"""extend the generic VRegistry with some cubicweb specific stuff

:organization: Logilab

:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

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

"""

__docformat__ = "restructuredtext en"

from warnings import warn

from logilab.common.decorators import cached, clear_cache

from logilab.common.interface import extend

from rql import RQLHelper

from cubicweb import Binary, UnknownProperty

from cubicweb.vregistry import VRegistry, ObjectNotFound, NoSelectableObject

_ = unicode

class DummyCursorError(Exception): pass

class RaiseCursor:

    @classmethod

    def execute(cls, rql, args=None, eid_key=None):

        raise DummyCursorError()

class CubicWebRegistry(VRegistry):

    """extend the generic VRegistry with some cubicweb specific stuff"""

    def __init__(self, config, debug=None, initlog=True):

        if initlog:

            # first init log service

            config.init_log(debug=debug)

        super(CubicWebRegistry, self).__init__(config)

        self.schema = None

        self.reset()

        self.initialized = False

    def items(self):

        return [item for item in self._registries.items()

                if not item[0] in ('propertydefs', 'propertyvalues')]

    def values(self):

        return [value for key,value in self._registries.items()

                if not key in ('propertydefs', 'propertyvalues')]

    def reset(self):

        self._registries = {}

        self._lastmodifs = {}

        self._needs_iface = {}

        # two special registries, propertydefs which care all the property

        # definitions, and propertyvals which contains values for those

        # properties

        self._registries['propertydefs'] = {}

        self._registries['propertyvalues'] = self.eprop_values = {}

        for key, propdef in self.config.eproperty_definitions():

            self.register_property(key, **propdef)

    def set_schema(self, schema):

        """set application'schema and load application objects"""

        self.schema = schema

        clear_cache(self, 'rqlhelper')

        # now we can load application's web objects

        self.register_objects(self.config.vregistry_path())

    def update_schema(self, schema):

        """update .schema attribute on registered objects, necessary for some

        tests

        """

        self.schema = schema

        for registry, regcontent in self._registries.items():

            if registry in ('propertydefs', 'propertyvalues'):

                continue

            for objects in regcontent.values():

                for obj in objects:

                    obj.schema = schema

    def register_if_interface_found(self, obj, ifaces, **kwargs):

        """register an object but remove it if no entity class implements one of

        the given interfaces

        """

        if not isinstance(ifaces,  (tuple, list)):

            self._needs_iface[obj] = frozenset((ifaces,))

        else:

            self._needs_iface[obj] = frozenset(ifaces)

        self.register(obj, **kwargs)

    def register(self, obj, **kwargs):

        super(CubicWebRegistry, self).register(obj, **kwargs)

        # XXX bw compat

        ifaces = getattr(obj, 'accepts_interfaces', None)

        if ifaces:

            self._needs_iface[obj] = frozenset(ifaces)

    def register_objects(self, path, force_reload=None):

        """overriden to remove objects requiring a missing interface"""

        if super(CubicWebRegistry, self).register_objects(path, force_reload):

            # clear etype cache if you don't want to run into deep weirdness

            clear_cache(self, 'etype_class')

            # we may want to keep interface dependent objects (e.g.for i18n

            # catalog generation)

            if not self.config.cleanup_interface_sobjects:

                return

            # remove vobjects that don't support any available interface

            interfaces = set()

            for classes in self.get('etypes', {}).values():

                for cls in classes:

                    interfaces.update(cls.__implements__)

            for obj, ifaces in self._needs_iface.items():

                if not ifaces & interfaces:

                    self.debug('kicking vobject %s (unsupported interface)', obj)

                    self.unregister(obj)

    def eid_rset(self, cursor, eid, etype=None):

        """return a result set for the given eid without doing actual query

        (we have the eid, we can suppose it exists and user has access to the

        entity)

        """

        msg = '.eid_rset is deprecated, use req.eid_rset'

        warn(msg, DeprecationWarning, stacklevel=2)

        try:

            return cursor.req.eid_rset(eid, etype)

        except AttributeError:

            # cursor is a session

            return cursor.eid_rset(eid, etype)

    @cached

    def etype_class(self, etype):

        """return an entity class for the given entity type.

