"""CubicWeb web client application object

: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"

import sys

from time import clock, time

from rql import BadRQLQuery

from cubicweb import set_log_methods, cwvreg

from cubicweb import (

    ValidationError, Unauthorized, AuthenticationError, NoSelectableObject,

    RepositoryError)

from cubicweb.web import LOGGER, component

from cubicweb.web import (

    StatusResponse, DirectResponse, Redirect, NotFound,

    RemoteCallFailed, ExplicitLogin, InvalidSession, RequestError)

# make session manager available through a global variable so the debug view can

# print information about web session

SESSION_MANAGER = None

class AbstractSessionManager(component.Component):

    """manage session data associated to a session identifier"""

    id = 'sessionmanager'

    def __init__(self):

        self.session_time = self.vreg.config['http-session-time'] or None

        assert self.session_time is None or self.session_time > 0

        self.cleanup_session_time = self.vreg.config['cleanup-session-time'] or 43200

        assert self.cleanup_session_time > 0

        self.cleanup_anon_session_time = self.vreg.config['cleanup-anonymous-session-time'] or 120

        assert self.cleanup_anon_session_time > 0

        if self.session_time:

            assert self.cleanup_session_time < self.session_time

            assert self.cleanup_anon_session_time < self.session_time

        self.authmanager = self.vreg.select('components', 'authmanager')

    def clean_sessions(self):

        """cleanup sessions which has not been unused since a given amount of

        time. Return the number of sessions which have been closed.

        """

        self.debug('cleaning http sessions')

        closed, total = 0, 0

        for session in self.current_sessions():

            no_use_time = (time() - session.last_usage_time)

            total += 1

            if session.anonymous_connection:

                if no_use_time >= self.cleanup_anon_session_time:

                    self.close_session(session)

                    closed += 1

            elif no_use_time >= self.cleanup_session_time:

                self.close_session(session)

                closed += 1

        return closed, total - closed

    def has_expired(self, session):

        """return True if the web session associated to the session is expired

        """

        return not (self.session_time is None or

                    time() < session.last_usage_time + self.session_time)

    def current_sessions(self):

        """return currently open sessions"""

        raise NotImplementedError()

    def get_session(self, req, sessionid):

        """return existing session for the given session identifier"""

        raise NotImplementedError()

    def open_session(self, req):

        """open and return a new session for the given request

        :raise ExplicitLogin: if authentication is required

        """

        raise NotImplementedError()

    def close_session(self, session):

        """close session on logout or on invalid session detected (expired out,

        corrupted...)

        """

        raise NotImplementedError()

class AbstractAuthenticationManager(component.Component):

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

    id = 'authmanager'

    def authenticate(self, req):

        """authenticate user and return corresponding user object

        :raise ExplicitLogin: if authentication is required (no authentication

        info found or wrong user/password)

        """

        raise NotImplementedError()

class CookieSessionHandler(object):

    """a session handler using a cookie to store the session identifier

    :cvar SESSION_VAR:

      string giving the name of the variable used to store the session

      identifier

    """

    SESSION_VAR = '__session'

    def __init__(self, appli):

        self.session_manager = appli.vreg.select('components', 'sessionmanager')

        global SESSION_MANAGER

        SESSION_MANAGER = self.session_manager

        if not 'last_login_time' in appli.vreg.schema:

            self._update_last_login_time = lambda x: None

    def clean_sessions(self):

        """cleanup sessions which has not been unused since a given amount of

        time

        """

        self.session_manager.clean_sessions()

    def set_session(self, req):

        """associate a session to the request

        Session id is searched from :

