import { useEffect, useState } from 'react';
import { RoomJoinRulesEventContent } from 'matrix-js-sdk/lib/types';
import { Room, RoomEvent, RoomEventHandlerMap } from 'matrix-js-sdk';
import { StateEvent } from '../../types/matrix/room';
import { useStateEvent } from './useStateEvent';
import { useMatrixClient } from './useMatrixClient';
import { createAccountDataListStore } from './createAccountDataListStore';

export const useRoomAvatar = (room: Room, dm?: boolean): string | undefined => {
  const avatarEvent = useStateEvent(room, StateEvent.RoomAvatar);

  if (dm) {
    return room.getAvatarFallbackMember()?.getMxcAvatarUrl();
  }
  const content = avatarEvent?.getContent();
  const avatarMxc = content && typeof content.url === 'string' ? content.url : undefined;

  return avatarMxc;
};

export const useRoomName = (room: Room): string => {
  const [name, setName] = useState(room.name);

  useEffect(() => {
    setName(room.name);

    const handleRoomNameChange: RoomEventHandlerMap[RoomEvent.Name] = () => {
      setName(room.name);
    };
    room.on(RoomEvent.Name, handleRoomNameChange);
    return () => {
      room.removeListener(RoomEvent.Name, handleRoomNameChange);
    };
  }, [room]);

  return name;
};

export const LOCAL_ROOM_NAMES_KEY = 'io.lotus.room_names';

export type LocalRoomNamesContent = { rooms: Record<string, string> };

type LocalRoomNamesMap = Record<string, string>;

// Shared, concurrency-safe store. See createAccountDataListStore for why the
// snapshot + write queue must be module-scoped: setAccountData does not update
// the SDK's local cache (it only resolves once the /sync echo lands), so a
// plain read-modify-write against getAccountData can lose a rename that is
// still in flight when a second rename is issued (fixed: back-to-back renames
// of different rooms no longer clobber each other).
const roomNamesStore = createAccountDataListStore<LocalRoomNamesMap, LocalRoomNamesContent>({
  eventType: LOCAL_ROOM_NAMES_KEY,
  read: (content) =>
    content && typeof content === 'object' && typeof content.rooms === 'object'
      ? content.rooms
      : {},
  write: (rooms) => ({ rooms }),
});

export function getLocalRoomNamesContent(
  mx: ReturnType<typeof useMatrixClient>,
): LocalRoomNamesContent {
  return { rooms: roomNamesStore.getLatest(mx) };
}

/**
 * Set (or clear, when `name` is empty) the local display name for a room.
 * Routed through the shared write queue so back-to-back renames of different
 * rooms are always computed from the latest snapshot instead of a stale one.
 */
export function setLocalRoomName(
  mx: ReturnType<typeof useMatrixClient>,
  roomId: string,
  name: string,
): Promise<void> {
  return roomNamesStore.enqueueWrite(mx, (current) => {
    if (!name) {
      const { [roomId]: _removed, ...rest } = current;
      return rest;
    }
    return { ...current, [roomId]: name };
  });
}

export const useLocalRoomName = (room: Room): string => {
  const mx = useMatrixClient();
  const localNames = roomNamesStore.useValue(mx);
  const [name, setName] = useState(room.name);

  useEffect(() => {
    setName(room.name);

    const handleRoomNameChange: RoomEventHandlerMap[RoomEvent.Name] = () => {
      setName(room.name);
    };
    room.on(RoomEvent.Name, handleRoomNameChange);
    return () => {
      room.removeListener(RoomEvent.Name, handleRoomNameChange);
    };
  }, [room]);

  return localNames[room.roomId] ?? name;
};

export const useHasLocalRoomName = (roomId: string): boolean => {
  const mx = useMatrixClient();
  const localNames = roomNamesStore.useValue(mx);
  return !!localNames[roomId];
};

export type RoomTopicContent = {
  topic: string;
  formatted_body?: string;
  format?: string;
};

export const useRoomTopic = (room: Room): RoomTopicContent | undefined => {
  const topicEvent = useStateEvent(room, StateEvent.RoomTopic);

  const content = topicEvent?.getContent();
  if (!content || typeof content.topic !== 'string') return undefined;

  return {
    topic: content.topic,
    formatted_body: typeof content.formatted_body === 'string' ? content.formatted_body : undefined,
    format: typeof content.format === 'string' ? content.format : undefined,
  };
};

export const useRoomJoinRule = (room: Room): RoomJoinRulesEventContent | undefined => {
  const mEvent = useStateEvent(room, StateEvent.RoomJoinRules);
  const joinRuleContent = mEvent?.getContent<RoomJoinRulesEventContent>();
  return joinRuleContent;
};