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

# Copyright (c) 2007 - 2014, Pascal Volk

# See COPYING for distribution information.

"""

   VirtualMailManager.handler

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

   A wrapper class. It wraps round all other classes and does some

   dependencies checks.

   Additionally it communicates with the PostgreSQL database, creates

   or deletes directories of domains or users.

"""

import os

import re

from shutil import rmtree

from stat import S_IRGRP, S_IROTH, S_IWGRP, S_IWOTH

from subprocess import Popen, PIPE

import psycopg2

from VirtualMailManager.account import Account

from VirtualMailManager.alias import Alias

from VirtualMailManager.aliasdomain import AliasDomain

from VirtualMailManager.catchall import CatchallAlias

from VirtualMailManager.common import exec_ok, lisdir

from VirtualMailManager.config import Config as Cfg

from VirtualMailManager.constants import MIN_GID, MIN_UID, \

     ACCOUNT_EXISTS, ALIAS_EXISTS, CONF_NOFILE, CONF_NOPERM, CONF_WRONGPERM, \

     DATABASE_ERROR, DOMAINDIR_GROUP_MISMATCH, DOMAIN_INVALID, \

     FOUND_DOTS_IN_PATH, INVALID_ARGUMENT, MAILDIR_PERM_MISMATCH, \

     NOT_EXECUTABLE, NO_SUCH_ACCOUNT, NO_SUCH_ALIAS, NO_SUCH_BINARY, \

     NO_SUCH_DIRECTORY, NO_SUCH_RELOCATED, RELOCATED_EXISTS, UNKNOWN_SERVICE, \

     VMM_ERROR, LOCALPART_INVALID, TYPE_ACCOUNT, TYPE_ALIAS, TYPE_RELOCATED

from VirtualMailManager.domain import Domain

from VirtualMailManager.emailaddress import DestinationEmailAddress, \

     EmailAddress, RE_LOCALPART

from VirtualMailManager.errors import \

     DomainError, NotRootError, PermissionError, VMMError

from VirtualMailManager.mailbox import new as new_mailbox

from VirtualMailManager.password import extract_scheme, verify_scheme

from VirtualMailManager.quotalimit import QuotaLimit

from VirtualMailManager.relocated import Relocated

from VirtualMailManager.serviceset import ServiceSet, SERVICES

from VirtualMailManager.transport import Transport

_ = lambda msg: msg

CFG_FILE = 'vmm.cfg'

CFG_PATH = '/root:/usr/local/etc:/etc'

RE_DOMAIN_SEARCH = """^[a-z0-9-\.]+$"""

OTHER_TYPES = {

    TYPE_ACCOUNT: (_('an account'), ACCOUNT_EXISTS),

    TYPE_ALIAS: (_('an alias'), ALIAS_EXISTS),

    TYPE_RELOCATED: (_('a relocated user'), RELOCATED_EXISTS),

}

class Handler(object):

    """Wrapper class to simplify the access on all the stuff from

    VirtualMailManager"""

    __slots__ = ('_cfg', '_cfg_fname', '_dbh', '_warnings')

    def __init__(self, skip_some_checks=False):

        """Creates a new Handler instance.

        ``skip_some_checks`` : bool

            When a derived class knows how to handle all checks this

            argument may be ``True``. By default it is ``False`` and

            all checks will be performed.

        Throws a NotRootError if your uid is greater 0.

        """

        self._cfg_fname = ''

        self._warnings = []

        self._cfg = None

        self._dbh = None

        if os.geteuid():

            raise NotRootError(_("You are not root.\n\tGood bye!\n"),

                               CONF_NOPERM)

        if self._check_cfg_file():

            self._cfg = Cfg(self._cfg_fname)

            self._cfg.load()

        if not skip_some_checks:

            self._cfg.check()

            self._chkenv()

    def _find_cfg_file(self):

        """Search the CFG_FILE in CFG_PATH.

        Raise a VMMError when no vmm.cfg could be found.

        """

        for path in CFG_PATH.split(':'):

            tmp = os.path.join(path, CFG_FILE)

            if os.path.isfile(tmp):

                self._cfg_fname = tmp

                break

        if not self._cfg_fname:

            raise VMMError(_("Could not find '%(cfg_file)s' in: "

                             "'%(cfg_path)s'") % {'cfg_file': CFG_FILE,

                           'cfg_path': CFG_PATH}, CONF_NOFILE)

    def _check_cfg_file(self):

        """Checks the configuration file, returns bool"""

        GRPRW = S_IRGRP | S_IWGRP

        OTHRW = S_IROTH | S_IWOTH

        self._find_cfg_file()

        fstat = os.stat(self._cfg_fname)

        if (fstat.st_uid == fstat.st_gid and fstat.st_mode & OTHRW) or \

           (fstat.st_uid != fstat.st_gid and fstat.st_mode & (GRPRW | OTHRW)):

            # TP: Please keep the backticks around the command. `chmod 0600 …`

            raise PermissionError(_("wrong permissions for '%(file)s': "

                                    "%(perms)s\n`chmod 0600 %(file)s` would "

                                    "be great.") % {'file': self._cfg_fname,

                                  'perms': oct(fstat.st_mode)[-4:]},

                                  CONF_WRONGPERM)

        else:

            return True

    def _chkenv(self):

        """Make sure our base_directory is a directory and that all

        required executables exists and are executable.

