cloudflare__vinext/tests/check.test.ts

import { describe, it, expect, beforeEach, afterEach } from "vite-plus/test";
import fs from "node:fs";
import path from "node:path";
import os from "node:os";
import {
  scanImports,
  analyzeConfig,
  checkLibraries,
  checkConventions,
  runCheck,
  formatReport,
  type CheckResult,
} from "../packages/vinext/src/check.js";

// ── Helpers ────────────────────────────────────────────────────────────────

let tmpDir: string;

beforeEach(() => {
  tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "vinext-check-"));
});

afterEach(() => {
  fs.rmSync(tmpDir, { recursive: true, force: true });
});

function writeFile(relPath: string, content: string) {
  const fullPath = path.join(tmpDir, relPath);
  fs.mkdirSync(path.dirname(fullPath), { recursive: true });
  fs.writeFileSync(fullPath, content);
}

// ── scanImports ────────────────────────────────────────────────────────────

describe("scanImports", () => {
  it("detects supported next/* imports", () => {
    writeFile(
      "app/page.tsx",
      `
      import Link from "next/link";
      import Image from "next/image";
    `,
    );

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(2);
    expect(items.find((i) => i.name === "next/link")?.status).toBe("supported");
    expect(items.find((i) => i.name === "next/image")?.status).toBe("supported");
  });

  it("detects partial imports", () => {
    writeFile("app/page.tsx", `import { GoogleFont } from "next/font/google";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/font/google");
    expect(items[0].status).toBe("partial");
  });

  it("reports accurate next/font/local detail", () => {
    writeFile("app/page.tsx", `import localFont from "next/font/local";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/font/local");
    expect(items[0].status).toBe("supported");
    expect(items[0].detail).toContain("className and variable modes both work");
  });

  it("detects unsupported imports", () => {
    writeFile("pages/amp.tsx", `import { useAmp } from "next/amp";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/amp");
    expect(items[0].status).toBe("unsupported");
  });

  it("detects server-only and client-only", () => {
    writeFile("lib/db.ts", `import "server-only";`);
    writeFile("components/button.tsx", `import "client-only";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(2);
    expect(items.find((i) => i.name === "server-only")?.status).toBe("supported");
    expect(items.find((i) => i.name === "client-only")?.status).toBe("supported");
  });

  it("tracks which files use each import", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile("app/about/page.tsx", `import Link from "next/link";`);

    const items = scanImports(tmpDir);
    const linkItem = items.find((i) => i.name === "next/link");
    expect(linkItem?.files).toHaveLength(2);
    expect(linkItem?.files).toContain("app/page.tsx");
    expect(linkItem?.files).toContain("app/about/page.tsx");
  });

  it("detects require() calls too", () => {
    writeFile("lib/util.js", `const router = require("next/router");`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/router");
    expect(items[0].status).toBe("supported");
  });

  it("returns empty for projects with no next imports", () => {
    writeFile("src/index.ts", `import React from "react";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(0);
  });

  it("marks unrecognized next/* imports as unsupported", () => {
    writeFile("app/page.tsx", `import foo from "next/nonexistent";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].status).toBe("unsupported");
    expect(items[0].detail).toContain("not recognized");
  });

  it("recognizes next/compat/router as supported", () => {
    writeFile("components/shared-nav.tsx", `import { useRouter } from "next/compat/router";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/compat/router");
    expect(items[0].status).toBe("supported");
  });

  it("recognizes next/form as supported", () => {
    writeFile("app/page.tsx", `import Form from "next/form";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/form");
    expect(items[0].status).toBe("supported");
  });

  it("recognizes next/web-vitals as supported", () => {
    writeFile("pages/_app.tsx", `import { reportWebVitals } from "next/web-vitals";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/web-vitals");
    expect(items[0].status).toBe("supported");
  });

  it("recognizes next/constants as supported", () => {
    writeFile("lib/phases.ts", `import { PHASE_DEVELOPMENT_SERVER } from "next/constants";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/constants");
    expect(items[0].status).toBe("supported");
  });

  it("recognizes `import { Metadata } from 'next'` as supported", () => {
    writeFile(
      "app/layout.tsx",
      `import { Metadata } from "next";\nexport const metadata: Metadata = { title: "App" };`,
    );

