# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
from trytond.pool import Pool
from trytond.config import config
from trytond.transaction import Transaction
from trytond import backend
from trytond.exceptions import LoginException


def _get_pool(dbname):
    database_list = Pool.database_list()
    pool = Pool(dbname)
    if dbname not in database_list:
        pool.init()
    return pool


def login(dbname, loginname, parameters, cache=True, language=None):
    context = {'language': language}
    with Transaction().start(dbname, 0, context=context) as transaction:
        pool = _get_pool(dbname)
        User = pool.get('res.user')
        try:
            user_id = User.get_login(loginname, parameters)
        except LoginException:
            # Let's store any changes done
            transaction.commit()
            raise
    if user_id:
        if not cache:
            return user_id
        with Transaction().start(dbname, user_id):
            Session = pool.get('ir.session')
            session, = Session.create([{}])
            return user_id, session.key
    return


def logout(dbname, user, session):
    with Transaction().start(dbname, 0):
        pool = _get_pool(dbname)
        Session = pool.get('ir.session')
        sessions = Session.search([
                ('key', '=', session),
                ])
        if not sessions:
            return
        session, = sessions
        name = session.create_uid.login
        Session.delete(sessions)
    return name


def check(dbname, user, session):
    DatabaseOperationalError = backend.get('DatabaseOperationalError')
    for count in range(config.getint('database', 'retry'), -1, -1):
        with Transaction().start(dbname, user) as transaction:
            pool = _get_pool(dbname)
            Session = pool.get('ir.session')
            try:
                if not Session.check(user, session):
                    return
                else:
                    return user
            except DatabaseOperationalError:
                if count:
                    continue
                raise
            finally:
                transaction.commit()