nEngine/packages/mcp/test/sprite-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 SpriteDef } 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-sprite-"));
  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 SPROUT_DEF: SpriteDef = {
  id: "parsnip-sprout",
  frames: [{ name: "idle", durationTicks: 1, layers: [{ shape: "rect", x: 8, y: 8, w: 16, h: 16, fill: "#66bb6a" }] }],
};

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

      expect(engine.registry.get<SpriteDef>("sprite", "parsnip-sprout")).toEqual(SPROUT_DEF);

      const file = await readFile(join(tmp, "sprites", "parsnip-sprout.yaml"), "utf8");
      expect(file).toContain("id: parsnip-sprout");
      expect(file).toContain("shape: rect");

      await engine.stop();
      const reloaded = createEngine({ contentDir: tmp });
      await reloaded.start();
      try {
        expect(reloaded.registry.get<SpriteDef>("sprite", "parsnip-sprout")).toEqual(SPROUT_DEF);
      } finally {
        await reloaded.stop();
      }
    } finally {
      await close();
    }
  });

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

      const invalid = await callText(gateway, "sprite.validate", {
        def: { id: "nope", frames: [{ layers: [{ shape: "rect", x: 0, y: 0, w: 4, h: 4, fill: "green" }] }] },
      });
      expect(invalid.ok).toBe(false);
      expect(invalid.text).toMatch(/fill/);

      const strictInvalid = await callText(gateway, "sprite.validate", {
        def: { id: "nope", frames: [{ layers: [{ shape: "rect", x: 0, y: 0, w: 4, h: 4, fill: "#ffffff", extra: 1 }] }] },
      });
      expect(strictInvalid.ok).toBe(false);
      expect(strictInvalid.text).toMatch(/Unrecognized key/);
    } finally {
      await close();
    }
  });

  it("sprite.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, "sprite.create", {
        def: { id: "broken", frames: [{ layers: [] }] },
      });
      expect(bad.ok).toBe(false);
      expect(engine.registry.get("sprite", "broken")).toBeUndefined();
      await expect(readFile(join(tmp, "sprites", "broken.yaml"))).rejects.toThrow();
    } finally {
      await close();
    }
  });

  it("duplicate sprite.create overwrites the existing definition", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "sprite.create", { def: SPROUT_DEF });
      const recreated = await callText(gateway, "sprite.create", {
        def: { id: "parsnip-sprout", frames: [{ layers: [{ shape: "circle", x: 8, y: 8, r: 4, fill: "#4caf50" }] }] },
      });
      expect(recreated.ok).toBe(true);

      const current = engine.registry.get<SpriteDef>("sprite", "parsnip-sprout");
      expect(current?.frames[0]?.layers[0]?.shape).toBe("circle");

      const file = await readFile(join(tmp, "sprites", "parsnip-sprout.yaml"), "utf8");
      expect(file).toContain("shape: circle");
    } finally {
      await close();
    }
  });

  it("sprite.update merges a patch, validates, rewrites the file, and re-registers", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "sprite.create", { def: SPROUT_DEF });
      const updated = await callText(gateway, "sprite.update", {
        id: "parsnip-sprout",
        patch: { frames: [{ layers: [{ shape: "circle", x: 8, y: 8, r: 6, fill: "#2e7d32" }] }] },
      });
      expect(updated.ok).toBe(true);
      const def = JSON.parse(updated.text) as SpriteDef;
      expect(def.frames[0]?.layers[0]).toEqual({ shape: "circle", x: 8, y: 8, r: 6, fill: "#2e7d32" });

      const file = await readFile(join(tmp, "sprites", "parsnip-sprout.yaml"), "utf8");
      expect(file).toContain("r: 6");

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

      const badPatch = await callText(gateway, "sprite.update", {
        id: "parsnip-sprout",
        patch: { frames: [{ layers: [] }] },
      });
      expect(badPatch.ok).toBe(false);
      expect(badPatch.text).toMatch(/frames/);
      expect(engine.registry.get<SpriteDef>("sprite", "parsnip-sprout")?.frames[0]?.layers[0]?.fill).toBe("#2e7d32");
    } finally {
      await close();
    }
  });

  it("sprite.list returns one-line summaries", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "sprite.create", { def: SPROUT_DEF });
      await callText(gateway, "sprite.create", {
        def: { id: "fence", frames: [{ layers: [{ shape: "rect", x: 0, y: 0, w: 4, h: 4, fill: "#8d6e63" }] }] },
      });
      const listed = await callText(gateway, "sprite.list");
      expect(listed.ok).toBe(true);
      expect(JSON.parse(listed.text)).toEqual({
        sprites: [
          { id: "parsnip-sprout", frameCount: 1 },
          { id: "fence", frameCount: 1 },
        ],
      });
    } finally {
      await close();
    }
  });

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

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

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

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

      const single = await gateway.readResource("sprite://parsnip-sprout");
      expect(JSON.parse(single.contents[0]?.text ?? "{}")).toEqual(SPROUT_DEF);

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

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