import requests
from django.conf import settings
from django.utils.dateparse import parse_datetime
from datetime import timedelta

from oauth.models import OAuth2Token
from oauth.oauth_client import oauth, fetch_token
from users.licenses import get_license_dict, is_myskillbox_product, TEACHER_KEY
from users.models import License

from core.logger import get_logger

logger = get_logger(__name__)

VALID_PRODUCT_STATES = ["waiting", "paid", "completed", "shipped"]

licenses = get_license_dict()


class HepClientException(Exception):
    pass


class HepClientUnauthorizedException(Exception):
    pass


class HepClientNoTokenException(Exception):
    pass


class HepClient:
    def _call(self, url, token_dict, method="get", data=None):
        headers = {"accept": "application/json"}

        if method == "post":
            response = oauth.hep.post(url, json=data, token=token_dict, headers=headers)
        elif method == "get":
            response = oauth.hep.get(
                url, params=data, token=token_dict, headers=headers
            )
        elif method == "put":
            response = oauth.hep.put(url, data=data, token=token_dict, headers=headers)

        return self._handle_response(response)

    def _handle_response(self, response):
        if response.status_code == 401:
            raise HepClientUnauthorizedException(response.status_code, response.json())
        elif response.status_code != 200:
            logger.warning(
                f"Hepclient error: Received {response.status_code} {response.json()}"
            )
            raise HepClientException(response.status_code, response.json())

        return response

    def _get_valid_token(self, request, token_dict):
        if request is None and token_dict is None:
            raise HepClientNoTokenException

        if not token_dict:
            token_dict = fetch_token("", request)
            if not token_dict:
                raise HepClientNoTokenException

        if OAuth2Token.is_dict_expired(token_dict):
            refresh_data = self._refresh_token(token_dict)
            token, refresh_success = OAuth2Token.update_dict_with_refresh_data(
                refresh_data, token_dict["access_token"]
            )
            if not refresh_success:
                raise HepClientUnauthorizedException

            token_dict = token.to_token()

        return token_dict

    def _refresh_token(self, token_dict):
        data = {
            "grant_type": "refresh_token",
            "refresh_token": token_dict["refresh_token"],
            "client_id": settings.AUTHLIB_OAUTH_CLIENTS["hep"]["client_id"],
            "client_secret": settings.AUTHLIB_OAUTH_CLIENTS["hep"]["client_secret"],
            "scope": "",
        }

        response = requests.post(
            f'{settings.AUTHLIB_OAUTH_CLIENTS["hep"]["api_base_url"]}/oauth/token',
            json=data,
        )
        return self._handle_response(response).json()

    def is_email_verified(self, user_data):
        return user_data["email_verified_at"] is not None

    def user_details(self, request=None, token_dict=None):
        token_dict = self._get_valid_token(request, token_dict)
        response = self._call("api/auth/user", token_dict)
        return response.json()["data"]

    def logout(self, request=None, token_dict=None):
        token_dict = self._get_valid_token(request, token_dict)
        self._call("api/auth/logout", token_dict, method="post")
        return True

    def fetch_eorders(self, request=None, token_dict=None):
        token_dict = self._get_valid_token(request, token_dict)
        data = {
            "filters[product_type]": "eLehrmittel",
        }
        response = self._call("api/partners/users/orders/search", token_dict, data=data)
        return response.json()["data"]

    def active_myskillbox_product_for_customer(self, request=None, token_dict=None):
        eorders = self.fetch_eorders(request=request, token_dict=token_dict)

        myskillbox_products = self._extract_myskillbox_products(eorders)

        if len(myskillbox_products) == 0:
            return None
        else:
            return self._get_active_product(myskillbox_products)

    def redeem_coupon(self, coupon_code, customer_id, request=None, token_dict=None):
        token_dict = self._get_valid_token(request, token_dict)
        try:
            response = self._call(
                f"api/partners/users/{customer_id}/coupons/redeem",
                token_dict,
                method="post",
                data={"code": coupon_code},
            )
        except HepClientException:
            logger.warning("could not redeem")
            return None

        response_data = response.json()
        return response_data

    def _extract_myskillbox_products(self, eorders):
        products = []

        for eorder in eorders:
            if "items" not in eorder:
                continue

            status = eorder.get("status", "")

            for entry in eorder["items"]:
                product = self.entry_to_product(
                    entry, self._get_item_activation(eorder), status
                )

                if product:
                    products.append(product)

        return products

    def entry_to_product(self, entry, activation_date, status):
        isbn = entry["isbn"]
        if is_myskillbox_product(isbn) and activation_date:
            return {
                "raw": entry,
                "activated": activation_date,
                "status": status,
                "order_id": entry["id"],
                "license": licenses[isbn],
                "isbn": entry["isbn"],
            }

        return None

    def _get_item_activation(self, eorder):
        if "created_at" in eorder:
            return parse_datetime(eorder["created_at"])
        else:
            return None

    def _get_active_product(self, products):
        def filter_valid_products(product):
            if product["status"] not in VALID_PRODUCT_STATES:
                return False

            expiry_delta = product["activated"] + timedelta(
                product["license"]["duration"]
            )

            return License.is_product_active(expiry_delta, product["isbn"])

        active_products = list(filter(filter_valid_products, products))

        if len(active_products) == 0:
            return None
        elif len(active_products) == 1:
            return active_products[0]
        else:
            return self._select_from_teacher_products(active_products)

    def _select_from_teacher_products(self, active_products):
        # select first teacher product, as they are all valid it does not matter which one
        for product in active_products:
            if product["license"]["edition"] == TEACHER_KEY:
                return product

        # select a student product, as they are all valid it does not matter which one
        return active_products[0]