# Copyright 2021 The Matrix.org Foundation C.I.C.
#
# 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 logging
from typing import TYPE_CHECKING

from synapse.http.server import (
    DirectServeHtmlResource,
    finish_request,
    respond_with_html,
)
from synapse.http.servlet import parse_string
from synapse.http.site import SynapseRequest

if TYPE_CHECKING:
    from synapse.server import HomeServer

logger = logging.getLogger(__name__)


class PickIdpResource(DirectServeHtmlResource):
    """IdP picker resource.

    This resource gets mounted under /_synapse/client/pick_idp. It serves an HTML page
    which prompts the user to choose an Identity Provider from the list.
    """

    def __init__(self, hs: "HomeServer"):
        super().__init__()
        self._sso_handler = hs.get_sso_handler()
        self._sso_login_idp_picker_template = (
            hs.config.sso.sso_login_idp_picker_template
        )
        self._server_name = hs.hostname

    async def _async_render_GET(self, request: SynapseRequest) -> None:
        client_redirect_url = parse_string(
            request, "redirectUrl", required=True, encoding="utf-8"
        )
        idp = parse_string(request, "idp", required=False)

        # if we need to pick an IdP, do so
        if not idp:
            return await self._serve_id_picker(request, client_redirect_url)

        # otherwise, redirect to the IdP's redirect URI
        providers = self._sso_handler.get_identity_providers()
        auth_provider = providers.get(idp)
        if not auth_provider:
            logger.info("Unknown idp %r", idp)
            self._sso_handler.render_error(
                request, "unknown_idp", "Unknown identity provider ID"
            )
            return

        sso_url = await auth_provider.handle_redirect_request(
            request, client_redirect_url.encode("utf8")
        )
        logger.info("Redirecting to %s", sso_url)
        request.redirect(sso_url)
        finish_request(request)

    async def _serve_id_picker(
        self, request: SynapseRequest, client_redirect_url: str
    ) -> None:
        # otherwise, serve up the IdP picker
        providers = self._sso_handler.get_identity_providers()
        html = self._sso_login_idp_picker_template.render(
            redirect_url=client_redirect_url,
            server_name=self._server_name,
            providers=providers.values(),
        )
        respond_with_html(request, 200, html)
