups']
                del self.message['Newsgroups']

            if 'NNTP-Posting-Host' in self.message:
                self.message['X-NNTP-Posting-Host'] = \
                    self.message['NNTP-Posting-Host']
                del self.message['NNTP-Posting-Host']
        except KeyError as ex:
            print(ex)

        try:
            # removing some others useless headers ....
            # that includes BOTH 'From ' and 'From'
            # 'Sender is usually set by INN, if ng is moderated...
            for key in ('Approved', 'From', 'Xref', 'Path', 'Lines', 'Sender'):
                if key in self.message:
                    del self.message[key]

            if 'Message-id' in self.message:
                msgid = self.message['Message-id']
                del self.message['Message-id']
                self.message['Message-Id'] = msgid
            else:
                # It should put a real user@domain
                self.heads_dict['Message-Id'] = 'pyg@puppapera.org'

            if 'References' in self.message and \
                    'In-Reply-To' not in self.message:
                refs = self.message['References'].split()
                self.message['In-Reply-To'] = refs[-1]

        except KeyError as message:
            print(message)

    def __sortheads(self):
        """make list sorting heads, Received: From: To: Subject: first,
           others, X-*, Resent-* last"""

        # put at top
        header_set = ('Received', 'From', 'To', 'Subject', 'Date')

        heads_dict = OrderedDict(self.message)
        for hdr in self.message.keys():
            del self.message[hdr]

        for k in header_set:
            if k in heads_dict:
                self.message[k] = heads_dict[k]

        for k in heads_dict:
            if not k.startswith('X-') and not k.startswith('Resent-') \
                    and k not in header_set:
                self.message[k] = heads_dict[k]

        for k in heads_dict:
            if k.startswith('X-'):
                self.message[k] = heads_dict[k]

        for k in heads_dict:
            if k.startswith('Resent-'):
                self.message[k] = heads_dict[k]

    def process_message(self):
        """phase 3:
        format rfc 822 headers from input article
        """
        self.__renameheads()  # remove other heads
        self.__sortheads()

    def sendarticle(self):
        """Talk to SMTP server and try to send email."""
        s = smtplib.SMTP(self.smtpserver)
        s.set_debuglevel(self.verbose)

        s.sendmail(self.envelope, self.rcpt, self.message.as_bytes())

        s.quit()