yaak-mountain-loop/src-web/hooks/usePinnedWebsocketConnection.ts

import { invoke } from '@tauri-apps/api/core';
import type { WebsocketConnection, WebsocketEvent } from '@yaakapp-internal/models';
import {
  mergeModelsInStore,
  replaceModelsInStore,
  websocketConnectionsAtom,
  websocketEventsAtom,
} from '@yaakapp-internal/models';
import { atom, useAtomValue } from 'jotai';
import { useEffect, useMemo } from 'react';
import { atomWithKVStorage } from '../lib/atoms/atomWithKVStorage';
import { jotaiStore } from '../lib/jotai';
import { activeRequestIdAtom } from './useActiveRequestId';

const pinnedWebsocketConnectionIdAtom = atomWithKVStorage<Record<string, string | null>>(
  'pinned-websocket-connection-ids',
  {},
);

function recordKey(activeRequestId: string | null, latestConnection: WebsocketConnection | null) {
  return `${activeRequestId}-${latestConnection?.id ?? 'none'}`;
}

export const activeWebsocketConnectionsAtom = atom<WebsocketConnection[]>((get) => {
  const activeRequestId = get(activeRequestIdAtom) ?? 'n/a';
  return get(websocketConnectionsAtom).filter((c) => c.requestId === activeRequestId) ?? [];
});

export const activeWebsocketConnectionAtom = atom<WebsocketConnection | null>((get) => {
  const activeRequestId = get(activeRequestIdAtom) ?? 'n/a';
  const activeConnections = get(activeWebsocketConnectionsAtom);
  const latestConnection = activeConnections[0] ?? null;
  const pinnedConnectionId = get(pinnedWebsocketConnectionIdAtom)[
    recordKey(activeRequestId, latestConnection)
  ];
  return activeConnections.find((c) => c.id === pinnedConnectionId) ?? activeConnections[0] ?? null;
});

export function setPinnedWebsocketConnectionId(id: string | null) {
  const activeRequestId = jotaiStore.get(activeRequestIdAtom);
  const activeConnections = jotaiStore.get(activeWebsocketConnectionsAtom);
  const latestConnection = activeConnections[0] ?? null;
  if (activeRequestId == null) return;
  jotaiStore.set(pinnedWebsocketConnectionIdAtom, (prev) => {
    return { ...prev, [recordKey(activeRequestId, latestConnection)]: id };
  });
}

export function useWebsocketEvents(connectionId: string | null) {
  const allEvents = useAtomValue(websocketEventsAtom);

  useEffect(() => {
    if (connectionId == null) {
      replaceModelsInStore('websocket_event', []);
      return;
    }

    // Fetch events from database, filtering out events from other connections and merging atomically
    invoke<WebsocketEvent[]>('models_websocket_events', { connectionId }).then((events) =>
      mergeModelsInStore('websocket_event', events, (e) => e.connectionId === connectionId),
    );
  }, [connectionId]);

  return useMemo(
    () => allEvents.filter((e) => e.connectionId === connectionId),
    [allEvents, connectionId],
  );
}