# matrix-appservice-kakaotalk - A Matrix-KakaoTalk puppeting bridge.
# Copyright (C) 2022 Tulir Asokan, Andrew Ferrazzutti
#
# 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 __future__ import annotations

from typing import TYPE_CHECKING, AsyncGenerator, AsyncIterable, Awaitable, cast
import asyncio
import time

from mautrix.bridge import BaseUser, async_getter_lock
from mautrix.types import (
    EventID,
    MessageType,
    RoomID,
    TextMessageEventContent,
    UserID,
)
from mautrix.util.bridge_state import BridgeState, BridgeStateEvent
from mautrix.util.opt_prometheus import Gauge, Summary, async_time
from mautrix.util.simple_lock import SimpleLock

from . import portal as po, puppet as pu
from .config import Config
from .db import User as DBUser

from .kt.client import Client
from .kt.client.errors import AuthenticationRequired, ResponseError
from .kt.types.api.struct.profile import ProfileStruct
from .kt.types.bson import Long
from .kt.types.channel.channel_info import ChannelInfo, NormalChannelInfo, NormalChannelData
from .kt.types.channel.channel_type import ChannelType
from .kt.types.chat.chat import Chatlog
from .kt.types.client.client_session import LoginDataItem, LoginResult
from .kt.types.oauth import OAuthCredential
from .kt.types.openlink.open_channel_info import OpenChannelData, OpenChannelInfo
from .kt.types.packet.chat.kickout import KnownKickoutType, KickoutRes

METRIC_CONNECT_AND_SYNC = Summary("bridge_connect_and_sync", "calls to connect_and_sync")
METRIC_MESSAGE = Summary("bridge_on_message", "calls to on_message")
METRIC_LOGGED_IN = Gauge("bridge_logged_in", "Users logged into the bridge")
METRIC_CONNECTED = Gauge("bridge_connected", "Bridge users connected to KakaoTalk")

if TYPE_CHECKING:
    from .__main__ import KakaoTalkBridge

BridgeState.human_readable_errors.update(
    {
        "kt-reconnection-error": "Failed to reconnect to KakaoTalk",
        # TODO Use for errors in Node backend that cause session to be lost
        #"kt-connection-error": "KakaoTalk disconnected unexpectedly",
        "kt-auth-error": "Authentication error from KakaoTalk: {message}",
        "logged-out": "You're not logged into KakaoTalk",
    }
)


class User(DBUser, BaseUser):
    temp_disconnect_notices: bool = True
    shutdown: bool = False
    config: Config

    by_mxid: dict[UserID, User] = {}
    by_ktid: dict[int, User] = {}

    client: Client | None

    _notice_room_lock: asyncio.Lock
    _notice_send_lock: asyncio.Lock
    is_admin: bool
    permission_level: str
    _is_logged_in: bool | None
    _is_connected: bool | None
    _connection_time: float
    _db_instance: DBUser | None
    _sync_lock: SimpleLock
    _logged_in_info: ProfileStruct | None
    _logged_in_info_time: float

    def __init__(
        self,
        mxid: UserID,
        ktid: Long | None = None,
        uuid: str | None = None,
        access_token: str | None = None,
        refresh_token: str | None = None,
        notice_room: RoomID | None = None,
    ) -> None:
        super().__init__(
            mxid=mxid,
            ktid=ktid,
            uuid=uuid,
            access_token=access_token,
            refresh_token=refresh_token,
            notice_room=notice_room
        )
        BaseUser.__init__(self)
        self.notice_room = notice_room
        self._notice_room_lock = asyncio.Lock()
        self._notice_send_lock = asyncio.Lock()
        (
            self.relay_whitelisted,
            self.is_whitelisted,
            self.is_admin,
            self.permission_level,
        ) = self.config.get_permissions(mxid)
        self._is_logged_in = None
        self._is_connected = None
        self._connection_time = time.monotonic()
        self._sync_lock = SimpleLock(
            "Waiting for thread sync to finish before handling %s", log=self.log
        )
        self._logged_in_info = None
        self._logged_in_info_time = 0

        self.client = None

    @classmethod
    def init_cls(cls, bridge: KakaoTalkBridge) -> AsyncIterable[Awaitable[bool]]:
        cls.bridge = bridge
        cls.config = bridge.config
        cls.az = bridge.az
        cls.temp_disconnect_notices = bridge.config["bridge.temporary_disconnect_notices"]
        return (user.reload_session(is_startup=True) async for user in cls.all_logged_in())

    @property
    def is_connected(self) -> bool | None:
        return self._is_connected

