import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { existsSync, mkdirSync, mkdtempSync, writeFileSync } from "node:fs";
import { join } from "node:path";
import { tmpdir } from "node:os";

describe("npx-resolver cache path", () => {
  const originalHome = process.env.HOME;
  const originalAgentDir = process.env.PI_CODING_AGENT_DIR;
  const originalNpmCache = process.env.NPM_CONFIG_CACHE;

  beforeEach(() => {
    vi.resetModules();
  });

  afterEach(() => {
    process.env.HOME = originalHome;
    if (originalAgentDir === undefined) {
      delete process.env.PI_CODING_AGENT_DIR;
    } else {
      process.env.PI_CODING_AGENT_DIR = originalAgentDir;
    }
    if (originalNpmCache === undefined) {
      delete process.env.NPM_CONFIG_CACHE;
    } else {
      process.env.NPM_CONFIG_CACHE = originalNpmCache;
    }
  });

  it("writes mcp-npx-cache.json to PI_CODING_AGENT_DIR", async () => {
    const home = mkdtempSync(join(tmpdir(), "pi-mcp-npx-home-"));
    const agentDir = mkdtempSync(join(tmpdir(), "pi-mcp-npx-agent-"));
    const npmCache = mkdtempSync(join(tmpdir(), "pi-mcp-npx-cache-"));

    process.env.HOME = home;
    process.env.PI_CODING_AGENT_DIR = agentDir;
    process.env.NPM_CONFIG_CACHE = npmCache;

    const packageDir = join(npmCache, "_npx", "fixture", "node_modules", "demo-pkg");
    mkdirSync(join(packageDir, "bin"), { recursive: true });
    writeFileSync(
      join(packageDir, "package.json"),
      JSON.stringify({ name: "demo-pkg", version: "1.0.0", bin: "bin/cli.js" }),
      "utf-8",
    );
    writeFileSync(join(packageDir, "bin", "cli.js"), "#!/usr/bin/env node\nconsole.log('ok')\n", "utf-8");

    const { resolveNpxBinary } = await import("../npx-resolver.ts");
    const result = await resolveNpxBinary("npx", ["-y", "demo-pkg"]);

    expect(result).not.toBeNull();
    expect(existsSync(join(agentDir, "mcp-npx-cache.json"))).toBe(true);
    expect(existsSync(join(home, ".pi", "agent", "mcp-npx-cache.json"))).toBe(false);
  });
});