import { useEffect } from 'react';
import { useAtomValue } from 'jotai';
import { Room } from 'matrix-js-sdk';
import { allRoomsAtom } from '../state/room-list/roomList';
import { useMatrixClient } from './useMatrixClient';
import { isTauri, invokeTauri } from './useTauri';

/** Cap the Jump List to a small, glanceable set of rooms. */
const MAX_ITEMS = 8;

/** Wait for room activity to settle before re-publishing the (native) list. */
const DEBOUNCE_MS = 1500;

type JumpItem = { title: string; uri: string };

/**
 * Build the `matrix:` deep link the desktop deep-link handler understands (see
 * `useDeepLinkNavigate`): `matrix:r/<alias>` for a canonical alias, otherwise
 * `matrix:roomid/<id>`. The sigil is dropped and the remainder is percent-encoded
 * because the handler decodes each segment with `decodeURIComponent`.
 */
const roomToUri = (room: Room): string => {
  const alias = room.getCanonicalAlias();
  if (alias && alias.startsWith('#')) {
    return `matrix:r/${encodeURIComponent(alias.slice(1))}`;
  }
  return `matrix:roomid/${encodeURIComponent(room.roomId.slice(1))}`;
};

/**
 * P5-36 — publish a Windows taskbar Jump List of the most recently-active rooms.
 * Rooms come from `allRoomsAtom` (the joined-room list), sorted by
 * `getLastActiveTimestamp` (mirroring the sort used elsewhere, e.g. the forward
 * dialog), with spaces excluded. The list is pushed to the native
 * `set_jump_list` command, debounced so bursts of activity don't thrash the
 * shell. No-op outside Tauri.
 */
export function useTauriJumpList(): void {
  const mx = useMatrixClient();
  const allRooms = useAtomValue(allRoomsAtom);

  useEffect(() => {
    if (!isTauri()) return undefined;

    const timeout = setTimeout(() => {
      const items: JumpItem[] = allRooms
        .map((roomId) => mx.getRoom(roomId))
        .filter((room): room is Room => room !== null && !room.isSpaceRoom())
        .sort((a, b) => (b.getLastActiveTimestamp() ?? 0) - (a.getLastActiveTimestamp() ?? 0))
        .slice(0, MAX_ITEMS)
        .map((room) => ({ title: room.name || room.roomId, uri: roomToUri(room) }));

      invokeTauri('set_jump_list', { items });
    }, DEBOUNCE_MS);

    return () => clearTimeout(timeout);
  }, [mx, allRooms]);
}