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next");
    expect(items[0].status).toBe("supported");
  });

  it("skips `import type` statements entirely", () => {
    writeFile(
      "app/page.tsx",
      `import type { Metadata } from "next";\nimport Link from "next/link";`,
    );

    const items = scanImports(tmpDir);
    // Should only find next/link, not next (since import type is skipped)
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/link");
  });

  it("skips `import type` for next/* paths too", () => {
    writeFile("app/page.tsx", `import type { NextRequest } from "next/server";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(0);
  });

  it("sorts unsupported first, then partial, then supported", () => {
    writeFile(
      "app/page.tsx",
      `
      import Link from "next/link";
      import { GoogleFont } from "next/font/google";
      import { useAmp } from "next/amp";
    `,
    );

    const items = scanImports(tmpDir);
    expect(items[0].status).toBe("unsupported");
    expect(items[1].status).toBe("partial");
    expect(items[2].status).toBe("supported");
  });

  it("ignores node_modules and .next directories", () => {
    writeFile("node_modules/foo/index.ts", `import Link from "next/link";`);
    writeFile(".next/server.js", `import Link from "next/link";`);
    writeFile("app/page.tsx", `import Image from "next/image";`);

    const items = scanImports(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next/image");
  });

  it("deduplicates files using the same import", () => {
    writeFile(
      "app/page.tsx",
      `
      import Link from "next/link";
      import Link from "next/link";
    `,
    );

    const items = scanImports(tmpDir);
    const linkItem = items.find((i) => i.name === "next/link");
    expect(linkItem?.files).toHaveLength(1);
  });

  it("recognizes next/dist/shared/lib/router-context.shared-runtime as supported", () => {
    writeFile(
      "lib/router.tsx",
      `import { RouterContext } from "next/dist/shared/lib/router-context.shared-runtime";`,
    );

    const items = scanImports(tmpDir);
    const item = items.find((i) => i.name === "next/dist/shared/lib/router-context.shared-runtime");
    expect(item?.status).toBe("supported");
  });

  it("recognizes all other shimmed next/dist/* paths as supported", () => {
    const distImports = [
      "next/dist/shared/lib/app-router-context.shared-runtime",
      "next/dist/shared/lib/app-router-context",
      "next/dist/shared/lib/utils",
      "next/dist/server/api-utils",
      "next/dist/server/web/spec-extension/cookies",
      "next/dist/compiled/@edge-runtime/cookies",
      "next/dist/server/app-render/work-unit-async-storage.external",
      "next/dist/client/components/work-unit-async-storage.external",
      "next/dist/client/components/request-async-storage.external",
      "next/dist/client/components/request-async-storage",
      "next/dist/client/components/navigation",
      "next/dist/server/config-shared",
    ];

    writeFile("lib/internals.ts", distImports.map((p) => `import * as m from "${p}";`).join("\n"));

    const items = scanImports(tmpDir);
    for (const p of distImports) {
      const item = items.find((i) => i.name === p);
      expect(item?.status, `expected ${p} to be supported`).toBe("supported");
    }
  });
});

// ── analyzeConfig ──────────────────────────────────────────────────────────

describe("analyzeConfig", () => {
  it("reports 'no config file' when none exists", () => {
    const items = analyzeConfig(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].name).toBe("next.config");
    expect(items[0].status).toBe("supported");
  });

  it("detects supported config options", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        basePath: "/docs",
        trailingSlash: true,
        reactStrictMode: true,
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "basePath")?.status).toBe("supported");
    expect(items.find((i) => i.name === "trailingSlash")?.status).toBe("supported");
    // reactStrictMode is reported as `partial` until vinext actually wraps the
    // hydrated root in `<React.StrictMode>` — currently the config is read but
    // not enforced. See `packages/vinext/src/check.ts` for the rationale.
    expect(items.find((i) => i.name === "reactStrictMode")?.status).toBe("partial");
  });

