#! /usr/bin/env python3

# Copyright (C) 2021 by the Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.

"""This script assumes the Mailman 3 smtp.log is at LOGPATH and the next
older generation is at LOGPATH + '.1'. It reads those two logs and accumulates
the total number of messages sent including administrivia by day and by list
and prints a simple report. You may need to adjust LOGPATH.
"""

import re
import datetime

TSRE = '(?P<time_stamp>[^(]*) \(\d+\)'
LOGRE = (' (?P<msgid><[^>]*>) smtp to '
         '(?P<listname>[^ ]*) for (?P<count>\d+) recips, completed ')
LOGPATH = '/opt/mailman/mm/var/logs/smtp.log'

def get_log_data(log):
    data = []
    with open(log) as fp:
        for line in fp.readlines():
            mo = re.match(TSRE, line)
            if mo:
                dt = datetime.datetime.strptime(mo.group('time_stamp'),
                                                '%b %d %H:%M:%S %Y')
            mo = re.search(LOGRE, line)
            if not mo:
                continue
            mid = mo.group('msgid')
            lname = mo.group('listname')
            count = int(mo.group('count'))
            data.append([dt, mid, lname, count])
        return data

def main():
    data = get_log_data(LOGPATH + '.1') + get_log_data(LOGPATH)
    days = dict()
    for dt, mid, lname, count in data:
        day = dt.strftime('%b %d')
        days.setdefault(day, []).append([lname, count])
    for day in days.keys():
        days[day].sort()
        lname = None
        tot = 0
        print(day)
        for l, c in days[day]:
            if l != lname:
                if lname is not None:
                    print(f'    {lname}: {tot}')
                lname = l
                tot = c
            else:
                tot += c
        print(f'    {lname}: {tot}')

if __name__ == '__main__':
    main()