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

import { mkdtemp, mkdir, readFile, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { describe, expect, it } from "vitest";
import { createEngine, type AnimalDef, type GrowthSystem } 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 CHICKEN_DEF = {
  id: "chicken",
  stages: [
    { name: "chick", days: 2, feedRequired: false },
    { name: "grown", days: 2, feedRequired: true },
    { name: "laying", days: 1, feedRequired: true },
  ],
  produces: [{ itemId: "egg", qty: 1 }],
};

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-animal-ns-"));
  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 growthOf(engine: ReturnType<typeof createEngine>): GrowthSystem {
  const growth = engine.systems.get<GrowthSystem>("growth");
  if (!growth) throw new Error("growth system not booted");
  return growth;
}

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

      expect(engine.registry.get<AnimalDef>("animal", "chicken")).toEqual(CHICKEN_DEF);

      const file = await readFile(join(tmp, "animals", "chicken.yaml"), "utf8");
      expect(file).toContain("id: chicken");
      expect(file).toContain("feedRequired: true");

      await engine.stop();
      const reloaded = createEngine({ contentDir: tmp });
      await reloaded.start();
      try {
        expect(reloaded.registry.get<AnimalDef>("animal", "chicken")).toEqual(CHICKEN_DEF);
      } finally {
        await reloaded.stop();
      }
    } finally {
      await close();
    }
  });

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

      const invalid = await callText(gateway, "animal.validate", {
        def: { id: "nope", stages: [], produces: [] },
      });
      expect(invalid.ok).toBe(false);
      expect(invalid.text).toMatch(/stages/);
      expect(invalid.text).toMatch(/at least 1 element/);
    } finally {
      await close();
    }
  });

  it("animal.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, "animal.create", {
        def: { id: "broken", stages: [{ name: "x", days: 0, feedRequired: true }], produces: [] },
      });
      expect(bad.ok).toBe(false);
      expect(engine.registry.get("animal", "broken")).toBeUndefined();
      await expect(readFile(join(tmp, "animals", "broken.yaml"))).rejects.toThrow();
    } finally {
      await close();
    }
  });

  it("animal.update merges a patch, validates, rewrites the file, and re-registers", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "animal.create", { def: CHICKEN_DEF });
      const updated = await callText(gateway, "animal.update", {
        id: "chicken",
        patch: { produces: [{ itemId: "egg", qty: 2 }] },
      });
      expect(updated.ok).toBe(true);
      const def = JSON.parse(updated.text) as AnimalDef;
      expect(def.produces).toEqual([{ itemId: "egg", qty: 2 }]);
      expect(def.stages).toHaveLength(3);

      const file = await readFile(join(tmp, "animals", "chicken.yaml"), "utf8");
      expect(file).toContain("qty: 2");

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

      const badPatch = await callText(gateway, "animal.update", { id: "chicken", patch: { stages: [] } });
      expect(badPatch.ok).toBe(false);
      expect(badPatch.text).toMatch(/stages/);
      expect(engine.registry.get<AnimalDef>("animal", "chicken")?.produces).toEqual([{ itemId: "egg", qty: 2 }]);
    } finally {
      await close();
    }
  });

  it("animal.list and animal.get return definitions", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "animal.create", { def: CHICKEN_DEF });
      const listed = await callText(gateway, "animal.list");
      expect(listed.ok).toBe(true);
      expect(JSON.parse(listed.text)).toEqual({ animals: [{ id: "chicken", stageCount: 3 }] });

      const got = await callText(gateway, "animal.get", { animalId: "chicken" });
      expect(got.ok).toBe(true);
      expect(JSON.parse(got.text)).toEqual(CHICKEN_DEF);