  it("detects unsupported webpack config", () => {
    writeFile(
      "next.config.js",
      `module.exports = {
        webpack: (config) => { return config; },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    const webpackItem = items.find((i) => i.name === "webpack");
    expect(webpackItem?.status).toBe("unsupported");
    expect(webpackItem?.detail).toContain("Vite replaces webpack");
  });

  it("detects partial image config", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        images: { remotePatterns: [{ hostname: "*.example.com" }] },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "images")?.status).toBe("partial");
  });

  it("detects experimental.ppr as unsupported", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        experimental: {
          ppr: true,
        },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "experimental.ppr")?.status).toBe("unsupported");
  });

  it("detects experimental.serverActions as supported", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        experimental: {
          serverActions: { allowedOrigins: ["my-domain.com"] },
        },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "experimental.serverActions")?.status).toBe("supported");
  });

  it("detects experimental.prefetchInlining as partial", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        experimental: {
          prefetchInlining: true,
        },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "experimental.prefetchInlining")?.status).toBe("partial");
  });

  it("detects experimental.swcEnvOptions as unsupported", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        experimental: {
          swcEnvOptions: {
            mode: "usage",
            coreJs: "3",
          },
        },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    const item = items.find((i) => i.name === "experimental.swcEnvOptions");
    expect(item?.status).toBe("unsupported");
    expect(item?.detail).toContain("not applicable");
  });

  it("detects allowedDevOrigins as supported", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        allowedDevOrigins: ["staging.example.com"],
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "allowedDevOrigins")?.status).toBe("supported");
  });

  it("detects i18n.domains as partial support", () => {
    writeFile(
      "next.config.js",
      `module.exports = {
        i18n: {
          locales: ["en", "fr"],
          defaultLocale: "en",
          domains: [{ domain: "example.fr", defaultLocale: "fr" }],
        },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "i18n")?.status).toBe("supported");
    expect(items.find((i) => i.name === "i18n.domains")?.status).toBe("partial");
  });

  it.each([
    ["experimental.ppr", "experimental", "ppr: true"],
    ["experimental.typedRoutes", "experimental", "typedRoutes: true"],
    ["experimental.serverActions", "experimental", "serverActions: { allowedOrigins: [] }"],
    ["experimental.prefetchInlining", "experimental", "prefetchInlining: true"],
    ["experimental.swcEnvOptions", "experimental", 'swcEnvOptions: { mode: "usage" }'],
    ["i18n.domains", "i18n", "domains: []"],
  ])("detects %s via generic dot-notation handling", (name, parent, body) => {
    writeFile("next.config.mjs", `export default { ${parent}: { ${body} } };`);
    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === name)).toBeDefined();
  });

  it("reads next.config.ts files", () => {
    writeFile("next.config.ts", `const config = { basePath: "/app" }; export default config;`);

    const items = analyzeConfig(tmpDir);
    expect(items.find((i) => i.name === "basePath")?.status).toBe("supported");
  });

  it("sorts unsupported configs first", () => {
    writeFile(
      "next.config.mjs",
      `export default {
        basePath: "/app",
        webpack: (config) => config,
        images: { domains: [] },
      };`,
    );

    const items = analyzeConfig(tmpDir);
    expect(items[0].status).toBe("unsupported"); // webpack
    expect(items[items.length - 1].status).toBe("supported"); // basePath
  });
});

