import clickreviews
import imp
import inspect
import os
import pkgutil

IRRELEVANT_MODULES = ['cr_common', 'cr_tests', 'cr_skeleton',
                      'sr_common', 'sr_tests', 'sr_skeleton',
                      'common']


def narrow_down_modules(modules):
    '''
    Get a list of file names or module names and filter out
    the ones we know are irrelevant.
    '''
    relevant_modules = []
    for module in modules:
        module_name = os.path.basename(module).replace('.py', '')
        if module_name not in IRRELEVANT_MODULES and \
                (module_name.startswith('cr_') or
                 module_name.startswith('sr_')):
            relevant_modules += [module]
    return relevant_modules


def get_modules():
    '''
    Here we have a look at all the modules in the
    clickreviews package and filter out a few which
    are not relevant.

    Basically we look at all the ones which are
    derived from [cs]r_common, where we can later on
    instantiate a *Review* object and run the
    necessary checks.
    '''

    all_modules = [name for _, name, _ in
                   pkgutil.iter_modules(clickreviews.__path__)]
    return narrow_down_modules(all_modules)


def find_main_class(module_name):
    '''
    This function will find the Click*Review class in
    the specified module.
    '''
    module = imp.load_source(module_name,
                             '%s/%s.py' % (clickreviews.__path__[0],
                                           module_name))

    classes = inspect.getmembers(module, inspect.isclass)

    def find_test_class(a):
        return (a[0].startswith('Click') or a[0].startswith('Snap')) and \
            not a[0].endswith('Exception') and \
            a[1].__module__ == module_name
    test_class = list(filter(find_test_class, classes))
    if not test_class:
        return None
    init_object = getattr(module, test_class[0][0])
    return init_object


def init_main_class(module_name, click_file, overrides=None):
    '''
    This function will instantiate the main Click*Review
    class of a given module and instantiate it with the
    location of the .click file we want to inspect.
    '''

    init_object = find_main_class(module_name)
    if not init_object:
        return None
    try:
        ob = init_object(click_file, overrides)
    except TypeError as e:
        print('Could not init %s: %s' % (init_object, str(e)))
        return None
    return ob
