import { expect, test } from "bun:test";
import { getStoreForTest, setStoreResolver } from "../src/store-bridge.ts";

function fakeStore(initial: { count: number }) {
  let state = { ...initial };
  const listeners = new Set<() => void>();
  return {
    snapshot: () => Object.freeze({ ...state }),
    subscribe(listener: () => void) {
      listeners.add(listener);
      return () => listeners.delete(listener);
    },
    actions: {
      increment: () => {
        state = { count: state.count + 1 };
        for (const listener of [...listeners]) listener();
      },
    },
  };
}

test("resolves a registered store and caches its snapshot", () => {
  const store = fakeStore({ count: 0 });
  setStoreResolver((name) => (name === "counter" ? store : undefined), ["counter"]);

  const bound = getStoreForTest<{ count: number }>("counter");
  expect(bound.getSnapshot()).toBe(bound.getSnapshot());

  bound.store.actions.increment!();
  expect(bound.getSnapshot().count).toBe(1);

  setStoreResolver(null);
});

test("throws a helpful error for an unknown store name", () => {
  setStoreResolver(
    (name) => (name === "counter" ? fakeStore({ count: 0 }) : undefined),
    ["counter"],
  );

  expect(() => getStoreForTest("typo")).toThrow(/Unknown WRNexus store "typo"/);
  expect(() => getStoreForTest("typo")).toThrow(/counter/);

  setStoreResolver(null);
});

test("throws when no resolver has been registered yet", () => {
  setStoreResolver(null);
  expect(() => getStoreForTest("counter")).toThrow(/before the island runtime registered/);
});