        If not, a VMMError will be raised"""

        dir_created = False

        basedir = self._cfg.dget('misc.base_directory')

        if not os.path.exists(basedir):

            old_umask = os.umask(0o006)

            os.makedirs(basedir, 0o771)

            os.chown(basedir, 0, 0)

            os.umask(old_umask)

            dir_created = True

        if not dir_created and not lisdir(basedir):

            raise VMMError(_("'%(path)s' is not a directory.\n(%(cfg_file)s: "

                             "section 'misc', option 'base_directory')") %

                           {'path': basedir, 'cfg_file': self._cfg_fname},

                           NO_SUCH_DIRECTORY)

        for opt, val in self._cfg.items('bin'):

            try:

                exec_ok(val)

            except VMMError as err:

                if err.code in (NO_SUCH_BINARY, NOT_EXECUTABLE):

                    raise VMMError(err.msg + _("\n(%(cfg_file)s: section "

                                   "'bin', option '%(option)s')") %

                                   {'cfg_file': self._cfg_fname,

                                    'option': opt}, err.code)

                else:

                    raise

    def _db_connect(self):

        """Return a new psycopg2 connection object."""

        if self._dbh is None or \

          (isinstance(self._dbh, psycopg2.extensions.connection) and

           self._dbh.closed):

            try:

                self._dbh = psycopg2.connect(

                        host=self._cfg.dget('database.host'),

                        sslmode=self._cfg.dget('database.sslmode'),

                        port=self._cfg.dget('database.port'),

                        database=self._cfg.dget('database.name'),

                        user=self._cfg.pget('database.user'),

                        password=self._cfg.pget('database.pass'))

                self._dbh.set_client_encoding('utf8')

                dbc = self._dbh.cursor()

                dbc.execute("SET NAMES 'UTF8'")

                dbc.close()

            except psycopg2.DatabaseError as err:

                raise VMMError(str(err), DATABASE_ERROR)

    def _chk_other_address_types(self, address, exclude):

        """Checks if the EmailAddress *address* is known as `TYPE_ACCOUNT`,

        `TYPE_ALIAS` or `TYPE_RELOCATED`, but not as the `TYPE_*` specified

        by *exclude*.  If the *address* is known as one of the `TYPE_*`s

        the according `TYPE_*` constant will be returned.  Otherwise 0 will

        be returned."""

        assert exclude in (TYPE_ACCOUNT, TYPE_ALIAS, TYPE_RELOCATED) and \

                isinstance(address, EmailAddress)

        if exclude is not TYPE_ACCOUNT:

            account = Account(self._dbh, address)

            if account:

                return TYPE_ACCOUNT

        if exclude is not TYPE_ALIAS:

            alias = Alias(self._dbh, address)

            if alias:

                return TYPE_ALIAS

        if exclude is not TYPE_RELOCATED:

            relocated = Relocated(self._dbh, address)

            if relocated:

                return TYPE_RELOCATED

        return 0

    def _is_other_address(self, address, exclude):

        """Checks if *address* is known for an Account (TYPE_ACCOUNT),

        Alias (TYPE_ALIAS) or Relocated (TYPE_RELOCATED), except for

        *exclude*.  Returns `False` if the address is not known for other

        types.

        Raises a `VMMError` if the address is known.

        """

        other = self._chk_other_address_types(address, exclude)

        if not other:

            return False

        # TP: %(a_type)s will be one of: 'an account', 'an alias' or

        # 'a relocated user'

        msg = _("There is already %(a_type)s with the address '%(address)s'.")

        raise VMMError(msg % {'a_type': OTHER_TYPES[other][0],

                              'address': address}, OTHER_TYPES[other][1])

    def _get_account(self, address):

        """Return an Account instances for the given address (str)."""

        address = EmailAddress(address)

        self._db_connect()

        return Account(self._dbh, address)

    def _get_alias(self, address):

        """Return an Alias instances for the given address (str)."""

        address = EmailAddress(address)

        self._db_connect()

        return Alias(self._dbh, address)

    def _get_catchall(self, domain):

        """Return a CatchallAlias instances for the given domain (str)."""

        self._db_connect()

        return CatchallAlias(self._dbh, domain)

    def _get_relocated(self, address):

        """Return a Relocated instances for the given address (str)."""

        address = EmailAddress(address)

        self._db_connect()

        return Relocated(self._dbh, address)

    def _get_domain(self, domainname):

        """Return a Domain instances for the given domain name (str)."""

        self._db_connect()

        return Domain(self._dbh, domainname)

    def _get_disk_usage(self, directory):

        """Estimate file space usage for the given directory.

