using FxpConvert.Common;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace NIFPGA
{
    public sealed class FPGAArrayFXPWriteProperty : FPGABaseProperty
    {
        Interop.NiFpgaDll_ReadArrayU8 Read;
        Interop.NiFpgaDll_WriteArrayU8 Write;
        private NiFpga_FxpTypeInfo _TypeInfo;
        private IFxpConvert _Convert;
        private ulong[] tempbuffer = new ulong[0];
        private double[] doubles = new double[0];
        private ulong[] tempvalue = new ulong[0];
        internal FPGAArrayFXPWriteProperty(FPGASession session, uint indicator, uint count,NiFpga_FxpTypeInfo typeInfo, IFxpConvert convert) : base(session, indicator,false)
        {
            _Convert = convert;
            Count = count;
            doubles = new double[count];
            tempvalue = new ulong[count];
            _TypeInfo = typeInfo;
            tempbuffer = new ulong[(int)Math.Ceiling(typeInfo.wordLength * count / (Unsafe.SizeOf<ulong>() * 8.0))];
            Read = _Session.GetDelegate<Interop.NiFpgaDll_ReadArrayU8>();
            Write = _Session.GetDelegate<Interop.NiFpgaDll_WriteArrayU8>();
        }
        private double[] GetData()
        {
            _Session.CheckResult(Read(_Session.Session, Indicator, ref Unsafe.As<ulong,byte>(ref tempbuffer[0]), (uint)tempbuffer.Length*8));

            int tempdatalen = Unsafe.SizeOf<ulong>() * 8;
            ulong mask = (1ul << _TypeInfo.wordLength) - 1;
            for (int i = 0; i < Count; i++)
            {
                int index = i * _TypeInfo.wordLength / tempdatalen;
                int bitindex = tempdatalen - (i * _TypeInfo.wordLength % tempdatalen);
                if (bitindex >= _TypeInfo.wordLength)
                {
                    tempvalue[i] = (tempbuffer[index] >> (bitindex - _TypeInfo.wordLength)) & mask;
                }
                else
                {
                    tempvalue[i] = (((tempbuffer[index] & ((1ul << bitindex) - 1)) << (_TypeInfo.wordLength - bitindex)) | (tempbuffer[index + 1] >> (tempdatalen - (_TypeInfo.wordLength - bitindex))));
                }
            }

            _Convert.FxpConvertToDouble(ref tempvalue[0], _TypeInfo, ref doubles[0], Count);
            return doubles;
        }
        private void SetData(double[] values)
        {
            if (values.Length != Count) return;
            _Convert.DoubleConvertToDxp(ref values[0], _TypeInfo, ref tempvalue[0], Count);
            int tempdatalen = Unsafe.SizeOf<ulong>() * 8;
            for (int i = 0; i < Count; i++)
            {
                int index = i * _TypeInfo.wordLength / tempdatalen;
                int bitindex = tempdatalen - (i * _TypeInfo.wordLength % tempdatalen);
                var b =(tempvalue[i] & ((1ul << _TypeInfo.wordLength) - 1));
                if (bitindex >= _TypeInfo.wordLength)
                {
                    tempbuffer[index] |= (b << (bitindex - _TypeInfo.wordLength));
                }
                else
                {
                    tempbuffer[index] |= (b >> (_TypeInfo.wordLength - bitindex));
                    tempbuffer[index + 1] |= ((b & ((1ul << (_TypeInfo.wordLength - bitindex)) - 1)) << (tempdatalen - (_TypeInfo.wordLength - bitindex)));
                }
            }
            _Session.CheckResult(Write(_Session.Session,Indicator, ref Unsafe.As<ulong,byte>(ref tempbuffer[0]), (uint)tempbuffer.Length*8));
        }
        public uint Count { get; }
        public double[] Value { get => GetData(); set => SetData(value); }
    }
}