nEngine/packages/mcp/test/shop-namespace.test.ts

import { mkdtemp, mkdir, readFile, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join, resolve } from "node:path";
import { describe, expect, it } from "vitest";
import { createEngine, type InventorySystem, type ShopDef } from "@nengine/core";
import { createEngineNamespaces, McpGateway } from "../src/index.js";

const TIME_YAML = [
  "id: default",
  "dayLengthTicks: 480",
  "seasons:",
  "  - { name: spring, dayCount: 28 }",
  "start: { day: 1, season: spring }",
  "",
].join("\n");

const FARM_YAML = [
  "id: farm",
  "width: 2",
  "height: 2",
  'tilesetRef: "tiles"',
  "spawn: { x: 0, y: 0 }",
  "layers:",
  "  - name: ground",
  "    data:",
  "      - [a, b]",
  "      - [b, a]",
  "",
].join("\n");

const GENERAL_STORE_DEF = {
  id: "general-store",
  buys: [{ itemId: "parsnip", price: 30 }],
  sells: [
    { itemId: "hoe", price: 500 },
    { itemId: "parsnip-seed", price: 20, stock: 99 },
  ],
};

interface Setup {
  engine: ReturnType<typeof createEngine>;
  gateway: McpGateway;
  tmp: string;
  close: () => Promise<void>;
}

async function setup(): Promise<Setup> {
  const tmp = await mkdtemp(join(tmpdir(), "farm-shop-"));
  await mkdir(join(tmp, "maps"), { recursive: true });
  await writeFile(join(tmp, "time.yaml"), TIME_YAML);
  await writeFile(join(tmp, "maps", "farm.yaml"), FARM_YAML);

  const engine = createEngine({ contentDir: tmp });
  const gateway = new McpGateway();
  for (const namespace of createEngineNamespaces(engine, { gateway })) {
    gateway.register(namespace);
  }
  await engine.start();
  return {
    engine,
    gateway,
    tmp,
    close: async () => {
      await engine.stop();
      await rm(tmp, { recursive: true, force: true });
    },
  };
}

async function callText(gateway: McpGateway, name: string, args: Record<string, unknown> = {}): Promise<{
  ok: boolean;
  text: string;
}> {
  const result = await gateway.callTool(name, args);
  return { ok: result.isError !== true, text: result.content[0]?.text ?? "" };
}

function registerItems(engine: ReturnType<typeof createEngine>): void {
  engine.registry.register("item", { id: "hoe", name: "Hoe", kind: "tool", stackable: false });
  engine.registry.register("item", { id: "parsnip-seed", name: "Parsnip Seed", kind: "seed", stackable: true });
  engine.registry.register("item", { id: "parsnip", name: "Parsnip", kind: "material", stackable: true });
}

function setGold(engine: ReturnType<typeof createEngine>, gold: number): void {
  const player = engine.world.get("player");
  if (!player) throw new Error("player entity not seeded");
  player.gold = gold;
}

function inventoryOf(engine: ReturnType<typeof createEngine>): InventorySystem {
  const inv = engine.systems.get<InventorySystem>("inventory");
  if (!inv) throw new Error("inventory system not booted");
  return inv;
}

describe("shop namespace", () => {
  it("shop.create writes content/shops/<id>.yaml, registers live, and persists across restart", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      const created = await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      expect(created.ok).toBe(true);
      expect(JSON.parse(created.text) as ShopDef).toEqual(GENERAL_STORE_DEF);

      expect(engine.registry.get<ShopDef>("shop", "general-store")).toEqual(GENERAL_STORE_DEF);

      const file = await readFile(join(tmp, "shops", "general-store.yaml"), "utf8");
      expect(file).toContain("id: general-store");
      expect(file).toContain("buys:");
      expect(file).toContain("stock: 99");

      await engine.stop();
      const reloaded = createEngine({ contentDir: tmp });
      await reloaded.start();
      try {
        expect(reloaded.registry.get<ShopDef>("shop", "general-store")).toEqual(GENERAL_STORE_DEF);
      } finally {
        await reloaded.stop();
      }
    } finally {
      await close();
    }
  });

  it("shop.validate accepts a valid def and rejects an invalid one", async () => {
    const { gateway, close } = await setup();
    try {
      const valid = await callText(gateway, "shop.validate", { def: GENERAL_STORE_DEF });
      expect(valid.ok).toBe(true);
      expect(JSON.parse(valid.text)).toEqual(GENERAL_STORE_DEF);

