import importlib
import inspect
import itertools
import logging
import threading
import unittest

from .. import tools
from .common import TagsSelector, OdooSuite
from .runner import OdooTestResult


_logger = logging.getLogger(__name__)
def get_test_modules(module):
    """ Return a list of module for the addons potentially containing tests to
    feed unittest.TestLoader.loadTestsFromModule() """
    # Try to import the module
    results = _get_tests_modules('odoo.addons', module)

    try:
        importlib.import_module('odoo.upgrade.%s' % module)
    except ImportError:
        pass
    else:
        results += _get_tests_modules('odoo.upgrade', module)

    return results


def _get_tests_modules(path, module):
    modpath = '%s.%s' % (path, module)
    try:
        mod = importlib.import_module('.tests', modpath)
    except ImportError as e:  # will also catch subclass ModuleNotFoundError of P3.6
        # Hide ImportErrors on `tests` sub-module, but display other exceptions
        if e.name == modpath + '.tests' and e.msg.startswith('No module named'):
            return []
        _logger.exception('Can not `import %s`.', module)
        return []
    except Exception as e:
        _logger.exception('Can not `import %s`.', module)
        return []
    if hasattr(mod, 'fast_suite') or hasattr(mod, 'checks'):
        _logger.warning(
            "Found deprecated fast_suite or checks attribute in test module "
            "%s. These have no effect in or after version 8.0.",
            mod.__name__)

    result = [mod_obj for name, mod_obj in inspect.getmembers(mod, inspect.ismodule)
              if name.startswith('test_')]
    return result

def make_suite(module_names, position='at_install'):
    """ Creates a test suite for all the tests in the specified modules,
    filtered by the provided ``position`` and the current test tags

    :param list[str] module_names: modules to load tests from
    :param str position: "at_install" or "post_install"
    """
    config_tags = TagsSelector(tools.config['test_tags'])
    position_tag = TagsSelector(position)
    tests = (
        t
        for module_name in module_names
        for m in get_test_modules(module_name)
        for t in unwrap_suite(unittest.TestLoader().loadTestsFromModule(m))
        if position_tag.check(t) and config_tags.check(t)
    )
    return OdooSuite(sorted(tests, key=lambda t: t.test_sequence))

def run_suite(suite, module_name=None):
    # avoid dependency hell
    from ..modules import module
    module.current_test = module_name
    threading.currentThread().testing = True

    results = OdooTestResult()
    suite(results)

    threading.currentThread().testing = False
    module.current_test = None
    return results

def unwrap_suite(test):
    """
    Attempts to unpack testsuites (holding suites or cases) in order to
    generate a single stream of terminals (either test cases or customized
    test suites). These can then be checked for run/skip attributes
    individually.

    An alternative would be to use a variant of @unittest.skipIf with a state
    flag of some sort e.g. @unittest.skipIf(common.runstate != 'at_install'),
    but then things become weird with post_install as tests should *not* run
    by default there
    """
    if isinstance(test, unittest.TestCase):
        yield test
        return

    subtests = list(test)
    # custom test suite (no test cases)
    if not len(subtests):
        yield test
        return

    for item in itertools.chain.from_iterable(unwrap_suite(t) for t in subtests):
        yield item