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

Author: Cosimo Alfarano
Date: June 11 2000

whitelist.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.

whitelist manage a list of trusted user.
"""

import sys
import time
import fcntl

import wlp


class whitelist(object):
    """whitelist handling class

    Do you really want anyone can post? Ah ah ah.
    """

    wl = {}
    debug = None
    logf = None    # filedescriptor

    # constants
    DENY = 0
    ACCEPT = 1

    def __init__(self, wlfile='wl.pyg', logfile='pyg.log', debug=0):

        self.debug = debug

        try:
            wlp.setfilebyname(wlfile)
        except (Exception), (errno, message):
            print 'Opening %s: %s (errno %d)' % (wlfile, message, errno)
            sys.exit(0)

        # dict is a { ownername : {variable: value}} dictionary of dictionaries
        self.wl = wlp.mkdict()

#        print 'owner: option = value'
#        for owner in self.wl.keys():
#            for option in self.wl[owner].keys():
#                print '%s: %s = %s' % (owner,option,self.wl[owner][option])

        try:
            self.logf = open(logfile, 'a')
            self.lock()
        except (Exception), message:
            print '%s\nAre you authorized to use this program? ' % message
            sys.exit(1)

    def lock(self):
        fcntl.flock(self.logf.fileno(), fcntl.LOCK_EX)

    # to unlock fd locked, usually fd are unlocked after process exit()
    def unlock(self):
        fcntl.flock(self.logf.fileno(), fcntl.LOCK_UN)

    def checkfrom(self, fromhead):
        """have you permission to be here, sir?"""
        for owner in self.wl.keys():
#            if(self.wl[owner]['From'] == fromhead[:-1]): # remove '\n'
            # here colon after 'From' IS required, because binary module wl
            # expects it.
            # TODO: when switching to the python lexxing, remove this
            # limitation.
            if fromhead[:-1].find(self.wl[owner]['From:']) >= 0:
                return owner
            else:
                return None

    def log(self, string):
        """Captain Diary, Astral Date 962555394 from epoch.
        it rawly write a line in logfile. Remeber to indent it, if you
        like.
        """
        self.logf.write(string + '\n')

    def logmsg(self, heads, ok=DENY, owner=None):
        """who are walking through my gate?
        log
        """

        ltime = time.ctime(time.time())

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

        if ok == self.ACCEPT:
            self.logf.write('Permission Accorded ')
        else:
            self.logf.write('Permission Denied ')

        self.logf.write('at %s (%s)\n' % (ltime, tzone))
        if owner is not None:
            self.logf.write('\tWLOwner: ' + owner + '\n')
        self.logf.write('\tFrom: ' + heads.get('From', 'NOT PRESENT\n'))
        self.logf.write('\tSubject: ' + heads.get('Subject', 'NOT PRESENT\n'))
        self.logf.write('\tSender: ' + heads.get('Sender', 'NOT PRESENT\n'))
        self.logf.write('\tDate: ' + heads.get('Date', 'NOT PRESENT\n'))

        # some client create Message-Id other Message-ID.
        if 'Message-ID' in heads:
            self.logf.write('\tMessage-ID: ' + heads.get('Message-ID'))
        else:
            self.logf.write('\tMessage-Id: ' + heads.get('Message-Id',
                                                        'NOT PRESENT\n'))

        # X-Newsgroups: and To: are present if user is trusted, else
        # Newsgroup: exists since no changes on nntp headers are done.
        if 'X-Newsgroups' in heads:
            self.logf.write('\tTo: ' + heads.get('To', 'NOT PRESENT\n'))
            self.logf.write('\tX-Newsgroups: ' + heads.get('X-Newsgroups',
                                                          'NOT PRESENT\n'))
        else:
            self.logf.write('\tNewsgroups: ' +
                           heads.get('Newsgroups', 'NOT PRESENT\n'))

        self.logf.write('\n')