# -*- coding: UTF-8 -*-

# Copyright (c) 2010, Pascal Volk

# See COPYING for distribution information.

"""

    VirtualMailManager.mailbox

    ~~~~~~~~~~~~~~~~~~~~~~~~~~

    VirtualMailManager's mailbox classes for the Maildir, single dbox

    (sdbox) and multi dbox (mdbox) mailbox formats.

"""

import os

import re

from binascii import a2b_base64, b2a_base64

from subprocess import Popen, PIPE

from VirtualMailManager.account import Account

from VirtualMailManager.common import lisdir

from VirtualMailManager.errors import VMMError

from VirtualMailManager.constants import VMM_ERROR

__all__ = ('new', 'Maildir', 'SingleDbox', 'MultiDbox',

           'utf8_to_mutf7', 'mutf7_to_utf8')

cfg_dget = lambda option: None

def _mbase64_encode(inp, dest):

    if inp:

        mb64 = b2a_base64(''.join(inp).encode('utf-16be'))

        dest.append('&%s-' % mb64.rstrip('\n=').replace('/', ','))

        del inp[:]

def _mbase64_to_unicode(mb64):

    return unicode(a2b_base64(mb64.replace(',', '/') + '==='), 'utf-16be')

def utf8_to_mutf7(src):

    """

    Converts the international mailbox name `src` into a modified

    version version of the UTF-7 encoding.

    """

    ret = []

    tmp = []

    for c in src:

        ordc = ord(c)

        if 0x20 <= ordc <= 0x25 or 0x27 <= ordc <= 0x7E:

            _mbase64_encode(tmp, ret)

            ret.append(c)

        elif ordc == 0x26:

            _mbase64_encode(tmp, ret)

            ret.append('&-')

        else:

            tmp.append(c)

    _mbase64_encode(tmp, ret)

    return ''.join(ret)

def mutf7_to_utf8(src):

    """

    Converts the mailbox name `src` from modified UTF-7 encoding to UTF-8.

    """

    ret = []

    tmp = []

    for c in src:

        if c == '&' and not tmp:

            tmp.append(c)

        elif c == '-' and tmp:

            if len(tmp) is 1:

                ret.append('&')

            else:

                ret.append(_mbase64_to_unicode(''.join(tmp[1:])))

            tmp = []

        elif tmp:

            tmp.append(c)

        else:

            ret.append(c)

    if tmp:

        ret.append(_mbase64_to_unicode(''.join(tmp[1:])))

    return ''.join(ret)

class Mailbox(object):

    """Base class of all mailbox classes."""

    __slots__ = ('_boxes', '_root', '_sep', '_user')

    FILE_MODE = 0600

    _ctrl_chr_re = re.compile('[\x00-\x1F\x7F-\x9F]')

    _box_name_re = re.compile('^[\x20-\x25\x27-\x7E]+$')

    def __init__(self, account):

        """

        Creates a new mailbox instance.

        Use one of the `Maildir`, `SingleDbox` or `MultiDbox` classes.

        """

        assert isinstance(account, Account) and lisdir(account.home)

        self._user = account

        self._boxes = []

        self._root = self._user.mail_location.directory

        self._sep = '/'

        os.chdir(self._user.home)

    def _add_boxes(self, mailboxes, subscribe):

        raise NotImplementedError

    def _validate_box_name(self, name, good, bad):

        """

        Validates the mailboxes name `name`.  When the name is valid, it

        will be added to the `good` set.  Invalid mailbox names will be

        appended to the `bad` list.

        """

        name = name.strip()

        if not name:

            return

        if self.__class__._ctrl_chr_re.search(name):  # no control chars

            bad.append(name)

            return

        if name[0] in (self._sep, '~'):

            bad.append(name)

            return

        if self._sep == '/':

            if '//' in name or '/./' in name or '/../' in name or \

               name.startswith('../'):

                bad.append(name)

                return

        if '/' in name or '..' in name:

            bad.append(name)

            return

        if not self.__class__._box_name_re.match(name):

            tmp = utf8_to_mutf7(name)

            if name == mutf7_to_utf8(tmp):

                if self._user.mail_location.mbformat == 'maildir':

                    good.add(tmp)

                else:

                    good.add(name)

                return

            else:

                bad.append(name)

                return

        good.add(name)

    def add_boxes(self, mailboxes, subscribe):

        """

        Create all mailboxes from the `mailboxes` list in the user's

        mail directory.  When `subscribe` is ``True`` all created mailboxes

        will be listed in the subscriptions file.

        Returns a list of invalid mailbox names, if any.

