"""
written by:     Lawrence McDaniel
                https://lawrencemcdaniel.com

date:           oct-2022

usage:          Abstract class implementation of BaseOAuth2 to handle the field 
                mapping and data converstions between the dict that WP Oauth 
                returns versus the dict that Open edX actually needs.
"""
from abc import abstractmethod
import json
from urllib.parse import urlencode
from urllib.request import urlopen
from social_core.backends.oauth import BaseOAuth2

from logging import getLogger
logger = getLogger(__name__)

VERBOSE_LOGGING = True
class StepwiseMathWPOAuth2(BaseOAuth2):
    """
    WP OAuth authentication backend customized for Open edX
    """

    # https://python-social-auth.readthedocs.io/en/latest/configuration/settings.html
    SOCIAL_AUTH_SANITIZE_REDIRECTS = True       # requires redirect domain to match the original initiating domain.
    ACCESS_TOKEN_METHOD = 'POST'

    # This is the string value that will appear in the LMS Django Admin
    # Third Party Authentication / Provider Configuration (OAuth)
    # setup page drop-down box titled, "Backend name:", just above
    # the "Client ID:" and "Client Secret:" fields.
    def name(self):
        return 'stepwisemath-oauth'

    # note: no slash at the end of the base url. Python Social Auth
    # might clean this up for you, but i'm not 100% certain of that.
    def BASE_URL(self):
        return "https://stepwisemath.ai"

    # the value of the scope separator is user-defined. Check the 
    # scopes field value for your oauth client in your wordpress host.
    # the wp-oauth default value for scopes is 'basic' but can be
    # changed to a list. example 'basic, email, profile'. This 
    # list can be delimited with commas, spaces, whatever.
    def SCOPE_SEPARATOR(self):
        return ","

    @property
    def base_url(self) -> str:
        return self.BASE_URL

    # override AUTHORIZATION_URL in parent class
    # see https://wp-oauth.com/docs/general/endpoints/
    @property
    def AUTHORIZATION_URL(self) -> str:
        return f"{self.base_url}/oauth/authorize"

    # overrides ACCESS_TOKEN_URL from parent class
    @property
    # see https://wp-oauth.com/docs/general/endpoints/
    def ACCESS_TOKEN_URL(self) -> str:
        return f"{self.base_url}/oauth/token"

    # overrides USER_QUERY from parent class
    # see https://wp-oauth.com/docs/general/endpoints/
    @property
    def USER_QUERY(self) -> str:
        return f"{self.base_url}/oauth/me"

    # overrides EXTRA_DATA from parent class
    # see https://python-social-auth.readthedocs.io/en/latest/backends/implementation.html
    @property
    def EXTRA_DATA(self) -> list:
        return [
            ('id', 'id'),
            ('username', 'username'),
            ('email', 'email'),
            ('first_name', 'first_name'),
            ('last_name', 'last_name'),
            ('fullname', 'fullname'),
            ('is_superuser', 'is_superuser'),
            ('is_staff', 'is_staff'),
            ('date_joined', 'date_joined'),
        ]

    # implementation of get_user_details()
    # see https://python-social-auth.readthedocs.io/en/latest/backends/implementation.html
    def get_user_details(self, response) -> dict:
        """Return user details from the WP account"""

        if type(response)==dict:
            if ('ID' not in response.keys()) or ('user_email' not in response.keys()):
                logger.info('get_user_details() -  response object lacks required keys. exiting.')
                return {}

        if VERBOSE_LOGGING:
            if not response:
                logger.info('get_user_details() -  response is missing. exiting.')
                return {}

            logger.info('get_user_details() -  start. response: {response}'.format(
                response=json.dumps(response, sort_keys=True, indent=4)
                ))

        # try to parse out the first and last names
        split_name = response.get('display_name', '').split()
        first_name = split_name[0] if len(split_name) > 0 else ''
        last_name = split_name[-1] if len(split_name) == 2 else ''

        # check for superuser / staff status
        user_roles = response.get('user_roles', [])        
        super_user = 'administrator' in user_roles
        is_staff = 'administrator' in user_roles

        user_details = {
            'id': int(response.get('ID'), 0),
            'username': response.get('user_email', ''),
            'wp_username': response.get('user_login', ''),
            'email': response.get('user_email', ''),
            'first_name': first_name,
            'last_name': last_name,
            'fullname': response.get('display_name', ''),
            'is_superuser': super_user,
            'is_staff': is_staff,
            'refresh_token': response.get('refresh_token', ''),
            'scope': response.get('scope', ''),
            'token_type': response.get('token_type', ''),
            'date_joined': response.get('user_registered', ''),
            'user_status': response.get('user_status', ''),
        }
        if VERBOSE_LOGGING:
            logger.info('get_user_details() -  complete. user_details: {user_details}'.format(
                user_details=json.dumps(user_details, sort_keys=True, indent=4)
                ))
        return user_details

    # implementation of user_data()
    # note that in the case of wp oauth, the response object returned by self.USER_QUERY
    # is the same as the response object passed to get_user_details().
    #
    # see https://python-social-auth.readthedocs.io/en/latest/backends/implementation.html
    def user_data(self, access_token, *args, **kwargs) -> dict:
        """Loads user data from service"""

        url = f'{self.USER_QUERY}?' + urlencode({
            'access_token': access_token
        })

        if VERBOSE_LOGGING:
            logger.info("user_data() url: {url}".format(url=url))

        try:
            response = json.loads(self.urlopen(url))
            user_details = self.get_user_details(response)
            return user_details
        except ValueError as e:
            logger.error('user_data() did not work: {err}'.format(err=e))
            return None

    # utility function. not part of psa.
    def urlopen(self, url):
        return urlopen(url).read().decode("utf-8")