class ScmModel(BaseModel):

    """

    Generic Scm Model

    """

    def __get_repo(self, instance):

        cls = Repository

        if isinstance(instance, cls):

            return instance

        elif isinstance(instance, int) or safe_str(instance).isdigit():

            return cls.get(instance)

        elif isinstance(instance, basestring):

            return cls.get_by_repo_name(instance)

        elif instance:

            raise Exception('given object must be int, basestr or Instance'

                            ' of %s got %s' % (type(cls), type(instance)))

    @LazyProperty

    def repos_path(self):

        """

        Get's the repositories root path from database

        """

        q = self.sa.query(RhodeCodeUi).filter(RhodeCodeUi.ui_key == '/').one()

        return q.ui_value

    def repo_scan(self, repos_path=None):

        """

        Listing of repositories in given path. This path should not be a

        repository itself. Return a dictionary of repository objects

        :param repos_path: path to directory containing repositories

        """

        if repos_path is None:

            repos_path = self.repos_path

        log.info('scanning for repositories in %s' % repos_path)

        baseui = make_ui('db')

        repos = {}

        for name, path in get_filesystem_repos(repos_path, recursive=True):

            # name need to be decomposed and put back together using the /

            # since this is internal storage separator for rhodecode

            name = Repository.normalize_repo_name(name)

            try:

                if name in repos:

                    raise RepositoryError('Duplicate repository name %s '

                                          'found in %s' % (name, path))

                else:

                    klass = get_backend(path[0])

                    if path[0] == 'hg' and path[0] in BACKENDS.keys():

                        repos[name] = klass(safe_str(path[1]), baseui=baseui)

                    if path[0] == 'git' and path[0] in BACKENDS.keys():

                        repos[name] = klass(path[1])

            except OSError:

                continue

        log.debug('found %s paths with repositories' % (len(repos)))

        return repos

    def get_repos(self, all_repos=None, sort_key=None, simple=False):

        """

        Get all repos from db and for each repo create it's

        backend instance and fill that backed with information from database

        :param all_repos: list of repository names as strings

            give specific repositories list, good for filtering

        :param sort_key: initial sorting of repos

        :param simple: use SimpleCachedList - one without the SCM info

        """

        if all_repos is None:

            all_repos = self.sa.query(Repository)\

                        .filter(Repository.group_id == None)\

                        .order_by(func.lower(Repository.repo_name)).all()

        if simple:

            repo_iter = SimpleCachedRepoList(all_repos,

                                             repos_path=self.repos_path,

                                             order_by=sort_key)

        else:

            repo_iter = CachedRepoList(all_repos,

                                       repos_path=self.repos_path,

                                       order_by=sort_key)

        return repo_iter

    def get_repos_groups(self, all_groups=None):

        if all_groups is None:

            all_groups = RepoGroup.query()\

                .filter(RepoGroup.group_parent_id == None).all()

    def mark_for_invalidation(self, repo_name):

        """

        Puts cache invalidation task into db for

        further global cache invalidation

        :param repo_name: this repo that should invalidation take place

        """

        invalidated_keys = CacheInvalidation.set_invalidate(repo_name=repo_name)

        repo = Repository.get_by_repo_name(repo_name)

        if repo:

            repo.update_changeset_cache()

        return invalidated_keys

    def toggle_following_repo(self, follow_repo_id, user_id):

        f = self.sa.query(UserFollowing)\

            .filter(UserFollowing.follows_repo_id == follow_repo_id)\

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                self.sa.delete(f)

                action_logger(UserTemp(user_id),

                              'stopped_following_repo',

                              RepoTemp(follow_repo_id))

                return

            except:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_repo_id = follow_repo_id

            self.sa.add(f)

            action_logger(UserTemp(user_id),

                          'started_following_repo',

                          RepoTemp(follow_repo_id))

        except:

            log.error(traceback.format_exc())

            raise

    def toggle_following_user(self, follow_user_id, user_id):

        f = self.sa.query(UserFollowing)\

            .filter(UserFollowing.follows_user_id == follow_user_id)\

            .filter(UserFollowing.user_id == user_id).scalar()

        if f is not None:

            try:

                self.sa.delete(f)

                return

            except:

                log.error(traceback.format_exc())

                raise

        try:

            f = UserFollowing()

            f.user_id = user_id

            f.follows_user_id = follow_user_id

            self.sa.add(f)

        except:

            log.error(traceback.format_exc())

            raise

    def is_following_repo(self, repo_name, user_id, cache=False):

        r = self.sa.query(Repository)\

            .filter(Repository.repo_name == repo_name).scalar()

        f = self.sa.query(UserFollowing)\

            .filter(UserFollowing.follows_repository == r)\

            .filter(UserFollowing.user_id == user_id).scalar()

        return f is not None

    def is_following_user(self, username, user_id, cache=False):

        u = User.get_by_username(username)

        f = self.sa.query(UserFollowing)\

            .filter(UserFollowing.follows_user == u)\

            .filter(UserFollowing.user_id == user_id).scalar()

        return f is not None

    def get_followers(self, repo):

        repo = self._get_repo(repo)

        return self.sa.query(UserFollowing)\

                .filter(UserFollowing.follows_repository == repo).count()

    def get_forks(self, repo):

        repo = self._get_repo(repo)

        return self.sa.query(Repository)\

                .filter(Repository.fork == repo).count()