#!/usr/bin/env node
/**
 * PreToolUse hook: the remote approval gate.
 *
 * Asks the daemon what to do with this tool call. The daemon holds the request open while
 * your phone decides, then answers allow/deny. Every failure path here is fail-open —
 * a daemon that is down, slow, or confused must not be able to block your agent.
 *
 * Denying is the only outcome that changes behaviour, and approving only lets through a
 * call Grok was already about to make. This hook can never introduce a new command.
 */

import {
  APPROVAL_HOOK_TIMEOUT_SECS,
  baseUrl,
  envEnvelope,
  hookHeaders,
  postJson,
  readConfig,
  readStdinJson,
} from "./glance-lib.mjs";

function allow() {
  process.exit(0);
}

function deny(reason) {
  // Belt and braces: the documented deny signals are a JSON decision on stdout *and*
  // exit code 2. We emit both so a change in precedence cannot silently allow.
  process.stdout.write(
    JSON.stringify({ decision: "deny", reason: reason || "Denied from grok-glance" }),
  );
  process.exit(2);
}

const payload = envEnvelope(await readStdinJson());
const cfg = readConfig();

// Finish inside the hook's own timeout from hooks.json, with room to spare: if Grok Build
// kills us first, the fail-open path below never gets to run.
const waitMs = Math.min(
  APPROVAL_HOOK_TIMEOUT_SECS * 1000 - 10_000,
  Number(cfg.approval?.timeoutMs ?? 90_000) + 15_000,
);

try {
  const { data } = await postJson(
    `${baseUrl(cfg)}/hook/approve`,
    payload,
    waitMs,
    hookHeaders(),
  );
  if (data && data.decision === "deny") deny(data.reason);
  allow();
} catch {
  allow();
}