        - # form variable

        - cookie

        if no session id is found, open a new session for the connected user

        or request authentification as needed

        :raise Redirect: if authentication has occured and succeed

        """

        assert req.cnx is None # at this point no cnx should be set on the request

        cookie = req.get_cookie()

        try:

            sessionid = str(cookie[self.SESSION_VAR].value)

        except KeyError: # no session cookie

            session = self.open_session(req)

        else:

            try:

                session = self.get_session(req, sessionid)

            except InvalidSession:

                try:

                    session = self.open_session(req)

                except ExplicitLogin:

                    req.remove_cookie(cookie, self.SESSION_VAR)

                    raise

        # remember last usage time for web session tracking

        session.last_usage_time = time()

    def get_session(self, req, sessionid):

        return self.session_manager.get_session(req, sessionid)

    def open_session(self, req):

        session = self.session_manager.open_session(req)

        cookie = req.get_cookie()

        cookie[self.SESSION_VAR] = session.sessionid

        req.set_cookie(cookie, self.SESSION_VAR, maxage=None)

        # remember last usage time for web session tracking

        session.last_usage_time = time()

        if not session.anonymous_connection:

            self._postlogin(req)

        return session

    def _update_last_login_time(self, req):

        try:

            req.execute('SET X last_login_time NOW WHERE X eid %(x)s',

                        {'x' : req.user.eid}, 'x')

            req.cnx.commit()

        except (RepositoryError, Unauthorized):

            # ldap user are not writeable for instance

            req.cnx.rollback()

        except:

            req.cnx.rollback()

            raise

    def _postlogin(self, req):

        """postlogin: the user has been authenticated, redirect to the original

        page (index by default) with a welcome message

        """

        # Update last connection date

        # XXX: this should be in a post login hook in the repository, but there

        #      we can't differentiate actual login of automatic session

        #      reopening. Is it actually a problem?

        self._update_last_login_time(req)

        args = req.form

        args['__message'] = req._('welcome %s !') % req.user.login

        if 'vid' in req.form:

            args['vid'] = req.form['vid']

        if 'rql' in req.form:

            args['rql'] = req.form['rql']

        path = req.relative_path(False)

        if path == 'login':

            path = 'view'

        raise Redirect(req.build_url(path, **args))

    def logout(self, req):

        """logout from the instance by cleaning the session and raising

        `AuthenticationError`

        """

        self.session_manager.close_session(req.cnx)

        req.remove_cookie(req.get_cookie(), self.SESSION_VAR)

        raise AuthenticationError()

class CubicWebPublisher(object):

    """the publisher is a singleton hold by the web frontend, and is responsible

    to publish HTTP request.

    """

    def __init__(self, config, debug=None,

                 session_handler_fact=CookieSessionHandler,

                 vreg=None):

        super(CubicWebPublisher, self).__init__()

        # connect to the repository and get instance's schema

        if vreg is None:

            vreg = cwvreg.CubicWebRegistry(config, debug=debug)

        self.vreg = vreg

        self.info('starting web instance from %s', config.apphome)

        self.repo = config.repository(vreg)

        if not vreg.initialized:

            self.config.init_cubes(self.repo.get_cubes())

            vreg.init_properties(self.repo.properties())

        vreg.set_schema(self.repo.get_schema())

        # set the correct publish method

        if config['query-log-file']:

            from threading import Lock

            self._query_log = open(config['query-log-file'], 'a')

            self.publish = self.log_publish

            self._logfile_lock = Lock()

        else:

            self._query_log = None

            self.publish = self.main_publish

        # instantiate session and url resolving helpers

        self.session_handler = session_handler_fact(self)

        self.url_resolver = vreg.select('components', 'urlpublisher')

    def connect(self, req):

        """return a connection for a logged user object according to existing

        sessions (i.e. a new connection may be created or an already existing

        one may be reused

        """

        self.session_handler.set_session(req)

    # publish methods #########################################################

    def log_publish(self, path, req):

        """wrapper around _publish to log all queries executed for a given

        accessed path

        """

        try:

            return self.main_publish(path, req)

        finally:

            cnx = req.cnx

            self._logfile_lock.acquire()

            try:

                try:

                    result = ['\n'+'*'*80]

                    result.append(req.url())

                    result += ['%s %s -- (%.3f sec, %.3f CPU sec)' % q for q in cnx.executed_queries]

                    cnx.executed_queries = []

                    self._query_log.write('\n'.join(result).encode(req.encoding))

                    self._query_log.flush()

                except Exception:

                    self.exception('error while logging queries')

            finally:

                self._logfile_lock.release()

    def select_controller(self, oid, req):

        try:

            return self.vreg.select('controllers', oid, req=req, appli=self)

        except NoSelectableObject:

            raise Unauthorized(req._('not authorized'))

    def main_publish(self, path, req):