// ── checkLibraries ─────────────────────────────────────────────────────────

describe("checkLibraries", () => {
  it("returns empty when no package.json", () => {
    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(0);
  });

  it("returns empty when no known libraries are used", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: { react: "^19.0.0", "some-lib": "^1.0.0" },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(0);
  });

  it("detects supported libraries", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: { "next-themes": "^0.3.0", tailwindcss: "^3.0.0", zod: "^3.0.0" },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(3);
    expect(items.every((i) => i.status === "supported")).toBe(true);
  });

  it("detects unsupported libraries", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: { "@auth/nextjs": "^5.0.0", "next-auth": "^4.0.0" },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(2);
    expect(items.every((i) => i.status === "unsupported")).toBe(true);
  });

  it("detects @clerk/nextjs as partial", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: { "@clerk/nextjs": "^7.0.0" },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].status).toBe("partial");
    expect(items[0].detail).toContain("clerkMiddleware");
  });

  it("detects supported CSS-in-JS libraries", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: { "styled-components": "^6.0.0" },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(1);
    expect(items[0].status).toBe("supported");
    expect(items[0].detail).toContain("useServerInsertedHTML");
  });

  it("checks both dependencies and devDependencies", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: { tailwindcss: "^3.0.0" },
        devDependencies: { prisma: "^5.0.0" },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items).toHaveLength(2);
    expect(items.find((i) => i.name === "tailwindcss")).toBeDefined();
    expect(items.find((i) => i.name === "prisma")).toBeDefined();
  });

  it("sorts unsupported libraries first", () => {
    writeFile(
      "package.json",
      JSON.stringify({
        dependencies: {
          tailwindcss: "^3.0.0",
          "next-auth": "^4.0.0",
          "@sentry/nextjs": "^7.0.0",
        },
      }),
    );

    const items = checkLibraries(tmpDir);
    expect(items[0].status).toBe("unsupported");
    expect(items[items.length - 1].status).toBe("supported");
  });
});

// ── checkConventions ───────────────────────────────────────────────────────

describe("checkConventions", () => {
  it("detects pages directory", () => {
    writeFile("pages/index.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name === "Pages Router (pages/)")).toBeDefined();
    expect(items.find((i) => i.name.includes("1 page"))?.status).toBe("supported");
  });

  it("detects app directory", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile(
      "app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name === "App Router (app/)")).toBeDefined();
    expect(items.find((i) => i.name.includes("1 page"))?.status).toBe("supported");
    expect(items.find((i) => i.name.includes("1 layout"))?.status).toBe("supported");
  });

  it("detects middleware.ts", () => {
    writeFile("middleware.ts", `export function middleware() {}`);

    // Also need pages or app directory
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const mw = items.find((i) => i.name.includes("middleware.ts"));
    expect(mw?.status).toBe("supported");
    expect(mw?.name).toContain("deprecated");
  });

  it("detects middleware.js", () => {
    writeFile("middleware.js", `export function middleware() {}`);
    writeFile("pages/index.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const mw = items.find((i) => i.name.includes("middleware.ts"));
    expect(mw?.status).toBe("supported");
    expect(mw?.name).toContain("deprecated");
  });

  it("detects proxy.ts (Next.js 16)", () => {
    writeFile("proxy.ts", `export default function proxy() {}`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const proxy = items.find((i) => i.name.includes("proxy.ts"));
    expect(proxy?.status).toBe("supported");
    expect(proxy?.name).toContain("Next.js 16");
  });

  it("prefers proxy.ts over middleware.ts in check", () => {
    writeFile("proxy.ts", `export default function proxy() {}`);
    writeFile("middleware.ts", `export function middleware() {}`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    // Should show proxy.ts, not middleware.ts
    expect(items.find((i) => i.name.includes("proxy.ts"))).toBeDefined();
    expect(items.find((i) => i.name.includes("middleware.ts"))).toBeUndefined();
  });

  it("detects src/app directory when app/ is not at root", () => {
    writeFile("src/app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile(
      "src/app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name === "App Router (src/app/)")).toBeDefined();
    expect(items.find((i) => i.name.includes("1 page"))?.status).toBe("supported");
    expect(items.find((i) => i.name.includes("1 layout"))?.status).toBe("supported");
  });

  it("detects src/pages directory when pages/ is not at root", () => {
    writeFile("src/pages/index.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name === "Pages Router (src/pages/)")).toBeDefined();
    expect(items.find((i) => i.name.includes("1 page"))?.status).toBe("supported");
  });

  it("prefers root-level app/ over src/app/", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile("src/app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name === "App Router (app/)")).toBeDefined();
    // src/app/ should also be detected (both exist)
  });

  it("reports unsupported when no pages/ or app/ directory", () => {
    writeFile("src/index.ts", `console.log("hi");`);