    @is_connected.setter
    def is_connected(self, val: bool | None) -> None:
        if self._is_connected != val:
            self._is_connected = val
            self._connection_time = time.monotonic()

    @property
    def connection_time(self) -> float:
        return self._connection_time

    @property
    def has_state(self) -> bool:
        # TODO If more state is needed, consider returning a saved LoginResult
        return bool(self.access_token and self.refresh_token)

    # region Database getters

    def _add_to_cache(self) -> None:
        self.by_mxid[self.mxid] = self
        if self.ktid:
            self.by_ktid[self.ktid] = self

    @classmethod
    async def all_logged_in(cls) -> AsyncGenerator["User", None]:
        users = await super().all_logged_in()
        user: cls
        for user in users:
            try:
                yield cls.by_mxid[user.mxid]
            except KeyError:
                user._add_to_cache()
                yield user

    @classmethod
    @async_getter_lock
    async def get_by_mxid(cls, mxid: UserID, *, create: bool = True) -> User | None:
        if pu.Puppet.get_id_from_mxid(mxid) or mxid == cls.az.bot_mxid:
            return None
        try:
            return cls.by_mxid[mxid]
        except KeyError:
            pass

        user = cast(cls, await super().get_by_mxid(mxid))
        if user is not None:
            user._add_to_cache()
            return user

        if create:
            cls.log.debug(f"Creating user instance for {mxid}")
            user = cls(mxid)
            await user.insert()
            user._add_to_cache()
            return user

        return None

    @classmethod
    @async_getter_lock
    async def get_by_ktid(cls, ktid: int) -> User | None:
        try:
            return cls.by_ktid[ktid]
        except KeyError:
            pass

        user = cast(cls, await super().get_by_ktid(ktid))
        if user is not None:
            user._add_to_cache()
            return user

        return None

    async def get_uuid(self, force: bool = False) -> str:
        if self.uuid is None or force:
            self.uuid = await self._generate_uuid()
            # TODO Maybe don't save yet
            await self.save()
        return self.uuid

    @classmethod
    async def _generate_uuid(cls) -> str:
        return await Client.generate_uuid(await super().get_all_uuids())

    # endregion

    @property
    def oauth_credential(self) -> OAuthCredential:
        return OAuthCredential(
            self.ktid,
            self.uuid,
            self.access_token,
            self.refresh_token,
        )

    @oauth_credential.setter
    def oauth_credential(self, oauth_credential: OAuthCredential) -> None:
        self.ktid = oauth_credential.userId
        self.access_token = oauth_credential.accessToken
        self.refresh_token = oauth_credential.refreshToken
        if self.uuid != oauth_credential.deviceUUID:
            self.log.warning(f"UUID mismatch: expected {self.uuid}, got {oauth_credential.deviceUUID}")
            self.uuid = oauth_credential.deviceUUID

    async def get_own_info(self) -> ProfileStruct:
        if not self._logged_in_info or self._logged_in_info_time + 60 * 60 < time.monotonic():
            self._logged_in_info = await self.client.get_own_profile()
            self._logged_in_info_time = time.monotonic()
        return self._logged_in_info

    async def _load_session(self, is_startup: bool) -> bool:
        if self._is_logged_in and is_startup:
            return True
        elif not self.has_state:
            # If we have a user in the DB with no state, we can assume
            # KT logged us out and the bridge has restarted
            await self.push_bridge_state(
                BridgeStateEvent.BAD_CREDENTIALS,
                error="logged-out",
            )
            return False
        client = Client(self, log=self.log.getChild("ktclient"))
        user_info = await client.start()
        # NOTE On failure, client.start throws instead of returning False
        self.log.info("Loaded session successfully")
        self.client = client
        self._logged_in_info = user_info
        self._logged_in_info_time = time.monotonic()
        self._track_metric(METRIC_LOGGED_IN, True)
        self._is_logged_in = True
        self.is_connected = None
        asyncio.create_task(self.post_login(is_startup=is_startup))
        return True

    async def _send_reset_notice(self, e: AuthenticationRequired, edit: EventID | None = None) -> None:
        await self.send_bridge_notice(
            "Got authentication error from KakaoTalk:\n\n"
            f"> {e.message}\n\n"
            "If you changed your KakaoTalk password, this "
            "is normal and you just need to log in again.",
            edit=edit,
            important=True,
            state_event=BridgeStateEvent.BAD_CREDENTIALS,
            error_code="kt-auth-error",
            error_message=str(e),
        )
        await self.logout(remove_ktid=False)

