# Copyright 2018 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import datetime
import json
import os

import mock
import pytest
from six.moves import http_client

from google.auth import _helpers
from google.auth import crypt
from google.auth import exceptions
from google.auth import impersonated_credentials
from google.auth import transport
from google.auth.impersonated_credentials import Credentials
from google.oauth2 import service_account

DATA_DIR = os.path.join(os.path.dirname(__file__), '', 'data')

with open(os.path.join(DATA_DIR, 'privatekey.pem'), 'rb') as fh:
    PRIVATE_KEY_BYTES = fh.read()

SERVICE_ACCOUNT_JSON_FILE = os.path.join(DATA_DIR, 'service_account.json')

with open(SERVICE_ACCOUNT_JSON_FILE, 'r') as fh:
    SERVICE_ACCOUNT_INFO = json.load(fh)

SIGNER = crypt.RSASigner.from_string(PRIVATE_KEY_BYTES, '1')
TOKEN_URI = 'https://example.com/oauth2/token'


@pytest.fixture
def mock_donor_credentials():
    with mock.patch('google.oauth2._client.jwt_grant', autospec=True) as grant:
        grant.return_value = (
            "source token",
            _helpers.utcnow() + datetime.timedelta(seconds=500),
            {})
        yield grant


class TestImpersonatedCredentials(object):

    SERVICE_ACCOUNT_EMAIL = 'service-account@example.com'
    TARGET_PRINCIPAL = 'impersonated@project.iam.gserviceaccount.com'
    TARGET_SCOPES = ['https://www.googleapis.com/auth/devstorage.read_only']
    DELEGATES = []
    LIFETIME = 3600
    SOURCE_CREDENTIALS = service_account.Credentials(
            SIGNER, SERVICE_ACCOUNT_EMAIL, TOKEN_URI)

    def make_credentials(self, lifetime=LIFETIME):
        return Credentials(
            source_credentials=self.SOURCE_CREDENTIALS,
            target_principal=self.TARGET_PRINCIPAL,
            target_scopes=self.TARGET_SCOPES,
            delegates=self.DELEGATES,
            lifetime=lifetime)

    def test_default_state(self):
        credentials = self.make_credentials()
        assert not credentials.valid
        assert credentials.expired

    def make_request(self, data, status=http_client.OK,
                     headers=None, side_effect=None):
        response = mock.create_autospec(transport.Response, instance=False)
        response.status = status
        response.data = _helpers.to_bytes(data)
        response.headers = headers or {}

        request = mock.create_autospec(transport.Request, instance=False)
        request.side_effect = side_effect
        request.return_value = response

        return request

    def test_refresh_success(self, mock_donor_credentials):
        credentials = self.make_credentials(lifetime=None)
        token = 'token'

        expire_time = (
            _helpers.utcnow().replace(microsecond=0) +
            datetime.timedelta(seconds=500)).isoformat('T') + 'Z'
        response_body = {
            "accessToken": token,
            "expireTime": expire_time
        }

        request = self.make_request(
            data=json.dumps(response_body),
            status=http_client.OK)

        credentials.refresh(request)

        assert credentials.valid
        assert not credentials.expired

    def test_refresh_failure_malformed_expire_time(
            self, mock_donor_credentials):
        credentials = self.make_credentials(lifetime=None)
        token = 'token'

        expire_time = (
            _helpers.utcnow() + datetime.timedelta(seconds=500)).isoformat('T')
        response_body = {
            "accessToken": token,
            "expireTime": expire_time
        }

        request = self.make_request(
            data=json.dumps(response_body),
            status=http_client.OK)

        with pytest.raises(exceptions.RefreshError) as excinfo:
            credentials.refresh(request)

        assert excinfo.match(impersonated_credentials._REFRESH_ERROR)

        assert not credentials.valid
        assert credentials.expired

    def test_refresh_failure_unauthorzed(self, mock_donor_credentials):
        credentials = self.make_credentials(lifetime=None)

        response_body = {
            "error": {
              "code": 403,
              "message": "The caller does not have permission",
              "status": "PERMISSION_DENIED"
            }
        }

        request = self.make_request(
            data=json.dumps(response_body),
            status=http_client.UNAUTHORIZED)

        with pytest.raises(exceptions.RefreshError) as excinfo:
            credentials.refresh(request)

        assert excinfo.match(impersonated_credentials._REFRESH_ERROR)

        assert not credentials.valid
        assert credentials.expired

    def test_refresh_failure_http_error(self, mock_donor_credentials):
        credentials = self.make_credentials(lifetime=None)

        response_body = {}

        request = self.make_request(
            data=json.dumps(response_body),
            status=http_client.HTTPException)

        with pytest.raises(exceptions.RefreshError) as excinfo:
            credentials.refresh(request)

        assert excinfo.match(impersonated_credentials._REFRESH_ERROR)

        assert not credentials.valid
        assert credentials.expired

    def test_expired(self):
        credentials = self.make_credentials(lifetime=None)
        assert credentials.expired