import { QueryClient } from '@tanstack/react-query'

// Module-level singleton — shared across SSR hydration, tRPC, and all
// components so mutations/invalidations hit the same cache.
let queryClient: QueryClient | undefined

export function getQueryClient() {
  if (!queryClient) {
    queryClient = new QueryClient({
      defaultOptions: {
        queries: {
          staleTime: 30 * 1000,
          retry: 2,
          refetchOnWindowFocus: false,
          // Refetch when a screen remounts (navigating back to it) even within
          // staleTime — the web equivalent of native useMarkDataFetchers.
          refetchOnMount: 'always',
        },
      },
    })
  }
  return queryClient
}