        Try to find out a specific class for this kind of entity or

        default to a dump of the class registered for 'Any'

        """

        etype = str(etype)

        if etype == 'Any':

            return self.select(self.registry_objects('etypes', 'Any'), 'Any')

        eschema = self.schema.eschema(etype)

        baseschemas = [eschema] + eschema.ancestors()

        # browse ancestors from most specific to most generic and

        # try to find an associated custom entity class

        for baseschema in baseschemas:

            btype = str(baseschema)

            try:

                cls = self.select(self.registry_objects('etypes', btype), etype)

                break

            except ObjectNotFound:

                pass

        else:

            # no entity class for any of the ancestors, fallback to the default

            # one

            cls = self.select(self.registry_objects('etypes', 'Any'), etype)

        # add class itself to the list of implemented interfaces, as well as the

        # Any entity class so we can select according to class using the

        # `implements` selector

        extend(cls, cls)

        extend(cls, self.etype_class('Any'))

        return cls

    def render(self, registry, oid, req, **context):

        """select an object in a given registry and render it

        - registry: the registry's name

        - oid : the view to call

        - req : the HTTP request         

        """

        objclss = self.registry_objects(registry, oid)

        try:

            rset = context.pop('rset')

        except KeyError:

            rset = None

        selected = self.select(objclss, req, rset, **context)

        return selected.dispatch(**context)

    def main_template(self, req, oid='main', **context):

        """display query by calling the given template (default to main),

        and returning the output as a string instead of requiring the [w]rite

        method as argument

        """

        res = self.render('templates', oid, req, **context)

        if isinstance(res, unicode):

            return res.encode(req.encoding)

        assert isinstance(res, str)

        return res

    def possible_vobjects(self, registry, *args, **kwargs):

        """return an ordered list of possible app objects in a given registry,

        supposing they support the 'visible' and 'order' properties (as most

        visualizable objects)

        """

        return [x for x in sorted(self.possible_objects(registry, *args, **kwargs),

                                  key=lambda x: x.propval('order'))

                if x.propval('visible')]

    def possible_actions(self, req, rset, **kwargs):

        if rset is None:

            actions = self.possible_vobjects('actions', req, rset)

        else:

            actions = rset.possible_actions() # cached implementation

        result = {}

        for action in actions:

            result.setdefault(action.category, []).append(action)

        return result

    def possible_views(self, req, rset, **kwargs):

        """return an iterator on possible views for this result set

        views returned are classes, not instances

        """

        for vid, views in self.registry('views').items():

            if vid[0] == '_':

                continue

            try:

                view = self.select(views, req, rset, **kwargs)

                if view.linkable():

                    yield view

            except NoSelectableObject:

                continue

            except Exception:

                self.exception('error while trying to list possible %s views for %s',

                               vid, rset)

    def select_box(self, oid, *args, **kwargs):

        """return the most specific view according to the result set"""

        try:

            return self.select_object('boxes', oid, *args, **kwargs)

        except NoSelectableObject:

            return

    def select_action(self, oid, *args, **kwargs):

        """return the most specific view according to the result set"""

        try:

            return self.select_object('actions', oid, *args, **kwargs)

        except NoSelectableObject:

            return

    def select_component(self, cid, *args, **kwargs):

        """return the most specific component according to the result set"""

        try:

            return self.select_object('components', cid, *args, **kwargs)

        except (NoSelectableObject, ObjectNotFound):

            return

    def select_view(self, __vid, req, rset, **kwargs):

        """return the most specific view according to the result set"""

        views = self.registry_objects('views', __vid)

        return self.select(views, req, rset, **kwargs)

    # properties handling #####################################################

    def user_property_keys(self, withsitewide=False):

        if withsitewide:

            return sorted(self['propertydefs'])

        return sorted(k for k, kd in self['propertydefs'].iteritems()

                      if not kd['sitewide'])

    def register_property(self, key, type, help, default=None, vocabulary=None,

                          sitewide=False):

        """register a given property"""

        properties = self._registries['propertydefs']

        assert type in YAMS_TO_PY

        properties[key] = {'type': type, 'vocabulary': vocabulary, 

                           'default': default, 'help': help,

                           'sitewide': sitewide}

    def property_info(self, key):

