import argparse

import sys

import subprocess

def parse_config_settings_args(config_settings):

    """

    Given a list of config `KEY=VALUE` formatted config settings,

    return a dictionary that can be passed to PEP 517 hook functions.

    """

    if not config_settings:

        return config_settings

    new_config_settings = {}

    for arg in config_settings:

        key, _, value = arg.partition('=')

        if key in new_config_settings:

            if not isinstance(new_config_settings[key], list):

                # convert the existing value to a list

                new_config_settings[key] = [new_config_settings[key]]

            new_config_settings[key].append(value)

        else:

            new_config_settings[key] = value

    return new_config_settings

def get_config_settings_args(config_settings):

    """

    Given a dictionary of PEP 517 backend config_settings,

    yield --config-settings args that can be passed to pip's CLI

    """

    if not config_settings:

        return

    for key, values in config_settings.items():

        if not isinstance(values, list):

            values = [values]

        for value in values:

            if value == '':

                yield f'--config-settings={key}'

            else:

                yield f'--config-settings={key}={value}'

def build_wheel(*, wheeldir, stdout=None, config_settings=None):

    command = (

        sys.executable,

        '-m', 'pip',

        'wheel',

        '--wheel-dir', wheeldir,

        '--no-deps',

        '--use-pep517',

        '--no-build-isolation',

        '--disable-pip-version-check',

        '--no-clean',

        '--progress-bar', 'off',

        '--verbose',

        *get_config_settings_args(config_settings),

        '.',

    )

    cp = subprocess.run(command, stdout=stdout)

    return cp.returncode

def parse_args(argv=None):

    parser = argparse.ArgumentParser(prog='%pyproject_wheel')

    parser.add_argument('wheeldir', help=argparse.SUPPRESS)

    parser.add_argument(

        '-C',

        dest='config_settings',

        action='append',

        help='Configuration settings to pass to the PEP 517 backend',

    )

    args = parser.parse_args(argv)

    args.config_settings = parse_config_settings_args(args.config_settings)

    return args

if __name__ == '__main__':

    sys.exit(build_wheel(**vars(parse_args())))