gr = gr.options(FromCache(

                            "sql_cache_short",

                            "get_group_%s" % _hash_key(group_name)

                            )

            )

        return gr.scalar()

    @property

    def parents(self):

        parents_recursion_limit = 5

        groups = []

        if self.parent_group is None:

            return groups

        cur_gr = self.parent_group

        groups.insert(0, cur_gr)

        cnt = 0

        while 1:

            cnt += 1

            gr = getattr(cur_gr, 'parent_group', None)

            cur_gr = cur_gr.parent_group

            if gr is None:

                break

            if cnt == parents_recursion_limit:

                # this will prevent accidental infinit loops

                log.error('group nested more than %s' %

                          parents_recursion_limit)

                break

            groups.insert(0, gr)

        return groups

    @property

    def children(self):

        return RepoGroup.query().filter(RepoGroup.parent_group == self)

    @property

    def name(self):

        return self.group_name.split(RepoGroup.url_sep())[-1]

    @property

    def full_path(self):

        return self.group_name

    @property

    def full_path_splitted(self):

        return self.group_name.split(RepoGroup.url_sep())

    @property

    def repositories(self):

        return Repository.query()\

                .filter(Repository.group == self)\

                .order_by(Repository.repo_name)

    @property

    def repositories_recursive_count(self):

        cnt = self.repositories.count()

        def children_count(group):

            cnt = 0

            for child in group.children:

                cnt += child.repositories.count()

                cnt += children_count(child)

            return cnt

        return cnt + children_count(self)

    def _recursive_objects(self, include_repos=True):

        all_ = []

        def _get_members(root_gr):

            if include_repos:

                for r in root_gr.repositories:

                    all_.append(r)

            childs = root_gr.children.all()

            if childs:

                for gr in childs:

                    all_.append(gr)

                    _get_members(gr)

        _get_members(self)

        return [self] + all_

    def recursive_groups_and_repos(self):

        """

        Recursive return all groups, with repositories in those groups

        """

        return self._recursive_objects()

    def recursive_groups(self):

        """

        Returns all children groups for this group including children of children

        """

        return self._recursive_objects(include_repos=False)

    def get_new_name(self, group_name):

        """

        returns new full group name based on parent and new name

        :param group_name:

        """

        path_prefix = (self.parent_group.full_path_splitted if

                       self.parent_group else [])

        return RepoGroup.url_sep().join(path_prefix + [group_name])

class Permission(Base, BaseModel):

    __tablename__ = 'permissions'

    __table_args__ = (

        Index('p_perm_name_idx', 'permission_name'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    PERMS = [

        ('repository.none', _('Repository no access')),

        ('repository.read', _('Repository read access')),

        ('repository.write', _('Repository write access')),

        ('repository.admin', _('Repository admin access')),

        ('group.none', _('Repository group no access')),

        ('group.read', _('Repository group read access')),

        ('group.write', _('Repository group write access')),

        ('group.admin', _('Repository group admin access')),

        ('hg.admin', _('RhodeCode Administrator')),

        ('hg.create.none', _('Repository creation disabled')),

        ('hg.create.repository', _('Repository creation enabled')),

        ('hg.fork.none', _('Repository forking disabled')),

        ('hg.fork.repository', _('Repository forking enabled')),

        ('hg.register.none', _('Register disabled')),

        ('hg.register.manual_activate', _('Register new user with RhodeCode '

                                          'with manual activation')),

        ('hg.register.auto_activate', _('Register new user with RhodeCode '

                                        'with auto activation')),

    ]