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

  it("animal.spawn creates an entity; unknown def and bad coords are error results", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "animal.create", { def: CHICKEN_DEF });

      const spawned = await callText(gateway, "animal.spawn", { animalId: "chicken", x: 3, y: 3 });
      expect(spawned.ok).toBe(true);
      expect(JSON.parse(spawned.text)).toEqual({
        id: "animal:chicken:1",
        type: "animal",
        animalId: "chicken",
        x: 3,
        y: 3,
        stageIndex: 0,
        daysInStage: 0,
        fed: false,
      });

      const unknown = await callText(gateway, "animal.spawn", { animalId: "cow", x: 0, y: 0 });
      expect(unknown.ok).toBe(false);
      expect(unknown.text).toMatch(/unknown animal def: cow/);

      const bad = await callText(gateway, "animal.spawn", { animalId: "chicken", x: -1, y: 0 });
      expect(bad.ok).toBe(false);
      expect(bad.text).toMatch(/non-negative integers/);
    } finally {
      await close();
    }
  });

  it("animal.feed sets the fed flag and animal.stage force-advances (fires animal-grow)", async () => {
    const { engine, gateway, close } = await setup();
    try {
      await callText(gateway, "animal.create", { def: CHICKEN_DEF });
      await callText(gateway, "animal.spawn", { animalId: "chicken", x: 3, y: 3 });

      const grew: number[] = [];
      engine.hooks.on("onAnimalGrow", (ctx) => {
        const animal = ctx.world.query({ type: "animal" })[0] as { stageIndex?: number } | undefined;
        grew.push(animal?.stageIndex ?? -1);
      });

      const fed = await callText(gateway, "animal.feed", { id: "animal:chicken:1" });
      expect(fed.ok).toBe(true);
      expect(JSON.parse(fed.text)).toEqual({ id: "animal:chicken:1", animalId: "chicken", fed: true });

      const staged = await callText(gateway, "animal.stage", { id: "animal:chicken:1", stageIndex: 2 });
      expect(staged.ok).toBe(true);
      expect(JSON.parse(staged.text)).toEqual({
        id: "animal:chicken:1",
        animalId: "chicken",
        animalDefId: "chicken",
        stageIndex: 2,
        stage: "laying",
      });
      expect(grew).toEqual([2]);

      const unknownFeed = await callText(gateway, "animal.feed", { id: "ghost" });
      expect(unknownFeed.ok).toBe(false);
      expect(unknownFeed.text).toMatch(/unknown animal: ghost/);

      const badStage = await callText(gateway, "animal.stage", { id: "animal:chicken:1", stageIndex: 9 });
      expect(badStage.ok).toBe(false);
      expect(badStage.text).toMatch(/out of range/);
    } finally {
      await close();
    }
  });

  it("animal.entities lists placed animals; growth step advances them through the mechanism", async () => {
    const { engine, gateway, close } = await setup();
    try {
      await callText(gateway, "animal.create", { def: CHICKEN_DEF });
      await callText(gateway, "animal.spawn", { animalId: "chicken", x: 3, y: 3 });

      const listed = await callText(gateway, "animal.entities");
      expect(listed.ok).toBe(true);
      expect(JSON.parse(listed.text)).toEqual({
        animals: [{ id: "animal:chicken:1", type: "animal", animalId: "chicken", x: 3, y: 3, stageIndex: 0, daysInStage: 0, fed: false }],
      });

      growthOf(engine).feed("animal:chicken:1");
      growthOf(engine).step(480);
      growthOf(engine).step(480);
      const animal = engine.world.get("animal:chicken:1") as { stageIndex?: number };
      expect(animal.stageIndex).toBe(1);
    } finally {
      await close();
    }
  });

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

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

      const single = await gateway.readResource("animal://chicken");
      expect(JSON.parse(single.contents[0]?.text ?? "{}")).toEqual(CHICKEN_DEF);

      await expect(gateway.readResource("animal://missing")).rejects.toThrow(/animal not found: missing/);
    } finally {
      await close();
    }
  });

  it("serves the animal.create-prompt prompt", async () => {
    const { gateway, close } = await setup();
    try {
      const prompt = await gateway.getPrompt("animal.create-prompt", {});
      const text = prompt.messages[0]?.content.text ?? "";
      expect(text).toContain("stages");
      expect(text).toContain("feedRequired");
      expect(text).toContain("produces");
      expect(text).toContain("animal.validate");
      expect(text).toContain("content/animals/<id>.yaml");
    } finally {
      await close();
    }
  });
});