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

# Copyright (c) 2008 - 2013, Pascal Volk

# See COPYING for distribution information.

"""

    VirtualMailManager.transport

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

    Virtual Mail Manager's Transport class to manage the transport for

    domains and accounts.

"""

_ = lambda msg: msg

class Transport(object):

    """A wrapper class that provides access to the transport table"""

    __slots__ = ('_tid', '_transport', '_dbh')

    def __init__(self, dbh, tid=None, transport=None):

        """Creates a new Transport instance.

        Either tid or transport must be specified. When both arguments

        are given, tid will be used.

        Keyword arguments:

        dbh -- a psycopg2._psycopg.connection

        tid -- the id of a transport (int)

        transport -- the value of the transport (str)

        """

        self._dbh = dbh

        self._tid = 0

        assert any((tid, transport))

        if tid:

            assert not isinstance(tid, bool) and isinstance(tid, int)

            self._load_by_id(tid)

        else:

            assert isinstance(transport, str)

            self._transport = transport

            self._load_by_name()

    @property

    def tid(self):

        """The transport's unique ID."""

        return self._tid

    @property

    def transport(self):

        """The transport's value, ex: 'dovecot:'"""

        return self._transport

    def __eq__(self, other):

        if isinstance(other, self.__class__):

            return self._tid == other._tid

        return NotImplemented

    def __ne__(self, other):

        if isinstance(other, self.__class__):

            return self._tid != other._tid

        return NotImplemented

    def __str__(self):

        return self._transport

    def _load_by_id(self, tid):

        """load a transport by its id from the database"""

        dbc = self._dbh.cursor()

        dbc.execute('SELECT transport FROM transport WHERE tid = %s', (tid,))

        result = dbc.fetchone()

        dbc.close()

        if not result:

            raise ValueError('Unknown transport id specified: %r' % tid)

        self._transport = result[0]

        self._tid = tid

    def _load_by_name(self):

        """Load a transport by its transport name from the database."""

        dbc = self._dbh.cursor()

        dbc.execute('SELECT tid FROM transport WHERE transport = %s',

                    (self._transport,))

        result = dbc.fetchone()

        dbc.close()

        if result:

            self._tid = result[0]

        else:

            self._save()

    def _save(self):

        """Save the new transport in the database."""

        dbc = self._dbh.cursor()

        dbc.execute("SELECT nextval('transport_id')")

        self._tid = dbc.fetchone()[0]

        dbc.execute('INSERT INTO transport (tid, transport) VALUES (%s, %s)',

                    (self._tid, self._transport))

        self._dbh.commit()

        dbc.close()

del _