import logging

from django.core.exceptions import ImproperlyConfigured
from oauth2_provider.contrib.rest_framework import TokenMatchesOASRequirements, OAuth2Authentication
from rest_framework.permissions import (
    IsAuthenticated, BasePermission
)

log = logging.getLogger("oauth2_provider")


class IsAuthenticatedOrTokenMatchesOASRequirements(TokenMatchesOASRequirements):
    def has_permission(self, request, view):
        is_authenticated = IsAuthenticated().has_permission(request, view)
        oauth2authenticated = False
        if is_authenticated:
            oauth2authenticated = isinstance(request.successful_authenticator, OAuth2Authentication)

        token_has_scope = TokenMatchesOASRequirements()
        return (is_authenticated and not oauth2authenticated) or token_has_scope.has_permission(request, view)


class ActionMatchesOASRequirements(BasePermission):
    def has_permission(self, request, view):
        token = request.auth

        if not token:
            return False

        if hasattr(token, "scope"):  # OAuth 2
            # {'get': 'retrieve', 'put': 'update', 'patch': 'partial_update', 'delete': 'destroy', 'head': 'retrieve'}

            required_action_scopes = self.get_required_action_scopes(request, view)

            action = request.action.upper()
            if action in required_action_scopes:
                log.debug(
                    "Required scopes actions to access resource: {0}".format(
                        required_action_scopes[action]
                    )
                )
                for alt in required_action_scopes[action]:
                    if token.is_valid(alt):
                        return True
                return False
            else:
                log.warning("no scope alternates defined for method {0}".format(m))
                return False

        assert False, (
            "ActionMatchesOASRequirements requires the"
            "`oauth2_provider.rest_framework.OAuth2Authentication` authentication "
            "class to be used."
        )

    def get_required_action_scopes(self, request, view):
        try:
            return getattr(view, "required_action_scopes")
        except AttributeError:
            raise ImproperlyConfigured(
                "ActionMatchesOASRequirements requires the view to"
                " define the required_action_scopes attribute"
            )


class IsAuthenticatedOrActionMatchesOASRequirements(ActionMatchesOASRequirements):
    def has_permission(self, request, view):
        is_authenticated = IsAuthenticated().has_permission(request, view)
        oauth2authenticated = False
        if is_authenticated:
            oauth2authenticated = isinstance(request.successful_authenticator, OAuth2Authentication)

        action_has_scope = ActionMatchesOASRequirements()
        return (is_authenticated and not oauth2authenticated) or action_has_scope.has_permission(request, view)