# copyright 2003-2010 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/>.
"""
A RelationTag object is an object which allows to link a configuration
information to a relation definition. For instance, the standard
primary view uses a RelationTag object (uicfg.primaryview_section) to
get the section to display relations.

.. sourcecode:: python

   # display ``entry_of`` relations in the ``relations`` section in the ``BlogEntry`` primary view
   uicfg.primaryview_section.tag_subject_of(('BlogEntry', 'entry_of', '*'),
                                             'relations')

   # hide every relation ``entry_of`` in the ``Blog`` primary view
   uicfg.primaryview_section.tag_object_of(('*', 'entry_of', 'Blog'), 'hidden')

Three primitives are defined:
   * ``tag_subject_of`` tag a relation in the subject's context
   * ``tag_object_of`` tag a relation in the object's context
   * ``tag_attribute`` shortcut for tag_subject_of
"""
__docformat__ = "restructuredtext en"

import logging

from logilab.common.logging_ext import set_log_methods

RTAGS = []
def register_rtag(rtag):
    RTAGS.append(rtag)

def _ensure_str_key(key):
    return tuple(str(k) for k in key)

class RelationTags(object):
    """a tag store for full relation definitions :

         (subject type, relation type, object type, tagged)

    allowing to set tags using wildcard (eg '*') as subject type / object type

    This class associates a single tag to each key.
    """
    _allowed_values = None
    _initfunc = None
    def __init__(self, name=None, initfunc=None, allowed_values=None):
        self._name = name or '<unknown>'
        self._tagdefs = {}
        if allowed_values is not None:
            self._allowed_values = allowed_values
        if initfunc is not None:
            self._initfunc = initfunc
        register_rtag(self)

    def __repr__(self):
        return '%s: %s' % (self._name, repr(self._tagdefs))

    # dict compat
    def __getitem__(self, key):
        return self.get(*key)
    __contains__ = __getitem__

    def clear(self):
        self._tagdefs.clear()

    def _get_keys(self, stype, rtype, otype, tagged):
        keys = []
        if '*' not in (stype, otype):
            keys.append(('*', rtype, '*', tagged))
        if '*' != stype:
            keys.append(('*', rtype, otype, tagged))
        if '*' != otype:
            keys.append((stype, rtype, '*', tagged))
        keys.append((stype, rtype, otype, tagged))
        return keys

    def init(self, schema, check=True):
        # XXX check existing keys against schema
        if check:
            for (stype, rtype, otype, tagged), value in self._tagdefs.items():
                for ertype in (stype, rtype, otype):
                    if ertype != '*' and not ertype in schema:
                        self.warning('removing rtag %s: %s, %s undefined in schema',
                                     (stype, rtype, otype, tagged), value, ertype)
                        self.del_rtag(stype, rtype, otype, tagged)
                        break
        if self._initfunc is not None:
            self.apply(schema, self._initfunc)

    def apply(self, schema, func):
        for eschema in schema.entities():
            if eschema.final:
                continue
            for rschema, tschemas, role in eschema.relation_definitions(True):
                for tschema in tschemas:
                    if role == 'subject':
                        sschema, oschema = eschema, tschema
                    else:
                        sschema, oschema = tschema, eschema
                    func(self, sschema, rschema, oschema, role)

    # rtag declaration api ####################################################

    def tag_attribute(self, key, *args, **kwargs):
        key = list(key)
        key.append('*')
        key.append('subject')
        self.tag_relation(key, *args, **kwargs)

    def tag_subject_of(self, key, *args, **kwargs):
        key = list(key)
        key.append('subject')
        self.tag_relation(key, *args, **kwargs)

    def tag_object_of(self, key, *args, **kwargs):
        key = list(key)
        key.append('object')
        self.tag_relation(key, *args, **kwargs)

    def tag_relation(self, key, tag):
        assert len(key) == 4, 'bad key: %s' % list(key)
        if self._allowed_values is not None:
            assert tag in self._allowed_values, \
                   '%r is not an allowed tag (should be in %s)' % (
                tag, self._allowed_values)
        self._tagdefs[_ensure_str_key(key)] = tag
        return tag

    # rtag runtime api ########################################################

    def del_rtag(self, *key):
        del self._tagdefs[key]

    def get(self, *key):
        for key in reversed(self._get_keys(*key)):
            try:
                return self._tagdefs[key]
            except KeyError:
                continue
        return None

    def etype_get(self, etype, rtype, role, ttype='*'):
        if role == 'subject':
            return self.get(etype, rtype, ttype, role)
        return self.get(ttype, rtype, etype, role)

    # 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


class RelationTagsSet(RelationTags):
    """This class associates a set of tags to each key.
    """
    tag_container_cls = set

    def tag_relation(self, key, tag):
        rtags = self._tagdefs.setdefault(_ensure_str_key(key),
                                         self.tag_container_cls())
        rtags.add(tag)
        return rtags

    def get(self, stype, rtype, otype, tagged):
        rtags = self.tag_container_cls()
        for key in self._get_keys(stype, rtype, otype, tagged):
            try:
                rtags.update(self._tagdefs[key])
            except KeyError:
                continue
        return rtags


class RelationTagsDict(RelationTagsSet):
    """This class associates a set of tags to each key."""
    tag_container_cls = dict

    def tag_relation(self, key, tag):
        key = _ensure_str_key(key)
        try:
            rtags = self._tagdefs[key]
            rtags.update(tag)
            return rtags
        except KeyError:
            self._tagdefs[key] = tag
            return tag

    def setdefault(self, key, tagkey, tagvalue):
        key = _ensure_str_key(key)
        try:
            rtags = self._tagdefs[key]
            rtags.setdefault(tagkey, tagvalue)
            return rtags
        except KeyError:
            self._tagdefs[key] = {tagkey: tagvalue}
            return self._tagdefs[key]


class RelationTagsBool(RelationTags):
    _allowed_values = frozenset((True, False))


class NoTargetRelationTagsDict(RelationTagsDict):

    @property
    def name(self):
        return self.__class__.name

    # tag_subject_of / tag_object_of issue warning if '*' is not given as target
    # type, while tag_relation handle it silently since it may be used during
    # initialization
    def tag_subject_of(self, key, tag):
        subj, rtype, obj = key
        if obj != '*':
            self.warning('using explict target type in %s.tag_subject_of() '
                         'has no effect, use (%s, %s, "*") instead of (%s, %s, %s)',
                         self.name, subj, rtype, subj, rtype, obj)
        super(NoTargetRelationTagsDict, self).tag_subject_of((subj, rtype, '*'), tag)

    def tag_object_of(self, key, tag):
        subj, rtype, obj = key
        if subj != '*':
            self.warning('using explict subject type in %s.tag_object_of() '
                         'has no effect, use ("*", %s, %s) instead of (%s, %s, %s)',
                         self.name, rtype, obj, subj, rtype, obj)
        super(NoTargetRelationTagsDict, self).tag_object_of(('*', rtype, obj), tag)

    def tag_relation(self, key, tag):
        if key[-1] == 'subject' and key[-2] != '*':
            if isinstance(key, tuple):
                key = list(key)
            key[-2] = '*'
        elif key[-1] == 'object' and key[0] != '*':
            if isinstance(key, tuple):
                key = list(key)
            key[0] = '*'
        super(NoTargetRelationTagsDict, self).tag_relation(key, tag)
set_log_methods(RelationTags, logging.getLogger('cubicweb.rtags'))