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.status === "unsupported")).toBeDefined();
    expect(items.find((i) => i.name.includes("No pages/ or app/"))).toBeDefined();
  });

  it("counts API routes separately", () => {
    writeFile("pages/index.tsx", `export default function Home() { return <div/>; }`);
    writeFile("pages/api/hello.ts", `export default function handler(req, res) { res.json({}) }`);
    writeFile("pages/api/users.ts", `export default function handler(req, res) { res.json({}) }`);

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name.includes("2 API route"))).toBeDefined();
  });

  it("detects custom _app and _document", () => {
    writeFile("pages/index.tsx", `export default function Home() { return <div/>; }`);
    writeFile(
      "pages/_app.tsx",
      `export default function App({ Component, pageProps }) { return <Component {...pageProps} /> }`,
    );
    writeFile("pages/_document.tsx", `export default function Document() {}`);

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name === "Custom _app")?.status).toBe("supported");
    expect(items.find((i) => i.name === "Custom _document")?.status).toBe("supported");
  });

  it("detects App Router conventions (loading, error, not-found)", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile(
      "app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );
    writeFile(
      "app/loading.tsx",
      `export default function Loading() { return <div>Loading...</div>; }`,
    );
    writeFile(
      "app/error.tsx",
      `"use client"; export default function Error() { return <div>Error</div>; }`,
    );
    writeFile(
      "app/not-found.tsx",
      `export default function NotFound() { return <div>Not Found</div>; }`,
    );

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name.includes("loading"))?.status).toBe("supported");
    expect(items.find((i) => i.name.includes("error"))?.status).toBe("supported");
    expect(items.find((i) => i.name.includes("not-found"))?.status).toBe("supported");
  });

  it("detects route handlers in App Router", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile(
      "app/api/hello/route.ts",
      `export function GET() { return Response.json({ hello: "world" }); }`,
    );

    const items = checkConventions(tmpDir);
    expect(items.find((i) => i.name.includes("1 route handler"))).toBeDefined();
  });

  it("flags missing type:module in package.json", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile("package.json", JSON.stringify({ dependencies: { react: "^19.0.0" } }));

    const items = checkConventions(tmpDir);
    const typeModule = items.find((i) => i.name.includes('"type": "module"'));
    expect(typeModule).toBeDefined();
    expect(typeModule?.status).toBe("unsupported");
    expect(typeModule?.detail).toContain("vinext init");
  });

  it("does not flag type:module when present", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { react: "^19.0.0" } }),
    );

    const items = checkConventions(tmpDir);
    const typeModule = items.find((i) => i.name.includes('"type": "module"'));
    expect(typeModule).toBeUndefined();
  });

  it("detects ViewTransition import from react", () => {
    writeFile(
      "app/page.tsx",
      `import { ViewTransition } from "react";\nexport default function Home() { return <ViewTransition><div/></ViewTransition>; }`,
    );

    const items = checkConventions(tmpDir);
    const vt = items.find((i) => i.name.includes("ViewTransition"));
    expect(vt).toBeDefined();
    expect(vt?.status).toBe("partial");
    expect(vt?.detail).toContain("passthrough fallback");
    expect(vt?.files).toHaveLength(1);
  });

  it("does not flag ViewTransition when not imported", () => {
    writeFile(
      "app/page.tsx",
      `import React from "react";\nexport default function Home() { return <div/>; }`,
    );

    const items = checkConventions(tmpDir);
    const vt = items.find((i) => i.name.includes("ViewTransition"));
    expect(vt).toBeUndefined();
  });

