import { readdir, readFile } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { describe, expect, it } from "vitest";

const sourceDirectory = path.join(path.dirname(fileURLToPath(import.meta.url)), "..", "src");

async function sourceFiles(): Promise<string[]> {
  const entries = await readdir(sourceDirectory);
  return entries.filter((entry) => entry.endsWith(".ts")).sort();
}

/**
 * This package is bundled into a browser. `@ekklesia/module-sdk` re-exports all of
 * `@ekklesia/contracts`, which pulls Zod, Drizzle, and semver behind one barrel export, so a single
 * value import from a backend package here would drag that whole graph into every module UI bundle
 * (ADR 0022). The dependency on `@ekklesia/contracts` is deliberately type-only and must stay that
 * way; `import type` is erased at build time, a plain `import` is not.
 */
describe("module UI SDK stays browser-safe", () => {
  it("imports nothing from another package at all, at type level or runtime", async () => {
    // Stronger than "type-only imports are fine". A type-only import is erased at runtime but still
    // drags the imported package's *type graph* into every consuming program — which is exactly how
    // Node globals reached browser-only module UI before ADR 0024. This package now imports nothing
    // external, so there is no graph to drag.
    for (const file of await sourceFiles()) {
      const source = await readFile(path.join(sourceDirectory, file), "utf8");
      const externalImports = [...source.matchAll(/^(?:import|export)\s[^;]*?from\s+"([^"]+)"/gmu)]
        .map(([, specifier]) => specifier)
        .filter((specifier) => specifier !== undefined && !specifier.startsWith("."));

      expect(externalImports, `${file} imports outside this package`).toEqual([]);
    }
  });

  it("declares no dependencies whatsoever", async () => {
    const manifestPath = path.join(sourceDirectory, "..", "package.json");
    const manifest = JSON.parse(await readFile(manifestPath, "utf8")) as {
      dependencies?: Record<string, string>;
      peerDependencies?: Record<string, string>;
    };

    expect(Object.keys(manifest.dependencies ?? {})).toEqual([]);
    expect(Object.keys(manifest.peerDependencies ?? {})).toEqual([]);
  });

  it("does not depend on a UI framework, so the contract stays framework-neutral", async () => {
    const manifestPath = path.join(sourceDirectory, "..", "package.json");
    const manifest = JSON.parse(await readFile(manifestPath, "utf8")) as {
      dependencies?: Record<string, string>;
      devDependencies?: Record<string, string>;
      peerDependencies?: Record<string, string>;
    };
    const declared = [
      ...Object.keys(manifest.dependencies ?? {}),
      ...Object.keys(manifest.devDependencies ?? {}),
      ...Object.keys(manifest.peerDependencies ?? {}),
    ];

    // React is the supported way to *author* module UI. It is deliberately absent from the host
    // contract, so a host never has to match a module's rendering library.
    for (const framework of ["react", "react-dom", "vue", "svelte", "preact"]) {
      expect(declared).not.toContain(framework);
    }
    // Backend graphs must not reappear through a development dependency either.
    for (const backend of ["drizzle-orm", "zod", "semver", "@ekklesia/contracts"]) {
      expect(declared).not.toContain(backend);
    }
  });
});