        """return dictionary containing description associated to the given

        property key (including type, defaut value, help and a site wide

        boolean)

        """

        try:

            return self._registries['propertydefs'][key]

        except KeyError:

            if key.startswith('system.version.'):

                soft = key.split('.')[-1]

                return {'type': 'String', 'sitewide': True,

                        'default': None, 'vocabulary': None,

                        'help': _('%s software version of the database') % soft}

            raise UnknownProperty('unregistered property %r' % key)

    def property_value(self, key):

        try:

            return self._registries['propertyvalues'][key]

        except KeyError:

            return self._registries['propertydefs'][key]['default']

    def typed_value(self, key, value):

        """value is an unicode string, return it correctly typed. Let potential

        type error propagates.

        """

        pdef = self.property_info(key)

        try:

            value = YAMS_TO_PY[pdef['type']](value)

        except (TypeError, ValueError):

            raise ValueError(_('bad value'))

        vocab = pdef['vocabulary']

        if vocab is not None:

            if callable(vocab):

                vocab = vocab(key, None) # XXX need a req object

            if not value in vocab:

                raise ValueError(_('unauthorized value'))

        return value

    def init_properties(self, propvalues):

        """init the property values registry using the given set of couple (key, value)

        """

        self.initialized = True

        values = self._registries['propertyvalues']

        for key, val in propvalues:

            try:

                values[key] = self.typed_value(key, val)

            except ValueError:

                self.warning('%s (you should probably delete that property '

                             'from the database)', ex)

            except UnknownProperty, ex:

                self.warning('%s (you should probably delete that property '

                             'from the database)', ex)

    def property_value_widget(self, propkey, req=None, **attrs):

        """return widget according to key's type / vocab"""

        from cubicweb.web.widgets import StaticComboBoxWidget, widget_factory

        if req is None:

            tr = unicode

        else:

            tr = req._

        try:

            pdef = self.property_info(propkey)

        except UnknownProperty, ex:

            self.warning('%s (you should probably delete that property '

                         'from the database)', ex)

            return widget_factory(self, 'EProperty', self.schema['value'], 'String',

                                  description=u'', **attrs)

        req.form['value'] = pdef['default'] # XXX hack to pass the default value

        vocab = pdef['vocabulary']

        if vocab is not None:

            if callable(vocab):

                # list() just in case its a generator function

                vocabfunc = lambda e: list(vocab(propkey, req))

            else:

                vocabfunc = lambda e: vocab

            w = StaticComboBoxWidget(self, 'EProperty', self.schema['value'], 'String',

                                     vocabfunc=vocabfunc, description=tr(pdef['help']),

                                     **attrs)

        else:

            w = widget_factory(self, 'EProperty', self.schema['value'], pdef['type'],

                               description=tr(pdef['help']), **attrs)

        return w

    def parse(self, session, rql, args=None):

        rqlst = self.rqlhelper.parse(rql)

        def type_from_eid(eid, session=session):

            return session.describe(eid)[0]

        self.rqlhelper.compute_solutions(rqlst, {'eid': type_from_eid}, args)

        return rqlst

    @property

    @cached

    def rqlhelper(self):

        return RQLHelper(self.schema,

                         special_relations={'eid': 'uid', 'has_text': 'fti'})

class MulCnxCubicWebRegistry(CubicWebRegistry):

    """special registry to be used when an application has to deal with

    connections to differents repository. This class add some additional wrapper

    trying to hide buggy class attributes since classes are not designed to be

    shared.

    """

    def etype_class(self, etype):

        """return an entity class for the given entity type.

        Try to find out a specific class for this kind of entity or

        default to a dump of the class registered for 'Any'

        """

        usercls = super(MulCnxCubicWebRegistry, self).etype_class(etype)

        usercls.e_schema = self.schema.eschema(etype)

        return usercls

    def select(self, vobjects, *args, **kwargs):

        """return an instance of the most specific object according

        to parameters

        raise NoSelectableObject if not object apply

        """

        for vobject in vobjects:

            vobject.vreg = self

            vobject.schema = self.schema

            vobject.config = self.config

        return super(MulCnxCubicWebRegistry, self).select(vobjects, *args, **kwargs)