        """method called by the main publisher to process <path>

        should return a string containing the resulting page or raise a

        `NotFound` exception

        :type path: str

        :param path: the path part of the url to publish

        :type req: `web.Request`

        :param req: the request object

        :rtype: str

        :return: the result of the pusblished url

        """

        path = path or 'view'

        # don't log form values they may contains sensitive information

        self.info('publish "%s" (form params: %s)', path, req.form.keys())

        # remove user callbacks on a new request (except for json controllers

        # to avoid callbacks being unregistered before they could be called)

        tstart = clock()

        try:

            try:

                ctrlid, rset = self.url_resolver.process(req, path)

                try:

                    controller = self.vreg.select('controllers', ctrlid, req,

                                                  appli=self)

                except NoSelectableObject:

                    raise Unauthorized(req._('not authorized'))

                req.update_search_state()

                result = controller.publish(rset=rset)

                if req.cnx is not None:

                    # req.cnx is None if anonymous aren't allowed and we are

                    # displaying the cookie authentication form

                    req.cnx.commit()

            except (StatusResponse, DirectResponse):

                req.cnx.commit()

                raise

            except Redirect:

                # redirect is raised by edit controller when everything went fine,

                # so try to commit

                try:

                    req.cnx.commit()

                except ValidationError, ex:

                    self.validation_error_handler(req, ex)

                except Unauthorized, ex:

                    req.data['errmsg'] = req._('You\'re not authorized to access this page. '

                                               'If you think you should, please contact the site administrator.')

                    self.error_handler(req, ex, tb=False)

                except Exception, ex:

                    self.error_handler(req, ex, tb=True)

                else:

                    # delete validation errors which may have been previously set

                    if '__errorurl' in req.form:

                        req.del_session_data(req.form['__errorurl'])

                    raise

            except (AuthenticationError, NotFound, RemoteCallFailed):

                raise

            except ValidationError, ex:

                self.validation_error_handler(req, ex)

            except (Unauthorized, BadRQLQuery, RequestError), ex:

                self.error_handler(req, ex, tb=False)

            except Exception, ex:

                self.error_handler(req, ex, tb=True)

        finally:

            if req.cnx is not None:

                try:

                    req.cnx.rollback()

                except:

                    pass # ignore rollback error at this point

        self.info('query %s executed in %s sec', req.relative_path(), clock() - tstart)

        return result

    def validation_error_handler(self, req, ex):

        ex.errors = dict((k, v) for k, v in ex.errors.items())

        if '__errorurl' in req.form:

            forminfo = {'errors': ex,

                        'values': req.form,

                        'eidmap': req.data.get('eidmap', {})

                        }

            req.set_session_data(req.form['__errorurl'], forminfo)

            raise Redirect(req.form['__errorurl'])

        self.error_handler(req, ex, tb=False)

    def error_handler(self, req, ex, tb=False):

        excinfo = sys.exc_info()

        self.exception(repr(ex))

        req.set_header('Cache-Control', 'no-cache')

        req.remove_header('Etag')

        req.message = None

        req.reset_headers()

        try:

            req.data['ex'] = ex

            if tb:

                req.data['excinfo'] = excinfo

            req.form['vid'] = 'error'

            errview = self.vreg.select('views', 'error', req)

            template = self.main_template_id(req)

            content = self.vreg.main_template(req, template, view=errview)

        except:

            content = self.vreg.main_template(req, 'error-template')

        raise StatusResponse(500, content)

    def need_login_content(self, req):

        return self.vreg.main_template(req, 'login')

    def loggedout_content(self, req):

        return self.vreg.main_template(req, 'loggedout')

    def notfound_content(self, req):

        req.form['vid'] = '404'