# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

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

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""Repository users' and internal' sessions."""

from __future__ import with_statement

__docformat__ = "restructuredtext en"

import sys

import threading

from time import time

from uuid import uuid4

from warnings import warn

from logilab.common.deprecation import deprecated

from rql import CoercionError

from rql.nodes import ETYPE_PYOBJ_MAP, etype_from_pyobj

from yams import BASE_TYPES

from cubicweb import Binary, UnknownEid, QueryError, schema

from cubicweb.selectors import objectify_selector

from cubicweb.req import RequestSessionBase

from cubicweb.dbapi import ConnectionProperties

from cubicweb.utils import make_uid, RepeatList

from cubicweb.rqlrewrite import RQLRewriter

from cubicweb.server.edition import EditedEntity

ETYPE_PYOBJ_MAP[Binary] = 'Bytes'

NO_UNDO_TYPES = schema.SCHEMA_TYPES.copy()

NO_UNDO_TYPES.add('CWCache')

# is / is_instance_of are usually added by sql hooks except when using

# dataimport.NoHookRQLObjectStore, and we don't want to record them

# anyway in the later case

NO_UNDO_TYPES.add('is')

NO_UNDO_TYPES.add('is_instance_of')

NO_UNDO_TYPES.add('cw_source')

# XXX rememberme,forgotpwd,apycot,vcsfile

def _make_description(selected, args, solution):

    """return a description for a result set"""

    description = []

    for term in selected:

        description.append(term.get_type(solution, args))

    return description

@objectify_selector

def is_user_session(cls, req, **kwargs):

    """repository side only selector returning 1 if the session is a regular

    user session and not an internal session

    """

    return not req.is_internal_session

@objectify_selector

def is_internal_session(cls, req, **kwargs):

    """repository side only selector returning 1 if the session is not a regular

    user session but an internal session

    """

    return req.is_internal_session

class hooks_control(object):

    """context manager to control activated hooks categories.

    If mode is session.`HOOKS_DENY_ALL`, given hooks categories will

    be enabled.

    If mode is session.`HOOKS_ALLOW_ALL`, given hooks categories will

    be disabled.

    .. sourcecode:: python

       with hooks_control(self.session, self.session.HOOKS_ALLOW_ALL, 'integrity'):

           # ... do stuff with all but 'integrity' hooks activated

       with hooks_control(self.session, self.session.HOOKS_DENY_ALL, 'integrity'):

           # ... do stuff with none but 'integrity' hooks activated

    """

    def __init__(self, session, mode, *categories):

        self.session = session

        self.mode = mode

        self.categories = categories

    def __enter__(self):

        self.oldmode = self.session.set_hooks_mode(self.mode)

        if self.mode is self.session.HOOKS_DENY_ALL:

            self.changes = self.session.enable_hook_categories(*self.categories)

        else:

            self.changes = self.session.disable_hook_categories(*self.categories)

    def __exit__(self, exctype, exc, traceback):

        if self.changes:

            if self.mode is self.session.HOOKS_DENY_ALL:

                self.session.disable_hook_categories(*self.changes)

            else:

                self.session.enable_hook_categories(*self.changes)

        self.session.set_hooks_mode(self.oldmode)

INDENT = ''

class security_enabled(object):

    """context manager to control security w/ session.execute, since by

    default security is disabled on queries executed on the repository

    side.

    """

    def __init__(self, session, read=None, write=None):

        self.session = session

        self.read = read

        self.write = write

    def __enter__(self):

#        global INDENT

        if self.read is not None:

            self.oldread = self.session.set_read_security(self.read)

#            print INDENT + 'read', self.read, self.oldread

        if self.write is not None:

            self.oldwrite = self.session.set_write_security(self.write)

#            print INDENT + 'write', self.write, self.oldwrite

#        INDENT += '  '

    def __exit__(self, exctype, exc, traceback):

#        global INDENT

#        INDENT = INDENT[:-2]

        if self.read is not None:

            self.session.set_read_security(self.oldread)

#            print INDENT + 'reset read to', self.oldread

        if self.write is not None:

            self.session.set_write_security(self.oldwrite)

