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

const packageDirectory = path.dirname(path.dirname(fileURLToPath(import.meta.url)));

async function sourceFiles(): Promise<readonly string[]> {
  const directory = path.join(packageDirectory, "src");
  const entries = await readdir(directory);
  return entries
    .filter((entry) => entry.endsWith(".ts"))
    .map((entry) => path.join(directory, entry));
}

/**
 * The design contract is imported by the Dashboard shell, by module UI artifacts, and by contributed
 * renderers. It inherits exactly the rule ADR 0024 established for `@ekklesia/module-ui-sdk`: it
 * must not be able to pull a backend type graph — and with it Node's global declarations — into a
 * browser program.
 */
describe("the design token package stays browser-safe", () => {
  it("declares no runtime dependency at all", async () => {
    const manifest = JSON.parse(
      await readFile(path.join(packageDirectory, "package.json"), "utf8"),
    ) as { dependencies?: Record<string, string>; peerDependencies?: Record<string, string> };

    expect(manifest.dependencies).toBeUndefined();
    expect(manifest.peerDependencies).toBeUndefined();
  });

  it("imports nothing outside its own source", async () => {
    for (const file of await sourceFiles()) {
      const source = await readFile(file, "utf8");
      const specifiers = [...source.matchAll(/from\s+"([^"]+)"/gmu)].map(([, specifier]) =>
        String(specifier),
      );

      expect(specifiers.every((specifier) => specifier.startsWith("."))).toBe(true);
    }
  });

  it("never names a Node built-in or reads the environment", async () => {
    for (const file of await sourceFiles()) {
      const source = await readFile(file, "utf8");

      expect(source).not.toContain('"node:');
      expect(source).not.toContain("process.env");
      expect(source).not.toContain("globalThis.process");
    }
  });
});