using System.Reflection;
using System.Reflection.Emit;

namespace WCS.Core;

/// <summary>
///     动态创建接口实例
/// </summary>
/// <typeparam name="T">接口</typeparam>
/// <typeparam name="TBase">基类</typeparam>
public static class Generator<T, TBase> where TBase : IProtocolProxy
{
    private const MethodAttributes METHOD_ATTRIBUTES =
        MethodAttributes.Public | MethodAttributes.NewSlot | MethodAttributes.Virtual | MethodAttributes.Final |
        MethodAttributes.HideBySig;

    private static readonly TypeBuilder tb;
    private static readonly Type Type;

    static Generator()
    {
        if (!typeof(T).IsInterface)
            throw new Exception("T必须是interface");
        if (!typeof(TBase).IsClass)
            throw new Exception("TBase必须是class");

        var myAssemblyName = new AssemblyName();
        myAssemblyName.Name = typeof(T).Name + "_Generate";
        var myAssembly = AssemblyBuilder.DefineDynamicAssembly(myAssemblyName, AssemblyBuilderAccess.RunAndCollect);
        //AssemblyBuilder myAssembly = AssemblyBuilder.DefineDynamicAssembly(myAssemblyName, AssemblyBuilderAccess.RunAndSave);


        var myModule = myAssembly.DefineDynamicModule("Main");
        tb = myModule.DefineType(typeof(T).Name + "_Generate", TypeAttributes.Public, typeof(TBase),
            new[] { typeof(T) });
        InitConstructors();
        InitMethods();
        InitProperties();
        InitEvents();
        try
        {
            Type = tb.CreateTypeInfo().AsType(); //.CreateType();
        }
        catch (Exception ex)
        {
        }
        //myAssembly.Save(typeof(T).Name + ".dll");
    }

    private static void InitConstructors()
    {
        foreach (var cons in typeof(TBase).GetConstructors())
        {
            var pTypes = cons.GetParameters().Select(v => v.ParameterType).ToArray();
            var build = tb.DefineConstructor(cons.Attributes, CallingConventions.Standard, pTypes);
            for (var i = 0; i < pTypes.Length; i++) build.DefineParameter(i + 1, ParameterAttributes.In, "p" + i);
            var il = build.GetILGenerator();
            il.Emit(OpCodes.Ldarg_0);
            for (var i = 0; i < pTypes.Length; i++) il.Emit(OpCodes.Ldarg, i + 1);
            il.Emit(OpCodes.Call, cons);
            //il.Emit(OpCodes.Pop);
            il.Emit(OpCodes.Ret);
        }
    }

    private static void InitMethods()
    {
        var ms = GetInterfaces().SelectMany(v => v.GetMethods()).ToArray();
        ms = ms.Where(v => !v.IsSpecialName).ToArray();
        foreach (var m in ms) GenerateMethod(m);
    }

    private static void InitProperties()
    {
        var ps = GetInterfaces().SelectMany(v => v.GetProperties());
        ps = GetMembers().OfType<PropertyInfo>();
        foreach (var p in ps)
        {
            if (typeof(TBase).GetProperty(p.Name,
                    BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic) != null) continue;
            var pTypes = p.GetIndexParameters().Select(v => v.ParameterType).ToArray();
            var pb = tb.DefineProperty(p.Name, p.Attributes, p.PropertyType, pTypes);
            if (p.CanRead)
            {
                if (pTypes.Length > 0)
                {
                    //索引器
                    var mb = GenerateIndexer(p.GetGetMethod());
                    pb.SetGetMethod(mb);
                }
                else
                {
                    var mb = GenerateProperty(p.GetGetMethod());
                    pb.SetGetMethod(mb);
                }
            }

            if (p.CanWrite)
            {
                if (pTypes.Length > 0)
                {
                    var mb = GenerateIndexer(p.GetSetMethod());
                    pb.SetSetMethod(mb);
                }
                else
                {
                    var mb = GenerateProperty(p.GetSetMethod());
                    pb.SetSetMethod(mb);
                }
            }
        }
    }

    private static void InitEvents()
    {
        var evts = GetInterfaces().SelectMany(v => v.GetEvents());

