/**
 * Identical tool-call stationarity. No Bare imports.
 * Same name+args 4 times → nudge; 8 times → stuck.
 */

const NUDGE_AFTER = 4;
const STOP_AFTER = 8;

function fingerprint(name, args) {
  let a = args;
  try {
    a = JSON.stringify(args || {});
  } catch (_) {
    a = String(args);
  }
  return String(name || '') + ':' + a;
}

function create() {
  return { last: null, count: 0, nudged: false };
}

function observe(st, name, args) {
  if (!st) return 0;
  const fp = fingerprint(name, args);
  if (st.last === fp) st.count += 1;
  else {
    st.last = fp;
    st.count = 1;
    st.nudged = false;
  }
  return st.count;
}

function shouldNudge(st) {
  return !!(st && st.count >= NUDGE_AFTER && st.count < STOP_AFTER && !st.nudged);
}

function shouldStop(st) {
  return !!(st && st.count >= STOP_AFTER);
}

function nudgeText() {
  return 'You are repeating the same tool call. Try a different approach, a different path, or finish.';
}

function markNudged(st) {
  if (st) st.nudged = true;
}

module.exports = {
  NUDGE_AFTER,
  STOP_AFTER,
  fingerprint,
  create,
  observe,
  shouldNudge,
  shouldStop,
  nudgeText,
  markNudged,
};