import { Writable, computed, pattern } from "commonfabric";

const KEY = "k";
const ANY_KEY: string = "k";

// FIXTURE: computed-element-access-dynamic-key
// Verifies: an element access whose key can name any member reads the whole static prefix above the key, so the receiver keeps that prefix
//   catalog.get().offers[key.get()].space, offers[ANY_KEY], offers[String(KEY)], and offers[k] in a map callback each keep catalog in the lift's input
//   items.get()[idx.get()] directly on the `.get()` result keeps items the same way
//   a typed capture read through offers[ANY_KEY] keeps offers whole and drops its unread meta
// Context: Every lift has at least two captures, so a dropped read would shrink one out
export default pattern(() => {
  const catalog = new Writable<Record<string, any>>({ offers: {} });
  const n = new Writable<number>(0);
  const key = new Writable<string>("k");
  const items = new Writable<number[]>([]);
  const idx = new Writable<number>(0);
  const keys = new Writable<string[]>(["k"]);
  const typed = new Writable<{
    offers: Record<string, { space: string }>;
    meta: { x: number };
  }>({ offers: {}, meta: { x: 1 } });

  const captureKey = computed(() =>
    n.get() === 1 && catalog.get().offers[key.get()].space === "room"
  );
  const stringTypedKey = computed(() =>
    n.get() === 1 && catalog.get().offers[ANY_KEY].space === "room"
  );
  const callKey = computed(() =>
    n.get() === 1 && catalog.get().offers[String(KEY)].space === "room"
  );
  const callbackParameterKey = computed(() =>
    keys.get().map((k) => n.get() === 1 && catalog.get().offers[k].space)
  );
  const indexOnGetResult = computed(() => n.get() + items.get()[idx.get()]!);
  const typedAnyKey = computed(() =>
    n.get() === 1 && typed.get().offers[ANY_KEY]?.space === "room"
  );

  return {
    captureKey,
    stringTypedKey,
    callKey,
    callbackParameterKey,
    indexOnGetResult,
    typedAnyKey,
  };
});