        foreach (var evt in evts)
        {
            var eb = tb.DefineEvent(evt.Name, evt.Attributes, evt.EventHandlerType);
            var add = GenerateEventEnabled(evt, evt.GetAddMethod());
            eb.SetAddOnMethod(add);
            var remove = GenerateEventEnabled(evt, evt.GetRemoveMethod());
            eb.SetRemoveOnMethod(remove);
        }
    }

    private static MethodBuilder GenerateMethod(MethodInfo m)
    {
        var pTypes = m.GetParameters().Select(v => v.ParameterType).ToArray();
        var mb = tb.DefineMethod(m.Name, METHOD_ATTRIBUTES, CallingConventions.Standard, m.ReturnType, pTypes);
        var ilGen = mb.GetILGenerator();


        ilGen.DeclareLocal(typeof(object[])); //声明object数组变量  

        #region 参数准备

        ilGen.Emit(OpCodes.Ldarg_0); //this
        ilGen.Emit(OpCodes.Ldstr, m.Name); //string name  


        ilGen.Emit(OpCodes.Ldc_I4_S, pTypes.Length); //数组长度
        ilGen.Emit(OpCodes.Newarr, typeof(object)); //数组
        ilGen.Emit(OpCodes.Stloc_0);


        for (var i = 0; i < pTypes.Length; i++)
        {
            ilGen.Emit(OpCodes.Ldloc_0);
            ilGen.Emit(OpCodes.Ldc_I4_S, i);
            ilGen.Emit(OpCodes.Ldarg_S, 1 + i);
            ilGen.Emit(OpCodes.Box, pTypes[i]);
            ilGen.Emit(OpCodes.Stelem_Ref);
        }

        #endregion

        ilGen.Emit(OpCodes.Ldloc_0);

        if (m.ReturnType != typeof(void))
        {
            var mi = typeof(TBase).GetMethod("CallReturn",
                BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
            mi = mi.MakeGenericMethod(m.ReturnType);
            ilGen.Emit(OpCodes.Call, mi);
            var local = ilGen.DeclareLocal(m.ReturnType);
            ilGen.Emit(OpCodes.Stloc_1, local);
            ilGen.Emit(OpCodes.Ldloc_1, local);
        }
        else
        {
            var mi = typeof(TBase).GetMethod("CallVoid",
                BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
            ilGen.Emit(OpCodes.Call, mi);
        }

        ilGen.Emit(OpCodes.Ret);
        return mb;
    }

    private static MethodBuilder GenerateProperty(MethodInfo m)
    {
        var pTypes = m.GetParameters().Select(v => v.ParameterType).ToArray();
        var mb = tb.DefineMethod(m.Name, METHOD_ATTRIBUTES, CallingConventions.Standard, m.ReturnType, pTypes);
        var ilGen = mb.GetILGenerator();


        #region 参数准备

        ilGen.Emit(OpCodes.Ldarg_0); //this
        ilGen.Emit(OpCodes.Ldstr, m.Name.Replace("set_", "").Replace("get_", "")); //string name   

        #endregion

        if (m.Name.StartsWith("set_"))
        {
            ilGen.Emit(OpCodes.Ldarg_1); //value  准备参数 
            var mi = typeof(TBase).GetMethod("Set",
                BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
            mi = mi.MakeGenericMethod(pTypes);
            ilGen.Emit(OpCodes.Call, mi); //调用基类方法  
            //ilGen.Emit(OpCodes.Pop);
        }
        else
        {
            var mi = typeof(TBase).GetMethod("Get",
                BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
            mi = mi.MakeGenericMethod(m.ReturnType);
            ilGen.Emit(OpCodes.Call, mi); //调用方法

            #region 返回值

            var local = ilGen.DeclareLocal(m.ReturnType);
            ilGen.Emit(OpCodes.Stloc_0, local);
            ilGen.Emit(OpCodes.Ldloc_0, local);