  it("detects PostCSS string-form plugins", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile("postcss.config.mjs", `export default {\n  plugins: ["@tailwindcss/postcss"]\n};`);

    const items = checkConventions(tmpDir);
    const postcss = items.find((i) => i.name.includes("PostCSS"));
    expect(postcss).toBeDefined();
    expect(postcss?.status).toBe("partial");
    expect(postcss?.detail).toContain("string-form");
  });

  it("does not flag PostCSS when no config exists", () => {
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const postcss = items.find((i) => i.name.includes("PostCSS"));
    expect(postcss).toBeUndefined();
  });

  it("detects __dirname usage in server files", () => {
    writeFile("lib/db.ts", `import path from "path";\nconst dir = path.join(__dirname, "data");`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeDefined();
    expect(cjs?.status).toBe("unsupported");
    expect(cjs?.detail).toContain("fileURLToPath");
    expect(cjs?.detail).toContain("import.meta.dirname");
    expect(cjs?.files).toContain("lib/db.ts");
  });

  it("detects __filename usage", () => {
    writeFile("lib/logger.ts", `const file = __filename;`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeDefined();
    expect(cjs?.files).toContain("lib/logger.ts");
  });

  it("detects both __dirname and __filename in same file", () => {
    writeFile("lib/util.ts", `const dir = __dirname;\nconst file = __filename;`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeDefined();
    expect(cjs?.files).toContain("lib/util.ts");
    // Only one item for both globals
    expect(
      items.filter((i) => i.name.includes("__dirname") || i.name.includes("__filename")),
    ).toHaveLength(1);
  });

  it("does not flag __dirname inside string literals", () => {
    writeFile(
      "lib/comment.ts",
      `const msg = "use __dirname instead";\nexport default function Home() { return null; }`,
    );
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeUndefined();
  });

  it("does not flag __dirname inside comments", () => {
    writeFile("lib/note.ts", `// Previously used __dirname here\nexport const x = 1;`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeUndefined();
  });

  it("does not flag __dirname inside a plain template literal (no interpolation)", () => {
    writeFile("lib/msg.ts", "const msg = `use __dirname instead`;");
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeUndefined();
  });

  it("detects __dirname inside a template expression ${...}", () => {
    writeFile("lib/db.ts", "const dir = `${__dirname}/views`;");
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeDefined();
    expect(cjs?.files).toContain("lib/db.ts");
  });

  it("does not flag __dirname when not used at all", () => {
    writeFile(
      "lib/esm.ts",
      `import { fileURLToPath } from "url";\nimport { dirname } from "path";\nconst __dirname = dirname(fileURLToPath(import.meta.url));`,
    );
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    // The ESM pattern itself reassigns __dirname — this is fine and should not be flagged
    // because users are already using the correct ESM idiom.
    // Our scanner will see `__dirname` in the assignment target — that's an edge case we accept.
    // This test just ensures we don't crash.
    const items = checkConventions(tmpDir);
    // No assertion on presence/absence — just verify it doesn't throw
    expect(Array.isArray(items)).toBe(true);
  });

  it("tracks multiple files that use __dirname", () => {
    writeFile("lib/a.ts", `const d = __dirname;`);
    writeFile("lib/b.ts", `const f = __filename;`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);

    const items = checkConventions(tmpDir);
    const cjs = items.find((i) => i.name.includes("__dirname"));
    expect(cjs).toBeDefined();
    expect(cjs?.files).toHaveLength(2);
    expect(cjs?.files).toContain("lib/a.ts");
    expect(cjs?.files).toContain("lib/b.ts");
  });
});

