##############################################################################
#
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
# 
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
# 
##############################################################################
""" Expressions in a web-configurable workflow.

$Id: Expression.py 74063 2007-04-09 21:23:43Z tseaver $
"""
from warnings import warn

import Globals
from Globals import Persistent
from Acquisition import aq_inner, aq_parent
from AccessControl import getSecurityManager, ClassSecurityInfo
from DateTime import DateTime

from Products.CMFCore.WorkflowCore import ObjectDeleted, ObjectMoved
from Products.CMFCore.Expression import Expression
from Products.CMFCore.interfaces import ISiteRoot
from Products.PageTemplates.Expressions import getEngine
from Products.PageTemplates.Expressions import SecureModuleImporter


# We don't import SafeMapping from Products.PageTemplates.TALES
# because it's deprecated in Zope 2.10
from MultiMapping import MultiMapping
class SafeMapping(MultiMapping):
    """Mapping with security declarations and limited method exposure.

    Since it subclasses MultiMapping, this class can be used to wrap
    one or more mapping objects.  Restricted Python code will not be
    able to mutate the SafeMapping or the wrapped mappings, but will be
    able to read any value.
    """
    __allow_access_to_unprotected_subobjects__ = 1
    push = pop = None
    _push = MultiMapping.push
    _pop = MultiMapping.pop


class StateChangeInfo:
    '''
    Provides information for expressions and scripts.
    '''
    _date = None

    ObjectDeleted = ObjectDeleted
    ObjectMoved = ObjectMoved

    security = ClassSecurityInfo()
    security.setDefaultAccess('allow')

    def __init__(self, object, workflow, status=None, transition=None,
                 old_state=None, new_state=None, kwargs=None):
        if kwargs is None:
            kwargs = {}
        else:
            # Don't allow mutation
            kwargs = SafeMapping(kwargs)
        if status is None:
            tool = aq_parent(aq_inner(workflow))
            status = tool.getStatusOf(workflow.id, object)
            if status is None:
                status = {}
        if status:
            # Don't allow mutation
            status = SafeMapping(status)
        self.object = object
        self.workflow = workflow
        self.old_state = old_state
        self.new_state = new_state
        self.transition = transition
        self.status = status
        self.kwargs = kwargs

    def __getitem__(self, name):
        if name[:1] != '_' and hasattr(self, name):
            return getattr(self, name)
        raise KeyError, name

    def getHistory(self):
        wf = self.workflow
        tool = aq_parent(aq_inner(wf))
        wf_id = wf.id
        h = tool.getHistoryOf(wf_id, self.object)
        if h:
            return map(lambda dict: dict.copy(), h)  # Don't allow mutation
        else:
            return ()

    def getPortal(self):
        ob = aq_inner(self.object)
        while ob is not None:
            if ISiteRoot.providedBy(ob):
                return ob
            if getattr(ob, '_isPortalRoot', None) is not None:
                # BBB
                warn("The '_isPortalRoot' marker attribute for site "
                     "roots is deprecated and will be removed in "
                     "CMF 2.3;  please mark the root object with "
                     "'ISiteRoot' instead.",
                     DeprecationWarning, stacklevel=2)
                return ob
            ob = aq_parent(ob)
        return None

    def getDateTime(self):
        date = self._date
        if not date:
            date = self._date = DateTime()
        return date

Globals.InitializeClass(StateChangeInfo)


def createExprContext(sci):
    '''
    An expression context provides names for TALES expressions.
    '''
    ob = sci.object
    wf = sci.workflow
    container = aq_parent(aq_inner(ob))
    data = {
        'here':         ob,
        'object':       ob,
        'container':    container,
        'folder':       container,
        'nothing':      None,
        'root':         ob.getPhysicalRoot(),
        'request':      getattr( ob, 'REQUEST', None ),
        'modules':      SecureModuleImporter,
        'user':         getSecurityManager().getUser(),
        'state_change': sci,
        'transition':   sci.transition,
        'status':       sci.status,
        'kwargs':       sci.kwargs,
        'workflow':     wf,
        'scripts':      wf.scripts,
        }
    return getEngine().getContext(data)

