# -*- coding: utf-8 -*-
##############################################################################
#
# Copyright (c) 2002, 2005 Nexedi SARL and Contributors. All Rights Reserved.
#                    Sebastien Robin <seb@nexedi.com>
#                    Jean-Paul Smets <jp@nexedi.com>
#                    Romain Courteaud <romain@nexedi.com>
#                    Nicolas Delaby <nicolas@nexedi.com>
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from PropertyExistence import PropertyExistence
from Products.CMFCore.Expression import Expression

class AttributeUnicity(PropertyExistence):
  """
    This constraint class allows to check
    attribute unicity.
    Configuration example:
    { 'id'            : 'title',
      'description'   : 'Title must be unique',
      'type'          : 'AttributeUnicity',
      'title': "python: {'portal_type': object.getPortalType(), 'title': object.getTitle(), 'validation_state': 'validated'}",
      'condition' : 'object/getTitle',
    },
  """

  _message_id_list = ['message_invalid_attribute_unicity',]

  message_invalid_attribute_unicity = "Attribute ${attribute_name} "\
       "value is ${value} but should be unique"

  def _checkConsistency(self, obj, fixit=0):
    """Check the object's consistency.
      We will make sure that each non None constraint_definition is 
      satisfied (unicity)
      This Constraint use portal_catalog
    """
    errors = PropertyExistence._checkConsistency(self, obj, fixit=fixit)
    for attribute_name, expression_criterion_dict in self.constraint_definition.items():
      message_id = None
      mapping = dict(attribute_name=attribute_name)
      #Evaluate expression_criterion_dict
      expression = Expression(expression_criterion_dict)
      from Products.ERP5Type.Utils import createExpressionContext
      econtext = createExpressionContext(obj)
      criterion_dict = expression(econtext)
      from Products.ZSQLCatalog.SQLCatalog import Query, NegatedQuery
      # Add uid in criterion keys to avoid fetching current object.
      criterion_dict['query'] = NegatedQuery(Query(uid=obj.getUid()))
      portal = obj.getPortalObject()
      result = portal.portal_catalog.countResults(**criterion_dict)[0][0]
      if result >= 1:
        mapping['value'] = criterion_dict.get(attribute_name)
        message_id = 'message_invalid_attribute_unicity'
      # Generate error
      if message_id is not None:
        errors.append(self._generateError(obj,
                        self._getMessage(message_id), mapping))
    return errors