// ── runCheck ───────────────────────────────────────────────────────────────

describe("runCheck", () => {
  it("returns a complete result with all sections", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile(
      "app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { tailwindcss: "^3.0.0" } }),
    );

    const result = runCheck(tmpDir);
    expect(result.imports).toBeDefined();
    expect(result.config).toBeDefined();
    expect(result.libraries).toBeDefined();
    expect(result.conventions).toBeDefined();
    expect(result.summary).toBeDefined();
  });

  it("calculates score correctly — 100% for all supported", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile(
      "app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { tailwindcss: "^3.0.0" } }),
    );

    const result = runCheck(tmpDir);
    // All items should be supported: next/link, no config file, tailwindcss, App Router, 1 page, 1 layout
    expect(result.summary.unsupported).toBe(0);
    expect(result.summary.score).toBe(100);
  });

  it("calculates score correctly — partial items count 50%", () => {
    // 1 supported import (next/link) + 1 partial import (next/font/google) + no-config (supported) + 2 conventions (App Router + 1 page)
    writeFile(
      "app/page.tsx",
      `
      import Link from "next/link";
      import { GoogleFont } from "next/font/google";
    `,
    );

    const result = runCheck(tmpDir);
    expect(result.summary.partial).toBeGreaterThan(0);
    expect(result.summary.score).toBeLessThan(100);
    expect(result.summary.score).toBeGreaterThan(0);
  });

  it("calculates score correctly — unsupported items drag score down", () => {
    writeFile(
      "app/page.tsx",
      `
      import { useAmp } from "next/amp";
    `,
    );
    writeFile("next.config.mjs", `export default { webpack: (config) => config };`);
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { "next-auth": "^4.0.0" } }),
    );

    const result = runCheck(tmpDir);
    expect(result.summary.unsupported).toBeGreaterThan(0);
    expect(result.summary.score).toBeLessThan(100);
  });

  it("reports correct totals", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { tailwindcss: "^3.0.0" } }),
    );

    const result = runCheck(tmpDir);
    const total = result.summary.supported + result.summary.partial + result.summary.unsupported;
    expect(total).toBe(result.summary.total);
  });

  it("returns 100% score for empty project with no pages or app", () => {
    // Empty project — only an unsupported "no pages/ or app/" item
    writeFile("src/index.ts", `console.log("hi");`);

    const result = runCheck(tmpDir);
    // Should have 1 unsupported item (no pages/app directory)
    expect(result.summary.unsupported).toBe(1);
    expect(result.summary.score).toBeLessThan(100);
  });

  it("calculates score correctly for src/app project", () => {
    writeFile("src/app/page.tsx", `import Link from "next/link";`);
    writeFile(
      "src/app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { tailwindcss: "^3.0.0" } }),
    );

    const result = runCheck(tmpDir);
    expect(result.summary.unsupported).toBe(0);
    expect(result.summary.score).toBe(100);
  });
});

// ── formatReport ───────────────────────────────────────────────────────────

describe("formatReport", () => {
  it("produces a string with section headers", () => {
    writeFile(
      "app/page.tsx",
      `
      import Link from "next/link";
      import { GoogleFont } from "next/font/google";
    `,
    );
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { tailwindcss: "^3.0.0" } }),
    );

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("vinext compatibility report");
    expect(report).toContain("Imports");
    expect(report).toContain("Libraries");
    expect(report).toContain("Project structure");
    expect(report).toContain("Overall");
    expect(report).toContain("% compatible");
  });

  it("shows issues section when there are unsupported items", () => {
    writeFile("app/page.tsx", `import { useAmp } from "next/amp";`);
    writeFile("package.json", JSON.stringify({ type: "module", dependencies: {} }));

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("Issues to address");
    expect(report).toContain("next/amp");
  });

  it("lists affected files under unsupported items in issues section", () => {
    writeFile("lib/db.ts", `const dir = path.join(__dirname, "data");`);
    writeFile("app/page.tsx", `export default function Home() { return <div/>; }`);
    writeFile("package.json", JSON.stringify({ type: "module", dependencies: {} }));

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("Issues to address");
    expect(report).toContain("__dirname");
    expect(report).toContain("lib/db.ts");
  });

  it("shows partial support section when there are partial items", () => {
    writeFile("app/page.tsx", `import { GoogleFont } from "next/font/google";`);
    writeFile("package.json", JSON.stringify({ type: "module", dependencies: {} }));

