# copyright 2003-2012 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/>.
"""
.. _appobject:

The `AppObject` class
---------------------

The AppObject class is the base class for all dynamically loaded objects
(application objects) accessible through the vregistry.

We can find a certain number of attributes and methods defined in this class and
common to all the application objects.

.. autoclass:: AppObject
"""
__docformat__ = "restructuredtext en"

from logging import getLogger

from logilab.common.deprecation import deprecated, class_renamed
from logilab.common.decorators import classproperty
from logilab.common.logging_ext import set_log_methods
from logilab.common.registry import yes

# XXX for bw compat
from logilab.common.registry import objectify_predicate, traced_selection, Predicate


objectify_selector = deprecated('[3.15] objectify_selector has been '
                                'renamed to objectify_predicates in '
                                'logilab.common.registry')(objectify_predicate)
traced_selection = deprecated('[3.15] traced_selection has been '
                              'moved to logilab.common.registry')(traced_selection)
Selector = class_renamed('Selector', Predicate,
                         '[3.15] Selector has been renamed to Predicate '
                         'in logilab.common.registry')

@deprecated('[3.15] lltrace decorator can now be removed')
def lltrace(func):
    return func

# the base class for all appobjects ############################################

class AppObject(object):
    """This is the base class for CubicWeb application objects which are
    selected according to a context (usually at least a request and a result
    set).

    The following attributes should be set on concrete appobject classes:

    :attr:`__registry__`
      name of the registry for this object (string like 'views',
      'templates'...)

    :attr:`__regid__`
      object's identifier in the registry (string like 'main',
      'primary', 'folder_box')

    :attr:`__select__`
      class'selector

    Moreover, the `__abstract__` attribute may be set to True to indicate that a
    class is abstract and should not be registered.

    At selection time, the following attributes are set on the instance:

    :attr:`_cw`
      current request
    :attr:`cw_extra_kwargs`
      other received arguments

    And also the following, only if `rset` is found in arguments (in which case
    rset/row/col will be removed from `cwextra_kwargs`):

    :attr:`cw_rset`
      context result set or None

    :attr:`cw_row`
      if a result set is set and the context is about a particular cell in the
      result set, and not the result set as a whole, specify the row number we
      are interested in, else None

    :attr:`cw_col`
      if a result set is set and the context is about a particular cell in the
      result set, and not the result set as a whole, specify the col number we
      are interested in, else None


    .. Note::

      * do not inherit directly from this class but from a more specific class
        such as `AnyEntity`, `EntityView`, `AnyRsetView`, `Action`...

      * to be recordable, a subclass has to define its registry (attribute
        `__registry__`) and its identifier (attribute `__regid__`). Usually
        you don't have to take care of the registry since it's set by the base
        class, only the identifier `id`

      * application objects are designed to be loaded by the vregistry and
        should be accessed through it, not by direct instantiation, besides
        to use it as base classe.


      * When we inherit from `AppObject` (even not directly), you *always* have
        to use **super()** to get the methods and attributes of the superclasses,
        and not use the class identifier.

        For example, instead of writting::

          class Truc(PrimaryView):
              def f(self, arg1):
                  PrimaryView.f(self, arg1)

        You must write::

          class Truc(PrimaryView):
              def f(self, arg1):
                  super(Truc, self).f(arg1)

    """
    __registry__ = None
    __regid__ = None
    __select__ = yes()

    @classproperty
    def __registries__(cls):
        if cls.__registry__ is None:
            return ()
        return (cls.__registry__,)

    @classmethod
    def __registered__(cls, registry):
        """called by the registry when the appobject has been registered.

        It must return the object that will be actually registered (this may be
        the right hook to create an instance for example). By default the
        appobject is returned without any transformation.
        """
        pdefs = getattr(cls, 'cw_property_defs', {})
        for propid, pdef in pdefs.items():
            pdef = pdef.copy() # may be shared
            pdef['default'] = getattr(cls, propid, pdef['default'])
            pdef['sitewide'] = getattr(cls, 'site_wide', pdef.get('sitewide'))
            registry.vreg.register_property(cls._cwpropkey(propid), **pdef)
        assert callable(cls.__select__), cls
        return cls

    def __init__(self, req, **extra):
        super(AppObject, self).__init__()
        self._cw = req
        try:
            self.cw_rset = extra.pop('rset')
            self.cw_row = extra.pop('row', None)
            self.cw_col = extra.pop('col', None)
        except KeyError:
            pass
        self.cw_extra_kwargs = extra

    # persistent class properties ##############################################
    #
    # optional `cw_property_defs` dict on a class defines available persistent
    # properties for this class:
    #
    # * key: id of the property (the actual CWProperty key is build using
    #        <registry name>.<obj id>.<property id>
    # * value: tuple (property type, vocabfunc, default value, property description)
    #         possible types are those used by `logilab.common.configuration`
    #
    # notice that when it exists multiple objects with the same id (adaptation,
    # overriding) only the first encountered definition is considered, so those
    # objects can't try to have different default values for instance.
    #
    # you can then access to a property value using self.cw_propval, where self
    # is an instance of class

    @classmethod
    def _cwpropkey(cls, propid):
        """return cw property key for the property of the given id for this
        class
        """
        return '%s.%s.%s' % (cls.__registry__, cls.__regid__, propid)

    def cw_propval(self, propid):
        """return cw property value associated to key

        <cls.__registry__>.<cls.id>.<propid>
        """
        return self._cw.property_value(self._cwpropkey(propid))

    # these are overridden by set_log_methods below
    # only defining here to prevent pylint from complaining
    info = warning = error = critical = exception = debug = lambda msg,*a,**kw: None

set_log_methods(AppObject, getLogger('cubicweb.appobject'))

# defined here to avoid warning on usage on the AppObject class
yes = deprecated('[3.15] yes has been moved to logilab.common.registry')(yes)