#:organization: Logilab
#:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
#:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
#:license: GNU Lesser General Public License, v2.1 - 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 = [('*', rtype, '*', tagged),
                ('*', rtype, otype, tagged),
                (stype, rtype, '*', tagged),
                (stype, rtype, otype, tagged)]
        if stype == '*' or otype == '*':
            keys.remove( ('*', rtype, '*', tagged) )
            if stype == '*':
                keys.remove( ('*', rtype, otype, tagged) )
            if otype == '*':
                keys.remove( (stype, rtype, '*', 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():
            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)



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))


set_log_methods(RelationTags, logging.getLogger('cubicweb.rtags'))