import asyncio
import json
import logging as log
from contextlib import suppress
from dataclasses import dataclass, field
from datetime import datetime
from typing import Optional, Tuple
from urllib.parse import quote

import nio

from . import utils
from .html_markdown import HTML_PROCESSOR
from .matrix_client import MatrixClient
from .models.items import Account, Room, TypeSpecifier


@dataclass
class NioCallbacks:
    """Register callbacks for nio's request responses and room events.

    For every nio `Response` and `Event` subclasses, this class can have a
    method named `on<ClassName>` (e.g. `onRoomMessageText`) that will
    automatically be registered in nio.

    For room event content strings, the `%1` and `%2` placeholders
    refer to the event's sender and who this event targets (`state_key`).
    These are processed from QML, to allow translations of the strings.
    """

    client: MatrixClient = field()


    def __post_init__(self) -> None:
        """Register our methods as callbacks."""

        for name, class_ in utils.classes_defined_in(nio.responses).items():
            with suppress(AttributeError):
                method = getattr(self, f"on{name}")
                self.client.add_response_callback(method, class_)

        for name, class_ in utils.classes_defined_in(nio.events).items():
            with suppress(AttributeError):
                method = getattr(self, f"on{name}")
                self.client.add_event_callback(method, class_)

        self.client.add_ephemeral_callback(
            self.onTypingNoticeEvent, nio.events.TypingNoticeEvent,
        )


    # Response callbacks

    async def onSyncResponse(self, resp: nio.SyncResponse) -> None:
        for room_id, info in resp.rooms.join.items():
            if room_id not in self.client.past_tokens:
                self.client.past_tokens[room_id] = info.timeline.prev_batch

        # TODO: way of knowing if a nio.MatrixRoom is left
        for room_id, info in resp.rooms.leave.items():
            # TODO: handle in nio, these are rooms that were left before
            # starting the client.
            if room_id not in self.client.all_rooms:
                log.warning("Left room not in MatrixClient.rooms: %r", room_id)
                continue

            # TODO: handle left events in nio async client
            for ev in info.timeline.events:
                if isinstance(ev, nio.RoomMemberEvent):
                    await self.onRoomMemberEvent(
                        self.client.all_rooms[room_id], ev,
                    )

            await self.client.register_nio_room(
                self.client.all_rooms[room_id], left=True,
            )

        if not self.client.first_sync_done.is_set():
            self.client.load_rooms_task = asyncio.ensure_future(
                self.client.load_rooms_without_visible_events(),
            )

            self.client.first_sync_done.set()
            self.client.first_sync_date = datetime.now()

            account = self.client.models[Account][self.client.user_id]
            account.first_sync_done = True


    async def onErrorResponse(self, resp: nio.ErrorResponse) -> None:
        # TODO: show something in the client, must be seen on login screen too
        try:
            log.warning("%s - %s", resp, json.dumps(vars(resp), indent=4))
        except Exception:
            log.warning(repr(resp))


    # Event callbacks

    async def onRoomMessageText(self, room, ev) -> None:
        co = HTML_PROCESSOR.filter(
            ev.formatted_body
            if ev.format == "org.matrix.custom.html" else
            utils.plain2html(ev.body),
        )
        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomMessageNotice(self, room, ev) -> None:
        await self.onRoomMessageText(room, ev)


    async def onRoomMessageEmote(self, room, ev) -> None:
        await self.onRoomMessageText(room, ev)


    async def onRoomMessageUnknown(self, room, ev) -> None:
        co = f"%1 sent an unsupported <b>{ev.msgtype}</b> message"
        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomMessageMedia(self, room, ev) -> None:
        info             = ev.source["content"].get("info", {})
        media_crypt_dict = ev.source["content"].get("file", {})
        thumb_info       = info.get("thumbnail_info", {})
        thumb_crypt_dict = info.get("thumbnail_file", {})

        await self.client.register_nio_event(
            room,
            ev,
            content        = "",
            inline_content = ev.body,

