using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace Encompass
{
    internal class UberEngine : Engine
    {
        private readonly IEnumerable<Type> _componentTypes;
        private readonly IEnumerable<Type> _messageTypes;
        public Entity Entity { get; private set; }

        public UberEngine(IEnumerable<Type> componentTypes, IEnumerable<Type> messageTypes)
        {
            _componentTypes = componentTypes;
            _messageTypes = messageTypes;
            ReadTypes.UnionWith(componentTypes);
            WriteTypes.UnionWith(componentTypes);
            SendTypes.UnionWith(messageTypes);
            ReceiveTypes.UnionWith(messageTypes);
        }

        public void Write()
        {
            Entity = CreateEntity();

            foreach (var type in _componentTypes)
            {
                var instanceParam = new object[] { Entity, Activator.CreateInstance(type) };
                var setComponentMethod = typeof(Engine).GetMethod("SetComponent", BindingFlags.NonPublic | BindingFlags.Instance);
                var genericSetComponentMethod = setComponentMethod.MakeGenericMethod(type);
                genericSetComponentMethod.Invoke(this, instanceParam);
            }
        }

        // we can't reflect invoke on Span returns right now... tragic
        public override void Update(double dt)
        {
            foreach (var type in _componentTypes)
            {
                CallGenericMethod(type, "ReadComponent", null);
                //CallGenericMethod(type, "ReadComponents", null);
                CallGenericMethod(type, "ReadEntity", null);
                //CallGenericMethod(type, "ReadEntities", null);
                CallGenericMethod(type, "GetComponent", new object[] { Entity });
                CallGenericMethod(type, "HasComponent", 1, new object[] { Entity });
                CallGenericMethod(type, "SomeComponent", null);
                CallGenericMethod(type, "DestroyWith", null);
                CallGenericMethod(type, "DestroyAllWith", null);
                CallGenericMethod(type, "RemoveComponent", new object[] { Entity });
            }

            foreach (var type in _messageTypes)
            {
                CallGenericMethod(type, "SendMessageIgnoringTimeDilation", new object[] { Activator.CreateInstance(type), 1 });
                CallGenericMethod(type, "SendMessage", 1, new object[] { Activator.CreateInstance(type) });
                CallGenericMethod(type, "SendMessage", 2, new object[] { Activator.CreateInstance(type), 1 });
                CallGenericMethod(type, "ReadMessage", null);

                //CallGenericMethod(type, "ReadMessages", null);
                CallGenericMethod(type, "SomeMessage", null);
                if (typeof(IHasEntity).IsAssignableFrom(type))
                {
                    CallGenericMethod(type, "ReadMessagesWithEntity", new object[] { Entity });
                    CallGenericMethod(type, "ReadMessageWithEntity", new object[] { Entity });
                    CallGenericMethod(type, "SomeMessageWithEntity", new object[] { Entity });
                }
            }
        }

        // trying to use PrepareMethod because we can't reflect invoke methods that return a span...
        private void CallGenericMethod(Type type, string methodName, object[] parameters)
        {
            var readComponentMethod = typeof(Engine).GetMethod(methodName, BindingFlags.NonPublic | BindingFlags.Instance);
            var genericReadComponentMethod = readComponentMethod.MakeGenericMethod(type);
            genericReadComponentMethod.Invoke(this, parameters);
            // RuntimeHelpers.PrepareMethod(genericReadComponentMethod.MethodHandle);
        }

        private void CallGenericMethod(Type type, string methodName, Type[] types, object[] parameters)
        {
            var readComponentMethod = typeof(Engine).GetMethod(methodName, BindingFlags.NonPublic | BindingFlags.Instance, null, types, null);
            var genericReadComponentMethod = readComponentMethod.MakeGenericMethod(type);
            genericReadComponentMethod.Invoke(this, parameters);
            // RuntimeHelpers.PrepareMethod(genericReadComponentMethod.MethodHandle);
        }

        private void CallGenericMethod(Type type, string methodName, int argumentNum, object[] parameters)
        {
            var method = typeof(Engine).GetRuntimeMethods().Where(m => m.Name == methodName && m.GetParameters().Length == argumentNum).First();
            var genericMethod = method.MakeGenericMethod(type);
            genericMethod.Invoke(this, parameters);
            // RuntimeHelpers.PrepareMethod(genericMethod.MethodHandle);
        }
    }
}