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("Partial support");
    expect(report).toContain("next/font/google");
  });

  it("does not show issues section when everything is supported", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile(
      "app/layout.tsx",
      `export default function Layout({ children }) { return <html><body>{children}</body></html>; }`,
    );
    writeFile(
      "package.json",
      JSON.stringify({ type: "module", dependencies: { tailwindcss: "^3.0.0" } }),
    );

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).not.toContain("Issues to address");
    expect(report).not.toContain("Partial support");
  });

  it("includes file count for imports", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile("app/about/page.tsx", `import Link from "next/link";`);
    writeFile("package.json", JSON.stringify({ type: "module", dependencies: {} }));

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("2 files");
  });

  it("handles empty result gracefully", () => {
    const emptyResult: CheckResult = {
      imports: [],
      config: [],
      libraries: [],
      conventions: [],
      summary: { supported: 0, partial: 0, unsupported: 0, total: 0, score: 100 },
    };

    const report = formatReport(emptyResult);
    expect(report).toContain("vinext compatibility report");
    expect(report).toContain("100% compatible");
  });

  it("includes actionable next steps", () => {
    writeFile("app/page.tsx", `import Link from "next/link";`);
    writeFile("package.json", JSON.stringify({ type: "module", dependencies: {} }));

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("Recommended next steps");
    expect(report).toContain("vinext init");
    expect(report).toContain("Or manually");
    expect(report).toContain('"type": "module"');
    expect(report).toContain("@vitejs/plugin-react");
    expect(report).toContain("@vitejs/plugin-rsc");
    expect(report).toContain("react-server-dom-webpack");
    expect(report).toContain("vite.config.ts");
    expect(report).toContain("npx vite dev");
  });

  it("does not list App Router-only packages in manual install steps for Pages Router projects", () => {
    writeFile("pages/index.tsx", `export default function Home() { return <div />; }`);
    writeFile("package.json", JSON.stringify({ type: "module", dependencies: {} }));

    const result = runCheck(tmpDir);
    const report = formatReport(result);

    expect(report).toContain("@vitejs/plugin-react");
    expect(report).not.toContain("@vitejs/plugin-rsc");
    expect(report).not.toContain("react-server-dom-webpack");
  });
});

// ── Integration: running against fixtures ──────────────────────────────────

describe("integration: pages-basic fixture", () => {
  const fixtureDir = path.resolve(import.meta.dirname, "./fixtures/pages-basic");

  it("detects Pages Router conventions", () => {
    const items = checkConventions(fixtureDir);
    expect(items.find((i) => i.name === "Pages Router (pages/)")).toBeDefined();
  });

  it("detects config options from next.config.mjs", () => {
    const items = analyzeConfig(fixtureDir);
    expect(items.find((i) => i.name === "redirects")).toBeDefined();
    expect(items.find((i) => i.name === "rewrites")).toBeDefined();
    expect(items.find((i) => i.name === "headers")).toBeDefined();
    expect(items.find((i) => i.name === "env")).toBeDefined();
  });

  it("runCheck produces a valid report", () => {
    const result = runCheck(fixtureDir);
    expect(result.summary.total).toBeGreaterThan(0);
    expect(result.summary.score).toBeGreaterThanOrEqual(0);
    expect(result.summary.score).toBeLessThanOrEqual(100);
  });
});

describe("integration: app-basic fixture", () => {
  const fixtureDir = path.resolve(import.meta.dirname, "./fixtures/app-basic");

  it("detects App Router conventions", () => {
    const items = checkConventions(fixtureDir);
    expect(items.find((i) => i.name === "App Router (app/)")).toBeDefined();
  });

  it("runCheck produces a valid report", () => {
    const result = runCheck(fixtureDir);
    expect(result.summary.total).toBeGreaterThan(0);
    expect(result.summary.score).toBeGreaterThanOrEqual(0);
    expect(result.summary.score).toBeLessThanOrEqual(100);
  });
});