# copyright 2010-2012 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/>.

"""some basic entity adapter implementations, for interfaces used in the

framework itself.

"""

__docformat__ = "restructuredtext en"

from itertools import chain

from warnings import warn

from logilab.mtconverter import TransformError

from logilab.common.decorators import cached

from cubicweb import ValidationError, view

from cubicweb.predicates import is_instance, relation_possible, match_exception

class IEmailableAdapter(view.EntityAdapter):

    __regid__ = 'IEmailable'

    __select__ = relation_possible('primary_email') | relation_possible('use_email')

    def get_email(self):

        if getattr(self.entity, 'primary_email', None):

            return self.entity.primary_email[0].address

        if getattr(self.entity, 'use_email', None):

            return self.entity.use_email[0].address

        return None

    def allowed_massmail_keys(self):

        """returns a set of allowed email substitution keys

        The default is to return the entity's attribute list but you might

        override this method to allow extra keys.  For instance, a Person

        class might want to return a `companyname` key.

        """

        return set(rschema.type

                   for rschema, attrtype in self.entity.e_schema.attribute_definitions()

                   if attrtype.type not in ('Password', 'Bytes'))

    def as_email_context(self):

        """returns the dictionary as used by the sendmail controller to

        build email bodies.

        NOTE: the dictionary keys should match the list returned by the

        `allowed_massmail_keys` method.

        """

        return dict( (attr, getattr(self.entity, attr))

                     for attr in self.allowed_massmail_keys() )

class INotifiableAdapter(view.EntityAdapter):

    __regid__ = 'INotifiable'

    __select__ = is_instance('Any')

    def notification_references(self, view):

        """used to control References field of email send on notification

        for this entity. `view` is the notification view.

        Should return a list of eids which can be used to generate message

        identifiers of previously sent email(s)

        """

        itree = self.entity.cw_adapt_to('ITree')

        if itree is not None:

            return itree.path()[:-1]

        return ()

class IFTIndexableAdapter(view.EntityAdapter):

    """standard adapter to handle fulltext indexing

    .. automethod:: cubicweb.entities.adapters.IFTIndexableAdapter.fti_containers

    .. automethod:: cubicweb.entities.adapters.IFTIndexableAdapter.get_words

    """

    __regid__ = 'IFTIndexable'

    __select__ = is_instance('Any')

    def fti_containers(self, _done=None):

        """return the list of entities to index when handling ``self.entity``

        The actual list of entities depends on ``fulltext_container`` usage

        in the datamodel definition

        """

        if _done is None:

            _done = set()

        entity = self.entity

        _done.add(entity.eid)

        containers = tuple(entity.e_schema.fulltext_containers())

        if containers:

            for rschema, target in containers:

                if target == 'object':

                    targets = getattr(entity, rschema.type)

                else:

                    targets = getattr(entity, 'reverse_%s' % rschema)

                for entity in targets:

                    if entity.eid in _done:

                        continue

                    for container in entity.cw_adapt_to('IFTIndexable').fti_containers(_done):

                        yield container

                        yielded = True

        else:

            yield entity

    # weight in ABCD

    entity_weight = 1.0

    attr_weight = {}

    def get_words(self):

        """used by the full text indexer to get words to index

        this method should only be used on the repository side since it depends

        on the logilab.database package

        :rtype: list

        :return: the list of indexable word of this entity

        """

        from logilab.database.fti import tokenize

        # take care to cases where we're modyfying the schema

        entity = self.entity

        pending = self._cw.transaction_data.setdefault('pendingrdefs', set())

        words = {}

        for rschema in entity.e_schema.indexable_attributes():

            if (entity.e_schema, rschema) in pending:

                continue

            weight = self.attr_weight.get(rschema, 'C')

            try:

                value = entity.printable_value(rschema, format='text/plain')

            except TransformError:

                continue

            except Exception:

                self.exception("can't add value of %s to text index for entity %s",

                               rschema, entity.eid)

                continue

            if value:

                words.setdefault(weight, []).extend(tokenize(value))

        for rschema, role in entity.e_schema.fulltext_relations():

            if role == 'subject':

                for entity_ in getattr(entity, rschema.type):

                    merge_weight_dict(words, entity_.cw_adapt_to('IFTIndexable').get_words())

            else: # if role == 'object':

                for entity_ in getattr(entity, 'reverse_%s' % rschema.type):

                    merge_weight_dict(words, entity_.cw_adapt_to('IFTIndexable').get_words())

        return words

def merge_weight_dict(maindict, newdict):

    for weight, words in newdict.iteritems():

        maindict.setdefault(weight, []).extend(words)

class IDownloadableAdapter(view.EntityAdapter):

    """interface for downloadable entities"""

    __regid__ = 'IDownloadable'

    __abstract__ = True

    def download_url(self, **kwargs): # XXX not really part of this interface

        """return an url to download entity's content"""

        raise NotImplementedError

    def download_content_type(self):

        """return MIME type of the downloadable content"""

        raise NotImplementedError

    def download_encoding(self):

        """return encoding of the downloadable content"""

        raise NotImplementedError

    def download_file_name(self):

        """return file name of the downloadable content"""

        raise NotImplementedError

    def download_data(self):

        """return actual data of the downloadable content"""

        raise NotImplementedError

# XXX should propose to use two different relations for children/parent

class ITreeAdapter(view.EntityAdapter):

    """This adapter has to be overriden to be configured using the

    tree_relation, child_role and parent_role class attributes to benefit from

    this default implementation.

    This adapter provides a tree interface. It has to be overriden to be

    configured using the tree_relation, child_role and parent_role class

    attributes to benefit from this default implementation.

    This class provides the following methods:

    .. automethod: iterparents

    .. automethod: iterchildren

    .. automethod: prefixiter

    .. automethod: is_leaf

    .. automethod: is_root

    .. automethod: root

    .. automethod: parent

    .. automethod: children

    .. automethod: different_type_children

    .. automethod: same_type_children

    .. automethod: children_rql

    .. automethod: path

    """

    __regid__ = 'ITree'

    __abstract__ = True

    child_role = 'subject'

    parent_role = 'object'

    def children_rql(self):

        """Returns RQL to get the children of the entity."""

        return self.entity.cw_related_rql(self.tree_relation, self.parent_role)

    def different_type_children(self, entities=True):

        """Return children entities of different type as this entity.

        According to the `entities` parameter, return entity objects or the

        equivalent result set.

        """

        res = self.entity.related(self.tree_relation, self.parent_role,

                                  entities=entities)

        eschema = self.entity.e_schema

        if entities:

            return [e for e in res if e.e_schema != eschema]

        return res.filtered_rset(lambda x: x.e_schema != eschema, self.entity.cw_col)

    def same_type_children(self, entities=True):

        """Return children entities of the same type as this entity.

        According to the `entities` parameter, return entity objects or the

        equivalent result set.

        """

        res = self.entity.related(self.tree_relation, self.parent_role,

                                  entities=entities)

        eschema = self.entity.e_schema

        if entities:

            return [e for e in res if e.e_schema == eschema]

        return res.filtered_rset(lambda x: x.e_schema is eschema, self.entity.cw_col)

    def is_leaf(self):

        """Returns True if the entity does not have any children."""

        return len(self.children()) == 0

    def is_root(self):

        """Returns true if the entity is root of the tree (e.g. has no parent).

        """

        return self.parent() is None

    def root(self):

        """Return the root entity of the tree."""

        return self._cw.entity_from_eid(self.path()[0])

    def parent(self):

        """Returns the parent entity if any, else None (e.g. if we are on the

        root).

        """

        try:

            return self.entity.related(self.tree_relation, self.child_role,

                                       entities=True)[0]

        except (KeyError, IndexError):

            return None

    def children(self, entities=True, sametype=False):

        """Return children entities.

