#!/usr/bin/env python

# -*- coding: utf-8 -*-

# Copyright 2009 - 2010 Pascal Volk

# See COPYING for distribution information.

__author__ = 'Pascal Volk'

__version__ = '0.1.2'

__date__ = '2009-07-03'

import os

import re

import fileinput

class NiXSapmSum(object):

    """

    Small log parser class to parse and summarize NiX Spam DNSBL lookup

    based rejects from a mail log file.

    """

    __slots__ = ('_doms', '_mxs', '_repo')

    """Regular expression pattern for mail logs from Postfix"""

    def __init__(self):

        self._doms = {}

        self._mxs  = {}

        self._repo = None

    def setLogFormat(self, format='postfix'):

        if format == 'postfix':

        else:

            raise Exception('MTA/Logformat not supported yet.')

    def parseLog(self, filehandle):

        for l in filehandle:

            mo = self._repo.match(l)

            if mo:

                mx = mo.group(1)

                try:

                    self._mxs[mx] += 1

                except KeyError:

                    self._mxs[mx]  = 1

    def countByDom(self):

        for mx in self._mxs.keys():

            try:

                self._doms[dom] += self._mxs[mx]

            except KeyError:

                self._doms[dom]  = self._mxs[mx]

    def getDomains(self):

        return self._doms

    def getMXs(self):

        return self._mxs

def getOptionParser():

    from optparse import OptionParser

    description = 'NiX Spam DNSBL lookup based rejects summarizer'

    usage  = 'usage: %prog [options] maillog [maillog [...]]'

    version = '%prog '+__version__

    parser = OptionParser(description=description,usage=usage,version=version)

    parser.add_option('-d', action='store_true', dest='countByDom',

            default=False, help='summarize all MX by domain')

    parser.add_option('-m', action='store_false', dest='countByDom',

            help='count per MX host [default]')

    parser.add_option('-o', dest='oFormat', default='table',metavar='FORMAT',

            choices=('csv', 'table'),

            help='the output format: table or csv [default: %default]')

    parser.add_option('-p', action='store_true', dest='percent', default=False,

            help='show also percentages in table output [default: %default]')

    parser.add_option('-s', dest='order', default='name', metavar='SORTBY',

            help='arrange output by: name or count [default: %default]')

    parser.add_option('-t', dest='format', default='postfix',metavar='MTA',

            choices=('postfix',),

            help='MTA that generated the maillog [default: %default]')

    return parser

def check_files(log_files):

    """Checks that all files from *log_files* exist and all of them are

    readable.

    If a file doesn't exist or is not readable, it will be removed from

    *log_files* set.

    This function will return *True*, if at least one file has passed the

    checks. Otherwise *False* will be returned. And the *log_files* set

    will be emptied.

    :param log_files: set of file names

    :type log_files: set

    :rtype: bool"""

    assert isinstance(log_files, set), 'log_files argument must be a set'

    lf_copy = log_files.copy()

    for lf in lf_copy:

        if not os.path.isfile(lf):

            os.sys.stderr.write('Warning: No such file: %r\n' % lf)

            log_files.remove(lf)

        elif not os.access(lf, os.R_OK):

            os.sys.stderr.write('Warning: Cannot read file: %r\n' % lf)

            log_files.remove(lf)

    if log_files:

        return True

    return False

def buildTable(output, domains, percent, orderBy):

    k = 0 if orderBy == 'name' else 1

    doms = sorted(domains.items(), lambda d,c: cmp(d[k],c[k]), reverse=k)

    dlen = len(max(domains.iterkeys(), key=len)) + 1

    clen = len(str(max(domains.values())))

    total = sum(domains.values())

    if percent:

        format = ' %%%ds  %%%dd  %%6.2f %%%%\n' % (-dlen, clen)

        for d, c in doms:

            dfrac = 100./total*c

            output.write(format % (d, c, dfrac))

        output.write('%s\n' % ((clen+dlen+14)*'-'))

        output.write(format % ('total', total, 100))

    else:

        format = ' %%%ds  %%%dd\n' % (-dlen, clen)

        for d in doms:

            output.write(format % d)

        output.write('%s\n' % ((clen+dlen+4)*'-'))

        output.write(format % ('total', total))

def showResult(nixspamsum, options):

    if options.countByDom:

        nixspamsum.countByDom()

        domains = nixspamsum.getDomains()

    else:

        domains = nixspamsum.getMXs()

    if not domains:

        print "No NiX Spam DNSBL rejects found"

        return

    from cStringIO import StringIO

    output = StringIO()

    # build the table

    if options.oFormat == 'table':

        buildTable(output, domains, options.percent, options.order)

    # generate comma separated values

    elif options.oFormat == 'csv':

        order = domains.keys()

        order.sort()

        for d in order:

            output.write("'%s',%d\n" % (d, domains[d]))

    # should never be reached

    else:

        print "Oops, error in function showResult() happend"

    # show the result

    print output.getvalue()

def main():

    parser = getOptionParser()

    opts, args = parser.parse_args()

    if not args:

        parser.error('No log file specified')

    # drop duplicates

    log_files = set(args)

    # remove inexistent/unreadable files

    if not check_files(log_files):

        os.sys.stderr.write('No readable log files found\n')

        return 1

    nixss = NiXSapmSum()

    nixss.setLogFormat(opts.format)

    fi = fileinput.FileInput(log_files, openhook=fileinput.hook_compressed)

    nixss.parseLog(fi)

    fi.close()

    showResult(nixss, opts)

    return 0

if __name__ == '__main__':

    os.sys.exit(main())