using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using Mistox.Attributes;
using MsgPack.Serialization;

namespace Mistox {
    public class DataPacket {

        // The length of the packet header in bytes
        public static readonly int HeaderLength = 3;

        // Data Packet Properties
        public byte PacketType { get; set; } = 0x00;
        public ushort DataLength { get; set; } = 0;
        public byte[] PacketData { get; set; } = [];




        //               8b.      16b.        ?
        // Data Packet [ Type | DataLength | Data ]

        // Helper classes
        public static byte[] Serialize<T>( T Object ) {
            mPacket attribute = typeof(T).GetCustomAttribute<mPacket>(false);
            DataPacket packet = new DataPacket();
            if (attribute != null) {
                using ( MemoryStream stream = new MemoryStream() ) {
                    MessagePackSerializer serializer = MessagePackSerializer.Get<T>();
                    serializer.Pack( stream, Object );
                    packet.PacketData = stream.ToArray();
                    packet.DataLength = (ushort)packet.PacketData.Length;
                    return new byte[]{ packet.PacketType }.Join( BitConverter.GetBytes( packet.DataLength )).Join(packet.PacketData);
                }
            }
            throw new Exception( "The datastructure " + typeof(T).Name + " is not an mPacket" );
        }

        public object Deserialize() {
            Type type = Type.GetType( NetworkPackets[PacketType] );
            MessagePackSerializer Serilizer = MessagePackSerializer.Get(type);
            using( MemoryStream ms = new MemoryStream( PacketData ) ) {
                return Serilizer.Unpack( ms );
            }
        }




        // Fills out the NetworkPacket Lookup Dictionary
        public static readonly Dictionary<byte, string> NetworkPackets = new();
        public static void BuildNetworkPacketList() {
            Type[] allClasses = Assembly.GetExecutingAssembly().GetTypes();
            foreach( Type cur in allClasses) {
                mPacket attribute = cur.GetCustomAttribute<mPacket>(false);
                if (attribute != null) {
                    NetworkPackets[attribute.ID] = cur.FullName + "," + cur.Assembly.FullName;
                }
            }
        }

    }
}