/**
 * Split a tool-call list into sequential vs parallel groups.
 * Same-path write_file / search_replace share a lock key.
 */

const SEQUENTIAL = new Set([
  'ask_user_question',
  'exit_plan_mode',
  'update_goal',
  'enter_plan_mode',
  'task',
  'send_subagent_message',
  'wait_tasks',
  'kill_task',
]);

function isSequential(name) {
  return SEQUENTIAL.has(String(name || ''));
}

function pathLockKey(name, args) {
  args = args || {};
  if (name === 'write_file' || name === 'search_replace') {
    return String(args.path || args.file || '')
      .replace(/\\/g, '/')
      .replace(/\/+/g, '/');
  }
  return '';
}

function groups(calls) {
  const out = [];
  let current = null;
  for (const call of calls || []) {
    const seq = isSequential(call && call.name);
    if (seq) {
      if (current) {
        out.push(current);
        current = null;
      }
      out.push({ sequential: true, calls: [call] });
    } else {
      if (!current) current = { sequential: false, calls: [] };
      current.calls.push(call);
    }
  }
  if (current) out.push(current);
  return out;
}

function withPathLock(locks, key, fn) {
  if (!key) return Promise.resolve().then(fn);
  const prev = locks.get(key) || Promise.resolve();
  const curr = prev.then(fn, fn);
  locks.set(
    key,
    curr.then(
      () => {},
      () => {}
    )
  );
  return curr;
}

module.exports = { SEQUENTIAL, isSequential, pathLockKey, groups, withPathLock };