/******************************
* 说明：动态求值(功能类似于Bs Eval)
* 创建人：龚宇超
* 创建日期：2017-07-24
* 修改人：
* 修改日期：
* 修改备注：
* 版本：1.0.0.0
******************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.CodeDom.Compiler;
using System.Data;
using System.Data.SqlClient;
using Microsoft.JScript;
using Microsoft.JScript.Vsa;
using Lskj.Expression;

namespace Lskj.Util
{
    /// <summary>
    /// 动态求值(功能类似于Bs Eval)
    /// </summary>
    public class EvalHelper
    {
        /// <summary>
        /// 数据连接
        /// </summary>
        public static SqlConnection _connection;
        private static object mEvaluator = null;
        private static Type mEvaluatorType = null;
        private static readonly string mJscriptSource =
            @"class Evaluator
                {
                    public function Eval(expr : String) : String 
                    { 
                        return eval(expr); 
                    }
                }";

        /// <summary>
        /// 构造JScript的编译驱动代码
        /// </summary>
        static EvalHelper()
        {
            //CodeDomProvider provider = CodeDomProvider.CreateProvider("JScript");
            //CompilerParameters parameters;
            //parameters = new CompilerParameters();
            //parameters.GenerateInMemory = true;
            //CompilerResults results;
            //results = provider.CompileAssemblyFromSource(parameters, mJscriptSource);
            //Assembly assembly = results.CompiledAssembly;
            //mEvaluatorType = assembly.GetType("Evaluator");
            //mEvaluator = Activator.CreateInstance(mEvaluatorType);
        }

        /// <summary>
        /// <para>说明：计算表达式</para>
        /// <para>异常：会抛出Exception,遇到无法计算的公式.</para>
        /// <para>创建人：龚宇超</para>
        /// <para>创建日期：2017-07-24 </para>
        /// <para>修改人：</para>
        /// <para>修改日期：</para>
        /// <para>修改备注：</para>
        /// <para>版本：1.0</para>
        /// </summary>
        /// <param name="statement">表达式:如(1+2+3-5)</param>
        /// <returns>计算结果</returns>
        public static object Eval(string statement)
        {
            return Eval2(statement);
            //object obj = string.Empty;
            //try
            //{
            //    obj = mEvaluatorType.InvokeMember(
            //               "Eval",
            //               BindingFlags.InvokeMethod,
            //               null,
            //               mEvaluator,
            //               new object[] { statement }
            //     );
            //}
            //catch (Exception e)
            //{

            //}
            //return obj;
        }


        /// <summary>
        /// <para>说明：计算表达式</para>
        /// <para>异常：会抛出Exception,遇到无法计算的公式.</para>
        /// <para>创建人：王一帆</para>
        /// <para>创建日期：2020-03-04 </para>
        /// <para>修改人：</para>
        /// <para>修改日期：</para>
        /// <para>修改备注：</para>
        /// <para>版本：2.0</para>
        /// </summary>
        /// <param name="statement">表达式:如(1+2+3-5)</param>
        /// <returns>计算结果</returns>
        public static object Eval2(string statement)
        {
            object obj = string.Empty;
            try
            {
                JSCaller caller = new JSCaller();
                obj = caller.Eval(statement);
                //obj = "0";
                //obj = _evaluatorType.InvokeMember(
                //           "Eval",
                //           BindingFlags.InvokeMethod,
                //           null,
                //           _evaluator,
                //           new object[] { statement }
                // );
            }
            catch (Exception ex)
            {
                //MessageBox.Show("请仔细检查配置列条件[" + statement + "]" + ex.StackTrace + "\r\n" + ex.Message);

            }
            //if (string.IsNullOrEmpty(obj + ""))
            //    return true;
            return obj;
        }
        /// <summary>
        /// <para>说明：(新版)计算表达式</para>
        /// <para>异常：会抛出Exception,遇到无法计算的公式.</para>
        /// <para>创建人：王一帆</para>
        /// <para>创建日期：2022-04-12 </para>
        /// <para>修改人：</para>
        /// <para>修改日期：</para>
        /// <para>修改备注：</para>
        /// <para>版本：1.0</para>
        /// </summary>
        /// <param name="statement">表达式:如(1+2+3-5)</param>
        /// <returns>计算结果</returns>
        //public static object Eval(string statement)
        //{
        //    object obj = string.Empty;
        //    try
        //    {
        //        Express exp = new Express("", statement);
        //        obj = exp.Eval((DataRow)null);
        //    }
        //    catch (Exception e)
        //    {

        //    }
        //    return obj;
        //}

    }
}