# coding: utf-8
from __future__ import absolute_import, division, print_function, unicode_literals

from abc import ABCMeta, abstractmethod
from contextlib import contextmanager

from six import add_metaclass


@add_metaclass(ABCMeta)
class BaseRepository(object):
    def clear_caches(self):
        """Should clear any caches used by the implementation."""

    def freshen_build_caches(self):
        """Should start with fresh build/source caches."""

    @abstractmethod
    def find_best_match(self, ireq):
        """
        Return a Version object that indicates the best match for the given
        InstallRequirement according to the repository.
        """

    @abstractmethod
    def get_dependencies(self, ireq):
        """
        Given a pinned, URL, or editable InstallRequirement, returns a set of
        dependencies (also InstallRequirements, but not necessarily pinned).
        They indicate the secondary dependencies for the given requirement.
        """

    @abstractmethod
    def get_hashes(self, ireq):
        """
        Given a pinned InstallRequire, returns a set of hashes that represent
        all of the files for a given requirement. It is not acceptable for an
        editable or unpinned requirement to be passed to this function.
        """

    @abstractmethod
    @contextmanager
    def allow_all_wheels(self):
        """
        Monkey patches pip.Wheel to allow wheels from all platforms and Python versions.
        """

    @abstractmethod
    def copy_ireq_dependencies(self, source, dest):
        """
        Notifies the repository that `dest` is a copy of `source`, and so it
        has the same dependencies. Otherwise, once we prepare an ireq to assign
        it its name, we would lose track of those dependencies on combining
        that ireq with others.
        """