    async def is_logged_in(self, _override: bool = False) -> bool:
        if not self.has_state or not self.client:
            return False
        if self._is_logged_in is None or _override:
            try:
                self._is_logged_in = bool(await self.get_own_info())
            except Exception:
                self.log.exception("Exception checking login status")
                self._is_logged_in = False
        return self._is_logged_in

    async def reload_session(
        self, event_id: EventID | None = None, retries: int = 3, is_startup: bool = False
    ) -> None:
        try:
            await self._load_session(is_startup=is_startup)
        except AuthenticationRequired as e:
            await self._send_reset_notice(e, edit=event_id)
        # TODO Throw a ResponseError on network failures
        except ResponseError as e:
            will_retry = retries > 0
            retry = "Retrying in 1 minute" if will_retry else "Not retrying"
            notice = f"Failed to connect to KakaoTalk: unknown response error {e}. {retry}"
            if will_retry:
                await self.send_bridge_notice(
                    notice,
                    edit=event_id,
                    state_event=BridgeStateEvent.TRANSIENT_DISCONNECT,
                )
                await asyncio.sleep(60)
                await self.reload_session(event_id, retries - 1, is_startup)
            else:
                await self.send_bridge_notice(
                    notice,
                    edit=event_id,
                    important=True,
                    state_event=BridgeStateEvent.UNKNOWN_ERROR,
                    error_code="kt-reconnection-error",
                )
        except Exception:
            self.log.exception("Error connecting to KakaoTalk")
            await self.send_bridge_notice(
                "Failed to connect to KakaoTalk: unknown error (see logs for more details)",
                edit=event_id,
                state_event=BridgeStateEvent.UNKNOWN_ERROR,
                error_code="kt-reconnection-error",
            )

    async def logout(self, *, remove_ktid: bool = True, reset_device: bool = False) -> None:
        if self.client:
            # TODO Look for a logout API call
            await self.client.stop()
        if remove_ktid:
            await self.push_bridge_state(BridgeStateEvent.LOGGED_OUT)
        self._track_metric(METRIC_LOGGED_IN, False)

        if reset_device:
            self.uuid = await self._generate_uuid()
        self.access_token = None
        self.refresh_token = None

        self._is_logged_in = False
        self.is_connected = None
        self.client = None

        if self.ktid and remove_ktid:
            #await UserPortal.delete_all(self.ktid)
            del self.by_ktid[self.ktid]
            self.ktid = None

        await self.save()

    async def post_login(self, is_startup: bool) -> None:
        self.log.info("Running post-login actions")
        self._add_to_cache()

        try:
            puppet = await pu.Puppet.get_by_ktid(self.ktid)

            if puppet.custom_mxid != self.mxid and puppet.can_auto_login(self.mxid):
                self.log.info(f"Automatically enabling custom puppet")
                await puppet.switch_mxid(access_token="auto", mxid=self.mxid)
        except Exception:
            self.log.exception("Failed to automatically enable custom puppet")

        # TODO Check if things break when a live message comes in during syncing
        if self.config["bridge.sync_on_startup"] or not is_startup:
            sync_count = self.config["bridge.initial_chat_sync"]
        else:
            sync_count = None
        # TODO Don't auto-connect on startup if user's last state was disconnected
        await self.connect_and_sync(sync_count)

    async def get_direct_chats(self) -> dict[UserID, list[RoomID]]:
        return {
            pu.Puppet.get_mxid_from_id(portal.ktid): [portal.mxid]
            async for portal in po.Portal.get_all_by_receiver(self.ktid)
            if portal.mxid
        }

    @async_time(METRIC_CONNECT_AND_SYNC)
    async def connect_and_sync(self, sync_count: int | None) -> bool:
        # TODO Look for a way to sync all channels without (re-)logging in
        try:
            login_result = await self.client.connect()
            await self.on_connect()
            await self._sync_channels(login_result, sync_count)
            return True
        except AuthenticationRequired as e:
            await self.send_bridge_notice(
                f"Got authentication error from KakaoTalk:\n\n> {e.message}\n\n",
                important=True,
                state_event=BridgeStateEvent.BAD_CREDENTIALS,
                error_code="kt-auth-error",
                error_message=str(e),
            )
            await self.logout(remove_ktid=False)
        except Exception as e:
            self.log.exception("Failed to connect and sync")
            await self.push_bridge_state(BridgeStateEvent.UNKNOWN_ERROR, message=str(e))
        return False

    async def _sync_channels(self, login_result: LoginResult, sync_count: int | None) -> None:
        if sync_count is None:
            sync_count = self.config["bridge.initial_chat_sync"]
        if not sync_count:
            self.log.debug("Skipping channel syncing")
            return
        if not login_result.channelList:
            self.log.debug("No channels to sync")
            return
        # TODO What about removed channels? Don't early-return then

