"""
Module providing backend independent mixin class. It requires that
InMemoryChangeset class is working properly at backend class.
"""
import os
import time
import shutil
import datetime
from kallithea.tests.vcs.conf import SCM_TESTS, get_new_dir

from kallithea.lib import vcs
from kallithea.lib.vcs.utils.compat import unittest
from kallithea.lib.vcs.nodes import FileNode


class BackendTestMixin(object):
    """
    This is a backend independent test case class which should be created
    with ``type`` method.

    It is required to set following attributes at subclass:

    - ``backend_alias``: alias of used backend (see ``vcs.BACKENDS``)
    - ``repo_path``: path to the repository which would be created for set of
      tests
    - ``recreate_repo_per_test``: If set to ``False``, repo would NOT be created
      before every single test. Defaults to ``True``.
    """
    recreate_repo_per_test = True

    @classmethod
    def get_backend(cls):
        return vcs.get_backend(cls.backend_alias)

    @classmethod
    def _get_commits(cls):
        commits = [
            {
                'message': u'Initial commit',
                'author': u'Joe Doe <joe.doe@example.com>',
                'date': datetime.datetime(2010, 1, 1, 20),
                'added': [
                    FileNode('foobar', content='Foobar'),
                    FileNode('foobar2', content='Foobar II'),
                    FileNode('foo/bar/baz', content='baz here!'),
                ],
            },
            {
                'message': u'Changes...',
                'author': u'Jane Doe <jane.doe@example.com>',
                'date': datetime.datetime(2010, 1, 1, 21),
                'added': [
                    FileNode('some/new.txt', content='news...'),
                ],
                'changed': [
                    FileNode('foobar', 'Foobar I'),
                ],
                'removed': [],
            },
        ]
        return commits

    @classmethod
    def setUpClass(cls):
        Backend = cls.get_backend()
        cls.backend_class = Backend
        cls.repo_path = get_new_dir(str(time.time()))
        cls.repo = Backend(cls.repo_path, create=True)
        cls.imc = cls.repo.in_memory_changeset
        cls.default_branch = cls.repo.DEFAULT_BRANCH_NAME

        for commit in cls._get_commits():
            for node in commit.get('added', []):
                cls.imc.add(FileNode(node.path, content=node.content))
            for node in commit.get('changed', []):
                cls.imc.change(FileNode(node.path, content=node.content))
            for node in commit.get('removed', []):
                cls.imc.remove(FileNode(node.path))

            cls.tip = cls.imc.commit(message=unicode(commit['message']),
                                     author=unicode(commit['author']),
                                     date=commit['date'])

    @classmethod
    def tearDownClass(cls):
        if not getattr(cls, 'recreate_repo_per_test', False) and \
            'VCS_REMOVE_TEST_DIRS' in os.environ:
            shutil.rmtree(cls.repo_path)

    def setUp(self):
        if getattr(self, 'recreate_repo_per_test', False):
            self.__class__.setUpClass()

    def tearDown(self):
        if getattr(self, 'recreate_repo_per_test', False) and \
            'VCS_REMOVE_TEST_DIRS' in os.environ:
            shutil.rmtree(self.repo_path)


# For each backend create test case class
for alias in SCM_TESTS:
    attrs = {
        'backend_alias': alias,
    }
    cls_name = ''.join(('%s base backend test' % alias).title().split())
    bases = (BackendTestMixin, unittest.TestCase)
    globals()[cls_name] = type(cls_name, bases, attrs)


if __name__ == '__main__':
    unittest.main()