using Qrakhen.Qamp.Core.Values.Objects;
using System.Reflection;

namespace Qrakhen.Qamp.Core.Values.Native;

public class NativeMemberAttribute(string? name = null) : Attribute
{
   public string? Name { get; } = name;
}

public class NativeMember(string name, MemberInfo info)
{
   public string Name { get; } = name;
   public MemberInfo MemberInfo { get; } = info;
}

public class NativeProperty(string name, 
                            PropertyInfo info, 
                            bool readOnly) : NativeMember(name, info)
{
   public bool ReadOnly { get; } = readOnly;
   public PropertyInfo PropertyInfo => (MemberInfo as PropertyInfo)!; 
}

public class NativeMethod(string name, 
                          MethodInfo info) : NativeMember(name, info)
{
   public MethodInfo MethodInfo => (MemberInfo as MethodInfo)!;
}

public static class NativeLinker
{
   private static readonly Dictionary<Type, Dictionary<string, NativeMember>> _linked = [];

   private static Dictionary<string, NativeMember> GetLinkTable<T>() => GetLinkTable(typeof(T));

   private static Dictionary<string, NativeMember> GetLinkTable(Type type)
   {
      if (!_linked.TryGetValue(type, out Dictionary<string, NativeMember>? table))
      {
         table = Compile(type);
      }

      if (table == null)
      {
         throw new QampException($"{type.Name} has no native members that could be accessed.");
      }

      return table;
   }

   private static M GetNativeMember<T, M>(string name) where M : NativeMember
      => GetNativeMember<M>(typeof(T), name);

   private static T GetNativeMember<T>(Type type, string name)
   {
      if (GetLinkTable(type).TryGetValue(name, out NativeMember? member)) {
         if (member is T typedMember) {
            return typedMember;
         }
      }

      throw new QampException($"{type.Name} has no member {name} that could be accessed.");
   }

   public static Value GetProperty<TObj>(TObj obj, string name)
   {
      var property = GetNativeMember<TObj, NativeProperty>(name);
      return Value.Void; //new Value(property.PropertyInfo.GetValue(obj));
   }

   public static void SetProperty<TObj>(TObj obj, string name, Value value)
   {
      
   }

   public static Value CallMember<TObj>(TObj obj, string name, Value[] args)
   {
      var method = GetNativeMember<TObj, NativeMethod>(name);

      return Value.Void;
   }

   private static void Compile(Type type, string method, int argCount)
   {

   }

   private static void Compile(Type type, string member)
   {

   }

   private static Dictionary<string, NativeMember> Compile(Type type)
   {
      var members = type.GetMembers();
      var table = new Dictionary<string, NativeMember>();
      foreach (var member in members)
      {
         var attr = member.GetCustomAttribute<NativeMemberAttribute>();
         if (attr == null)
            continue;

         NativeMember? native = null;
         if (member is PropertyInfo propertyInfo)
         {
            native = new NativeProperty(attr.Name ?? member.Name,
                                        propertyInfo,
                                        propertyInfo.CanWrite);
         }

         if (member is MethodInfo methodInfo)
         {
            native = new NativeMethod(attr.Name ?? methodInfo.Name,
                                      methodInfo);
         }

         if (native == null)
            throw new Exception("meh.");

         table[native.Name] = native;
      }

      return _linked[type] = table;
   }
}

/*
public delegate Value Getter(Obj? self);
public delegate void Setter(Obj? self, Value value);
public delegate Value Method(Obj? self, Value[] args);

public class NativeMember(string name, bool isStatic)
{
   public readonly string Name = name;
   public readonly bool IsStatic = isStatic;
}

public class NativeConst(string name, Value value) 
   : NativeMember(name, true)
{
   public readonly Value Value = value;
}

public class NativeGetter(string name, bool isStatic, Getter getter) 
   : NativeMember(name, isStatic)
{
   public readonly Getter Getter = getter;
}

public class NativeSetter(string name, bool isStatic, Getter getter, Setter setter) 
   : NativeGetter(name, isStatic, getter)
{
   public readonly Setter Setter = setter;
}

public class NativeMethod(string name, bool isStatic, Method method) 
   : NativeMember(name, isStatic)
{
   public readonly Method Method = method;
}

public static class Natives
{
   private static readonly Dictionary<Type, Dictionary<string, NativeMember>> _members = [];
   private static readonly Dictionary<Type, Dictionary<string, NativeMember>> _membersStatic = [];

   private static Dictionary<string, NativeMember> Prepare(Type type, string name, bool isStatic)
   {
      if (!type.IsAssignableTo(typeof(Obj)))
         throw new QampException($"Only object types may have native members assigned. The provided type {type} can not have any attached properties or members. Use extensions to handle that type.");

      var target = isStatic ? _membersStatic : _members;

      if (!target.ContainsKey(type))
         target.Add(type, []);

      if (target[type].ContainsKey(name))
         throw new QampException($"Can not register native {(isStatic ? "static" : "")} member {name} for {type}, that member was already defined.");

      return target[type];
   }

   public static void Register(Type type, NativeMember member)
   {
      var target = Prepare(type, member.Name, member.IsStatic);
      target[member.Name] = member;
   }

   public static void Register(Type type, string name, Value constant)
   {
      Register(type, new NativeConst(name, constant));
   }

   public static void Register(Type type, MethodInfo info, Method method)
   {
      Register(type, new NativeMethod(info.Name, info.IsStatic, method));
   }
}*/