#            print INDENT + 'reset write to', self.oldwrite

class TransactionData(object):

    def __init__(self, txid):

        self.transactionid = txid

class Session(RequestSessionBase):

    """tie session id, user, connections pool and other session data all

    together

    """

    is_internal_session = False

    def __init__(self, user, repo, cnxprops=None, _id=None):

        super(Session, self).__init__(repo.vreg)

        self.id = _id or make_uid(user.login.encode('UTF8'))

        cnxprops = cnxprops or ConnectionProperties('inmemory')

        self.user = user

        self.repo = repo

        self.cnxtype = cnxprops.cnxtype

        self.timestamp = time()

        self.default_mode = 'read'

        # support undo for Create Update Delete entity / Add Remove relation

        if repo.config.creating or repo.config.repairing or self.is_internal_session:

            self.undo_actions = ()

        else:

            self.undo_actions = set(repo.config['undo-support'].upper())

            if self.undo_actions - set('CUDAR'):

                raise Exception('bad undo-support string in configuration')

        # short cut to querier .execute method

        self._execute = repo.querier.execute

        # shared data, used to communicate extra information between the client

        # and the rql server

        self.data = {}

        # i18n initialization

        self.set_language(cnxprops.lang)

        # internals

        self._tx_data = {}

        self.__threaddata = threading.local()

        self._threads_in_transaction = set()

        self._closed = False

        self._closed_lock = threading.Lock()

    def __unicode__(self):

        return '<%ssession %s (%s 0x%x)>' % (

            self.cnxtype, unicode(self.user.login), self.id, id(self))

    def set_tx_data(self, txid=None):

        if txid is None:

            txid = threading.currentThread().getName()

        try:

            self.__threaddata.txdata = self._tx_data[txid]

        except KeyError:

            self.__threaddata.txdata = self._tx_data[txid] = TransactionData(txid)

    @property

    def _threaddata(self):

        try:

            return self.__threaddata.txdata

        except AttributeError:

            self.set_tx_data()

            return self.__threaddata.txdata

    def hijack_user(self, user):

        """return a fake request/session using specified user"""

        session = Session(user, self.repo)

        threaddata = session._threaddata

        threaddata.pool = self.pool

        # share pending_operations, else operation added in the hi-jacked

        # session such as SendMailOp won't ever be processed

        threaddata.pending_operations = self.pending_operations

        # everything in transaction_data should be copied back but the entity

        # type cache we don't want to avoid security pb

        threaddata.transaction_data = self.transaction_data.copy()

        threaddata.transaction_data.pop('ecache', None)

        return session

    def add_relation(self, fromeid, rtype, toeid):

        """provide direct access to the repository method to add a relation.

        This is equivalent to the following rql query:

          SET X rtype Y WHERE X eid  fromeid, T eid toeid

        without read security check but also all the burden of rql execution.

        You may use this in hooks when you know both eids of the relation you

        want to add.

        """

        self.add_relations([(rtype, [(fromeid,  toeid)])])

    def add_relations(self, relations):

        '''set many relation using a shortcut similar to the one in add_relation

        relations is a list of 2-uples, the first element of each

        2-uple is the rtype, and the second is a list of (fromeid,

        toeid) tuples

        '''

        edited_entities = {}

        relations_dict = {}

        with security_enabled(self, False, False):

            for rtype, eids in relations:

                if self.vreg.schema[rtype].inlined:

                    for fromeid, toeid in eids:

                        if fromeid not in edited_entities:

                            entity = self.entity_from_eid(fromeid)

                            edited = EditedEntity(entity)

                            edited_entities[fromeid] = edited

                        else:

                            edited = edited_entities[fromeid]

                        edited.edited_attribute(rtype, toeid)

                else:

                    relations_dict[rtype] = eids

            self.repo.glob_add_relations(self, relations_dict)

            for edited in edited_entities.itervalues():

                self.repo.glob_update_entity(self, edited)

    def delete_relation(self, fromeid, rtype, toeid):

        """provide direct access to the repository method to delete a relation.

