nxdns/admin/src/features/overview/overviewWindow.ts

/**
 * One period, one request, one window.
 *
 * The five per-panel endpoints this replaces could each answer for a different
 * span, so the page had to reconcile five window identities, retry the laggards
 * and fail the ones that stayed behind. `GET /api/overview` answers every panel
 * out of a single read transaction: the totals, both timelines and both
 * breakdowns describe the same span and the same database state by construction,
 * and none of that reconciliation has anything left to reconcile.
 *
 * What remains is the one rule a single request does not settle by itself.
 * `keepPreviousData` holds the body of the period the reader just left — a
 * complete, self-consistent answer, and still the wrong one to draw under the
 * new label — so a body is a member of this window only while its own `period`
 * is the selected one. Until then the page is loading.
 */

import { useCallback } from "react";
import { keepPreviousData, useQuery } from "@tanstack/react-query";
import { overviewQuery } from "@/lib/queries";
import type { Overview, Period } from "@/lib/types";

export type Panel<T> =
	{ status: "loading" } | { status: "error"; error: unknown; retry: () => void } | { status: "ready"; data: T };

export function useOverviewWindow(period: Period): Panel<Overview> {
	const query = useQuery({ ...overviewQuery(period), placeholderData: keepPreviousData });
	const { refetch } = query;
	const retry = useCallback(() => void refetch(), [refetch]);

	if (query.isError) return { status: "error", error: query.error, retry };
	if (query.data !== undefined && query.data.period === period) return { status: "ready", data: query.data };
	return { status: "loading" };
}