"use client";

import { createContext, useContext, type ReactNode } from "react";
import type { CitationView } from "../../lib/report/views";

// A PAGE'S CITATIONS, ONCE. Every inline marker (InlineCite) on a report page
// needs its citation's view — the label's href, the number, the preview card.
// Handing each marker its own copy as a prop would serialize that view into the
// page's RSC payload once per marker; a page with hundreds of markers paid for
// it hundreds of times. Instead the page wraps its content in one
// CitationsProvider, whose map is serialized once, and each marker carries only
// its id and reads the view here at render time (on the server for the HTML,
// in the browser for the preview).

const CitationsContext = createContext<Readonly<Record<string, CitationView>> | null>(null);

export function CitationsProvider({
  citations,
  children,
}: {
  citations: Readonly<Record<string, CitationView>>;
  children: ReactNode;
}) {
  return <CitationsContext.Provider value={citations}>{children}</CitationsContext.Provider>;
}

// The view of citation `id` from the nearest provider, or undefined.
export function useCitation(id: string | undefined): CitationView | undefined {
  const map = useContext(CitationsContext);
  return id !== undefined && map && Object.hasOwn(map, id) ? map[id] : undefined;
}