    # defines which permissions are more important higher the more important

    PERM_WEIGHTS = {

        'repository.none': 0,

        'repository.read': 1,

        'repository.write': 3,

        'repository.admin': 4,

        'group.none': 0,

        'group.read': 1,

        'group.write': 3,

        'group.admin': 4,

        'hg.fork.none': 0,

        'hg.fork.repository': 1,

        'hg.create.none': 0,

        'hg.create.repository':1

    }

    permission_id = Column("permission_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    permission_name = Column("permission_name", String(255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)

    permission_longname = Column("permission_longname", String(255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)

    def __unicode__(self):

        return u"<%s('%s:%s')>" % (

            self.__class__.__name__, self.permission_id, self.permission_name

        )

    @classmethod

    def get_by_key(cls, key):

        return cls.query().filter(cls.permission_name == key).scalar()

    @classmethod

    def get_default_perms(cls, default_user_id):

        q = Session().query(UserRepoToPerm, Repository, cls)\

         .join((Repository, UserRepoToPerm.repository_id == Repository.repo_id))\

         .join((cls, UserRepoToPerm.permission_id == cls.permission_id))\

         .filter(UserRepoToPerm.user_id == default_user_id)

        return q.all()

    @classmethod

    def get_default_group_perms(cls, default_user_id):

        q = Session().query(UserRepoGroupToPerm, RepoGroup, cls)\

         .join((RepoGroup, UserRepoGroupToPerm.group_id == RepoGroup.group_id))\

         .join((cls, UserRepoGroupToPerm.permission_id == cls.permission_id))\

         .filter(UserRepoGroupToPerm.user_id == default_user_id)

        return q.all()

class UserRepoToPerm(Base, BaseModel):

    __tablename__ = 'repo_to_perm'

    __table_args__ = (

        UniqueConstraint('user_id', 'repository_id', 'permission_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    repo_to_perm_id = Column("repo_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    repository_id = Column("repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=False, unique=None, default=None)

    user = relationship('User')

    repository = relationship('Repository')

    permission = relationship('Permission')

    @classmethod

    def create(cls, user, repository, permission):

        n = cls()

        n.user = user

        n.repository = repository

        n.permission = permission

        Session().add(n)

        return n

    def __unicode__(self):

        return u'<user:%s => %s >' % (self.user, self.repository)

class UserToPerm(Base, BaseModel):

    __tablename__ = 'user_to_perm'

    __table_args__ = (

        UniqueConstraint('user_id', 'permission_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    user_to_perm_id = Column("user_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    user = relationship('User')

    permission = relationship('Permission', lazy='joined')

class UserGroupRepoToPerm(Base, BaseModel):

    __tablename__ = 'users_group_repo_to_perm'

    __table_args__ = (

        UniqueConstraint('repository_id', 'users_group_id', 'permission_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    users_group_to_perm_id = Column("users_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    repository_id = Column("repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=False, unique=None, default=None)

    users_group = relationship('UserGroup')

    permission = relationship('Permission')

    repository = relationship('Repository')

    @classmethod

    def create(cls, users_group, repository, permission):

        n = cls()

        n.users_group = users_group

        n.repository = repository

        n.permission = permission

        Session().add(n)

        return n

    def __unicode__(self):

        return u'<userGroup:%s => %s >' % (self.users_group, self.repository)

class UserGroupToPerm(Base, BaseModel):

    __tablename__ = 'users_group_to_perm'

    __table_args__ = (

        UniqueConstraint('users_group_id', 'permission_id',),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    users_group_to_perm_id = Column("users_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    users_group = relationship('UserGroup')

    permission = relationship('Permission')

class UserRepoGroupToPerm(Base, BaseModel):

    __tablename__ = 'user_repo_group_to_perm'

    __table_args__ = (

        UniqueConstraint('user_id', 'group_id', 'permission_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    group_to_perm_id = Column("group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)

    group_id = Column("group_id", Integer(), ForeignKey('groups.group_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    user = relationship('User')

    group = relationship('RepoGroup')

    permission = relationship('Permission')

class UserGroupRepoGroupToPerm(Base, BaseModel):