        This is equivalent to the following rql query:

          DELETE X rtype Y WHERE X eid  fromeid, T eid toeid

        without read security check but also all the burden of rql execution.

        You may use this in hooks when you know both eids of the relation you

        want to delete.

        """

        with security_enabled(self, False, False):

            if self.vreg.schema[rtype].inlined:

                entity = self.entity_from_eid(fromeid)

                entity.cw_attr_cache[rtype] = None

                self.repo.glob_update_entity(self, entity, set((rtype,)))

            else:

                self.repo.glob_delete_relation(self, fromeid, rtype, toeid)

    # relations cache handling #################################################

    def update_rel_cache_add(self, subject, rtype, object, symmetric=False):

        self._update_entity_rel_cache_add(subject, rtype, 'subject', object)

        if symmetric:

            self._update_entity_rel_cache_add(object, rtype, 'subject', subject)

        else:

            self._update_entity_rel_cache_add(object, rtype, 'object', subject)

    def update_rel_cache_del(self, subject, rtype, object, symmetric=False):

        self._update_entity_rel_cache_del(subject, rtype, 'subject', object)

        if symmetric:

            self._update_entity_rel_cache_del(object, rtype, 'object', object)

        else:

            self._update_entity_rel_cache_del(object, rtype, 'object', subject)

    def _update_entity_rel_cache_add(self, eid, rtype, role, targeteid):

        try:

            entity = self.entity_cache(eid)

        except KeyError:

            return

        rcache = entity.cw_relation_cached(rtype, role)

        if rcache is not None:

            rset, entities = rcache

            rset = rset.copy()

            entities = list(entities)

            rset.rows.append([targeteid])

            if not isinstance(rset.description, list): # else description not set

                rset.description = list(rset.description)

            rset.description.append([self.describe(targeteid)[0]])

            targetentity = self.entity_from_eid(targeteid)

            if targetentity.cw_rset is None:

                targetentity.cw_rset = rset

                targetentity.cw_row = rset.rowcount

                targetentity.cw_col = 0

            rset.rowcount += 1

            entities.append(targetentity)

            entity._cw_related_cache['%s_%s' % (rtype, role)] = (

                rset, tuple(entities))

    def _update_entity_rel_cache_del(self, eid, rtype, role, targeteid):

        try:

            entity = self.entity_cache(eid)

        except KeyError:

            return

        rcache = entity.cw_relation_cached(rtype, role)

        if rcache is not None:

            rset, entities = rcache

            for idx, row in enumerate(rset.rows):

                if row[0] == targeteid:

                    break

            else:

                # this may occurs if the cache has been filed by a hook

                # after the database update

                self.debug('cache inconsistency for %s %s %s %s', eid, rtype,

                           role, targeteid)

                return

            rset = rset.copy()

            entities = list(entities)

            del rset.rows[idx]

            if isinstance(rset.description, list): # else description not set

                del rset.description[idx]

            del entities[idx]

            rset.rowcount -= 1

            entity._cw_related_cache['%s_%s' % (rtype, role)] = (

                rset, tuple(entities))

    # resource accessors ######################################################

    def system_sql(self, sql, args=None, rollback_on_failure=True):

        """return a sql cursor on the system database"""

        if sql.split(None, 1)[0].upper() != 'SELECT':

            self.mode = 'write'

        source = self.pool.source('system')

        try:

            return source.doexec(self, sql, args, rollback=rollback_on_failure)

        except (source.OperationalError, source.InterfaceError):

            if not rollback_on_failure:

                raise

            source.warning("trying to reconnect")

            self.pool.reconnect(source)

            return source.doexec(self, sql, args, rollback=rollback_on_failure)

    def set_language(self, language):

        """i18n configuration for translation"""

        language = language or self.user.property_value('ui.language')

        try:

            gettext, pgettext = self.vreg.config.translations[language]

            self._ = self.__ = gettext

            self.pgettext = pgettext

        except KeyError:

            language = self.vreg.property_value('ui.language')

            try:

                gettext, pgettext = self.vreg.config.translations[language]

                self._ = self.__ = gettext