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:
            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]