# -*- coding: future_fstrings -*-
# mautrix-telegram - A Matrix-Telegram puppeting bridge
# Copyright (C) 2018 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 aiohttp import web
from typing import Awaitable, Callable, Dict, Optional, Tuple, TYPE_CHECKING
import asyncio
import logging
import json

from telethon.utils import get_peer_id, resolve_id
from telethon.tl.types import ChatForbidden, ChannelForbidden, TypeChat
from mautrix_appservice import AppService, MatrixRequestError, IntentError

from ...types import MatrixUserID, TelegramID
from ...user import User
from ...portal import Portal
from ...commands.portal import user_has_power_level, get_initial_state
from ..common import AuthAPI

if TYPE_CHECKING:
    from ...context import Context


class ProvisioningAPI(AuthAPI):
    log = logging.getLogger("mau.web.provisioning")

    def __init__(self, context: "Context") -> None:
        super().__init__(context.loop)
        self.secret = context.config["appservice.provisioning.shared_secret"]
        self.az = context.az  # type: AppService
        self.context = context  # type: Context

        self.app = web.Application(loop=context.loop, middlewares=[self.error_middleware])

        portal_prefix = "/portal/{mxid:![^/]+}"
        self.app.router.add_route("GET", f"{portal_prefix}", self.get_portal_by_mxid)
        self.app.router.add_route("GET", "/portal/{tgid:-[0-9]+}", self.get_portal_by_tgid)
        self.app.router.add_route("POST", portal_prefix + "/connect/{chat_id:-[0-9]+}",
                                  self.connect_chat)
        self.app.router.add_route("POST", f"{portal_prefix}/create", self.create_chat)
        self.app.router.add_route("POST", f"{portal_prefix}/disconnect", self.disconnect_chat)

        user_prefix = "/user/{mxid:@[^:]*:[^/]+}"
        self.app.router.add_route("GET", f"{user_prefix}", self.get_user_info)
        self.app.router.add_route("GET", f"{user_prefix}/chats", self.get_chats)

        self.app.router.add_route("POST", f"{user_prefix}/logout", self.logout)
        self.app.router.add_route("POST", f"{user_prefix}/login/bot_token", self.send_bot_token)
        self.app.router.add_route("POST", f"{user_prefix}/login/request_code", self.request_code)
        self.app.router.add_route("POST", f"{user_prefix}/login/send_code", self.send_code)
        self.app.router.add_route("POST", f"{user_prefix}/login/send_password", self.send_password)

    async def get_portal_by_mxid(self, request: web.Request) -> web.Response:
        err = self.check_authorization(request)
        if err is not None:
            return err

        mxid = request.match_info["mxid"]
        portal = Portal.get_by_mxid(mxid)
        if not portal:
            return self.get_error_response(404, "portal_not_found",
                                           "Portal with given Matrix ID not found.")
        return web.json_response({
            "mxid": portal.mxid,
            "chat_id": get_peer_id(portal.peer),
            "peer_type": portal.peer_type,
            "title": portal.title,
            "about": portal.about,
            "username": portal.username,
            "megagroup": portal.megagroup,
        })

    async def get_portal_by_tgid(self, request: web.Request) -> web.Response:
        err = self.check_authorization(request)
        if err is not None:
            return err

        try:
            tgid, _ = resolve_id(int(request.match_info["tgid"]))
        except ValueError:
            return self.get_error_response(400, "tgid_invalid",
                                           "Given chat ID is not valid.")
        portal = Portal.get_by_tgid(tgid)
        if not portal:
            return self.get_error_response(404, "portal_not_found",
                                           "Portal to given Telegram chat not found.")
        return web.json_response({
            "mxid": portal.mxid,
            "chat_id": get_peer_id(portal.peer),
            "peer_type": portal.peer_type,
            "title": portal.title,
            "about": portal.about,
            "username": portal.username,
            "megagroup": portal.megagroup,
        })

    async def connect_chat(self, request: web.Request) -> web.Response:
        err = self.check_authorization(request)
        if err is not None:
            return err

        room_id = request.match_info["mxid"]
        if Portal.get_by_mxid(room_id):
            return self.get_error_response(409, "room_already_bridged",
                                           "Room is already bridged to another Telegram chat.")

