#
#  Copyright (C) 2018 Bloomberg LP
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU Lesser General Public
#  License as published by the Free Software Foundation; either
#  version 2 of the License, or (at your option) any later version.
#
#  This library is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
#  Lesser General Public License for more details.
#
#  You should have received a copy of the GNU Lesser General Public
#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
#
#  Authors:
#        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>
#        Jim MacArthur <jim.macarthur@codethink.co.uk>

"""
Foundation types
================

"""

from enum import Enum


class Scope(Enum):
    """Defines the scope of dependencies to include for a given element
    when iterating over the dependency graph in APIs like
    :func:`Element.dependencies() <buildstream.element.Element.dependencies>`
    """

    ALL = 1
    """All elements which the given element depends on, following
    all elements required for building. Including the element itself.
    """

    BUILD = 2
    """All elements required for building the element, including their
    respective run dependencies. Not including the given element itself.
    """

    RUN = 3
    """All elements required for running the element. Including the element
    itself.
    """


class Consistency():
    """Defines the various consistency states of a :class:`.Source`.
    """

    INCONSISTENT = 0
    """Inconsistent

    Inconsistent sources have no explicit reference set. They cannot
    produce a cache key, be fetched or staged. They can only be tracked.
    """

    RESOLVED = 1
    """Resolved

    Resolved sources have a reference and can produce a cache key and
    be fetched, however they cannot be staged.
    """

    CACHED = 2
    """Cached

    Cached sources have a reference which is present in the local
    source cache. Only cached sources can be staged.
    """


# _KeyStrength():
#
# Strength of cache key
#
class _KeyStrength(Enum):

    # Includes strong cache keys of all build dependencies and their
    # runtime dependencies.
    STRONG = 1

    # Includes names of direct build dependencies but does not include
    # cache keys of dependencies.
    WEAK = 2