    __tablename__ = 'users_group_repo_group_to_perm'

    __table_args__ = (

        UniqueConstraint('users_group_id', 'group_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    users_group_repo_group_to_perm_id = Column("users_group_repo_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)

    group_id = Column("group_id", Integer(), ForeignKey('groups.group_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    users_group = relationship('UserGroup')

    permission = relationship('Permission')

    group = relationship('RepoGroup')

class Statistics(Base, BaseModel):

    __tablename__ = 'statistics'

    __table_args__ = (

         UniqueConstraint('repository_id'),

         {'extend_existing': True, 'mysql_engine': 'InnoDB',

          'mysql_charset': 'utf8'}

    )

    stat_id = Column("stat_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    repository_id = Column("repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=False, unique=True, default=None)

    stat_on_revision = Column("stat_on_revision", Integer(), nullable=False)

    commit_activity = Column("commit_activity", LargeBinary(1000000), nullable=False)#JSON data

    commit_activity_combined = Column("commit_activity_combined", LargeBinary(), nullable=False)#JSON data

    languages = Column("languages", LargeBinary(1000000), nullable=False)#JSON data

    repository = relationship('Repository', single_parent=True)

class UserFollowing(Base, BaseModel):

    __tablename__ = 'user_followings'

    __table_args__ = (

        UniqueConstraint('user_id', 'follows_repository_id'),

        UniqueConstraint('user_id', 'follows_user_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    user_following_id = Column("user_following_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)

    follows_repo_id = Column("follows_repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=True, unique=None, default=None)

    follows_user_id = Column("follows_user_id", Integer(), ForeignKey('users.user_id'), nullable=True, unique=None, default=None)

    follows_from = Column('follows_from', DateTime(timezone=False), nullable=True, unique=None, default=datetime.datetime.now)

    user = relationship('User', primaryjoin='User.user_id==UserFollowing.user_id')

    follows_user = relationship('User', primaryjoin='User.user_id==UserFollowing.follows_user_id')

    follows_repository = relationship('Repository', order_by='Repository.repo_name')

    @classmethod

    def get_repo_followers(cls, repo_id):

        return cls.query().filter(cls.follows_repo_id == repo_id)

class CacheInvalidation(Base, BaseModel):

    __tablename__ = 'cache_invalidation'

    __table_args__ = (

        UniqueConstraint('cache_key'),

        Index('key_idx', 'cache_key'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    # cache_id, not used

    cache_id = Column("cache_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    # cache_key as created by _get_cache_key

    cache_key = Column("cache_key", String(255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)

    # cache_args is a repo_name

    cache_args = Column("cache_args", String(255, convert_unicode=False, assert_unicode=None), nullable=True, unique=None, default=None)

    # instance sets cache_active True when it is caching,

    # other instances set cache_active to False to indicate that this cache is invalid

    cache_active = Column("cache_active", Boolean(), nullable=True, unique=None, default=False)

    def __init__(self, cache_key, repo_name=''):

        self.cache_key = cache_key

        self.cache_args = repo_name

        self.cache_active = False

    def __unicode__(self):

        return u"<%s('%s:%s')>" % (self.__class__.__name__,

                                  self.cache_id, self.cache_key)

    def get_prefix(self):

        """

        Guess prefix that might have been used in _get_cache_key to generate self.cache_key .

        Only used for informational purposes in repo_edit.html .

        """

    @classmethod

    def _get_cache_key(cls, key):

        """

        Wrapper for generating a unique cache key for this instance and "key".

        key must / will start with a repo_name which will be stored in .cache_args .

        """

        import rhodecode

        prefix = rhodecode.CONFIG.get('instance_id', '')

        return "%s%s" % (prefix, key)

    @classmethod

    def _get_or_create_inv_obj(cls, key, repo_name):

        inv_obj = Session().query(cls).filter(cls.cache_key == key).scalar()

        if not inv_obj:

            try:

                inv_obj = CacheInvalidation(key, repo_name)

                Session().add(inv_obj)

                Session().commit()

            except Exception:

                log.error(traceback.format_exc())

                Session().rollback()

        return inv_obj

    @classmethod

    def invalidate(cls, key):

        """

        Returns Invalidation object if the local cache with the given key is invalid,

        None otherwise.