        Arguments:

        `directory` : basestring

          The directory to summarize recursively disk usage for

        """

        if lisdir(directory):

            return Popen([self._cfg.dget('bin.du'), "-hs", directory],

                         stdout=PIPE).communicate()[0].decode().split('\t')[0]

        else:

            self._warnings.append(_('No such directory: %s') % directory)

            return 0

    def _make_domain_dir(self, domain):

        """Create a directory for the `domain` and its accounts."""

        cwd = os.getcwd()

        hashdir, domdir = domain.directory.split(os.path.sep)[-2:]

        dir_created = False

        os.chdir(self._cfg.dget('misc.base_directory'))

        old_umask = os.umask(0o022)

        if not os.path.exists(hashdir):

            os.mkdir(hashdir, 0o711)

            os.chown(hashdir, 0, 0)

            dir_created = True

        if not dir_created and not lisdir(hashdir):

            raise VMMError(_("'%s' is not a directory.") % hashdir,

                           NO_SUCH_DIRECTORY)

        if os.path.exists(domain.directory):

            raise VMMError(_("The file/directory '%s' already exists.") %

                           domain.directory, VMM_ERROR)

        os.mkdir(os.path.join(hashdir, domdir),

                 self._cfg.dget('domain.directory_mode'))

        os.chown(domain.directory, 0, domain.gid)

        os.umask(old_umask)

        os.chdir(cwd)

    def _make_home(self, account):

        """Create a home directory for the new Account *account*."""

        domdir = account.domain.directory

        if not lisdir(domdir):

            self._make_domain_dir(account.domain)

        os.umask(0o007)

        uid = account.uid

        os.chdir(domdir)

        os.mkdir('%s' % uid, self._cfg.dget('account.directory_mode'))

        os.chown('%s' % uid, uid, account.gid)

    def _make_account_dirs(self, account):

        """Create all necessary directories for the account."""

        oldpwd = os.getcwd()

        self._make_home(account)

        mailbox = new_mailbox(account)

        mailbox.create()

        folders = self._cfg.dget('mailbox.folders').split(':')

        if any(folders):

            bad = mailbox.add_boxes(folders,

                                    self._cfg.dget('mailbox.subscribe'))

            if bad:

                self._warnings.append(_("Skipped mailbox folders:") +

                                      '\n\t- ' + '\n\t- '.join(bad))

        os.chdir(oldpwd)

    def _delete_home(self, domdir, uid, gid):

        """Delete a user's home directory.

        Arguments:

        `domdir` : basestring

          The directory of the domain the user belongs to

          (commonly AccountObj.domain.directory)

        `uid` : int

          The user's UID (commonly AccountObj.uid)

        `gid` : int

          The user's GID (commonly AccountObj.gid)

        """

        assert all(isinstance(xid, int) for xid in (uid, gid)) and \

                isinstance(domdir, str)

        if uid < MIN_UID or gid < MIN_GID:

            raise VMMError(_("UID '%(uid)u' and/or GID '%(gid)u' are less "

                             "than %(min_uid)u/%(min_gid)u.") % {'uid': uid,

                           'gid': gid, 'min_gid': MIN_GID, 'min_uid': MIN_UID},

                           MAILDIR_PERM_MISMATCH)

        if domdir.count('..'):

            raise VMMError(_('Found ".." in domain directory path: %s') %

                           domdir, FOUND_DOTS_IN_PATH)

        if not lisdir(domdir):

            raise VMMError(_("No such directory: %s") % domdir,

                           NO_SUCH_DIRECTORY)

        os.chdir(domdir)

        userdir = '%s' % uid

        if not lisdir(userdir):

            self._warnings.append(_("No such directory: %s") %

                                  os.path.join(domdir, userdir))

            return

        mdstat = os.lstat(userdir)

        if (mdstat.st_uid, mdstat.st_gid) != (uid, gid):

            raise VMMError(_('Detected owner/group mismatch in home '

                             'directory.'), MAILDIR_PERM_MISMATCH)

        rmtree(userdir, ignore_errors=True)

    def _delete_domain_dir(self, domdir, gid):

        """Delete a domain's directory.

        Arguments:

        `domdir` : basestring

          The domain's directory (commonly DomainObj.directory)

        `gid` : int

          The domain's GID (commonly DomainObj.gid)

        """

        assert isinstance(domdir, str) and isinstance(gid, int)

        if gid < MIN_GID:

            raise VMMError(_("GID '%(gid)u' is less than '%(min_gid)u'.") %

                           {'gid': gid, 'min_gid': MIN_GID},

                           DOMAINDIR_GROUP_MISMATCH)

        if domdir.count('..'):

            raise VMMError(_('Found ".." in domain directory path: %s') %

                           domdir, FOUND_DOTS_IN_PATH)

        if not lisdir(domdir):

            self._warnings.append(_('No such directory: %s') % domdir)

            return

        dirst = os.lstat(domdir)

        if dirst.st_gid != gid:

            raise VMMError(_('Detected group mismatch in domain directory: '

                             '%s') % domdir, DOMAINDIR_GROUP_MISMATCH)