using System;
using System.Collections.Generic;
using System.Text;
using DTS.Common.Utilities;
using DTS.Common.Utilities.Logging;
using DTS.Common.Utils;

namespace DTS.Serialization.SliceRaw
{
    public partial class File
    {   ///
        /// <summary>
        /// Representation of the information found in a binary module timestamp header.
        /// </summary>
        /// 
        public class BinaryDasTimestampHeader
            : Exceptional,
              IDasTimestampHeader
        {
            ///
            /// <summary>
            /// "Magic Key" required for our binary file type.
            /// </summary>
            /// 
            public static uint RequiredMagicKey => 0xF15363C2; //persistentchannel's backwards

            public static uint CurrentVersionNumber => 0x01;

            /// <summary>
            /// Header version number required for our binary file type.
            /// </summary>
            public static List<uint> KnownHeaderVersionNumbers => new List<uint>(new uint[] { 0x01 });

            /// <summary>
            /// "Magic Key" relatively-UID <see cref="UInt32"/> for our binary file type.
            /// </summary>
            public uint MagicKey
            {
                get;
                set;
            }

            /// <summary>
            /// <see cref="UInt32"/> header version number for our binary file type.
            /// </summary>
            public uint HeaderVersionNumber
            {
                get;
                set;
            }

            /// <summary>
            /// Get/set offset of sample data start value.
            /// </summary>
            public ulong OffsetOfSampleDataStart
            {
                get;
                set;
            }

            /// <summary>
            /// Get/set number of samples.
            /// </summary>
            public ulong NumberOfSamples
            {
                get;
                set;
            }
            /// <summary>
            /// Get/set sample rate value.
            /// </summary>
            public uint NumberOfBitsPerSample
            {
                get;
                set;
            }

            /// <summary>
            /// Calculate the CRC32 for this binary channe header.
            /// </summary>
            /// 
            /// <returns>
            /// The CRC32 of the binary channel header.
            /// </returns>
            /// 
            private uint CalculateCrc32()
            {
                try
                {
                    var data = new List<byte>();

                    data.AddRange(BitConverter.GetBytes(MagicKey));
                    data.AddRange(BitConverter.GetBytes(HeaderVersionNumber));
                    data.AddRange(BitConverter.GetBytes(OffsetOfSampleDataStart));
                    data.AddRange(BitConverter.GetBytes(NumberOfSamples));
                    data.AddRange(BitConverter.GetBytes(NumberOfBitsPerSample));

                    if (data.Count % 2 > 0) data.Add(0x0);
                    var byteDataArray = data.ToArray();
                    //APILogger.Log($"[DTM]: data array for CRC: {BitConverter.ToString(byteDataArray)}");
                    ushort crc = 0xFFFF;
                    for (var i = 0; i < data.Count; i += 2)
                        crc = Utils.Math_DoCRC16Step(BitConverter.ToUInt16(byteDataArray, i), crc);
                    //APILogger.Log($"[DTM]: crc {crc}");
                    return crc;
                }

                catch (System.Exception ex)
                {
                    throw new Exception("encountered problem calculating CRC 32", ex);
                }
            }
            /// <summary>
            /// Get the CRC for the current state of the header.
            /// </summary>
            public uint Crc32
            {
                get
                {
                    try
                    {
                        return CalculateCrc32();
                    }

                    catch (System.Exception ex)
                    {
                        throw new Exception("encountered problem generating CRC for binary channel header information", ex);
                    }
                }
            }
        }
    }
}