        chat_id = request.match_info["chat_id"]
        if chat_id.startswith("-100"):
            tgid = TelegramID(int(chat_id[4:]))
            peer_type = "channel"
        elif chat_id.startswith("-"):
            tgid = TelegramID(-int(chat_id))
            peer_type = "chat"
        else:
            return self.get_error_response(400, "tgid_invalid", "Invalid Telegram chat ID.")

        user, err = await self.get_user(request.query.get("user_id", None), expect_logged_in=None,
                                        require_puppeting=False)
        if err is not None:
            return err
        elif user and not await user_has_power_level(room_id, self.az.intent, user, "bridge"):
            return self.get_error_response(403, "not_enough_permissions",
                                           "You do not have the permissions to bridge that room.")

        portal = Portal.get_by_tgid(tgid, peer_type=peer_type)
        if portal.mxid == room_id:
            return self.get_error_response(200, "bridge_exists",
                                           "Telegram chat is already bridged to that Matrix room.")
        elif portal.mxid:
            force = request.query.get("force", None)
            if force in ("delete", "unbridge"):
                delete = force == "delete"
                await portal.cleanup_room(portal.main_intent, portal.mxid, puppets_only=not delete,
                                          message=("Portal deleted (moving to another room)"
                                                   if delete
                                                   else "Room unbridged (portal moving to another "
                                                        "room)"))
            else:
                return self.get_error_response(409, "chat_already_bridged",
                                               "Telegram chat is already bridged to another "
                                               "Matrix room.")

        is_logged_in = user is not None and await user.is_logged_in()
        acting_user = user if is_logged_in else self.context.bot
        if not acting_user:
            return self.get_login_response(status=403, errcode="not_logged_in",
                                           error="You are not logged in and there is no relay bot.")

        entity = None  # type: Optional[TypeChat]
        try:
            entity = await acting_user.client.get_entity(portal.peer)
        except Exception:
            self.log.exception("Failed to get_entity(%s) for manual bridging.", portal.peer)

        if not entity or isinstance(entity, (ChatForbidden, ChannelForbidden)):
            if is_logged_in:
                return self.get_error_response(403, "user_not_in_chat",
                                               "Failed to get info of Telegram chat. "
                                               "Are you in the chat?")
            return self.get_error_response(403, "bot_not_in_chat",
                                           "Failed to get info of Telegram chat. "
                                           "Is the relay bot in the chat?")

        direct = False

        portal.mxid = room_id
        portal.title, portal.about, levels = await get_initial_state(self.az.intent, room_id)
        portal.photo_id = ""
        portal.save()

        asyncio.ensure_future(portal.update_matrix_room(user, entity, direct, levels=levels),
                              loop=self.loop)

        return web.Response(status=202, body="{}")

    async def create_chat(self, request: web.Request) -> web.Response:
        err = self.check_authorization(request)
        if err is not None:
            return err

        data = await self.get_data(request)
        if not data:
            return self.get_error_response(400, "json_invalid", "Invalid JSON.")

        room_id = request.match_info["mxid"]
        if Portal.get_by_mxid(room_id):
            return self.get_error_response(409, "room_already_bridged",
                                           "Room is already bridged to another Telegram chat.")

        user, err = await self.get_user(request.query.get("user_id", None), expect_logged_in=None,
                                        require_puppeting=False)
        if err is not None:
            return err
        elif not await user.is_logged_in() or user.is_bot:
            return self.get_error_response(403, "not_logged_in_real_account",
                                           "You are not logged in with a real account.")
        elif not await user_has_power_level(room_id, self.az.intent, user, "bridge"):
            return self.get_error_response(403, "not_enough_permissions",
                                           "You do not have the permissions to bridge that room.")

