using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Xml;
using IwbZero.Expr;
using IwbZero.ExprFunctions;
using IwbZero.ToolCommon.AssemblyHelpers;
using IwbZero.ToolCommon.StringModel;

namespace WeEngine.Functions
{
    public class ExprFunctionParam
    {
        public int Index { get; set; }
        public string Name { get; set; }
        public string ExprType { get; set; }
    }
    public class ExprFunction : IwbFunction
    {
        protected new IFunction Function;

        public ExprFunction()
        {
            Params= new List<ExprFunctionParam>();
        }

        public bool IsPublic { get; set; }
        public List<ExprFunctionParam> Params { get; set; }

        //public ExprFunction(IwbFunction f):this()
        //{
        //    Id = f.Id;
        //    FunctionId = f.FunctionId;
        //    FunctionName = f.FunctionName;
        //    FunctionClass = f.FunctionClass;
        //    FunctionDesc = f.FunctionDesc;
        //}
        /// <summary>
        /// 根据Id加载函数
        /// </summary>
        /// <param name="functionId"></param>
        /// <param name="fileFullClassName"></param>
        /// <returns></returns>
        public static ExprFunction LoadById(string functionId, string fileFullClassName = null)
        {
            var xmlNode = GetFunXmlNode(fileFullClassName);
            var fun = LoadByXml(xmlNode, functionId);
            return fun;
        }
        /// <summary>
        /// 加载函数
        /// </summary>
        /// <param name="xmlNode"></param>
        /// <param name="functionId"></param>
        /// <returns></returns>
        public  static ExprFunction LoadByXml(XmlNode xmlNode, string functionId)
        {
            if (!xmlNode.HasChildNodes)
            {
                return null;
            }
            foreach (XmlNode child in xmlNode.ChildNodes)
            {
                if (child.Attributes?["id"] != null && child.Attributes["id"].Value.UAndT() == functionId)
                {
                    ExprFunction function = new ExprFunction()
                    {
                        FunctionId = child.Attributes["id"].Value,
                        Id = functionId,
                    };
                    if (child.HasChildNodes)
                    {
                        foreach (XmlNode node in child.ChildNodes)
                        {
                            switch (node.Name.Trim())
                            {
                                case "Name":
                                    function.FunctionName = node.FirstChild?.Value;
                                    break;
                                case "ClassName":
                                    function.FunctionClass = node.FirstChild?.Value;
                                    break;
                                case "Description":
                                    function.FunctionDesc = node.FirstChild?.Value;
                                    break;
                            }
                        }
                    }

                    return function;
                }
            }

            return null;
        }

        /// <summary>
        /// 加载函数
        /// </summary>
        /// <param name="xmlNode"></param>
        /// <returns></returns>
        public  new static List<ExprFunction> LoadByXml(XmlNode xmlNode)
        {
            if (!xmlNode.HasChildNodes)
            {
                return null;
            }
            var funList = new List<ExprFunction>();
            foreach (XmlNode child in xmlNode.ChildNodes)
            {
                if (child.Attributes != null)
                {
                    ExprFunction function = new ExprFunction()
                    {
                        FunctionId = child.Attributes["id"].Value,
                    };
                    if (function.FunctionId != null) 
                        function.Id = function.FunctionId;
                    if (child.HasChildNodes)
                    {
                        foreach (XmlNode node in child.ChildNodes)
                        {
                            switch (node.Name.Trim())
                            {
                                case "Name":
                                    function.FunctionName = node.FirstChild?.Value;
                                    break;
                                case "ClassName":
                                    function.FunctionClass = node.FirstChild?.Value;
                                    break;
                                case "Description":
                                    function.FunctionDesc = node.FirstChild?.Value;
                                    break;
                                case "IsPublic":
                                    function.IsPublic = node.FirstChild?.Value.ValB()??false;
                                    break;
                                case "Params":
                                    if (node.HasChildNodes)
                                    {
                                        foreach (XmlNode childNode in node.ChildNodes)
                                        {
                                           

                                            function.Params.Add(CreateParams(childNode));

                                        }
                                    }
                                    break;
                            }
                        }
                    }
                    funList.Add(function);
                }
            }
            return funList;
        }

        private static ExprFunctionParam CreateParams(XmlNode xmlNode)
        {
            var funParam = new ExprFunctionParam();
            foreach (XmlNode node in xmlNode.ChildNodes)
            {
                switch (node.Name.Trim())
                {
                    case "Index":
                        funParam.Index = node.FirstChild?.Value.ValI() ?? 0;
                        break;
                    case "Name":
                        funParam.Name = node.FirstChild?.Value;
                        break;
                    case "ExprType":
                        funParam.ExprType = node.FirstChild?.Value;
                        break;
                }
            }

            return funParam;
        }


        /// <summary>
        /// 加载函数XML
        /// </summary>
        /// <param name="fileFullClassName"></param>
        /// <returns></returns>
        public static XmlNode GetFunXmlNode(string fileFullClassName=null)
        {
            fileFullClassName = fileFullClassName ?? @"WeEngine.Functions.function.xml";
            XmlDocument xDoc = new XmlDocument();
            Assembly asm = Assembly.GetExecutingAssembly();
            //Assembly asm2 = AssemblyHelper.LoadAssembly("WeEngine.Runtime.dll");
            //读取嵌入式资源
            Stream sm = asm.GetManifestResourceStream(fileFullClassName);
            if (sm != null)
            {
                xDoc.Load(sm);
            }
            if (!xDoc.HasChildNodes)
            {
                return null;
            }
            XmlNode xmlNode = xDoc.LastChild;
            return xmlNode;
        }



        /// <summary>
        /// 执行函数
        /// </summary>
        /// <param name="poRoot"></param>
        /// <returns></returns>
        public override string InvokeFunction(ExprObject poRoot)
        {
            string result = "";
            if (Function == null)
            {
                LoadFunction();
            }
            if (Function != null)
            {
                result = Function.Invoke(poRoot);
            }
            return result;
        }

        /// <summary>
        /// 加载函数
        /// </summary>
        protected override void LoadFunction()
        {
            if (FunctionClass != "")
            {
                object obj = AssemblyHelper.CreateInstance(FunctionClass);
                if (obj != null && obj is IFunction function)
                {
                    Function = function;
                }
            }
            if (Function == null)
            {
                throw new Exception($"Unable to load '{FunctionClass}' for function {FunctionName}.");
            }
        }
    }
}