#!/usr/bin/python


import cliapp
import email.parser
import glob
import mailbox
import os
import re
import shutil


received_date = re.compile(
    r'^from (.|\n)*; (Mon|Tue|Wed|Thu|Fri|Sat|Sun),\s+'
        r'(?P<day>\d+) '
        r'(?P<mon>Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) '
        r'(?P<year>\d+)',
    re.MULTILINE)

date_date = re.compile(
    r'^((Mon|Tue|Wed|Thu|Fri|Sat|Sun),\s+)?'
        r'(?P<day>\d+) '
        r'(?P<mon>Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) '
        r'(?P<year>\d+)')

montab = {
    'Jan': 1,
    'Feb': 2,
    'Mar': 3,
    'Apr': 4,
    'May': 5,
    'Jun': 6,
    'Jul': 7,
    'Aug': 8,
    'Sep': 9,
    'Oct': 10,
    'Nov': 11,
    'Dec': 12,
}


class PieniToMailArchive(cliapp.Application):

    def add_settings(self):
        self.settings.boolean(
            ['rsync-from-pieni'],
            'rsync new archived mails from pieni.net?')
        self.settings.string(
            ['maildirs-dir'],
            'where to put maildirs from pieni.net',
            default='maildirs')
        self.settings.string(
            ['mbox-dir'],
            'where to put archived mail mboxes',
            default='mboxes')

    def setup(self):
        self.mbox = None
        self.mbox_filename = None

    def cleanup(self):
        self.output.write('closing\n')
        if self.mbox != None:
            self.mbox.close()

    def process_args(self, args):
        if self.settings['rsync-from-pieni']:
            self.rsync_from_pieni()

        maildirs = self.settings['maildirs-dir']
        for dirname in sorted(glob.glob(maildirs + '/*/')):
            if self.is_maildir(dirname):
                self.output.write('processing: %s\n' % dirname)
                self.archive_mails_in_maildir(dirname)
                self.remove_maildir_if_empty(dirname)
            else:
                self.output.write('SKIPPING (not a maildir): %s\n' % dirname)

    def is_maildir(self, dirname):
        subdirs = ['cur', 'new', 'tmp']
        return all(os.path.exists(os.path.join(dirname, x)) for x in subdirs)

    def rsync_from_pieni(self):
        self.output.write('rsyncing from pieni.net\n')
        cliapp.runcmd(
            ['rsync', '-av', '--remove-source-files', 
             'pieni.net:backups/mail/.', self.settings['maildirs-dir'] + '/.'],
            stdout=self.output)
    
    def archive_mails_in_maildir(self, maildir):
        md = mailbox.Maildir(maildir, factory=None)
        parser = email.parser.Parser()
        for key, msg in md.iteritems():
            y, m, d = self.date_of(msg)
            
            filename = os.path.join(self.settings['mbox-dir'], '%04d.mbox' % y)
            existing = glob.glob(filename + '.*')
            if existing:
                self.output.write(
                    'WARNING: %s already has compressed(?) versions: %s' % 
                        (filename, ' '.join(existing)))
                continue

            if filename != self.mbox_filename:
                if self.mbox is not None:
                    self.mbox.close()
                self.mbox = mailbox.mbox(filename, create=True)
                self.mbox_filename = filename
            self.mbox.add(msg)
            md.remove(key)
        
        md.close()
        
    def date_of(self, msg):
        year = mon = day = 0

        rs = msg.get_all('Received')
        if rs:
            r = str(rs[0])
            m = received_date.match(r)
            if m:
                day = int(m.group('day'))
                mon = montab[m.group('mon')]
                year = int(m.group('year'))

        if year is 0 and 'Date' in msg:
            s = str(msg['Date'])
            m = date_date.match(s)
            if m:
                day = int(m.group('day'))
                mon = montab[m.group('mon')]
                year = int(m.group('year'))

        if 70 <= year < 100:
            year += 1900
        if year < 1988:
            year = mon = day = 0
        return year, mon, day

    def remove_maildir_if_empty(self, maildir):
        md = mailbox.Maildir(maildir, factory=None)
        remove = len(md) == 0
        md.close()
        if remove:
            shutil.rmtree(maildir)


PieniToMailArchive().run()