        try:
            title, about, _ = await get_initial_state(self.az.intent, room_id)
        except (MatrixRequestError, IntentError):
            return self.get_error_response(403, "bot_not_in_room",
                                           "The bridge bot is not in the given room.")

        about = data.get("about", about)

        title = data.get("title", title)
        if len(title) == 0:
            return self.get_error_response(400, "body_value_invalid", "Title can not be empty.")

        type = data.get("type", "")
        if type not in ("group", "chat", "supergroup", "channel"):
            return self.get_error_response(400, "body_value_invalid",
                                           "Given chat type is not valid.")

        supergroup = type == "supergroup"
        type = {
            "supergroup": "channel",
            "channel": "channel",
            "chat": "chat",
            "group": "chat",
        }[type]

        portal = Portal(tgid=None, mxid=room_id, title=title, about=about, peer_type=type)
        try:
            await portal.create_telegram_chat(user, supergroup=supergroup)
        except ValueError as e:
            portal.delete()
            return self.get_error_response(500, "unknown_error", e.args[0])

        return web.json_response({
            "chat_id": portal.tgid,
        }, status=201)

    async def disconnect_chat(self, request: web.Request) -> web.Response:
        err = self.check_authorization(request)
        if err is not None:
            return err

        portal = Portal.get_by_mxid(request.match_info["mxid"])
        if not portal or not portal.tgid:
            return self.get_error_response(404, "portal_not_found",
                                           "Room is not a portal.")

        user, err = await self.get_user(request.query.get("user_id", None), expect_logged_in=None,
                                        require_puppeting=False, require_user=False)
        if err is not None:
            return err
        elif user and not await user_has_power_level(portal.mxid, self.az.intent, user, "unbridge"):
            return self.get_error_response(403, "not_enough_permissions",
                                           "You do not have the permissions to unbridge that room.")

        delete = request.query.get("delete", "").lower() in ("true", "t", "1", "yes", "y")
        sync = request.query.get("delete", "").lower() in ("true", "t", "1", "yes", "y")

        coro = portal.cleanup_and_delete() if delete else portal.unbridge()
        if sync:
            try:
                await coro
            except Exception:
                self.log.exception("Failed to disconnect chat")
                return self.get_error_response(500, "exception", "Failed to disconnect chat")
        else:
            asyncio.ensure_future(coro, loop=self.loop)
        return web.json_response({}, status=200 if sync else 202)

    async def get_user_info(self, request: web.Request) -> web.Response:
        data, user, err = await self.get_user_request_info(request, expect_logged_in=None,
                                                           require_puppeting=False)
        if err is not None:
            return err

        user_data = None
        if await user.is_logged_in():
            me = await user.client.get_me()
            await user.update_info(me)
            user_data = {
                "id": user.tgid,
                "username": user.username,
                "first_name": me.first_name,
                "last_name": me.last_name,
                "phone": me.phone,
                "is_bot": user.is_bot,
            }
        return web.json_response({
            "telegram": user_data,
            "mxid": user.mxid,
            "permissions": user.permissions,
        })

    async def get_chats(self, request: web.Request) -> web.Response:
        data, user, err = await self.get_user_request_info(request, expect_logged_in=True)
        if err is not None:
            return err

        if not user.is_bot:
            chats = await user.get_dialogs()
            return web.json_response([{
                "id": get_peer_id(chat),
                "title": chat.title,
            } for chat in chats])
        else:
            return web.json_response([{
                "id": get_peer_id(chat.peer),
                "title": chat.title,
            } for chat in user.portals.values() if chat.tgid])

    async def send_bot_token(self, request: web.Request) -> web.Response:
        data, user, err = await self.get_user_request_info(request)
        if err is not None:
            return err
        return await self.post_login_token(user, data.get("token", ""))

    async def request_code(self, request: web.Request) -> web.Response:
        data, user, err = await self.get_user_request_info(request)
        if err is not None:
            return err
        return await self.post_login_phone(user, data.get("phone", ""))

    async def send_code(self, request: web.Request) -> web.Response:
        data, user, err = await self.get_user_request_info(request)
        if err is not None:
            return err
        return await self.post_login_code(user, data.get("code", 0), password_in_data=False)

    async def send_password(self, request: web.Request) -> web.Response:
        data, user, err = await self.get_user_request_info(request)
        if err is not None:
            return err
        return await self.post_login_password(user, data.get("password", ""))

    async def logout(self, request: web.Request) -> web.Response:
        _, user, err = await self.get_user_request_info(request, expect_logged_in=True,
                                                        require_puppeting=False,
                                                        want_data=False)
        if err is not None:
            return err
        await user.log_out()