            media_url        = ev.url,
            media_title      = ev.body,
            media_width      = info.get("w") or 0,
            media_height     = info.get("h") or 0,
            media_duration   = info.get("duration") or 0,
            media_size       = info.get("size") or 0,
            media_mime       = info.get("mimetype") or 0,
            media_crypt_dict = media_crypt_dict,

            thumbnail_url =
                info.get("thumbnail_url") or thumb_crypt_dict.get("url") or "",

            thumbnail_width      = thumb_info.get("w") or 0,
            thumbnail_height     = thumb_info.get("h") or 0,
            thumbnail_crypt_dict = thumb_crypt_dict,
        )


    async def onRoomEncryptedMedia(self, room, ev) -> None:
        await self.onRoomMessageMedia(room, ev)


    async def onRoomCreateEvent(self, room, ev) -> None:
        co = "%1 allowed users on other matrix servers to join this room" \
             if ev.federate else \
             "%1 blocked users on other matrix servers from joining this room"
        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomGuestAccessEvent(self, room, ev) -> None:
        allowed = "allowed" if ev.guest_access else "forbad"
        co      = f"%1 {allowed} guests to join the room"
        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomJoinRulesEvent(self, room, ev) -> None:
        access = "public" if ev.join_rule == "public" else "invite-only"
        co     = f"%1 made the room {access}"
        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomHistoryVisibilityEvent(self, room, ev) -> None:
        if ev.history_visibility == "shared":
            to = "all room members"
        elif ev.history_visibility == "world_readable":
            to = "any member or outsider"
        elif ev.history_visibility == "joined":
            to = "all room members, since the time they joined"
        elif ev.history_visibility == "invited":
            to = "all room members, since the time they were invited"
        else:
            to = "???"
            log.warning("Invalid visibility - %s",
                        json.dumps(vars(ev), indent=4))

        co = f"%1 made future room history visible to {to}"
        await self.client.register_nio_event(room, ev, content=co)


    async def onPowerLevelsEvent(self, room, ev) -> None:
        co = "%1 changed the room's permissions"  # TODO: improve
        await self.client.register_nio_event(room, ev, content=co)


    async def process_room_member_event(
        self, room: nio.MatrixRoom, ev: nio.RoomMemberEvent,
    ) -> Optional[Tuple[TypeSpecifier, str]]:
        """Return a `TypeSpecifier` and string describing a member event.

        Matrix member events can represent many actions:
        a user joined the room, a user banned another, a user changed their
        display name, etc.
        """
        if ev.prev_content == ev.content:
            return None

        prev            = ev.prev_content
        now             = ev.content
        membership      = ev.membership
        prev_membership = ev.prev_membership
        ev_date         = datetime.fromtimestamp(ev.server_timestamp / 1000)

        member_change = TypeSpecifier.membership_change

        # Membership changes
        if not prev or membership != prev_membership:
            reason = f". Reason: {now['reason']}" if now.get("reason") else ""

            if membership == "join":
                return (
                    member_change,
                    "%1 accepted their invitation"
                    if prev and prev_membership == "invite" else
                    "%1 joined the room",
                )

            if membership == "invite":
                return (member_change, "%1 invited %2 to the room")

            if membership == "leave":
                if ev.state_key == ev.sender:
                    return (
                        member_change,
                        f"%1 declined their invitation{reason}"
                        if prev and prev_membership == "invite" else
                        f"%1 left the room{reason}",
                    )

                return (
                    member_change,

                    f"%1 withdrew %2's invitation{reason}"
                    if prev and prev_membership == "invite" else

                    f"%1 unbanned %2 from the room{reason}"
                    if prev and prev_membership == "ban" else

                    f"%1 kicked out %2 from the room{reason}",
                )

            if membership == "ban":
                return (member_change, f"%1 banned %2 from the room{reason}")

        # Profile changes
        changed = []

        if prev and now["avatar_url"] != prev["avatar_url"]:
            changed.append("profile picture")  # TODO: <img>s

        if prev and now["displayname"] != prev["displayname"]:
            changed.append('display name from "{}" to "{}"'.format(
                prev["displayname"] or ev.state_key,
                now["displayname"] or ev.state_key,
            ))

        if changed:
            # Update our account profile if the event is newer than last update
            if ev.state_key == self.client.user_id:
                account = self.client.models[Account][self.client.user_id]
                updated = account.profile_updated

                if not updated or updated < ev_date:
                    account.profile_updated = ev_date
                    account.display_name    = now["displayname"] or ""
                    account.avatar_url      = now["avatar_url"] or ""

