# Copyright (C) 2020-2021  The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU Affero General Public License version 3, or any later version
# See top-level LICENSE file for more information

import json
from urllib.parse import urljoin, urlparse
import uuid

import pytest

from django.conf import settings
from django.http import QueryDict

from swh.auth.keycloak import KeycloakError
from swh.web.auth.models import OIDCUserOfflineTokens
from swh.web.auth.utils import decrypt_data
from swh.web.config import get_config
from swh.web.tests.django_asserts import assert_contains
from swh.web.tests.helpers import (
    check_html_get_response,
    check_http_get_response,
    check_http_post_response,
)
from swh.web.utils import reverse
from swh.web.webapp.urls import default_view as homepage_view


def _check_oidc_login_code_flow_data(
    request, response, keycloak_oidc, redirect_uri, scope="openid"
):
    parsed_url = urlparse(response["location"])

    authorization_url = keycloak_oidc.well_known()["authorization_endpoint"]
    query_dict = QueryDict(parsed_url.query)

    # check redirect url is valid
    assert urljoin(response["location"], parsed_url.path) == authorization_url
    assert "client_id" in query_dict
    assert query_dict["client_id"] == settings.OIDC_SWH_WEB_CLIENT_ID
    assert "response_type" in query_dict
    assert query_dict["response_type"] == "code"
    assert "redirect_uri" in query_dict
    assert query_dict["redirect_uri"] == redirect_uri
    assert "code_challenge_method" in query_dict
    assert query_dict["code_challenge_method"] == "S256"
    assert "scope" in query_dict
    assert query_dict["scope"] == scope
    assert "state" in query_dict
    assert "code_challenge" in query_dict

    # check a login_data has been registered in user session
    assert "login_data" in request.session
    login_data = request.session["login_data"]
    assert "code_verifier" in login_data
    assert "state" in login_data
    assert "redirect_uri" in login_data
    assert login_data["redirect_uri"] == query_dict["redirect_uri"]
    return login_data


def test_view_rendering_when_user_not_set_in_request(request_factory):
    request = request_factory.get("/")
    # Django RequestFactory do not set any user by default
    assert not hasattr(request, "user")

    response = homepage_view(request)
    assert response.status_code == 200


def test_oidc_generate_bearer_token_anonymous_user(client):
    """
    Anonymous user should be refused access with forbidden response.
    """
    url = reverse("oidc-generate-bearer-token")
    check_http_get_response(client, url, status_code=403)


def _generate_and_test_bearer_token(client, kc_oidc_mock):
    # user authenticates
    client.login(
        code="code", code_verifier="code-verifier", redirect_uri="redirect-uri"
    )
    # user initiates bearer token generation flow
    url = reverse("oidc-generate-bearer-token")
    response = check_http_get_response(client, url, status_code=302)
    request = response.wsgi_request
    redirect_uri = reverse("oidc-generate-bearer-token-complete", request=request)
    # check login data and redirection to Keycloak is valid
    login_data = _check_oidc_login_code_flow_data(
        request,
        response,
        kc_oidc_mock,
        redirect_uri=redirect_uri,
        scope="openid offline_access",
    )

    # once a user has identified himself in Keycloak, he is
    # redirected to the 'oidc-generate-bearer-token-complete' view
    # to get and save bearer token

    # generate authorization code / session state in the same
    # manner as Keycloak
    code = f"{str(uuid.uuid4())}.{str(uuid.uuid4())}.{str(uuid.uuid4())}"
    session_state = str(uuid.uuid4())

    token_complete_url = reverse(
        "oidc-generate-bearer-token-complete",
        query_params={
            "code": code,
            "state": login_data["state"],
            "session_state": session_state,
        },
    )

    nb_tokens = len(OIDCUserOfflineTokens.objects.all())
    response = check_http_get_response(client, token_complete_url, status_code=302)
    request = response.wsgi_request

    # check token has been generated and saved encrypted to database
    assert len(OIDCUserOfflineTokens.objects.all()) == nb_tokens + 1
    encrypted_token = OIDCUserOfflineTokens.objects.last().offline_token.tobytes()
    secret = get_config()["secret_key"].encode()
    salt = request.user.sub.encode()
    decrypted_token = decrypt_data(encrypted_token, secret, salt)
    oidc_profile = kc_oidc_mock.authorization_code(code=code, redirect_uri=redirect_uri)
    assert decrypted_token.decode("ascii") == oidc_profile["refresh_token"]

    # should redirect to tokens management Web UI
    assert response["location"] == reverse("oidc-profile") + "#tokens"

    return decrypted_token


@pytest.mark.django_db(transaction=True, reset_sequences=True)
def test_oidc_generate_bearer_token_authenticated_user_success(client, keycloak_oidc):
    """
    Authenticated user should be able to generate a bearer token using OIDC
    Authorization Code Flow.
    """
    _generate_and_test_bearer_token(client, keycloak_oidc)


def test_oidc_list_bearer_tokens_anonymous_user(client):
    """
    Anonymous user should be refused access with forbidden response.
    """
    url = reverse(
        "oidc-list-bearer-tokens", query_params={"draw": 1, "start": 0, "length": 10}
    )
    check_http_get_response(client, url, status_code=403)