      const invalid = await callText(gateway, "shop.validate", {
        def: { id: "nope", buys: [{ itemId: "x", price: 0 }], sells: [] },
      });
      expect(invalid.ok).toBe(false);
      expect(invalid.text).toMatch(/price/);
      expect(invalid.text).toMatch(/greater than 0/);
    } finally {
      await close();
    }
  });

  it("shop.create rejects an invalid def and does not write or register", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      const bad = await callText(gateway, "shop.create", {
        def: { id: "broken", buys: [{ itemId: "x", price: -5 }], sells: [] },
      });
      expect(bad.ok).toBe(false);
      expect(engine.registry.get("shop", "broken")).toBeUndefined();
      await expect(readFile(join(tmp, "shops", "broken.yaml"))).rejects.toThrow();
    } finally {
      await close();
    }
  });

  it("duplicate shop.create overwrites the existing definition", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      const recreated = await callText(gateway, "shop.create", {
        def: {
          ...GENERAL_STORE_DEF,
          sells: [...GENERAL_STORE_DEF.sells, { itemId: "parsnip", price: 45, stock: 10 }],
        },
      });
      expect(recreated.ok).toBe(true);

      const current = engine.registry.get<ShopDef>("shop", "general-store");
      expect(current?.sells).toHaveLength(3);

      const file = await readFile(join(tmp, "shops", "general-store.yaml"), "utf8");
      expect(file).toContain("itemId: parsnip");
      expect(file).toContain("stock: 10");
    } finally {
      await close();
    }
  });

  it("shop.update merges a patch, validates, rewrites the file, and re-registers", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      const updated = await callText(gateway, "shop.update", {
        id: "general-store",
        patch: { buys: [{ itemId: "parsnip", price: 40 }] },
      });
      expect(updated.ok).toBe(true);
      const def = JSON.parse(updated.text) as ShopDef;
      expect(def.buys).toEqual([{ itemId: "parsnip", price: 40 }]);
      expect(def.sells).toHaveLength(2);

      const file = await readFile(join(tmp, "shops", "general-store.yaml"), "utf8");
      expect(file).toContain("price: 40");

      const missing = await callText(gateway, "shop.update", { id: "nope", patch: { buys: [] } });
      expect(missing.ok).toBe(false);
      expect(missing.text).toMatch(/shop not found: nope/);

      const badPatch = await callText(gateway, "shop.update", { id: "general-store", patch: { sells: [{ itemId: "x", price: 0 }] } });
      expect(badPatch.ok).toBe(false);
      expect(badPatch.text).toMatch(/price/);
      expect(engine.registry.get<ShopDef>("shop", "general-store")?.buys).toEqual([
        { itemId: "parsnip", price: 40 },
      ]);
    } finally {
      await close();
    }
  });

  it("shop.list returns one-line summaries", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      const listed = await callText(gateway, "shop.list");
      expect(listed.ok).toBe(true);
      expect(JSON.parse(listed.text)).toEqual({
        shops: [{ id: "general-store", buyCount: 1, sellCount: 2 }],
      });
    } finally {
      await close();
    }
  });

  it("shop.get returns the full def; unknown id is an error result", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      const got = await callText(gateway, "shop.get", { shopId: "general-store" });
      expect(got.ok).toBe(true);
      expect(JSON.parse(got.text)).toEqual(GENERAL_STORE_DEF);

      const missing = await callText(gateway, "shop.get", { shopId: "nope" });
      expect(missing.ok).toBe(false);
      expect(missing.text).toMatch(/shop not found: nope/);
    } finally {
      await close();
    }
  });

  it("shop.buy deducts gold, grants inventory, and returns the transaction result", async () => {
    const { engine, gateway, close } = await setup();
    try {
      registerItems(engine);
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      setGold(engine, 100);

      const bought = await callText(gateway, "shop.buy", { shopId: "general-store", itemId: "parsnip-seed", qty: 2 });
      expect(bought.ok).toBe(true);
      expect(JSON.parse(bought.text)).toEqual({
        shopId: "general-store",
        itemId: "parsnip-seed",
        qty: 2,
        total: 40,
        gold: 60,
      });
      expect(engine.world.get("player")?.gold).toBe(60);
      expect(inventoryOf(engine).count("parsnip-seed")).toBe(2);
    } finally {
      await close();
    }
  });

