"""user authentication component

:organization: Logilab

:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from logilab.common.decorators import clear_cache

from cubicweb import AuthenticationError, BadConnectionId

from cubicweb.dbapi import repo_connect, ConnectionProperties

from cubicweb.web import ExplicitLogin, InvalidSession

from cubicweb.web.application import AbstractAuthenticationManager

class RepositoryAuthenticationManager(AbstractAuthenticationManager):

    """authenticate user associated to a request and check session validity"""

    def __init__(self):

        self.repo = self.config.repository(self.vreg)

        self.log_queries = self.config['query-log-file']

    def validate_session(self, req, session):

        """check session validity, and return eventually hijacked session

        :raise InvalidSession:

          if session is corrupted for a reason or another and should be closed

        """

        # with this authentication manager, session is actually a dbapi

        # connection

        cnx = session

        login = req.get_authorization()[0]

        try:

            # calling cnx.user() check connection validity, raise

            # BadConnectionId on failure

            user = cnx.user(req)

                cnx.close()

                raise InvalidSession('login mismatch')

        except BadConnectionId:

            # check if a connection should be automatically restablished

            if (login is None or login == cnx.login):

                login, password = cnx.login, cnx.password

                cnx = self.authenticate(req, login, password)

                user = cnx.user(req)

                # backport session's data

                cnx.data = session.data

            else:

                raise InvalidSession('bad connection id')

        # associate the connection to the current request

        req.set_connection(cnx, user)

        return cnx

    def authenticate(self, req, _login=None, _password=None):

        """authenticate user and return corresponding user object

        :raise ExplicitLogin: if authentication is required (no authentication

        info found or wrong user/password)

        Note: this method is violating AuthenticationManager interface by

        returning a session instance instead of the user. This is expected by

        the InMemoryRepositorySessionManager.

        """

        if _login is not None:

            login, password = _login, _password

        else:

            login, password = req.get_authorization()

        if not login:

            # No session and no login -> try anonymous

            login, password = self.vreg.config.anonymous_user()

            if not login: # anonymous not authorized

                raise ExplicitLogin()

        # remove possibly cached cursor coming from closed connection

        clear_cache(req, 'cursor')

        cnxprops = ConnectionProperties(self.vreg.config.repo_method,

                                        close=False, log=self.log_queries)

        try:

            cnx = repo_connect(self.repo, login, password, cnxprops=cnxprops)

        except AuthenticationError:

            req.set_message(req._('authentication failure'))

            # restore an anonymous connection if possible

            anonlogin, anonpassword = self.vreg.config.anonymous_user()

            if anonlogin and anonlogin != login:

                cnx = repo_connect(self.repo, anonlogin, anonpassword,

                                   cnxprops=cnxprops)

                self._init_cnx(cnx, anonlogin, anonpassword)

            else:

                raise ExplicitLogin()

        else:

            self._init_cnx(cnx, login, password)

        # associate the connection to the current request

        req.set_connection(cnx)

        return cnx

    def _init_cnx(self, cnx, login, password):

        # decorate connection

        if login == self.vreg.config.anonymous_user()[0]:

            cnx.anonymous_connection = True

        cnx.vreg = self.vreg

        cnx.login = login

        cnx.password = password