nEngine/packages/mcp/test/animation-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 AnimationDef } 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-animation-"));
  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 PLAYER_ANIM: AnimationDef = {
  id: "player",
  initial: "idle",
  states: [
    { id: "idle", spriteRef: "player", loop: true },
    { id: "walk", spriteRef: "player-walk", fps: 8, loop: true },
  ],
  transitions: [
    { from: "idle", to: "walk", on: "move" },
    { from: "walk", to: "idle", on: "idle" },
  ],
};

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

      expect(engine.registry.get<AnimationDef>("animation", "player")).toEqual(PLAYER_ANIM);

      const file = await readFile(join(tmp, "animations", "player.yaml"), "utf8");
      expect(file).toContain("id: player");
      expect(file).toContain("spriteRef: player-walk");

      await engine.stop();
      const reloaded = createEngine({ contentDir: tmp });
      await reloaded.start();
      try {
        expect(reloaded.registry.get<AnimationDef>("animation", "player")).toEqual(PLAYER_ANIM);
      } finally {
        await reloaded.stop();
      }
    } finally {
      await close();
    }
  });

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

      const badInitial = await callText(gateway, "animation.validate", {
        def: { id: "x", initial: "nope", states: [{ id: "idle", spriteRef: "player" }] },
      });
      expect(badInitial.ok).toBe(false);
      expect(badInitial.text).toMatch(/initial state must be a declared state/);

      const badTransition = await callText(gateway, "animation.validate", {
        def: { id: "x", initial: "idle", states: [{ id: "idle", spriteRef: "player" }], transitions: [{ from: "idle", to: "dance" }] },
      });
      expect(badTransition.ok).toBe(false);
      expect(badTransition.text).toMatch(/transition to must be a declared state/);

      const strictInvalid = await callText(gateway, "animation.validate", {
        def: { id: "x", initial: "idle", states: [{ id: "idle", spriteRef: "player", extra: 1 }] },
      });
      expect(strictInvalid.ok).toBe(false);
      expect(strictInvalid.text).toMatch(/Unrecognized key/);
    } finally {
      await close();
    }
  });

  it("animation.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, "animation.create", {
        def: { id: "broken", initial: "nope", states: [] },
      });
      expect(bad.ok).toBe(false);
      expect(engine.registry.get("animation", "broken")).toBeUndefined();
      await expect(readFile(join(tmp, "animations", "broken.yaml"))).rejects.toThrow();
    } finally {
      await close();
    }
  });

  it("duplicate animation.create overwrites the existing definition", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "animation.create", { def: PLAYER_ANIM });
      const recreated = await callText(gateway, "animation.create", {
        def: { id: "player", initial: "idle", states: [{ id: "idle", spriteRef: "player" }] },
      });
      expect(recreated.ok).toBe(true);

      const current = engine.registry.get<AnimationDef>("animation", "player");
      expect(current?.states).toHaveLength(1);

      const file = await readFile(join(tmp, "animations", "player.yaml"), "utf8");
      expect(file).toContain("states:");
      expect(file).not.toContain("player-walk");
    } finally {
      await close();
    }
  });

  it("animation.update merges a patch, validates, rewrites the file, and re-registers", async () => {
    const { engine, gateway, tmp, close } = await setup();
    try {
      await callText(gateway, "animation.create", { def: PLAYER_ANIM });
      const updated = await callText(gateway, "animation.update", {
        id: "player",
        patch: { initial: "walk", states: [{ id: "walk", spriteRef: "player-walk", fps: 6 }], transitions: [] },
      });
      expect(updated.ok).toBe(true);
      const def = JSON.parse(updated.text) as AnimationDef;
      expect(def.initial).toBe("walk");
      expect(def.states).toEqual([{ id: "walk", spriteRef: "player-walk", fps: 6 }]);

      const file = await readFile(join(tmp, "animations", "player.yaml"), "utf8");
      expect(file).toContain("fps: 6");

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

      const badPatch = await callText(gateway, "animation.update", {
        id: "player",
        patch: { initial: "nope" },
      });
      expect(badPatch.ok).toBe(false);
      expect(badPatch.text).toMatch(/initial/);
      expect(engine.registry.get<AnimationDef>("animation", "player")?.initial).toBe("walk");
    } finally {
      await close();
    }
  });

  it("animation.list returns one-line summaries", async () => {
    const { gateway, close } = await setup();
    try {
      await callText(gateway, "animation.create", { def: PLAYER_ANIM });
      const listed = await callText(gateway, "animation.list");
      expect(listed.ok).toBe(true);
      expect(JSON.parse(listed.text)).toEqual({ animations: [{ id: "player", stateCount: 2 }] });
    } finally {
      await close();
    }
  });

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

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

      const blank = await callText(gateway, "animation.get", { animationId: "" });
      expect(blank.ok).toBe(false);
      expect(blank.text).toMatch(/animation\.get: animationId must be a non-empty string/);
    } finally {
      await close();
    }
  });

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

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

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

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

  it("serves the animation.create-prompt prompt", async () => {
    const { gateway, close } = await setup();
    try {
      const prompt = await gateway.getPrompt("animation.create-prompt", {});
      const text = prompt.messages[0]?.content.text ?? "";
      expect(text).toContain("states");
      expect(text).toContain("animation.validate");
      expect(text).toContain("content/animations/<id>.yaml");
      expect(text).toContain("set-state player.anim");
    } finally {
      await close();
    }
  });
});