        """

        repo_name = key

        repo_name = remove_suffix(repo_name, '_README')

        repo_name = remove_suffix(repo_name, '_RSS')

        repo_name = remove_suffix(repo_name, '_ATOM')

        cache_key = cls._get_cache_key(key)

        inv_obj = cls._get_or_create_inv_obj(cache_key, repo_name)

        if inv_obj and not inv_obj.cache_active:

            # `cache_active = False` means that this cache

            # no longer is valid

            return inv_obj

    @classmethod

    def set_invalidate(cls, key=None, repo_name=None):

        """

        Mark this Cache key for invalidation, either by key or whole

        cache sets based on repo_name

        :param key:

        """

        invalidated_keys = []

        if key:

            assert not repo_name

            cache_key = cls._get_cache_key(key)

            inv_objs = Session().query(cls).filter(cls.cache_key == cache_key).all()

        else:

            assert repo_name

            inv_objs = Session().query(cls).filter(cls.cache_args == repo_name).all()

        try:

            for inv_obj in inv_objs:

                inv_obj.cache_active = False

                log.debug('marking %s key for invalidation based on key=%s,repo_name=%s'

                  % (inv_obj, key, safe_str(repo_name)))

                invalidated_keys.append(inv_obj.cache_key)

                Session().add(inv_obj)

            Session().commit()

        except Exception:

            log.error(traceback.format_exc())

            Session().rollback()

        return invalidated_keys

    @classmethod

    def set_valid(cls, cache_key):

        """

        Mark this cache key as active and currently cached

        """

        inv_obj = cls.query().filter(cls.cache_key == cache_key).scalar()

        inv_obj.cache_active = True

        Session().add(inv_obj)

        Session().commit()

    @classmethod

    def get_cache_map(cls):

        class cachemapdict(dict):

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

                self.fixkey = kwargs.pop('fixkey', False)

                super(cachemapdict, self).__init__(*args, **kwargs)

            def __getattr__(self, name):

                cache_key = name

                if self.fixkey:

                    cache_key = cls._get_cache_key(name)

                if cache_key in self.__dict__:

                    return self.__dict__[cache_key]

                else:

                    return self[cache_key]

            def __getitem__(self, name):

                cache_key = name

                if self.fixkey:

                    cache_key = cls._get_cache_key(name)

                try:

                    return super(cachemapdict, self).__getitem__(cache_key)

                except KeyError:

                    return None

        cache_map = cachemapdict(fixkey=True)

        for obj in cls.query().all():

            cache_map[obj.cache_key] = cachemapdict(obj.get_dict())

        return cache_map

class ChangesetComment(Base, BaseModel):

    __tablename__ = 'changeset_comments'

    __table_args__ = (

        Index('cc_revision_idx', 'revision'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    comment_id = Column('comment_id', Integer(), nullable=False, primary_key=True)

    repo_id = Column('repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    revision = Column('revision', String(40), nullable=True)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=True)

    line_no = Column('line_no', Unicode(10), nullable=True)

    hl_lines = Column('hl_lines', Unicode(512), nullable=True)

    f_path = Column('f_path', Unicode(1000), nullable=True)

    user_id = Column('user_id', Integer(), ForeignKey('users.user_id'), nullable=False)

    text = Column('text', UnicodeText(25000), nullable=False)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    modified_at = Column('modified_at', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    author = relationship('User', lazy='joined')

    repo = relationship('Repository')

    status_change = relationship('ChangesetStatus', cascade="all, delete, delete-orphan")

    pull_request = relationship('PullRequest', lazy='joined')

