import { readFileSync } from "node:fs";
import { describe, expect, it } from "vitest";

// The request layer, the notification store and the error boundary all log through lib/log.ts, so
// log.ts must not reach any of them at runtime: the import would be a cycle, and the module that
// logs a failure would load the one that failed. A type-only import is erased, so it does not count.
// The comment in log.ts said this for a long time while nothing checked it.

const LIB = new URL("./", import.meta.url);
const ALLOWED = ["log.ts", "storage.ts", "version.ts"];

/** The app modules `file` imports at runtime (relative, not `import type`), as lib/ file names. */
function runtimeImports(file: string): string[] {
  const text = readFileSync(new URL(file, LIB), "utf-8");
  return [...text.matchAll(/^import\s+(?!type\b)[^;]*?from\s+"(\.[^"]+)";/gms)].map(
    (m) => `${m[1]!.replace(/^\.\//, "")}.ts`,
  );
}

describe("lib/log.ts", () => {
  it("reaches only the build stamp and the key registry at runtime", () => {
    const seen = new Set<string>();
    const queue = ["log.ts"];
    while (queue.length) {
      const file = queue.pop()!;
      if (seen.has(file)) continue;
      seen.add(file);
      if (ALLOWED.includes(file)) queue.push(...runtimeImports(file));
    }
    expect([...seen].sort()).toEqual([...ALLOWED].sort());
  });
});