nEngine/packages/mcp/test/namespaces.test.ts

import { resolve } from "node:path";
import { describe, expect, it } from "vitest";
import { createEngine } from "@nengine/core";
import { createEngineNamespaces, McpGateway } from "../src/index.js";
import type { McpNamespace } from "../src/namespace.js";

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

interface Setup {
  engine: ReturnType<typeof createEngine>;
  gateway: McpGateway;
}

async function setup(): Promise<Setup> {
  const engine = createEngine({ contentDir, modsDir });
  const gateway = new McpGateway();
  for (const namespace of createEngineNamespaces(engine, { gateway })) {
    gateway.register(namespace);
  }
  await engine.start();
  return { engine, gateway };
}

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 ?? "" };
}

describe("engine namespaces", () => {
  it("server.info reports engine identity, content stats, subsystems, and time", async () => {
    const { engine, gateway } = await setup();
    try {
      const result = await callText(gateway, "server.info");
      expect(result.ok).toBe(true);
      const info = JSON.parse(result.text) as {
        engine: string;
        content: Record<string, string[]>;
        subsystems: { name: string; enabled: boolean }[];
        time: { day: number; season: string; tickInDay: number };
      };
      expect(info.engine).toBe("nengine");
      expect(info.content["map"]).toContain("farm");
      expect(info.content["time"]).toContain("default");
      expect(info.subsystems.map((s) => s.name).sort()).toEqual(["animal", "animation", "behavior", "crop", "dialogue", "item", "map", "mod", "npc", "particle", "placement", "player", "rng", "save", "scene", "server", "shader", "shop", "sound", "sprite", "time", "weather"]);
      expect(info.time).toEqual({ day: 1, season: "spring", tickInDay: 0 });
      expect(engine.registry.ids("map")).toEqual(["farm"]);
    } finally {
      await engine.stop();
    }
  });

  it("map.list and map.get return the normalized map plus player spawn", async () => {
    const { engine, gateway } = await setup();
    try {
      const listed = await callText(gateway, "map.list");
      const maps = (JSON.parse(listed.text) as { maps: { id: string; width: number; height: number }[] }).maps;
      expect(maps).toEqual([{ id: "farm", width: 12, height: 12, tilesetRef: "farm-tiles" }]);

      const got = await callText(gateway, "map.get");
      const map = JSON.parse(got.text) as { id: string; layers: unknown[]; spawn: { x: number; y: number }; player: { x: number; y: number } };
      expect(map.id).toBe("farm");
      expect(map.layers.length).toBe(1);
      expect(map.spawn).toEqual({ x: 2, y: 2 });
      expect(map.player).toMatchObject({ id: "player", type: "player", x: 2, y: 2 });

      const missing = await callText(gateway, "map.get", { mapId: "nope" });
      expect(missing.ok).toBe(false);
      expect(missing.text).toMatch(/map not found: nope/);
    } finally {
      await engine.stop();
    }
  });

  it("time.get, time.advance, and time.set read and mutate the TimeSystem", async () => {
    const { engine, gateway } = await setup();
    try {
      const initial = await callText(gateway, "time.get");
      expect(JSON.parse(initial.text)).toEqual({ day: 1, season: "spring", tickInDay: 0 });

      const advanced = await callText(gateway, "time.advance", { ticks: 480 });
      expect(JSON.parse(advanced.text)).toEqual({ day: 2, season: "spring", tickInDay: 0 });

      const engineTime = engine.systems.get("time");
      expect(engineTime?.get()).toEqual({ day: 2, season: "spring", tickInDay: 0 });

      const set = await callText(gateway, "time.set", { day: 12, season: "summer" });
      expect(JSON.parse(set.text)).toEqual({ day: 12, season: "summer", tickInDay: 0 });

      const invalid = await callText(gateway, "time.advance", { ticks: -1 });
      expect(invalid.ok).toBe(false);
      expect(invalid.text).toMatch(/positive integer/);
    } finally {
      await engine.stop();
    }
  });

  it("reads server, time, and template map resources", async () => {
    const { engine, gateway } = await setup();
    try {
      const status = await gateway.readResource("server://status");
      expect(JSON.parse(status.contents[0]?.text ?? "{}")).toMatchObject({ engine: "nengine" });

      const timeState = await gateway.readResource("time://state");
      expect(JSON.parse(timeState.contents[0]?.text ?? "{}")).toEqual({ day: 1, season: "spring", tickInDay: 0 });

      const mapResource = await gateway.readResource("map://farm");
      expect(JSON.parse(mapResource.contents[0]?.text ?? "{}")).toMatchObject({ id: "farm" });
    } finally {
      await engine.stop();
    }
  });

  it("serves the server.orient prompt", async () => {
    const { engine, gateway } = await setup();
    try {
      const prompt = await gateway.getPrompt("server.orient", {});
      const text = prompt.messages[0]?.content.text ?? "";
      expect(text).toContain("nEngine MCP server");
      expect(text).toContain("time.advance");
      expect(text).toContain("content/maps/<id>.yaml");
    } finally {
      await engine.stop();
    }
  });

  it("disabled namespaces vanish from listings and reject calls", async () => {
    const { engine, gateway } = await setup();
    try {
      gateway.disable("map");
      expect(gateway.listTools().map((tool) => tool.name)).not.toContain("map.list");
      expect(gateway.listTools().map((tool) => tool.name)).toContain("time.get");

      const rejected = await callText(gateway, "map.list");
      expect(rejected.ok).toBe(false);
      expect(rejected.text).toMatch(/namespace "map" is disabled/);

      gateway.enable("map");
      const restored = await callText(gateway, "map.list");
      expect(restored.ok).toBe(true);
    } finally {
      await engine.stop();
    }
  });
});