"""some utility functions for datastore initialization.

"""

__docformat__ = "restructuredtext en"

from google.appengine.api.datastore import Key, Entity, Put, Get, Query

from google.appengine.api import datastore_errors

_GROUP_CACHE = {} # XXX use memcache

def _get_group(groupname):

    try:

        return _GROUP_CACHE[groupname]

    except KeyError:

        key = Key.from_path('CWGroup', 'key_' + groupname, parent=None)

        try:

            group = Get(key)

        except datastore_errors.EntityNotFoundError:

            raise Exception('can\'t find required group %s, is your instance '

                            'correctly initialized (eg did you run the '

                            'initialization script) ?' % groupname)

        _GROUP_CACHE[groupname] = group

        return group

def create_user(login, password, groups):

    """create a cubicweb user"""

    from cubicweb.server.utils import crypt_password

    user = Entity('CWUser', name=login)

    user['s_login'] = unicode(login)

    user['s_upassword'] = crypt_password(password)

    set_user_groups(user, groups)

    Put(user)

    return user

def create_groups():

    """create initial cubicweb groups"""

    for groupname in ('managers', 'users', 'guests'):

        group = Entity('CWGroup', name='key_' + groupname)

        group['s_name'] = unicode(groupname)

        Put(group)

        _GROUP_CACHE[groupname] = group

def set_user_groups(user, groups):

    """set user in the given groups (as string). The given user entity

    (datastore.Entity) is not putted back to the repository, this is the caller

    responsability.

    """

    groups = [_get_group(g) for g in groups]

    user['s_in_group'] = [g.key() for g in groups] or None

    for group in groups:

        try:

            group['o_in_group'].append(user.key())

        except (KeyError, AttributeError):

            group['o_in_group'] = [user.key()]

        Put(group)

def init_relations(gaeentity, eschema):

    """set None for every subject relations which is not yet defined"""

    for rschema in eschema.subject_relations():

        if rschema in ('identity', 'has_text'):

            continue

        dsrelation = 's_' + rschema.type

        if not dsrelation in gaeentity:

            gaeentity[dsrelation] = None

    for rschema in eschema.object_relations():

        if rschema == 'identity':

            continue

        dsrelation = 'o_' + rschema.type

        if not dsrelation in gaeentity:

            gaeentity[dsrelation] = None

def fix_entities(schema):

    for etype in ('CWUser', 'CWGroup'):

        eschema = schema.eschema(etype)

        for gaeentity in Query(etype).Run():

            init_relations(gaeentity, eschema)

            # XXX o_is on CWEType entity

            gaeentity['s_is'] = Key.from_path('CWEType', 'key_' + etype, parent=None)

            Put(gaeentity)

def init_persistent_schema(ssession, schema):

    execute = ssession.execute

    rql = ('INSERT CWEType X: X name %(name)s, X description %(descr)s,'

           'X final FALSE')

    eschema = schema.eschema('CWEType')

    execute(rql, {'name': u'CWEType', 'descr': unicode(eschema.description)})

    for eschema in schema.entities():

        if eschema.final or eschema == 'CWEType':

            continue

        execute(rql, {'name': unicode(eschema),

                      'descr': unicode(eschema.description)})

def insert_versions(ssession, config):

    execute = ssession.execute

    # insert versions

    execute('INSERT CWProperty X: X pkey %(pk)s, X value%(v)s',

            {'pk': u'system.version.cubicweb',

             'v': unicode(config.cubicweb_version())})

    for cube in config.cubes():

        execute('INSERT CWProperty X: X pkey %(pk)s, X value%(v)s',

                {'pk': u'system.version.%s' % cube,

                 'v': unicode(config.cube_version(cube))})