using System;
using System.Runtime.InteropServices;

namespace PkmnLibSharp.Battling.Events
{
    public class BattleEventListener
    {
        public delegate void BattleEventDelegate(EventData evt);
        private delegate void BattleEventPtrDelegate(IntPtr ptr);

        private readonly BattleEventDelegate _del;
        // ReSharper disable once PrivateFieldCanBeConvertedToLocalVariable
        private readonly BattleEventPtrDelegate _innerDel;
        internal readonly IntPtr FunctionPtr;

        public BattleEventListener(BattleEventDelegate del)
        {
            _del = del;
            _innerDel = OnEventPtr;
            FunctionPtr = Marshal.GetFunctionPointerForDelegate(_innerDel);
        }

        private void OnEventPtr(IntPtr ptr)
        {
            var wrapped = WrapEventPtr(ptr);
            _del.Invoke(wrapped);
        }
        
        private static EventData WrapEventPtr(IntPtr ptr)
        {
            var evtType = (EventDataKind)Creaturelib.Generated.EventData.GetKind(ptr);
            switch (evtType)
            {
                case EventDataKind.Damage:
                    return new DamageEvent(evtType, ptr);
                case EventDataKind.Heal:
                    break;
                case EventDataKind.Faint:
                    break;
                case EventDataKind.DisplayText:
                    break;
                default:
                    break;
            }
            Creaturelib.Generated.EventData.Destruct(ptr);
            throw new NotImplementedException($"Unhandled battle event: '{evtType}'");
        }
    }
}