using System;
using System.Collections.Generic;
using Abp.Dependency;
using IwbZero.Expr;
using IwbZero.IwbBase;
using IwbZero.ToolCommon.StringModel;

namespace WeEngine.Functions
{
    public  class ExprModule
    {
        private static IdCollection _functions;
        public static string Evaluate(string exprStr)
        {
            string str = exprStr;
            try
            {
                ExprObject exprObj = new ExprObject(exprStr, ExprElements.Expression);
                if (EvalExpr.Parse(exprObj, true))
                {
                    str = Evaluate(exprObj);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }

            return str;
        }
        public static string Evaluate(string exprStr, Dictionary<string, object> variableValueDic)
        {
            var exprStr2 = EvalExpr.TransVariable(exprStr, variableValueDic);
            var str = Evaluate(exprStr2);
            return str;
        }
        private static string Evaluate(ExprObject exprObj)
        {
            string str = "";
            if (exprObj.ChildCount == 0)
            {
                return exprObj.Expr;
            }
            EvaluateAllChildren(exprObj);
            ExprObject expr = null;
            for (int i = 0; i < exprObj.ChildCount; i++)
            {
                ExprObject child = exprObj.GetChild(i);
                if (child.IsOperator)
                {
                    var @operator = child.GetOperator();
                    ExprObject expr3 = exprObj.GetChild(i + 1);
                    if (expr3 != null)
                    {
                        expr = @operator.Calculate(expr, expr3);
                        i++;
                    }
                }
                else if (expr == null)
                {
                    expr = child;
                }
            }

            if (expr != null) str = expr.Expr;
            return str;
        }
        //public static string Evaluate(ExprObject exprObj, Dictionary<string, object> variableValueDic)
        //{
        //    return Evaluate(exprObj.Expr,variableValueDic);
        //}
        private static  void EvaluateAllChildren(ExprObject exprObj)
        {
            if (exprObj != null)
            {
                for (int i = 0; i < exprObj.ChildCount; i++)
                {
                    ExprObject child = exprObj.GetChild(i);
                    EvaluateAllChildren(child);
                    if (child != null)
                    {
                        string str = null;
                        switch (child.ElementType)
                        {
                            case ExprElements.Function:
                                str = EvaluateFunction(child);
                                break;

                            case ExprElements.Variable:
                                //str = TransSessionVariables(child.Expr);
                                break;

                            case ExprElements.Expression:
                                str = Evaluate(child);
                                break;
                        }
                        if (str != null)
                        {
                            child.Expr = str;
                            child.ElementType = ExprElements.Value;
                        }
                    }
                }
            }
        }
        private static string EvaluateFunction(ExprObject exprObj)
        {
            string str = "";
            string functionId =exprObj.Expr.UAndT();
            if (functionId.IndexOf("IFUN", StringComparison.Ordinal) == 0)
            {
                return EvalExpr.EvaluateFunction(exprObj);
            }
            if (_functions == null)
            {
                _functions = new IdCollection();
            }
            ExprFunction function = (ExprFunction) _functions[functionId];
            if (function == null)
            {
                function = ExprFunction.LoadById(functionId);
                if (function != null)
                {
                    _functions.Add(function);
                }
            }
            if (function != null)
            {
                str = function.Invoke(exprObj);
            }
            return str;
        }
    }

    public interface IExprModuleManager
    {
        string Evaluate(string exprStr);
        string Evaluate(string exprStr, Dictionary<string, object> variableValueDic);
    }

    public class ExprModuleManager: IExprModuleManager,ISingletonDependency
    {
        public string Evaluate(string exprStr)
        {
            return ExprModule.Evaluate(exprStr);
        }

        public string Evaluate(string exprStr, Dictionary<string, object> variableValueDic)
        {
            return ExprModule.Evaluate(exprStr,variableValueDic);
        }
    }

    public class NullExprModuleManager : IExprModuleManager
    {
        public static NullExprModuleManager Instance = new NullExprModuleManager();
        public string Evaluate(string exprStr)
        {
            return exprStr;
        }

        public string Evaluate(string exprStr, Dictionary<string, object> variableValueDic)
        {
            return exprStr;
        }
    }
}