# -*- encoding: utf-8 -*-
from __future__ import unicode_literals
from datetime import datetime, timedelta
from django.contrib.auth import get_user_model
from django.test import RequestFactory, TestCase
from rest_framework.exceptions import AuthenticationFailed
from rest_framework_hmac.authentication import SignatureAuthentication
from . import settings
from .models import ApiKey
from hashlib import sha1
import hmac


class HMACTest(TestCase):
    def setUp(self):
        user_model = get_user_model()
        self.client = RequestFactory()
        self.user = user_model(
            username='robert',
            email='robert.kolner@gmail.com',
        )
        self.user.set_password('pass')
        self.user.save()

        key = ApiKey(name='Test Key', user=self.user)
        key.save()

        self.api_key = str(key.key)
        self.secret_key = str(key.secret)

    def test_post_form_passing_hmac_auth(self):
        """Ensure POSTing json over hmac auth with correct credentials passes"""
        data = {
            'uid': self.user.id,
            'email': 'not_testesen@test.com',
            'full_name': 'Leonidas'
        }
        self._send_request('put', '/', data)

    def test_send_expired(self):
        self._send_request('get', '/', send_expired=True)

    def _send_request(self, method, url, data=None, send_expired=False):
        timestamp = datetime.utcnow()
        if send_expired:
            timestamp -= timedelta(seconds=settings.EXPIRATION_TIME + 1)

        timestamp_string = timestamp.isoformat() + 'Z'
        signature_value = '(request-target): {0} {1}\nx-auth-timestamp: {2}\nx-auth-api-key: {3}'.format(
            method.lower(), url, timestamp_string, self.api_key
        )
        signature = hmac.new(self.secret_key, signature_value, sha1).hexdigest()

        headers = {
            settings.TIMESTAMP_HEADER: timestamp_string,
            settings.API_KEY_HEADER: self.api_key,
            settings.SIGNATURE_HEADER: 'signature {}'.format(signature)
        }
        request_data = self.client._encode_data(data, 'json')
        request = self.client.generic(
            method=method.upper(),
            path=url,
            data=request_data,
            content_type='application/json',
            **headers
        )

        authentication = SignatureAuthentication()
        try:
            user, token = authentication.authenticate(request)
            exc = None
        except AuthenticationFailed as e:
            user, token = None, None
            exc = e

        if send_expired:
            self.assertIsNone(user, "Expired token was accepted with for the user '{}' and key '{}'!".format(self.user, self.api_key))
        else:
            self.assertIsNotNone(user, "The user hasn't been authenticated! Error: " + str(exc))
            self.assertIsNotNone(token, "The user has been authenticated, but token wasn't returned! Error: " + str(exc))