# mautrix-signal - A Matrix-Signal puppeting bridge
# Copyright (C) 2020 Tulir Asokan
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
from typing import Awaitable, Dict, TYPE_CHECKING
import logging
import json

from aiohttp import web

from mausignald.types import Address
from mausignald.errors import TimeoutException
from mautrix.types import UserID
from mautrix.util.logging import TraceLogger

from .. import user as u

if TYPE_CHECKING:
    from ..__main__ import SignalBridge


class ProvisioningAPI:
    log: TraceLogger = logging.getLogger("mau.web.provisioning")
    app: web.Application
    bridge: 'SignalBridge'

    def __init__(self, bridge: 'SignalBridge', shared_secret: str) -> None:
        self.bridge = bridge
        self.app = web.Application()
        self.shared_secret = shared_secret
        self.app.router.add_get("/api/whoami", self.status)
        self.app.router.add_options("/api/link", self.login_options)
        self.app.router.add_options("/api/link/wait", self.login_options)
        # self.app.router.add_options("/api/register", self.login_options)
        # self.app.router.add_options("/api/register/code", self.login_options)
        self.app.router.add_options("/api/logout", self.login_options)
        self.app.router.add_post("/api/link", self.link)
        self.app.router.add_post("/api/link/wait", self.link_wait)
        # self.app.router.add_post("/api/register", self.register)
        # self.app.router.add_post("/api/register/code", self.register_code)
        self.app.router.add_post("/api/logout", self.logout)

    @property
    def _acao_headers(self) -> Dict[str, str]:
        return {
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Headers": "Authorization, Content-Type",
            "Access-Control-Allow-Methods": "POST, OPTIONS",
        }

    @property
    def _headers(self) -> Dict[str, str]:
        return {
            **self._acao_headers,
            "Content-Type": "application/json",
        }

    async def login_options(self, _: web.Request) -> web.Response:
        return web.Response(status=200, headers=self._headers)

    def check_token(self, request: web.Request) -> Awaitable['u.User']:
        try:
            token = request.headers["Authorization"]
            token = token[len("Bearer "):]
        except KeyError:
            raise web.HTTPBadRequest(text='{"error": "Missing Authorization header"}',
                                     headers=self._headers)
        except IndexError:
            raise web.HTTPBadRequest(text='{"error": "Malformed Authorization header"}',
                                     headers=self._headers)
        if token != self.shared_secret:
            raise web.HTTPForbidden(text='{"error": "Invalid token"}', headers=self._headers)
        try:
            user_id = request.query["user_id"]
        except KeyError:
            raise web.HTTPBadRequest(text='{"error": "Missing user_id query param"}',
                                     headers=self._headers)

        return u.User.get_by_mxid(UserID(user_id))

    async def status(self, request: web.Request) -> web.Response:
        user = await self.check_token(request)
        data = {
            "permissions": user.permission_level,
            "mxid": user.mxid,
            "signal": None,
        }
        if await user.is_logged_in():
            profile = await self.bridge.signal.get_profile(username=user.username,
                                                           address=Address(number=user.username))
            addr = profile.address if profile else None
            number = addr.number if addr else None
            uuid = addr.uuid if addr else None
            data["signal"] = {
                "number": number or user.username,
                "uuid": str(uuid or user.uuid or ""),
                "name": profile.name if profile else None,
            }
        return web.json_response(data, headers=self._acao_headers)

    async def link(self, request: web.Request) -> web.Response:
        user = await self.check_token(request)

        try:
            data = await request.json()
        except json.JSONDecodeError:
            raise web.HTTPBadRequest(text='{"error": "Malformed JSON"}', headers=self._headers)

        device_name = data.get("device_name", "Mautrix-Signal bridge")
        sess = await self.bridge.signal.start_link()

        user.command_status = {
            "action": "Link",
            "session_id": sess.session_id,
            "device_name": device_name,
        }

        return web.json_response({"uri": sess.uri}, headers=self._acao_headers)

    async def link_wait(self, request: web.Request) -> web.Response:
        user = await self.check_token(request)
        if not user.command_status or user.command_status["action"] != "Link":
            raise web.HTTPBadRequest(text='{"error": "No Signal linking started"}',
                                     headers=self._headers)
        session_id = user.command_status["session_id"]
        device_name = user.command_status["device_name"]
        try:
            account = await self.bridge.signal.finish_link(session_id=session_id,
                                                           device_name=device_name)
        except TimeoutException:
            raise web.HTTPBadRequest(text='{"error": "Signal linking timed out"}',
                                     headers=self._headers)
        except Exception:
            self.log.exception("Fatal error while waiting for linking to finish")
            raise web.HTTPInternalServerError(text='{"error": "Fatal error in Signal linking"}',
                                              headers=self._headers)
        else:
            await user.on_signin(account)
            return web.json_response({
                "number": account.username,
                "uuid": str(account.uuid),
            })

    async def logout(self, request: web.Request) -> web.Response:
        user = await self.check_token(request)
        if not user.username:
            raise web.HTTPNotFound(text='''{"error": "You're not logged in"}''',
                                   headers=self._headers)
        await user.logout()
        return web.json_response({}, headers=self._acao_headers)