"""Contains library functions"""
import os
from git.test.lib import (
    TestBase,
    GlobalsItemDeletorMetaCls
)
import shutil
import tempfile

from git import Repo

#{ Invvariants
k_env_git_repo = "GIT_PYTHON_TEST_GIT_REPO_BASE"
#} END invariants


#{ Utilities
def resolve_or_fail(env_var):
    """:return: resolved environment variable or raise EnvironmentError"""
    try:
        return os.environ[env_var]
    except KeyError:
        raise EnvironmentError("Please set the %r envrionment variable and retry" % env_var)
    # END exception handling

#} END utilities


#{ Base Classes

class TestBigRepoR(TestBase):

    """TestCase providing access to readonly 'big' repositories using the following 
    member variables:

    * gitrorepo

     * a big read-only git repository
    """

    #{ Invariants
    head_sha_2k = '235d521da60e4699e5bd59ac658b5b48bd76ddca'
    head_sha_50 = '32347c375250fd470973a5d76185cac718955fd5'
    #} END invariants

    #{ Configuration
    RepoCls = Repo
    #} END configuration

    @classmethod
    def setUp(cls):
        super(TestBigRepoR, cls).setUp()
        if cls.RepoCls is None:
            raise AssertionError("Require RepoCls in class %s to be set" % cls)
        # END assert configuration
        cls.rorepo = cls.RepoCls(resolve_or_fail(k_env_git_repo))


class TestBigRepoRW(TestBigRepoR):

    """As above, but provides a big repository that we can write to.

    Provides ``self.rwrepo``"""

    @classmethod
    def setUp(cls):
        super(TestBigRepoRW, cls).setUp()
        dirname = tempfile.mktemp()
        os.mkdir(dirname)
        cls.rwrepo = cls.rorepo.clone(dirname, shared=True, bare=True)

    @classmethod
    def tearDownAll(cls):
        shutil.rmtree(cls.rwrepo.working_dir)

#} END base classes