            #endregion
        }

        ilGen.Emit(OpCodes.Ret); //return
        return mb;
    }

    private static MethodBuilder GenerateIndexer(MethodInfo m)
    {
        var pTypes = m.GetParameters().Select(v => v.ParameterType).ToArray();
        var mb = tb.DefineMethod(m.Name, METHOD_ATTRIBUTES, CallingConventions.Standard, m.ReturnType, pTypes);
        var ilGen = mb.GetILGenerator();


        #region 参数准备

        ilGen.DeclareLocal(typeof(object[])); //声明object数组变量  

        ilGen.Emit(OpCodes.Ldarg_0); //this 

        ilGen.Emit(OpCodes.Ldc_I4_S, pTypes.Length); //数组长度
        ilGen.Emit(OpCodes.Newarr, typeof(object)); //数组
        ilGen.Emit(OpCodes.Stloc_0);


        var i = 0;
        for (i = 0; i < pTypes.Length; i++)
        {
            ilGen.Emit(OpCodes.Ldloc_0);
            ilGen.Emit(OpCodes.Ldc_I4_S, i);
            ilGen.Emit(OpCodes.Ldarg_S, 1 + i);
            ilGen.Emit(OpCodes.Box, pTypes[i]);
            ilGen.Emit(OpCodes.Stelem_Ref);
        }

        #endregion

        ilGen.Emit(OpCodes.Ldloc_0);

        if (m.Name.StartsWith("set"))
        {
            //ilGen.Emit(OpCodes.Ldarg_S, 1 + i);//value  准备参数 
            var mi = typeof(TBase).GetMethod("SetItem",
                BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
            ilGen.Emit(OpCodes.Call, mi); //调用基类方法  
            //ilGen.Emit(OpCodes.Pop);
        }
        else
        {
            var mi = typeof(TBase).GetMethod("GetItem",
                BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
            mi = mi.MakeGenericMethod(m.ReturnType);
            ilGen.Emit(OpCodes.Call, mi); //调用方法

            #region 返回值

            var local = ilGen.DeclareLocal(m.ReturnType);
            ilGen.Emit(OpCodes.Stloc_1, local);
            ilGen.Emit(OpCodes.Ldloc_1, local);

            #endregion
        }

        ilGen.Emit(OpCodes.Ret); //return
        return mb;
    }

    private static MethodBuilder GenerateEventEnabled(EventInfo evt, MethodInfo m)
    {
        var add = m.Name.StartsWith("add_");
        var n = m.DeclaringType.Name;
        var pTypes = m.GetParameters().Select(v => v.ParameterType).ToArray();
        var mb = tb.DefineMethod(m.Name, METHOD_ATTRIBUTES, CallingConventions.Standard, m.ReturnType, pTypes);
        var ilGen = mb.GetILGenerator();


        //ilGen.DeclareLocal(typeof(EventInfo));//声明字符串变量
        //ilGen.DeclareLocal(typeof(Delegate)); //value Delegate

        //ilGen.Emit(OpCodes.Ldstr, evt.Name);//string evtName 字符串值
        //ilGen.Emit(OpCodes.Stloc_0);//保存至变量
        //ilGen.Emit(OpCodes.Ldarg_1);//Delegate dlg
        //ilGen.Emit(OpCodes.Stloc_1);//保存至变量


        #region 参数准备

        ilGen.Emit(OpCodes.Ldarg_0);
        ilGen.Emit(OpCodes.Ldstr, evt.Name);
        ilGen.Emit(OpCodes.Ldarg_1);

        #endregion

        var mname = add ? "AddEvent" : "RemoveEvent";
        ilGen.Emit(OpCodes.Call,
            typeof(TBase).GetMethod(mname, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public));

        ilGen.Emit(OpCodes.Ret);
        return mb;
    }


    private static Type[] GetInterfaces()
    {
        var tInterface = typeof(T);
        var ts = tInterface.GetInterfaces().ToList();
        ts.Add(tInterface);
        return ts.ToArray();
    }

    private static MemberInfo[] GetMembers()
    {
        var members = GetInterfaces().SelectMany(v => v.GetMembers()).Distinct().ToArray();
        return members;
    }

    public static T Create(params object[] args)
    {
        return (T)Activator.CreateInstance(Type, args);
    }

    public static Type GetGenerateType()
    {
        return Type;
    }
}