        num_channels = len(login_result.channelList)
        sync_count = num_channels if sync_count < 0 else min(sync_count, num_channels)
        await self.push_bridge_state(BridgeStateEvent.BACKFILLING)
        self.log.debug(f"Syncing {sync_count} of {num_channels} channels...")
        for login_data in login_result.channelList[:sync_count]:
            try:
                await self._sync_channel(login_data)
            except AuthenticationRequired:
                raise
            except Exception:
                self.log.exception(f"Failed to sync channel {login_data.channel.channelId}")

        await self.update_direct_chats()

    async def _sync_channel(self, login_data: LoginDataItem) -> None:
        channel_data = login_data.channel
        self.log.debug(f"Syncing channel {channel_data.channelId} (last updated at {login_data.lastUpdate})")
        channel_info = channel_data.info
        if isinstance(channel_data, NormalChannelData):
            channel_data: NormalChannelData
            channel_info: NormalChannelInfo
            self.log.debug(f"Join time: {channel_info.joinTime}")
        elif isinstance(channel_data, OpenChannelData):
            channel_data: OpenChannelData
            self.log.debug(f"channel_data link ID: {channel_data.linkId}")
            channel_info: OpenChannelInfo
            self.log.debug(f"channel_info link ID: {channel_info.linkId}")
            self.log.debug(f"openToken: {channel_info.openToken}")
            self.log.debug(f"Is direct channel: {channel_info.directChannel}")
            self.log.debug(f"Has OpenLink: {channel_info.openLink is not None}")
        else:
            self.log.error(f"Unexpected channel type: {type(channel_data)}")

        channel_info: ChannelInfo
        self.log.debug(f"channel_info channel ID: {channel_info.channelId}")
        self.log.debug(f"Channel data/info IDs match: {channel_data.channelId == channel_info.channelId}")
        self.log.debug(f"Channel type: {channel_info.type}")
        self.log.debug(f"Active user count: {channel_info.activeUserCount}")
        self.log.debug(f"New chat count: {channel_info.newChatCount}")
        self.log.debug(f"New chat count invalid: {channel_info.newChatCountInvalid}")
        self.log.debug(f"Last chat log ID: {channel_info.lastChatLogId}")
        self.log.debug(f"Last seen log ID: {channel_info.lastSeenLogId}")
        self.log.debug(f"Has last chat log: {channel_info.lastChatLog is not None}")
        self.log.debug(f"metaMap: {channel_info.metaMap}")
        self.log.debug(f"User count: {len(channel_info.displayUserList)}")
        self.log.debug(f"Has push alert: {channel_info.pushAlert}")
        for display_user_info in channel_info.displayUserList:
            self.log.debug(f"Member: {display_user_info.nickname} - {display_user_info.profileURL} - {display_user_info.userId}")

        portal = await po.Portal.get_by_ktid(
            channel_info.channelId,
            kt_receiver=self.ktid,
            kt_type=channel_info.type
        )
        portal_info = await self.client.get_portal_channel_info(portal.channel_props)
        portal_info.channel_info = channel_info
        if not portal.mxid:
            await portal.create_matrix_room(self, portal_info)
        else:
            await portal.update_matrix_room(self, portal_info)
            await portal.backfill(self, is_initial=False, channel_info=channel_info)

    async def get_notice_room(self) -> RoomID:
        if not self.notice_room:
            async with self._notice_room_lock:
                # If someone already created the room while this call was waiting,
                # don't make a new room
                if self.notice_room:
                    return self.notice_room
                creation_content = {}
                if not self.config["bridge.federate_rooms"]:
                    creation_content["m.federate"] = False
                self.notice_room = await self.az.intent.create_room(
                    is_direct=True,
                    invitees=[self.mxid],
                    topic="KakaoTalk bridge notices",
                    creation_content=creation_content,
                )
                await self.save()
        return self.notice_room

    async def send_bridge_notice(
        self,
        text: str,
        edit: EventID | None = None,
        state_event: BridgeStateEvent | None = None,
        important: bool = False,
        error_code: str | None = None,
        error_message: str | None = None,
    ) -> EventID | None:
        if state_event:
            await self.push_bridge_state(
                state_event,
                error=error_code,
                message=error_message if error_code else text,
            )
        if self.config["bridge.disable_bridge_notices"]:
            return None
        event_id = None
        try:
            self.log.debug("Sending bridge notice: %s", text)
            content = TextMessageEventContent(
                body=text,
                msgtype=(MessageType.TEXT if important else MessageType.NOTICE),
            )
            if edit:
                content.set_edit(edit)
            # This is locked to prevent notices going out in the wrong order
            async with self._notice_send_lock:
                event_id = await self.az.intent.send_message(await self.get_notice_room(), content)
        except Exception:
            self.log.warning("Failed to send bridge notice", exc_info=True)
        return edit or event_id

