from django.conf import settings

from django.contrib.contenttypes.models import ContentType

from guardian.shortcuts import assign, remove_perm, get_users_with_perms, get_groups_with_perms

try:

    from threading import local

except ImportError:

    from django.utils._threading_local import local

_thread_locals = local()

def get_current_user():

    return getattr(_thread_locals, 'user', None)

def set_current_user(user):

    _thread_locals.user = user

def del_current_user():

    del _thread_locals.user

def protect_models():

    cls_list = ToProtect.get_models()

    if cls_list:

        user = get_current_user()

        for cls in ToProtect.get_models():

def unprotect_models():

    for cls in ToProtect.get_models():

            unprotect_model(cls)

class ToProtect(object):

    @staticmethod

    def get_models():

        if hasattr(ToProtect, 'cls_list'):

            return ToProtect.cls_list

        cls_list = []

        for cls_name in settings.USE_GROUP_PERMISSIONS:

            cls_type = ContentType.objects.get(model=cls_name.lower())

            cls_list.append(cls_type.model_class())

        ToProtect.cls_list = cls_list

        return cls_list

def protect_model(cls, user):   

    cls.safe_objects.user = user

    cls.safe_objects.check_perm = True

    cls.old_save = cls.save

    cls.old_delete = cls.delete

    class_name = cls.__name__.lower()

    cls.save = change_security(class_name)(cls.save)

    cls.delete = change_security(class_name)(cls.delete)    

def unprotect_model(cls): 

    if hasattr(cls, 'old_save'):

        cls.save = cls.old_save 

        cls.delete = cls.old_delete 

        del cls.old_save    

        del cls.old_delete

        cls.safe_objects.user = None 

def change_security(cls_name):

    def wrapper(func):

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

            if self.pk and not get_current_user().has_perm('change_%s' % cls_name, self):

                raise AttributeError('User %s is not allowed to change object %s' % (get_current_user(), self))

            return func(self, *args, **kwargs)

        return wrapped    

    return wrapper

def set_forbidden_stream(xml, user):

    cls = ContentType.objects.get(model='content')

    cls = cls.model_class()

    old_user = cls.safe_objects.user

    obj_list = cls.safe_objects.all()

    for elem in xml.xpath('/iri/medias/media'):

        if not obj_list.filter(iri_id=elem.get('id')):

            elem.set('video', settings.FORBIDDEN_STREAM_URL)

    cls.safe_objects.user = old_user 

    return xml

def add_change_attr(user, obj_list):

    """ 

     Add a change attribute set to True to objects of obj_list

     if permissions change_object is set with respect to user.

    """

    if len(obj_list) == 0:

        return []

    model_name = obj_list[0].__class__.__name__.lower()

    ctype = ContentType.objects.get(model=model_name)

    cls = ctype.model_class()

    if model_name in [cls_name.lower() for cls_name in settings.USE_GROUP_PERMISSIONS]:

    else:

        checker = None

    perm_name = "%s.change_%s" % (cls._meta.app_label, model_name)

    for obj in obj_list:

        if not checker or checker.has_perm(perm_name, obj):

            obj.change = True

        else:

            obj.change = False

    return obj_list

def assign_perm_to_obj(object, read_list, write_list, owner):

    name = object.__class__.__name__.lower()

    old_users = get_users_with_perms(object).exclude(id=owner.id)

    old_groups = get_groups_with_perms(object)

    for elem in read_list:

        assign('view_%s' % name, elem, object)

        if elem in write_list:

            assign('change_%s' % name, elem, object)

        else:

            remove_perm('change_%s' % name, elem, object)            

    def remove_perms(new_list, old_list, obj, name):

        for e in old_list:

            if e not in new_list:

                remove_perm('view_%s' % name, e, obj)

                remove_perm('change_%s' % name, e, obj)

    remove_perms(read_list, old_users, object, name)

    remove_perms(read_list, old_groups, object, name) 

def get_userlist(user, filter=None):

    if filter:

        user_list = user_list.filter(username__icontains=filter)

    elem_list = [{'name': u.username, 'id': u.id, 'type': 'user'} for u in user_list[0:settings.MAX_USERS_SEARCH]]

    return elem_list  

def get_userlist_model(object, owner):

    if hasattr(object, 'is_public') and object.is_public:

        return [None, None]

    users = get_users_with_perms(object, attach_perms=True)

    groups = get_groups_with_perms(object, attach_perms=True)

    object_name = object.__class__.__name__.lower()

    def create_dict (users_or_groups, name, groups=True):

        l = []

        admin_list = []

        for elem in users_or_groups.keys():

            if elem == owner:

                continue

            if groups:

                elem_dict = {'name': elem.name, 'type': 'group', 'id': elem.id}

            else:

                elem_dict = {'name': elem.username, 'type': 'user', 'id': elem.id}

            for perm in users_or_groups[elem]:

                if perm == 'change_%s' % name:

                    elem_dict['change'] = True

                    admin_list.append(elem_dict)

                    continue

            l.append(elem_dict)   

        return l, admin_list

    users_list, admin_users = create_dict(users, object_name, False)

    groups_list, admin_groups = create_dict(groups, object_name, True)

    return [users_list + groups_list, admin_users + admin_groups]

def get_userlist_group(group, user):

    members = group.user_set.all()

    admin = get_users_with_perms(group)

    member_list = []

    for u in members:

        if u == user:

            continue

        u_dict = {'name': u.username, 'id': u.id, 'type': 'user', 'change': False}

        if u in admin:

            u_dict['change'] = True

        member_list.append(u_dict)

    admin_list = [{'name': e.username, 'id': e.id, 'type': 'user', 'change': False} for e in admin]

    return [member_list, admin_list]