            # Hide profile events from the timeline - XXX
            self.client.skipped_events[room.room_id] += 1
            return None

            return (
                TypeSpecifier.profile_change,
                "%1 changed their {}".format(" and ".join(changed)),
            )

        log.warning("Unknown member event: %s", json.dumps(vars(ev), indent=4))
        return None


    async def onRoomMemberEvent(self, room, ev) -> None:
        type_and_content = await self.process_room_member_event(room, ev)

        if type_and_content is not None:
            type_specifier, content = type_and_content

            await self.client.register_nio_event(
                room, ev, content=content, type_specifier=type_specifier,
            )
        else:
            # Normally, register_nio_event() will call register_nio_room().
            # but in this case we don't have any event we want to register.
            await self.client.register_nio_room(room)


    async def onRoomAliasEvent(self, room, ev) -> None:
        if ev.canonical_alias:
            url  = f"https://matrix.to/#/{quote(ev.canonical_alias)}"
            link = f"<a href='{url}'>{ev.canonical_alias}</a>"
            co   = f"%1 set the room's main address to {link}"
        else:
            co = "%1 removed the room's main address"

        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomNameEvent(self, room, ev) -> None:
        if ev.name:
            co = f"%1 changed the room's name to \"{ev.name}\""
        else:
            co = "%1 removed the room's name"

        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomAvatarEvent(self, room, ev) -> None:
        if ev.avatar_url:
            co = "%1 changed the room's picture"
        else:
            co = "%1 removed the room's picture"

        await self.client.register_nio_event(
            room, ev, content=co, media_url=ev.avatar_url,
        )


    async def onRoomTopicEvent(self, room, ev) -> None:
        if ev.topic:
            topic = HTML_PROCESSOR.filter_inline(ev.topic)
            co    = f"%1 changed the room's topic to \"{topic}\""
        else:
            co = "%1 removed the room's topic"

        await self.client.register_nio_event(room, ev, content=co)


    async def onRoomEncryptionEvent(self, room, ev) -> None:
        co = "%1 turned on encryption for this room"
        await self.client.register_nio_event(room, ev, content=co)


    async def onMegolmEvent(self, room, ev) -> None:
        co = "%1 sent an undecryptable message"
        await self.client.register_nio_event(room, ev, content=co)


    async def onBadEvent(self, room, ev) -> None:
        co = f"%1 sent a malformed <b>{ev.type}</b> event"
        await self.client.register_nio_event(room, ev, content=co)


    async def onUnknownBadEvent(self, room, ev) -> None:
        co = "%1 sent a malformed event lacking a minimal structure"
        await self.client.register_nio_event(room, ev, content=co)


    async def onUnknownEvent(self, room, ev) -> None:
        co = f"%1 sent an unsupported <b>{ev.type}</b> event"
        await self.client.register_nio_event(room, ev, content=co)


    async def onUnknownEncryptedEvent(self, room, ev) -> None:
        co = (
            f"%1 sent an <b>{ev.type}</b> event encrypted with "
            f"unsupported <b>{ev.algorithm}</b> algorithm"
        )
        await self.client.register_nio_event(room, ev, content=co)


    async def onInviteEvent(self, room, ev) -> None:
        await self.client.register_nio_room(room)


    async def onTypingNoticeEvent(self, room, ev) -> None:
        # Prevent recent past typing notices from being shown for a split
        # second on client startup:
        if not self.client.first_sync_done.is_set():
            return

        if room.room_id not in self.client.models[Room, self.client.user_id]:
            return

        room_item = self.client.models[Room, self.client.user_id][room.room_id]

        room_item.typing_members = sorted(
            room.user_name(user_id) for user_id in ev.users
            if user_id not in self.client.backend.clients
        )