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

namespace DTS.Serialization.IRIGCH10.Packets
{
    public class TransportStreamHeader : ITransportStreamHeader
    {
        /*•	Transport Stream: 4-byte or 32-bit value.  (Byteswap to PC format.)
o	Bit [3:0]		4-bit Message Format is set to 1.
o	Bit [7:4] 	4-bit Message Type is set to 0.
o	Bit [31:8]	24-bit UDP message sequence number.  It is incremented by 1 for each packet sent out in stream including Time data packet, CGPD (TMATS), and Analog data packets.
*/
        private byte[] _bytes = new byte[4];
        public int MessageFormat { get; }
        public int MessageType { get; }
        public int SequenceNumber { get; }

        public TransportStreamHeader()
        {

        }
        public TransportStreamHeader(byte[] input)
        {
            if (null == input) { throw new NullReferenceException($"input is null"); }
            if (TRANSPORT_HEADER_LENGTH != input.Length) { throw new Exception($"Expected {TRANSPORT_HEADER_LENGTH} bytes, received {input.Length}"); }
            Buffer.BlockCopy(input, 0, _bytes, 0, TRANSPORT_HEADER_LENGTH);
            var int32 = BitConverter.ToInt32(input, 0);
            var bits = new BitArray(BitConverter.GetBytes(int32));
            MessageFormat = Utils.Utils.BitArrayToInt32(bits, 0, 3);
            MessageType = Utils.Utils.BitArrayToInt32(bits, 4, 7);
            SequenceNumber = Utils.Utils.BitArrayToInt32(bits, 8, 31);
            _bytes = input;
        }
        public const int TRANSPORT_HEADER_LENGTH = 4;
    }
}