using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace STcpHelper.Packet
{
    /// <summary>
    /// 4byte header
    /// </summary>
    public class STcpPacketHeader : ISTcpPacket
    {
        public PacketType Type { get; private set; }
        public short DataLength { get; private set; }

        public STcpPacketHeader(PacketType type, int dataLength)
        {
            Type = type;
            DataLength = (short)dataLength;
        }

        public STcpPacketHeader(byte[] buffer)
        {
            int cursor = 0;
            this.Type = (PacketType)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(buffer, cursor));
            cursor += 2;

            this.DataLength = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(buffer, cursor));
        }

        // [2bytes Type][2bytes Size]
        public byte[] Serialize()
        {
            byte[] type = BitConverter.GetBytes(IPAddress.HostToNetworkOrder((short)this.Type));
            byte[] size = BitConverter.GetBytes(IPAddress.HostToNetworkOrder(this.DataLength));

            return SBufferHelper.GetBuffer(type.Length + size.Length, type, size);
        }
    }
}