import { readdirSync, readFileSync } from "node:fs";
import { describe, expect, it } from "vitest";

// The whole app source: a state write can be made from any page.
const root = new URL("../../", import.meta.url);
const sources = () =>
  readdirSync(root, { recursive: true, encoding: "utf8" })
    .map((f) => f.replace(/\\/g, "/"))
    .filter((f) => /\.tsx?$/.test(f) && !f.includes(".test."))
    .map((f) => ({ f, src: readFileSync(new URL(f, root), "utf8") }));

// The api's own definitions of these writes, and the one module that may call them.
const ALLOWED = new Set([
  "lib/api/feed.ts",
  "lib/api/playlists.ts",
  "features/video/videoWrites.ts",
]);

// A related list and a live search are never refetched, so a state, Watch-later or playlist-item
// write that does not reach them (`markVideo`) leaves them showing the old mark for the session —
// the built-in Watch later list's items ARE the mark. videoWrites makes those writes and the mark
// together; a direct api call skips the mark.
const WRITES =
  /\bapi\s*\.\s*(setState|clearState|watchLaterAdd|watchLaterRemove|addToPlaylist|removeFromPlaylist|moveToPlaylist)\b/;

describe("a video's state, Watch-later and playlist-item writes", () => {
  it("go through features/video/videoWrites, never the api directly", () => {
    const offenders = sources()
      .filter(({ f }) => !ALLOWED.has(f))
      // Only the api object's members count (React's own `setState` is not ours) — named, not only
      // called: `(saved ? api.watchLaterAdd : api.watchLaterRemove)(id)` makes the write too. The
      // dot may sit on the next line of a chain.
      .filter(({ src }) => WRITES.test(src))
      .map(({ f }) => f);
    expect(offenders).toEqual([]);
  });

  it("catches a write named without being called on the spot, and a playlist item's", () => {
    expect(WRITES.test("(saved ? api.watchLaterAdd : api.watchLaterRemove)(id)")).toBe(true);
    expect(WRITES.test("await api\n  .removeFromPlaylist(listId, id)")).toBe(true);
    expect(WRITES.test("api.moveToPlaylist(a, id, b)")).toBe(true);
    expect(WRITES.test("this.setState(next); api.playlists()")).toBe(false);
  });
});