    async def fill_bridge_state(self, state: BridgeState) -> None:
        await super().fill_bridge_state(state)
        if self.ktid:
            state.remote_id = str(self.ktid)
            puppet = await pu.Puppet.get_by_ktid(self.ktid)
            state.remote_name = puppet.name

    async def get_bridge_states(self) -> list[BridgeState]:
        if not self.state:
            return []
        state = BridgeState(state_event=BridgeStateEvent.UNKNOWN_ERROR)
        if self.is_connected:
            state.state_event = BridgeStateEvent.CONNECTED
        # TODO
        #elif self._is_logged_in and self._is_reconnecting:
        #    state.state_event = BridgeStateEvent.TRANSIENT_DISCONNECT
        return [state]

    async def get_puppet(self) -> pu.Puppet | None:
        if not self.ktid:
            return None
        return await pu.Puppet.get_by_ktid(self.ktid)

    async def get_portal_with(self, puppet: pu.Puppet, create: bool = True) -> po.Portal | None:
        # TODO
        return None
        """
        if not self.ktid or not self.client:
            return None
        return await po.Portal.get_by_ktid(
            await self.client.get_dm_channel_id_for(puppet.ktid),
            kt_receiver=self.ktid,
            create=create,
            kt_type=KnownChannelType.DirectChat if puppet.ktid != self.ktid else KnownChannelType.MemoChat
        )
        """

    # region KakaoTalk event handling

    async def on_connect(self) -> None:
        now = time.monotonic()
        disconnected_at = self._connection_time
        max_delay = self.config["bridge.resync_max_disconnected_time"]
        first_connect = self.is_connected is None
        self.is_connected = True
        self._track_metric(METRIC_CONNECTED, True)
        if not first_connect and disconnected_at + max_delay < now:
            duration = int(now - disconnected_at)
            self.log.debug(f"Disconnection lasted {duration} seconds")
        elif self.temp_disconnect_notices:
            await self.send_bridge_notice("Connected to KakaoTalk chats")
        await self.push_bridge_state(BridgeStateEvent.CONNECTED)

    async def on_disconnect(self, res: KickoutRes | None) -> None:
        self.is_connected = False
        self._track_metric(METRIC_CONNECTED, False)
        if res:
            logout = False
            if res.reason == KnownKickoutType.LOGIN_ANOTHER:
                reason_str = "Logged in from another desktop client."
            elif res.reason == KnownKickoutType.CHANGE_SERVER:
                # TODO Reconnect automatically instead
                reason_str = "KakaoTalk backend server changed."
            elif res.reason == KnownKickoutType.ACCOUNT_DELETED:
                reason_str = "Your KakaoTalk account was deleted!"
                logout = True
            else:
                reason_str = f"Unknown reason ({res.reason})."
            if not logout:
                reason_suffix = " To reconnect, use the `sync` command."
                # TODO What bridge state to push?
            else:
                reason_suffix = " You are now logged out."
                await self.logout()
            await self.send_bridge_notice(f"Disconnected from KakaoTalk: {reason_str} {reason_suffix}")

    async def on_logged_in(self, oauth_credential: OAuthCredential) -> None:
        self.log.debug(f"Successfully logged in as {oauth_credential.userId}")
        self.oauth_credential = oauth_credential
        await self.push_bridge_state(BridgeStateEvent.CONNECTING)
        self.client = Client(self, log=self.log.getChild("ktclient"))
        await self.save()
        self._is_logged_in = True
        # TODO Retry network connection failures here, or in the client (like token refreshes are)?
        #      Should also catch unlikely authentication errors
        self._logged_in_info = await self.client.start()
        self._logged_in_info_time = time.monotonic()
        asyncio.create_task(self.post_login(is_startup=True))

    @async_time(METRIC_MESSAGE)
    async def on_message(self, evt: Chatlog, channel_id: Long, channel_type: ChannelType) -> None:
        portal = await po.Portal.get_by_ktid(
            channel_id,
            kt_receiver=self.ktid,
            kt_type=channel_type
        )
        puppet = await pu.Puppet.get_by_ktid(evt.sender.userId)
        await portal.backfill_lock.wait(evt.logId)
        if not puppet.name:
            portal.schedule_resync(self, puppet)
        await portal.handle_remote_message(self, puppet, evt)

    # TODO Many more handlers

    # endregion