"""relation tags store

: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"

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

    def __init__(self, initfunc=None, allowed_values=None):

        self._tagdefs = {}

        if allowed_values is not None:

            self._allowed_values = allowed_values

        self._initfunc = initfunc

    def __repr__(self):

        return repr(self._tagdefs)

    # dict compat

    def __getitem__(self, key):

        return self.get(*key)

    __contains__ = __getitem__

    def _get_keys(self, stype, rtype, otype, tagged):

        keys = [(rtype, tagged, '*', '*'),

                (rtype, tagged, '*', otype),

                (rtype, tagged, stype, '*'),

                (rtype, tagged, stype, otype)]

        if stype == '*' or otype == '*':

            keys.remove((rtype, tagged, '*', '*'))

            if stype == '*':

                keys.remove((rtype, tagged, '*', otype))

            if otype == '*':

                keys.remove((rtype, tagged, stype, '*'))

        return keys

    def init(self, schema):

        # XXX check existing keys against schema

        if self._initfunc is not None:

            for eschema in schema.entities():

                for rschema, tschemas, role in eschema.relation_definitions(True):

                    for tschema in tschemas:

                        if role == 'subject':

                            stype, otype = eschema, tschema

                        else:

                            stype, otype = tschema, eschema

                        self._initfunc(stype, rtype, otype, role)

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

    def tag_attribute(self, key, tag):

        key = list(key)

        key.append('*')

        self.tag_subject_of(key, tag)

    def tag_subject_of(self, key, tag):

        key = list(key)

        key.append('subject')

        self.tag_relation(key, tag)

    def tag_object_of(self, key, tag):

        key = list(key)

        key.append('object')

        self.tag_relation(key, tag)

    def tag_relation(self, key, tag):

        #if isinstance(key, basestring):

        #    stype, rtype, otype = key.split()

        #else:

        stype, rtype, otype, tagged = [str(k) for k in key]

        if self._allowed_values is not None:

            assert tag in self._allowed_values

        self._tagdefs[(rtype, tagged, stype, otype)] = tag

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

    def del_rtag(self, stype, rtype, otype, tagged):

        del self._tagdefs[(rtype, tagged, stype, otype)]

    def get(self, stype, rtype, otype, tagged):

        for key in reversed(self._get_keys(stype, rtype, otype, tagged)):

            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)

class RelationTagsSet(RelationTags):

    """This class associates a set of tags to each key."""

    def tag_relation(self, key, tag):

        stype, rtype, otype, tagged = [str(k) for k in key]

        rtags = self._tagdefs.setdefault((rtype, tagged, stype, otype), set())

        rtags.add(tag)

    def get(self, stype, rtype, otype, tagged):

        rtags = set()

        for key in self._get_keys(stype, rtype, otype, tagged):

            try:

                rtags.update(self._tagdefs[key])

            except KeyError:

                continue

        return rtags

class RelationTagsBool(RelationTags):

    _allowed_values = frozenset((True, False))