# 
# This file is part of Lodel 2 (https://github.com/OpenEdition)
#
# Copyright (C) 2015-2017 Cléo UMS-3287
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#


from lodel.leapi.datahandlers.base_classes import DataHandler
DataHandler.load_base_handlers()

## @defgroup lodel2_datahandlers Datahandlers
# @ingroup lodel2_leapi
# @ingroup lodel2_em

## @defgroup lodel2_dh_checks  Datahandlers datas checking
# @ingroup lodel2_datahandlers

## @package lodel.leapi.datahandlers Lodel2 datahandlers
#
# Datahandlers are object that handles datas check, construction and 
# consistency check
#


## @page lodel2_dh_checks_page Datahandlers datas checking
# @ingroup lodel2_dh_checks
#
# @section lodel2_dh_check_mech Datas checking mechanism
#
# The data checking mechanism is divided into 3 stages :
# 1. **value checking** : a basic value check. Example : is len(value) < 52 ?
# 2. **data construction** : for data that needs to be modified. Example :
# a date that will be transformed into a Datetime object associated with a 
# timezone
# 3. **data consistency checking** : performs a consistency checking on the 
# object from the "point of view" of the current field. Example : is the 
# given lodel_id an identifier of an Article ?
#
# @subsection lodel2_dh_check_impl Implementation
#
# Those three stages are implemented by 3 datahandlers methods :
# - @ref base_classes.DataHandler.check_data_value() "check_data_value"
# - @ref base_classes.DataHandler.construct_data() "construct_data"
# - @ref base_classes.DataHandler.check_data_value() "check_data_consitency"
#
# @note To ensure the calls of the base classes methods child classes implements
# those method with a '_' prefix : 
# - @ref base_classes.DataHandler._check_data_value "_check_data_value()"
# - @ref base_classes.DataHandler._construct_data() "_construct_data"
# - @ref base_classes.DataHandler._check_data_value() "_check_data_consitency"
#
# Examples of child classes can be found @ref datahandlers.datas "here"
#
# @subsubsection lodel2_dh_datas_construction Datas construction
#
# When constructing a data handled by a datahandler we may need to have access 
# to other datas in the object (see @ref base_classes.DataHandler.construct_data() "construct_data() arguments").
#
# The problem resides in the construction order, if we need other data we have
# to be sure that they are already constructed. To achieve this goal the data
# dictionary given as arguement to @ref base_classes.DataHandler.construct_data() "construct_data()"
# is a @ref base_classes.DatasConstructor "DatasConstructor" instance. This class
# checks if a data is constructed when trying to access it, if not it runs
# the corresponding construct_data() (and have a circular dependencies detection
# mechanism)
#
#@see base_classes.DatasConstructor.