"""NOTE:  copied/adapted from SQLAlchemy master for backwards compatibility;
   this should be removable when Alembic targets SQLAlchemy 1.0.0.
"""

try:
    # installed by bootstrap.py
    import alembic_plugin_base as plugin_base
except ImportError:
    # assume we're a package, use traditional import
    from . import plugin_base

import sys

py3k = sys.version_info >= (3, 0)

import pytest
import argparse
import inspect
import collections
import itertools

try:
    import xdist  # noqa
    has_xdist = True
except ImportError:
    has_xdist = False


def pytest_addoption(parser):
    group = parser.getgroup("sqlalchemy")

    def make_option(name, **kw):
        callback_ = kw.pop("callback", None)
        if callback_:
            class CallableAction(argparse.Action):
                def __call__(self, parser, namespace,
                             values, option_string=None):
                    callback_(option_string, values, parser)
            kw["action"] = CallableAction

        group.addoption(name, **kw)

    plugin_base.setup_options(make_option)
    plugin_base.read_config()


def pytest_configure(config):
    if hasattr(config, "slaveinput"):
        plugin_base.restore_important_follower_config(config.slaveinput)
        plugin_base.configure_follower(
            config.slaveinput["follower_ident"]
        )

    plugin_base.pre_begin(config.option)

    coverage = bool(getattr(config.option, "cov_source", False))
    plugin_base.set_coverage_flag(coverage)


def pytest_sessionstart(session):
    plugin_base.post_begin()

if has_xdist:
    _follower_count = itertools.count(1)

    def pytest_configure_node(node):
        # the master for each node fills slaveinput dictionary
        # which pytest-xdist will transfer to the subprocess

        plugin_base.memoize_important_follower_config(node.slaveinput)

        node.slaveinput["follower_ident"] = "test_%s" % next(_follower_count)
        from alembic.testing import provision
        provision.create_follower_db(node.slaveinput["follower_ident"])

    def pytest_testnodedown(node, error):
        from alembic.testing import provision
        provision.drop_follower_db(node.slaveinput["follower_ident"])


def pytest_collection_modifyitems(session, config, items):
    # look for all those classes that specify __backend__ and
    # expand them out into per-database test cases.

    # this is much easier to do within pytest_pycollect_makeitem, however
    # pytest is iterating through cls.__dict__ as makeitem is
    # called which causes a "dictionary changed size" error on py3k.
    # I'd submit a pullreq for them to turn it into a list first, but
    # it's to suit the rather odd use case here which is that we are adding
    # new classes to a module on the fly.

    rebuilt_items = collections.defaultdict(list)
    items[:] = [
        item for item in
        items if isinstance(item.parent, pytest.Instance)]
    test_classes = set(item.parent for item in items)
    for test_class in test_classes:
        for sub_cls in plugin_base.generate_sub_tests(
                test_class.cls, test_class.parent.module):
            if sub_cls is not test_class.cls:
                list_ = rebuilt_items[test_class.cls]

                for inst in pytest.Class(
                        sub_cls.__name__,
                        parent=test_class.parent.parent).collect():
                    list_.extend(inst.collect())

    newitems = []
    for item in items:
        if item.parent.cls in rebuilt_items:
            newitems.extend(rebuilt_items[item.parent.cls])
            rebuilt_items[item.parent.cls][:] = []
        else:
            newitems.append(item)

    # seems like the functions attached to a test class aren't sorted already?
    # is that true and why's that? (when using unittest, they're sorted)
    items[:] = sorted(newitems, key=lambda item: (
        item.parent.parent.parent.name,
        item.parent.parent.name,
        item.name
    ))


def pytest_pycollect_makeitem(collector, name, obj):
    if inspect.isclass(obj) and plugin_base.want_class(obj):
        return pytest.Class(name, parent=collector)
    elif inspect.isfunction(obj) and \
            isinstance(collector, pytest.Instance) and \
            plugin_base.want_method(collector.cls, obj):
        return pytest.Function(name, parent=collector)
    else:
        return []

_current_class = None


def pytest_runtest_setup(item):
    # here we seem to get called only based on what we collected
    # in pytest_collection_modifyitems.   So to do class-based stuff
    # we have to tear that out.
    global _current_class

    if not isinstance(item, pytest.Function):
        return

    # ... so we're doing a little dance here to figure it out...
    if _current_class is None:
        class_setup(item.parent.parent)
        _current_class = item.parent.parent

        # this is needed for the class-level, to ensure that the
        # teardown runs after the class is completed with its own
        # class-level teardown...
        def finalize():
            global _current_class
            class_teardown(item.parent.parent)
            _current_class = None
        item.parent.parent.addfinalizer(finalize)

    test_setup(item)


def pytest_runtest_teardown(item):
    # ...but this works better as the hook here rather than
    # using a finalizer, as the finalizer seems to get in the way
    # of the test reporting failures correctly (you get a bunch of
    # py.test assertion stuff instead)
    test_teardown(item)


def test_setup(item):
    plugin_base.before_test(item, item.parent.module.__name__,
                            item.parent.cls, item.name)


def test_teardown(item):
    plugin_base.after_test(item)


def class_setup(item):
    plugin_base.start_test_class(item.cls)


def class_teardown(item):
    plugin_base.stop_test_class(item.cls)
