"""
Module providing backend independent mixin class. It requires that
InMemoryChangeset class is working properly at backend class.
"""
import os
import time
import datetime

from kallithea.lib import vcs
from kallithea.lib.vcs.nodes import FileNode

from kallithea.tests.vcs.conf import SCM_TESTS, get_new_dir


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 setup_class(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'])

    def setup_method(self, method):
        if getattr(self, 'recreate_repo_per_test', False):
            self.__class__.setup_class()


# 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())
    globals()[cls_name] = type(cls_name, (_BackendTestMixin,), attrs)