    @staticmethod
    async def error_middleware(_, handler) -> Callable[[web.Request], Awaitable[web.Response]]:
        async def middleware_handler(request: web.Request) -> web.Response:
            try:
                return await handler(request)
            except web.HTTPException as ex:
                return web.json_response({
                    "error": f"Unhandled HTTP {ex.status}",
                    "errcode": f"unhandled_http_{ex.status}",
                }, status=ex.status)

        return middleware_handler

    @staticmethod
    def get_error_response(status=200, errcode="", error="") -> web.Response:
        return web.json_response({
            "error": error,
            "errcode": errcode,
        }, status=status)

    def get_mx_login_response(self, status=200, state="", username="", mxid="", message="",
                              error="", errcode=""):
        raise NotImplementedError()

    def get_login_response(self, status=200, state="", username="", mxid="", message="", error="",
                           errcode="") -> web.Response:
        if username:
            resp = {
                "state": "logged-in",
                "username": username,
            }
        elif message:
            resp = {
                "state": state,
                "message": message,
            }
        else:
            resp = {
                "error": error,
                "errcode": errcode,
            }
            if state:
                resp["state"] = state
        return web.json_response(resp, status=status)

    def check_authorization(self, request: web.Request) -> Optional[web.Response]:
        auth = request.headers.get("Authorization", "")
        if auth != f"Bearer {self.secret}":
            return self.get_error_response(error="Shared secret is not valid.",
                                           errcode="shared_secret_invalid",
                                           status=401)
        return None

    @staticmethod
    async def get_data(request: web.Request) -> Optional[dict]:
        try:
            return await request.json()
        except json.JSONDecodeError:
            return None

    async def get_user(self, mxid: MatrixUserID, expect_logged_in: Optional[bool] = False,
                       require_puppeting: bool = True, require_user: bool = True
                       ) -> Tuple[Optional[User], Optional[web.Response]]:
        if not mxid:
            if not require_user:
                return None, None
            return None, self.get_login_response(error="User ID not given.",
                                                 errcode="mxid_empty", status=400)

        user = await User.get_by_mxid(mxid).ensure_started(even_if_no_session=True)
        if require_puppeting and not user.puppet_whitelisted:
            return user, self.get_login_response(error="You are not whitelisted.",
                                                 errcode="mxid_not_whitelisted", status=403)
        if expect_logged_in is not None:
            logged_in = await user.is_logged_in()
            if not expect_logged_in and logged_in:
                return user, self.get_login_response(username=user.username, status=409,
                                                     error="You are already logged in.",
                                                     errcode="already_logged_in")
            elif expect_logged_in and not logged_in:
                return user, self.get_login_response(status=403, error="You are not logged in.",
                                                     errcode="not_logged_in")
        return user, None

    async def get_user_request_info(self, request: web.Request,
                                    expect_logged_in: Optional[bool] = False,
                                    require_puppeting: bool = False,
                                    want_data: bool = True,
                                    ) -> (Tuple[Optional[Dict],
                                                Optional[User],
                                                Optional[web.Response]]):
        err = self.check_authorization(request)
        if err is not None:
            return err

        data = None
        if want_data and (request.method == "POST" or request.method == "PUT"):
            data = await self.get_data(request)
            if not data:
                return None, None, self.get_login_response(error="Invalid JSON.",
                                                           errcode="json_invalid", status=400)

        mxid = request.match_info["mxid"]
        user, err = await self.get_user(mxid, expect_logged_in, require_puppeting)

        return data, user, err