
# OpenCDE - OpenCDE Python implementation
# Copyright (C) 2021 Prabhat Singh <singh01prabhat@gmail.com>
#
# This file is part of OpenCDE.
#
# OpenCDE is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# OpenCDE is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with OpenCDE.  If not, see <http://www.gnu.org/licenses/>.

from authlib.integrations.flask_oauth2 import (
    AuthorizationServer,
    ResourceProtector,
)
from authlib.integrations.sqla_oauth2 import (
    create_query_client_func,
    create_save_token_func,
    create_revocation_endpoint,
    create_bearer_token_validator,
)
from authlib.oauth2.rfc6749 import grants
from authlib.oauth2.rfc7636 import CodeChallenge
from .models import db, User
from .models import OAuth2Client, OAuth2AuthorizationCode, OAuth2Token


class AuthorizationCodeGrant(grants.AuthorizationCodeGrant):
    TOKEN_ENDPOINT_AUTH_METHODS = [
        "client_secret_basic",
        "client_secret_post",
        "none",
    ]

    def save_authorization_code(self, code, request):
        code_challenge = request.data.get("code_challenge")
        code_challenge_method = request.data.get("code_challenge_method")
        auth_code = OAuth2AuthorizationCode(
            code=code,
            client_id=request.client.client_id,
            redirect_uri=request.redirect_uri,
            scope=request.scope,
            user_id=request.user.id,
            code_challenge=code_challenge,
            code_challenge_method=code_challenge_method,
        )
        db.session.add(auth_code)
        db.session.commit()
        return auth_code

    def query_authorization_code(self, code, client):
        auth_code = OAuth2AuthorizationCode.query.filter_by(
            code=code, client_id=client.client_id
        ).first()
        if auth_code and not auth_code.is_expired():
            return auth_code

    def delete_authorization_code(self, authorization_code):
        db.session.delete(authorization_code)
        db.session.commit()

    def authenticate_user(self, authorization_code):
        return User.query.get(authorization_code.user_id)


class PasswordGrant(grants.ResourceOwnerPasswordCredentialsGrant):
    def authenticate_user(self, username, password):
        user = User.query.filter_by(username=username).first()
        if user is not None and user.check_password(password):
            return user


class RefreshTokenGrant(grants.RefreshTokenGrant):
    def authenticate_refresh_token(self, refresh_token):
        token = OAuth2Token.query.filter_by(refresh_token=refresh_token).first()
        if token and token.is_refresh_token_active():
            return token

    def authenticate_user(self, credential):
        return User.query.get(credential.user_id)

    def revoke_old_credential(self, credential):
        credential.revoked = True
        db.session.add(credential)
        db.session.commit()


query_client = create_query_client_func(db.session, OAuth2Client)
save_token = create_save_token_func(db.session, OAuth2Token)
authorization = AuthorizationServer(
    query_client=query_client,
    save_token=save_token,
)
require_oauth = ResourceProtector()


def config_oauth(app):
    authorization.init_app(app)

    # support all grants
    authorization.register_grant(grants.ImplicitGrant)
    authorization.register_grant(grants.ClientCredentialsGrant)
    authorization.register_grant(AuthorizationCodeGrant, [CodeChallenge(required=True)])
    authorization.register_grant(PasswordGrant)
    authorization.register_grant(RefreshTokenGrant)

    # support revocation
    revocation_cls = create_revocation_endpoint(db.session, OAuth2Token)
    authorization.register_endpoint(revocation_cls)

    # protect resource
    bearer_cls = create_bearer_token_validator(db.session, OAuth2Token)
    require_oauth.register_token_validator(bearer_cls())