    @classmethod

    def get_users(cls, revision=None, pull_request_id=None):

        """

        Returns user associated with this ChangesetComment. ie those

        who actually commented

        :param cls:

        :param revision:

        """

        q = Session().query(User)\

                .join(ChangesetComment.author)

        if revision:

            q = q.filter(cls.revision == revision)

        elif pull_request_id:

            q = q.filter(cls.pull_request_id == pull_request_id)

        return q.all()

class ChangesetStatus(Base, BaseModel):

    __tablename__ = 'changeset_statuses'

    __table_args__ = (

        Index('cs_revision_idx', 'revision'),

        Index('cs_version_idx', 'version'),

        UniqueConstraint('repo_id', 'revision', 'version'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    STATUS_NOT_REVIEWED = DEFAULT = 'not_reviewed'

    STATUS_APPROVED = 'approved'

    STATUS_REJECTED = 'rejected'

    STATUS_UNDER_REVIEW = 'under_review'

    STATUSES = [

        (STATUS_NOT_REVIEWED, _("Not Reviewed")),  # (no icon) and default

        (STATUS_APPROVED, _("Approved")),

        (STATUS_REJECTED, _("Rejected")),

        (STATUS_UNDER_REVIEW, _("Under Review")),

    ]

    changeset_status_id = Column('changeset_status_id', Integer(), nullable=False, primary_key=True)

    repo_id = Column('repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None)

    revision = Column('revision', String(40), nullable=False)

    status = Column('status', String(128), nullable=False, default=DEFAULT)

    changeset_comment_id = Column('changeset_comment_id', Integer(), ForeignKey('changeset_comments.comment_id'))

    modified_at = Column('modified_at', DateTime(), nullable=False, default=datetime.datetime.now)

    version = Column('version', Integer(), nullable=False, default=0)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=True)

    author = relationship('User', lazy='joined')

    repo = relationship('Repository')

    comment = relationship('ChangesetComment', lazy='joined')

    pull_request = relationship('PullRequest', lazy='joined')

    def __unicode__(self):

        return u"<%s('%s:%s')>" % (

            self.__class__.__name__,

            self.status, self.author

        )

    @classmethod

    def get_status_lbl(cls, value):

        return dict(cls.STATUSES).get(value)

    @property

    def status_lbl(self):

        return ChangesetStatus.get_status_lbl(self.status)

class PullRequest(Base, BaseModel):

    __tablename__ = 'pull_requests'

    __table_args__ = (

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    STATUS_NEW = u'new'

    STATUS_OPEN = u'open'

    STATUS_CLOSED = u'closed'

    pull_request_id = Column('pull_request_id', Integer(), nullable=False, primary_key=True)

    title = Column('title', Unicode(256), nullable=True)

    description = Column('description', UnicodeText(10240), nullable=True)

    status = Column('status', Unicode(256), nullable=False, default=STATUS_NEW)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    updated_on = Column('updated_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None)

    _revisions = Column('revisions', UnicodeText(20500))  # 500 revisions max

    org_repo_id = Column('org_repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    org_ref = Column('org_ref', Unicode(256), nullable=False)

    other_repo_id = Column('other_repo_id', Integer(), ForeignKey('repositories.repo_id'), nullable=False)

    other_ref = Column('other_ref', Unicode(256), nullable=False)

    @hybrid_property

    def revisions(self):

        return self._revisions.split(':')

    @revisions.setter

    def revisions(self, val):

        self._revisions = ':'.join(val)

    @property

    def org_ref_parts(self):

        return self.org_ref.split(':')

