import { describe, expect, test } from "bun:test";
import { batch, computed, effect, signal } from "../src/index.ts";

describe("reactive primitives", () => {
  test("signals skip no-op updates", () => {
    const value = signal(1);
    const seen: number[] = [];
    value.subscribe((next) => seen.push(next));
    value.set(1);
    value.set(2);
    expect(seen).toEqual([2]);
  });

  test("batch coalesces notifications", () => {
    const value = signal(0);
    const seen: number[] = [];
    value.subscribe((next) => seen.push(next));
    batch(() => {
      value.set(1);
      value.set(2);
      value.set(3);
    });
    expect(seen).toEqual([3]);
  });

  test("computed values and effects track dependencies", () => {
    const count = signal(2);
    const doubled = computed(() => count.get() * 2);
    const seen: number[] = [];
    const dispose = effect(() => {
      seen.push(doubled.get());
    });
    count.set(3);
    dispose();
    count.set(4);
    expect(seen).toEqual([4, 6]);
  });

  test("effects ignore accidental non-function return values", () => {
    const value = signal(0);
    const seen: number[] = [];
    const dispose = effect(() => seen.push(value.get()) as unknown as void);
    value.set(1);
    dispose();
    expect(seen).toEqual([0, 1]);
  });
});