// @vitest-environment jsdom
//
// A shared Plex link carries the collection filter as bare rating_keys — `?pf=collections%3D17045`
// says nothing about what 17045 is called. Opened cold, the sidebar token rendered that raw id and
// the applied-filter chip could only say "Collection". This hook resolves the missing ones.
//
// Two things it must NOT do: ask the server for a title the filter state already carries (the common
// case — the user picked the collection in the sidebar), and pull the whole collection list to find
// one name (431 collections / ~200 KB on the owner's library).
import { describe, it, expect, vi, beforeEach } from "vitest";
import { renderHook, waitFor } from "@testing-library/react";
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { createElement, type ReactNode } from "react";

const plexCollections = vi.fn();
vi.mock("./api", () => ({ api: { plexCollections: (...a: unknown[]) => plexCollections(...a) } }));

import { usePlexCollectionTitles } from "./usePlexCollectionTitles";

const wrap = () => {
  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
  return ({ children }: { children: ReactNode }) =>
    createElement(QueryClientProvider, { client: qc }, children);
};

const CATALOG: Record<string, string> = {
  "17045": "Pirates of the Caribbean Collection",
  "68231": "IMDb Top 250",
};

beforeEach(() => {
  plexCollections.mockReset();
  // Answer like the endpoint does: only the requested keys come back.
  plexCollections.mockImplementation((_lib: unknown, _q: unknown, keys: string[]) =>
    Promise.resolve({
      collections: (keys ?? []).map((id) => ({ id, title: CATALOG[id] })),
    }),
  );
});

describe("usePlexCollectionTitles", () => {
  it("resolves the ids the filter state has no title for", async () => {
    const { result } = renderHook(() => usePlexCollectionTitles(["17045"], undefined), {
      wrapper: wrap(),
    });
    await waitFor(() =>
      expect(result.current.titles["17045"]).toBe("Pirates of the Caribbean Collection"),
    );
    // Only the missing ids are asked for — nothing else.
    expect(plexCollections).toHaveBeenCalledWith(undefined, undefined, ["17045"]);
  });

  it("asks for nothing when every id already has a title", async () => {
    const known = { "17045": "Pirates of the Caribbean Collection" };
    const { result } = renderHook(() => usePlexCollectionTitles(["17045"], known), {
      wrapper: wrap(),
    });
    expect(result.current.titles["17045"]).toBe("Pirates of the Caribbean Collection");
    // Give a would-be fetch a chance to happen before asserting it did not.
    await new Promise((r) => setTimeout(r, 20));
    expect(plexCollections).not.toHaveBeenCalled();
  });

  it("asks only for the missing half of a mixed selection", async () => {
    const { result } = renderHook(
      () => usePlexCollectionTitles(["17045", "68231"], { "17045": "Already Known" }),
      { wrapper: wrap() },
    );
    await waitFor(() => expect(result.current.titles["68231"]).toBe("IMDb Top 250"));
    // The known id is not in the request — and its stored title survives the merge.
    expect(plexCollections).toHaveBeenCalledWith(undefined, undefined, ["68231"]);
    expect(result.current.titles["17045"]).toBe("Already Known");
  });

  it("treats the same ids in a different order as one query", async () => {
    const w = wrap();
    const a = renderHook(() => usePlexCollectionTitles(["68231", "17045"], undefined), {
      wrapper: w,
    });
    await waitFor(() => expect(a.result.current.titles["17045"]).toBeDefined());
    const calls = plexCollections.mock.calls.length;
    const b = renderHook(() => usePlexCollectionTitles(["17045", "68231"], undefined), {
      wrapper: w,
    });
    await waitFor(() => expect(b.result.current.titles["17045"]).toBeDefined());
    expect(plexCollections.mock.calls.length).toBe(calls);
  });

  it("returns nothing extra while the lookup is still in flight", () => {
    plexCollections.mockReturnValue(new Promise(() => {}));
    const { result } = renderHook(() => usePlexCollectionTitles(["17045"], undefined), {
      wrapper: wrap(),
    });
    // The caller falls back to its own label; it must not be handed a half-built map — and it is
    // told the names are on their way, so it draws a placeholder rather than the raw id.
    expect(result.current.titles["17045"]).toBeUndefined();
    expect(result.current.pending).toBe(true);
  });

  it("is not pending when nothing is missing, nor once the lookup answered", async () => {
    const known = renderHook(() => usePlexCollectionTitles(["17045"], { "17045": "Known" }), {
      wrapper: wrap(),
    });
    expect(known.result.current.pending).toBe(false);
    const cold = renderHook(() => usePlexCollectionTitles(["17045"], undefined), {
      wrapper: wrap(),
    });
    await waitFor(() => expect(cold.result.current.pending).toBe(false));
    expect(cold.result.current.titles["17045"]).toBe("Pirates of the Caribbean Collection");
  });
});