    @property

    def other_ref_parts(self):

        return self.other_ref.split(':')

    author = relationship('User', lazy='joined')

    reviewers = relationship('PullRequestReviewers',

                             cascade="all, delete, delete-orphan")

    org_repo = relationship('Repository', primaryjoin='PullRequest.org_repo_id==Repository.repo_id')

    other_repo = relationship('Repository', primaryjoin='PullRequest.other_repo_id==Repository.repo_id')

    statuses = relationship('ChangesetStatus')

    comments = relationship('ChangesetComment',

                             cascade="all, delete, delete-orphan")

    def is_closed(self):

        return self.status == self.STATUS_CLOSED

    @property

    def last_review_status(self):

        return self.statuses[-1].status if self.statuses else ''

    def __json__(self):

        return dict(

          revisions=self.revisions

        )

class PullRequestReviewers(Base, BaseModel):

    __tablename__ = 'pull_request_reviewers'

    __table_args__ = (

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    def __init__(self, user=None, pull_request=None):

        self.user = user

        self.pull_request = pull_request

    pull_requests_reviewers_id = Column('pull_requests_reviewers_id', Integer(), nullable=False, primary_key=True)

    pull_request_id = Column("pull_request_id", Integer(), ForeignKey('pull_requests.pull_request_id'), nullable=False)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=True)

    user = relationship('User')

    pull_request = relationship('PullRequest')

class Notification(Base, BaseModel):

    __tablename__ = 'notifications'

    __table_args__ = (

        Index('notification_type_idx', 'type'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    TYPE_CHANGESET_COMMENT = u'cs_comment'

    TYPE_MESSAGE = u'message'

    TYPE_MENTION = u'mention'

    TYPE_REGISTRATION = u'registration'

    TYPE_PULL_REQUEST = u'pull_request'

    TYPE_PULL_REQUEST_COMMENT = u'pull_request_comment'

    notification_id = Column('notification_id', Integer(), nullable=False, primary_key=True)

    subject = Column('subject', Unicode(512), nullable=True)

    body = Column('body', UnicodeText(50000), nullable=True)

    created_by = Column("created_by", Integer(), ForeignKey('users.user_id'), nullable=True)

    created_on = Column('created_on', DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    type_ = Column('type', Unicode(256))

    created_by_user = relationship('User')

    notifications_to_users = relationship('UserNotification', lazy='joined',

                                          cascade="all, delete, delete-orphan")

    @property

    def recipients(self):

        return [x.user for x in UserNotification.query()\

                .filter(UserNotification.notification == self)\

                .order_by(UserNotification.user_id.asc()).all()]

    @classmethod

    def create(cls, created_by, subject, body, recipients, type_=None):

        if type_ is None:

            type_ = Notification.TYPE_MESSAGE

        notification = cls()

        notification.created_by_user = created_by

        notification.subject = subject

        notification.body = body

        notification.type_ = type_

        notification.created_on = datetime.datetime.now()

        for u in recipients:

            assoc = UserNotification()

            assoc.notification = notification

            u.notifications.append(assoc)

        Session().add(notification)

        return notification

    @property

    def description(self):

        from rhodecode.model.notification import NotificationModel

        return NotificationModel().make_description(self)

class UserNotification(Base, BaseModel):

    __tablename__ = 'user_to_notification'

    __table_args__ = (

        UniqueConstraint('user_id', 'notification_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    user_id = Column('user_id', Integer(), ForeignKey('users.user_id'), primary_key=True)

    notification_id = Column("notification_id", Integer(), ForeignKey('notifications.notification_id'), primary_key=True)

    read = Column('read', Boolean, default=False)

    sent_on = Column('sent_on', DateTime(timezone=False), nullable=True, unique=None)

    user = relationship('User', lazy="joined")

    notification = relationship('Notification', lazy="joined",

                                order_by=lambda: Notification.created_on.desc(),)

    def mark_as_read(self):

        self.read = True

        Session().add(self)

class DbMigrateVersion(Base, BaseModel):

    __tablename__ = 'db_migrate_version'

    __table_args__ = (

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'},

    )

    repository_id = Column('repository_id', String(250), primary_key=True)

    repository_path = Column('repository_path', Text)

    version = Column('version', Integer)