  it("shop.buy error paths: missing shop, item not sold, insufficient gold, bad qty", async () => {
    const { engine, gateway, close } = await setup();
    try {
      registerItems(engine);
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      setGold(engine, 100);

      const noShop = await callText(gateway, "shop.buy", { shopId: "nope", itemId: "hoe", qty: 1 });
      expect(noShop.ok).toBe(false);
      expect(noShop.text).toMatch(/unknown shop: nope/);

      const notSold = await callText(gateway, "shop.buy", { shopId: "general-store", itemId: "parsnip", qty: 1 });
      expect(notSold.ok).toBe(false);
      expect(notSold.text).toMatch(/does not sell parsnip/);

      const broke = await callText(gateway, "shop.buy", { shopId: "general-store", itemId: "hoe", qty: 1 });
      expect(broke.ok).toBe(false);
      expect(broke.text).toMatch(/insufficient gold/);
      expect(engine.world.get("player")?.gold).toBe(100);

      const badQty = await callText(gateway, "shop.buy", { shopId: "general-store", itemId: "hoe", qty: 0 });
      expect(badQty.ok).toBe(false);
      expect(badQty.text).toMatch(/positive integer/);
    } finally {
      await close();
    }
  });

  it("shop.sell removes inventory, adds gold, and returns the transaction result", async () => {
    const { engine, gateway, close } = await setup();
    try {
      registerItems(engine);
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });
      inventoryOf(engine).give("parsnip", 3);

      const sold = await callText(gateway, "shop.sell", { shopId: "general-store", itemId: "parsnip", qty: 2 });
      expect(sold.ok).toBe(true);
      expect(JSON.parse(sold.text)).toEqual({
        shopId: "general-store",
        itemId: "parsnip",
        qty: 2,
        total: 60,
        gold: 60,
      });
      expect(engine.world.get("player")?.gold).toBe(60);
      expect(inventoryOf(engine).count("parsnip")).toBe(1);
    } finally {
      await close();
    }
  });

  it("shop.sell error paths: item not bought, insufficient inventory, missing shop", async () => {
    const { engine, gateway, close } = await setup();
    try {
      registerItems(engine);
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });

      const notBought = await callText(gateway, "shop.sell", { shopId: "general-store", itemId: "hoe", qty: 1 });
      expect(notBought.ok).toBe(false);
      expect(notBought.text).toMatch(/does not buy hoe/);

      inventoryOf(engine).give("parsnip", 1);
      const short = await callText(gateway, "shop.sell", { shopId: "general-store", itemId: "parsnip", qty: 5 });
      expect(short.ok).toBe(false);
      expect(short.text).toMatch(/insufficient parsnip/);
      expect(engine.world.get("player")?.gold).toBe(0);

      const noShop = await callText(gateway, "shop.sell", { shopId: "nope", itemId: "parsnip", qty: 1 });
      expect(noShop.ok).toBe(false);
      expect(noShop.text).toMatch(/unknown shop: nope/);
    } finally {
      await close();
    }
  });

  it("resources: shop://catalog and shop://{shopId}; missing id rejects", async () => {
    const { engine, gateway, close } = await setup();
    try {
      await callText(gateway, "shop.create", { def: GENERAL_STORE_DEF });

      const catalog = await gateway.readResource("shop://catalog");
      expect(JSON.parse(catalog.contents[0]?.text ?? "{}")).toEqual({ shops: [GENERAL_STORE_DEF] });

      const single = await gateway.readResource("shop://general-store");
      expect(JSON.parse(single.contents[0]?.text ?? "{}")).toEqual(GENERAL_STORE_DEF);

      await expect(gateway.readResource("shop://missing")).rejects.toThrow(/shop not found: missing/);
      expect(engine.registry.get("shop", "missing")).toBeUndefined();
    } finally {
      await close();
    }
  });

  it("serves the shop.create-prompt prompt", async () => {
    const { gateway, close } = await setup();
    try {
      const prompt = await gateway.getPrompt("shop.create-prompt", {});
      const text = prompt.messages[0]?.content.text ?? "";
      expect(text).toContain("buys");
      expect(text).toContain("sells");
      expect(text).toContain("stock");
      expect(text).toContain("shop.validate");
      expect(text).toContain("content/shops/<id>.yaml");
    } finally {
      await close();
    }
  });
});