@pytest.mark.django_db(transaction=True, reset_sequences=True)
def test_oidc_list_bearer_tokens(client, keycloak_oidc):
    """
    User with correct credentials should be allowed to list his tokens.
    """
    nb_tokens = 3

    for _ in range(nb_tokens):
        _generate_and_test_bearer_token(client, keycloak_oidc)

    url = reverse(
        "oidc-list-bearer-tokens", query_params={"draw": 1, "start": 0, "length": 10}
    )

    response = check_http_get_response(client, url, status_code=200)
    tokens_data = list(reversed(json.loads(response.content.decode("utf-8"))["data"]))

    for oidc_token in OIDCUserOfflineTokens.objects.all():
        assert (
            oidc_token.creation_date.isoformat()
            == tokens_data[oidc_token.id - 1]["creation_date"]
        )


def test_oidc_get_bearer_token_anonymous_user(client):
    """
    Anonymous user should be refused access with forbidden response.
    """
    url = reverse("oidc-get-bearer-token")
    check_http_post_response(client, url, status_code=403)


@pytest.mark.django_db(transaction=True, reset_sequences=True)
def test_oidc_get_bearer_token(client, keycloak_oidc):
    """
    User with correct credentials should be allowed to display a token.
    """
    nb_tokens = 3

    for i in range(nb_tokens):
        token = _generate_and_test_bearer_token(client, keycloak_oidc)

        url = reverse("oidc-get-bearer-token")

        response = check_http_post_response(
            client,
            url,
            status_code=200,
            data={"token_id": i + 1},
            content_type="text/plain",
        )
        assert response.content == token


@pytest.mark.django_db(transaction=True, reset_sequences=True)
def test_oidc_get_bearer_token_expired_token(client, keycloak_oidc):
    """
    User with correct credentials should be allowed to display a token.
    """

    _generate_and_test_bearer_token(client, keycloak_oidc)

    for kc_err_msg in ("Offline session not active", "Offline user session not found"):

        kc_error_dict = {
            "error": "invalid_grant",
            "error_description": kc_err_msg,
        }

        keycloak_oidc.refresh_token.side_effect = KeycloakError(
            error_message=json.dumps(kc_error_dict).encode(), response_code=400
        )

        url = reverse("oidc-get-bearer-token")

        response = check_http_post_response(
            client,
            url,
            status_code=400,
            data={"token_id": 1},
            content_type="text/plain",
        )
        assert (
            response.content == b"Bearer token has expired, please generate a new one."
        )


def test_oidc_revoke_bearer_tokens_anonymous_user(client):
    """
    Anonymous user should be refused access with forbidden response.
    """
    url = reverse("oidc-revoke-bearer-tokens")
    check_http_post_response(client, url, status_code=403)


@pytest.mark.django_db(transaction=True, reset_sequences=True)
def test_oidc_revoke_bearer_tokens(client, keycloak_oidc):
    """
    User with correct credentials should be allowed to revoke tokens.
    """
    nb_tokens = 3

    for _ in range(nb_tokens):
        _generate_and_test_bearer_token(client, keycloak_oidc)

    url = reverse("oidc-revoke-bearer-tokens")

    check_http_post_response(
        client,
        url,
        status_code=200,
        data={"token_ids": [1]},
    )
    assert len(OIDCUserOfflineTokens.objects.all()) == 2

    check_http_post_response(
        client,
        url,
        status_code=200,
        data={"token_ids": [2, 3]},
    )
    assert len(OIDCUserOfflineTokens.objects.all()) == 0


def test_oidc_profile_view_anonymous_user(client):
    """
    Non authenticated users should be redirected to login page when
    requesting profile view.
    """
    url = reverse("oidc-profile")
    login_url = reverse("oidc-login", query_params={"next": url})
    resp = check_http_get_response(client, url, status_code=302)
    assert resp["location"] == login_url


@pytest.mark.django_db(transaction=True, reset_sequences=True)
def test_oidc_profile_view(client, keycloak_oidc):
    """
    Authenticated users should be able to request the profile page
    and link to Keycloak account UI should be present.
    """
    url = reverse("oidc-profile")
    kc_config = get_config()["keycloak"]
    client_permissions = ["perm1", "perm2"]
    keycloak_oidc.client_permissions = client_permissions
    client.login(code="", code_verifier="", redirect_uri="")
    resp = check_html_get_response(
        client, url, status_code=200, template_used="profile.html"
    )
    user = resp.wsgi_request.user
    kc_account_url = (
        f"{kc_config['server_url']}realms/{kc_config['realm_name']}/account/"
    )
    assert_contains(resp, kc_account_url)
    assert_contains(resp, user.username)
    assert_contains(resp, user.first_name)
    assert_contains(resp, user.last_name)
    assert_contains(resp, user.email)
    for perm in client_permissions:
        assert_contains(resp, perm)