        """

        assert isinstance(mailboxes, list) and isinstance(subscribe, bool)

        good = set()

        bad = []

        for box in mailboxes:

            self._validate_box_name(box, good, bad)

        self._add_boxes(good, subscribe)

        return bad

    def create(self):

        """Create the INBOX in the user's mail directory."""

        raise NotImplementedError

class Maildir(Mailbox):

    """Class for Maildir++ mailboxes."""

    __slots__ = ('_subdirs')

    def __init__(self, account):

        """

        Create a new Maildir++ instance.

        Call the instance's create() method, in order to create the INBOX.

        For additional mailboxes use the add_boxes() method.

        """

        super(self.__class__, self).__init__(account)

        self._sep = '.'

        self._subdirs = ('cur', 'new', 'tmp')

    def _create_maildirfolder_file(self, path):

        """Mark the Maildir++ folder as Maildir folder."""

        maildirfolder_file = os.path.join(self._sep + path, 'maildirfolder')

        os.close(os.open(maildirfolder_file, os.O_CREAT | os.O_WRONLY,

                         self.__class__.FILE_MODE))

        os.chown(maildirfolder_file, self._user.uid, self._user.gid)

    def _make_maildir(self, path):

        """

        Create Maildir++ folders with the cur, new and tmp subdirectories.

        """

        mode = cfg_dget('account.directory_mode')

        uid = self._user.uid

        gid = self._user.gid

        os.mkdir(path, mode)

        os.chown(path, uid, gid)

        for subdir in self._subdirs:

            dir_ = os.path.join(path, subdir)

            os.mkdir(dir_, mode)

            os.chown(dir_, uid, gid)

    def _subscribe_boxes(self):

        """Writes all created mailboxes to the subscriptions file."""

        if not self._boxes:

            return

        subscriptions = open('subscriptions', 'w')

        subscriptions.write('\n'.join(self._boxes))

        subscriptions.write('\n')

        subscriptions.flush()

        subscriptions.close()

        os.chown('subscriptions', self._user.uid, self._user.gid)

        os.chmod('subscriptions', self.__class__.FILE_MODE)

        del self._boxes[:]

    def _add_boxes(self, mailboxes, subscribe):

        for mailbox in mailboxes:

            self._make_maildir(self._sep + mailbox)

            self._create_maildirfolder_file(mailbox)

            self._boxes.append(mailbox)

        if subscribe:

            self._subscribe_boxes()

    def create(self):

        """Creates a Maildir++ INBOX."""

        self._make_maildir(self._root)

        os.chdir(self._root)

class SingleDbox(Mailbox):

    """

    Class for (single) dbox mailboxes.

    See http://wiki.dovecot.org/MailboxFormat/dbox for details.

    """

    __slots__ = ()

    def __init__(self, account):

        """

        Create a new dbox instance.

        Call the instance's create() method, in order to create the INBOX.

        For additional mailboxes use the add_boxes() method.

        """

        assert cfg_dget('misc.dovecot_version') >= \

                account.mail_location.dovecot_version

        super(SingleDbox, self).__init__(account)

    def _doveadm_create(self, mailboxes, subscribe):

        """Wrap around Dovecot's doveadm"""

        cmd_args = [cfg_dget('bin.dovecotpw'), 'mailbox', 'create', '-u',

                    str(self._user.address)]

        if subscribe:

            cmd_args.append('-s')

        cmd_args.extend(mailboxes)

        process = Popen(cmd_args, stdout=PIPE, stderr=PIPE)

        stdout, stderr = process.communicate()

        if process.returncode:

            raise VMMError(stderr.strip(), VMM_ERROR)

    def create(self):

        """Create a dbox INBOX"""

        os.mkdir(self._root, cfg_dget('account.directory_mode'))

        os.chown(self._root, self._user.uid, self._user.gid)

        self._doveadm_create(('INBOX',), False)

        os.chdir(self._root)

    def _add_boxes(self, mailboxes, subscribe):

        self._doveadm_create(mailboxes, subscribe)

class MultiDbox(SingleDbox):

    """

    Class for multi dbox mailboxes.

    See http://wiki.dovecot.org/MailboxFormat/dbox#Multi-dbox for details.

    """

    __slots__ = ()

def new(account):

    """Create a new Mailbox instance for the given Account."""

    mbfmt = account.mail_location.mbformat

    if mbfmt == 'maildir':

        return Maildir(account)

    elif mbfmt == 'mdbox':

        return MultiDbox(account)

    elif mbfmt == 'sdbox':

        return SingleDbox(account)

    raise ValueError('unsupported mailbox format: %r' % mbfmt)

del cfg_dget