(function initExecutionGuard(root, factory) {
  const api = factory();
  if (typeof module === 'object' && module.exports) module.exports = api;
  root.LTJTExecutionGuard = api;
})(typeof self !== 'undefined' ? self : globalThis, function createExecutionGuard() {
  'use strict';

  const TERMINAL_STATES = new Set(['completed', 'blocked', 'cancelled', 'uncertain']);
  const WRITE_STATES = new Set(['write_started', 'submitted', 'uncertain', 'completed']);

  function rootTaskId(taskId) {
    return String(taskId || '').split('#')[0];
  }

  function acceptanceDecision(existing, executionId) {
    const normalizedExecutionId = String(executionId || '').trim();
    if (!normalizedExecutionId) {
      return { accepted: false, status: 'missing_execution_id', reason: '缺少服务端执行编号。' };
    }
    if (!existing) return { accepted: true, status: 'accepted', reason: '' };
    if (String(existing.execution_id || '') !== normalizedExecutionId) {
      return { accepted: false, status: 'duplicate_blocked', reason: '同一任务出现了不同执行编号。' };
    }
    return {
      accepted: false,
      status: TERMINAL_STATES.has(existing.state) ? 'already_finished' : 'already_started',
      reason: '该执行编号已经被插件接收，重复消息不会再次执行。'
    };
  }

  function failureState(existing) {
    return existing && WRITE_STATES.has(existing.state) ? 'uncertain' : 'blocked';
  }

  function canTransition(existing, executionId) {
    return Boolean(existing) && String(existing.execution_id || '') === String(executionId || '');
  }

  return {
    TERMINAL_STATES,
    WRITE_STATES,
    rootTaskId,
    acceptanceDecision,
    failureState,
    canTransition
  };
});