nEngine/packages/core/test/inventory.test.ts

import { resolve } from "node:path";
import { describe, expect, it } from "vitest";
import { createEngine, ContentRegistry, InventorySystem, World, WorldEventBus } from "../src/index.js";

const repoRoot = resolve(process.cwd(), "../..");
const contentDir = resolve(repoRoot, "content");
const modsDir = resolve(repoRoot, "mods");

function setup() {
  const world = new World();
  const registry = new ContentRegistry();
  const events = new WorldEventBus();
  world.create({ id: "player", type: "player", x: 0, y: 0 });
  const inv = new InventorySystem();
  inv.init({ world, registry, events });
  return { inv, world, events };
}

describe("InventorySystem", () => {
  it("init creates an inventory field on the player entity", () => {
    const { world } = setup();
    expect(world.get("player")?.inventory).toEqual({});
  });

  it("give/count/items roundtrip", () => {
    const { inv } = setup();
    expect(inv.give("hoe", 2)).toBe(2);
    expect(inv.give("hoe", 1)).toBe(3);
    expect(inv.count("hoe")).toBe(3);
    expect(inv.count("parsnip")).toBe(0);
    expect(inv.items()).toEqual({ hoe: 3 });
  });

  it("items() returns a snapshot copy, not a live reference", () => {
    const { inv } = setup();
    inv.give("hoe", 1);
    const snapshot = inv.items();
    inv.give("hoe", 1);
    expect(snapshot).toEqual({ hoe: 1 });
    expect(inv.items()).toEqual({ hoe: 2 });
  });

  it("give emits item-acquire with itemId, qty, and total", () => {
    const { inv, events } = setup();
    const seen: unknown[] = [];
    events.on("item-acquire", (p) => seen.push(p));
    inv.give("hoe", 2);
    expect(seen).toEqual([{ itemId: "hoe", qty: 2, total: 2 }]);
  });

  it("take decrements and emits item-use", () => {
    const { inv, events } = setup();
    const seen: unknown[] = [];
    events.on("item-use", (p) => seen.push(p));
    inv.give("hoe", 3);
    expect(inv.take("hoe", 1)).toBe(1);
    expect(seen).toEqual([{ itemId: "hoe", qty: 1, total: 2 }]);
    expect(inv.count("hoe")).toBe(2);
  });

  it("take clamps to the available quantity when insufficient", () => {
    const { inv, events } = setup();
    const seen: unknown[] = [];
    events.on("item-use", (p) => seen.push(p));
    inv.give("hoe", 3);
    expect(inv.take("hoe", 10)).toBe(3);
    expect(inv.count("hoe")).toBe(0);
    expect(inv.items()).toEqual({});
    expect(seen).toEqual([{ itemId: "hoe", qty: 3, total: 0 }]);
  });

  it("take of an absent item returns 0 and emits nothing", () => {
    const { inv, events } = setup();
    const seen: unknown[] = [];
    events.on("item-use", (p) => seen.push(p));
    expect(inv.take("hoe", 5)).toBe(0);
    expect(seen).toHaveLength(0);
  });

  it("give/take reject non-positive quantities", () => {
    const { inv } = setup();
    expect(() => inv.give("hoe", 0)).toThrow(/positive integer/);
    expect(() => inv.give("hoe", -1)).toThrow(/positive integer/);
    expect(() => inv.give("hoe", 1.5)).toThrow(/positive integer/);
    expect(() => inv.take("hoe", 0)).toThrow(/positive integer/);
  });

  it("wireEvents: inventory events fire onItemAcquire/onItemUse hooks with a HookContext", async () => {
    const engine = createEngine({ contentDir, modsDir });
    await engine.start();
    try {
      const acquired: unknown[] = [];
      const used: unknown[] = [];
      engine.hooks.on("onItemAcquire", (ctx) => {
        acquired.push({ world: ctx.world.get("player")?.id, time: ctx.time.get().day });
      });
      engine.hooks.on("onItemUse", (ctx) => {
        used.push({ world: ctx.world.get("player")?.id, time: ctx.time.get().day });
      });

      const inv = engine.systems.get<InventorySystem>("inventory");
      expect(inv).toBeDefined();
      inv!.give("hoe", 2);
      inv!.take("hoe", 1);

      expect(acquired).toEqual([{ world: "player", time: 1 }]);
      expect(used).toEqual([{ world: "player", time: 1 }]);
      expect(inv!.items()).toEqual({ hoe: 1 });
    } finally {
      await engine.stop();
    }
  });
});