function safeStringify(obj) {
  const seen = new WeakSet();
  return JSON.stringify(
    obj,
    (k, v) => {
      if (typeof v === "object" && v !== null) {
        if (seen.has(v)) return "[Circular]";
        seen.add(v);
      }
      if (typeof v === "function") return `[Function: ${v.name || "anonymous"}]`;
      if (typeof v === "bigint") return v.toString();
      return v;
    },
    2
  );
}

function pickEnvSample() {
  try {
    const env = (typeof process !== "undefined" && process && process.env) ? process.env : null;
    if (!env) return null;

    // only show safe-ish keys, no full dump
    const keys = Object.keys(env).sort();
    const filtered = keys.filter(k =>
      k.toLowerCase().includes("sub") ||
      k.toLowerCase().includes("store") ||
      k.toLowerCase().includes("script") ||
      k.toLowerCase().includes("url") ||
      k.toLowerCase().includes("option") ||
      k.toLowerCase().includes("param")
    );

    const sample = {};
    for (const k of filtered.slice(0, 50)) sample[k] = env[k];
    return { keysCount: keys.length, filteredKeys: filtered.slice(0, 100), sample };
  } catch (e) {
    return { error: String(e) };
  }
}

function getGlobalDollarKeys() {
  try {
    return Object.getOwnPropertyNames(globalThis).filter(k => k.startsWith("$")).sort();
  } catch {
    return [];
  }
}

// Safe "typeof" probes: never throws even if variable doesn't exist
const probes = {
  $content: typeof $content,
  $files: typeof $files,
  $options: typeof $options,

  $params: typeof $params,
  $args: typeof $args,
  $arguments: typeof $arguments,
  $argument: typeof $argument,
  $argv: typeof $argv,

  $ctx: typeof $ctx,
  $context: typeof $context,
  $request: typeof $request,
  $req: typeof $req,
  $url: typeof $url,
  $scriptUrl: typeof $scriptUrl,
  $script_url: typeof $script_url,

  ProxyUtils: typeof ProxyUtils,
  produceArtifact: typeof produceArtifact,

  process: typeof process,
};

const values = {};
function maybeSet(name, getter) {
  try {
    const v = getter();
    // Avoid huge outputs
    if (typeof v === "string") values[name] = v.length > 800 ? v.slice(0, 800) + "…(truncated)" : v;
    else values[name] = v;
  } catch (e) {
    values[name] = { error: String(e) };
  }
}

maybeSet("$options", () => (typeof $options !== "undefined" ? $options : null));
maybeSet("$params", () => (typeof $params !== "undefined" ? $params : null));
maybeSet("$args", () => (typeof $args !== "undefined" ? $args : null));
maybeSet("$arguments", () => (typeof $arguments !== "undefined" ? $arguments : null));
maybeSet("$argument", () => (typeof $argument !== "undefined" ? $argument : null));
maybeSet("$ctx", () => (typeof $ctx !== "undefined" ? $ctx : null));
maybeSet("$request", () => (typeof $request !== "undefined" ? $request : null));
maybeSet("$url", () => (typeof $url !== "undefined" ? $url : null));
maybeSet("$scriptUrl", () => (typeof $scriptUrl !== "undefined" ? $scriptUrl : null));
maybeSet("$script_url", () => (typeof $script_url !== "undefined" ? $script_url : null));

maybeSet("$contentPreview", () => (typeof $content === "string" ? $content.slice(0, 300) : $content));
maybeSet("$contentLength", () => (typeof $content === "string" ? $content.length : null));
maybeSet("$files", () => (typeof $files !== "undefined" ? $files : null));

const report = {
  probes,
  values,
  globalDollarKeys: getGlobalDollarKeys(),
  envSample: pickEnvSample(),
};

$content = safeStringify(report);