from json import dumps, loads
import re

from oauthlib.common import to_unicode


def plentymarkets_compliance_fix(session):

    def _to_snake_case(n):
        return re.sub('(.)([A-Z][a-z]+)', r'\1_\2', n).lower()

    def _compliance_fix(r):
        # Plenty returns the Token in CamelCase instead of _
        if 'application/json' in r.headers.get('content-type', {}) and r.status_code == 200:
            token = loads(r.text)
        else:
            return r

        fixed_token = {}
        for k, v in token.items():
            fixed_token[_to_snake_case(k)] = v

        r._content = to_unicode(dumps(fixed_token)).encode('UTF-8')
        return r

    session.register_compliance_hook('access_token_response', _compliance_fix)
    return session