        According to the `entities` parameter, return entity objects or the

        equivalent result set.

        """

        if sametype:

            return self.same_type_children(entities)

        else:

            return self.entity.related(self.tree_relation, self.parent_role,

                                       entities=entities)

    def iterparents(self, strict=True):

        """Return an iterator on the parents of the entity."""

        def _uptoroot(self):

            curr = self

            while True:

                curr = curr.parent()

                if curr is None:

                    break

                yield curr

                curr = curr.cw_adapt_to('ITree')

        if not strict:

            return chain([self.entity], _uptoroot(self))

        return _uptoroot(self)

    def iterchildren(self, _done=None):

        """Return an iterator over the item's children."""

        if _done is None:

            _done = set()

        for child in self.children():

            if child.eid in _done:

                self.error('loop in %s tree: %s', child.cw_etype.lower(), child)

                continue

            yield child

            _done.add(child.eid)

    def prefixiter(self, _done=None):

        """Return an iterator over the item's descendants in a prefixed order."""

        if _done is None:

            _done = set()

        if self.entity.eid in _done:

            return

        _done.add(self.entity.eid)

        yield self.entity

        for child in self.same_type_children():

            for entity in child.cw_adapt_to('ITree').prefixiter(_done):

                yield entity

    @cached

    def path(self):

        """Returns the list of eids from the root object to this object."""

        path = []

        adapter = self

        entity = adapter.entity

        while entity is not None:

            if entity.eid in path:

                self.error('loop in %s tree: %s', entity.cw_etype.lower(), entity)

                break

            path.append(entity.eid)

            try:

                # check we are not jumping to another tree

                if (adapter.tree_relation != self.tree_relation or

                    adapter.child_role != self.child_role):

                    break

                entity = adapter.parent()

                adapter = entity.cw_adapt_to('ITree')

            except AttributeError:

                break

        path.reverse()

        return path

# error handling adapters ######################################################

from cubicweb import UniqueTogetherError

class IUserFriendlyError(view.EntityAdapter):

    __regid__ = 'IUserFriendlyError'

    __abstract__ = True

    def __init__(self, *args, **kwargs):

        self.exc = kwargs.pop('exc')

        super(IUserFriendlyError, self).__init__(*args, **kwargs)

class IUserFriendlyUniqueTogether(IUserFriendlyError):

    __select__ = match_exception(UniqueTogetherError)

    def raise_user_exception(self):

        etype, rtypes = self.exc.args

        # Because of index name size limits (e.g: postgres around 64,

        # sqlserver around 128), we cannot be sure of what we got,

        # especially for the rtypes part.

        # Hence we will try to validate them, and handle invalid ones

        # in the most user-friendly manner ...

        _ = self._cw._

        schema = self.entity._cw.vreg.schema

        rtypes_msg = {}

        for rtype in rtypes:

            if rtype in schema:

                rtypes_msg[rtype] = _('%s is part of violated unicity constraint') % rtype

        globalmsg = _('some relations %sviolate a unicity constraint')

        if len(rtypes) != len(rtypes_msg): # we got mangled/missing rtypes

            globalmsg = globalmsg % _('(not all shown here) ')

        else:

            globalmsg = globalmsg % ''

        rtypes_msg['unicity constraint'] = globalmsg

        raise ValidationError(self.entity.eid, rtypes_msg)

# deprecated ###################################################################

class adapter_deprecated(view.auto_unwrap_bw_compat):

    """metaclass to print a warning on instantiation of a deprecated class"""

    def __call__(cls, *args, **kwargs):

        msg = getattr(cls, "__deprecation_warning__",

                      "%(cls)s is deprecated") % {'cls': cls.__name__}

        warn(msg, DeprecationWarning, stacklevel=2)

        return type.__call__(cls, *args, **kwargs)