nEngine/packages/mcp/test/map-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 MapDef } 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");

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-map-"));
  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 ?? "" };
}

const MEADOW_DEF: MapDef = {
  id: "meadow",
  width: 2,
  height: 2,
  tilesetRef: "tiles",
  spawn: { x: 0, y: 0 },
  layers: [{ name: "ground", data: [["grass", "grass"], ["grass", "grass"]] }],
};

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

      expect(engine.registry.get<MapDef>("map", "meadow")).toEqual(MEADOW_DEF);

      const file = await readFile(join(tmp, "maps", "meadow.yaml"), "utf8");
      expect(file).toContain("id: meadow");
      expect(file).toContain("grass");

      await engine.stop();
      const reloaded = createEngine({ contentDir: tmp });
      await reloaded.start();
      try {
        expect(reloaded.registry.get<MapDef>("map", "meadow")).toEqual(MEADOW_DEF);
      } finally {
        await reloaded.stop();
      }
    } finally {
      await close();
    }
  });

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

      const invalid = await callText(gateway, "map.validate", {
        def: { ...MEADOW_DEF, layers: [{ name: "ground", data: [["grass"]] }] },
      });
      expect(invalid.ok).toBe(false);
      expect(invalid.text).toMatch(/expected 2/);

      const badWidth = await callText(gateway, "map.validate", { def: { ...MEADOW_DEF, width: 0 } });
      expect(badWidth.ok).toBe(false);
      expect(badWidth.text).toMatch(/width/);
    } finally {
      await close();
    }
  });

  it("map.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, "map.create", {
        def: { ...MEADOW_DEF, layers: [{ name: "ground", data: [["grass"]] }] },
      });
      expect(bad.ok).toBe(false);
      expect(engine.registry.get("map", "meadow")).toBeUndefined();
      await expect(readFile(join(tmp, "maps", "meadow.yaml"))).rejects.toThrow();
    } finally {
      await close();
    }
  });

  it("duplicate map.create overwrites the existing definition", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "map.create", { def: MEADOW_DEF });
      const recreated = await callText(gateway, "map.create", {
        def: { ...MEADOW_DEF, tilesetRef: "meadow-tiles", walkable: { water: false } },
      });
      expect(recreated.ok).toBe(true);

      const current = engine.registry.get<MapDef>("map", "meadow");
      expect(current?.tilesetRef).toBe("meadow-tiles");
      expect(current?.walkable).toEqual({ water: false });

      const file = await readFile(join(tmp, "maps", "meadow.yaml"), "utf8");
      expect(file).toContain("meadow-tiles");
    } finally {
      await close();
    }
  });

  it("map.update merges a patch, validates, rewrites the file, and re-registers", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "map.create", { def: MEADOW_DEF });
      const updated = await callText(gateway, "map.update", {
        id: "meadow",
        patch: { tilesetRef: "renamed", spawn: { x: 1, y: 1 } },
      });
      expect(updated.ok).toBe(true);
      const def = JSON.parse(updated.text) as MapDef;
      expect(def.tilesetRef).toBe("renamed");
      expect(def.spawn).toEqual({ x: 1, y: 1 });
      expect(def.width).toBe(2);

      const file = await readFile(join(tmp, "maps", "meadow.yaml"), "utf8");
      expect(file).toContain("renamed");

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

      const badPatch = await callText(gateway, "map.update", { id: "meadow", patch: { layers: [] } });
      expect(badPatch.ok).toBe(false);
      expect(badPatch.text).toMatch(/layers/);
      expect(engine.registry.get<MapDef>("map", "meadow")?.tilesetRef).toBe("renamed");
    } finally {
      await close();
    }
  });

  it("map.list returns one-line summaries including created maps", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "map.create", { def: MEADOW_DEF });
      const listed = await callText(gateway, "map.list");
      expect(listed.ok).toBe(true);
      expect(JSON.parse(listed.text)).toEqual({
        maps: [
          { id: "farm", width: 2, height: 2, tilesetRef: "tiles" },
          { id: "meadow", width: 2, height: 2, tilesetRef: "tiles" },
        ],
      });
    } finally {
      await close();
    }
  });

  it("map.get returns the full def plus the player entity; unknown id is an error result", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "map.create", { def: MEADOW_DEF });
      const got = await callText(gateway, "map.get", { mapId: "meadow" });
      expect(got.ok).toBe(true);
      const map = JSON.parse(got.text) as Record<string, unknown>;
      expect(map.id).toBe("meadow");
      expect(map.width).toBe(2);
      expect(map.player).toMatchObject({ id: "player", type: "player", x: 0, y: 0 });

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

  it("map://{mapId} resource stays readable; missing id rejects", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "map.create", { def: MEADOW_DEF });
      const single = await gateway.readResource("map://meadow");
      expect(JSON.parse(single.contents[0]?.text ?? "{}")).toMatchObject({ id: "meadow", width: 2 });

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

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