using InnovEnergy.Lib.Protocols.Modbus.Protocol.Frames.Accessors;
using InnovEnergy.Lib.Protocols.Modbus.Protocol.Frames.Replies;

using static InnovEnergy.Lib.Protocols.Modbus.Protocol.Frames.Constants;
using static InnovEnergy.Lib.Protocols.Modbus.Protocol.FunctionCode;


namespace InnovEnergy.Lib.Protocols.Modbus.Protocol.Frames.Commands;

using MbFc = MbByte<FunctionCode>;

internal class ReadHoldingRegistersCommandFrame  : ModbusFrame
{

    internal const Int32 Size = 6;

    public MbAddress ReadAddress  => Data.AddressAt(2);
    public MbWord    NbToRead     => Data.WordAt(4);

    public Int32  ExpectedResponseSize => ReadHoldingRegistersResponseFrame.ExpectedSize(NbToRead);

    public ReadHoldingRegistersCommandFrame(Byte slave, UInt16 readAddress, UInt16 nValues) : base(Size)
    {
        if (nValues > MaxRegs)
            throw new ArgumentOutOfRangeException($"Maximum number of registers ({MaxRegs}) exceeeded!", nameof(nValues));

        SlaveAddress.Set(slave);
        FunctionCode.Set(ReadHoldingRegisters);
        ReadAddress .Set(readAddress);
        NbToRead    .Set(nValues);
    }


    private ReadHoldingRegistersCommandFrame(ArraySegment<Byte> data) : base(data)
    {
        if (data.Count != Size)
            throw new ArgumentException($"Expecting an array of size {Size}", nameof(data));

        AssertFunctionCode(ReadHoldingRegisters);
    }


    public ReadHoldingRegistersResponseFrame VerifyResponse(ModbusFrame response)
    {
        if (response.SlaveAddress != SlaveAddress)
            throw new UnexpectedResponseFieldException(nameof(response.SlaveAddress), SlaveAddress.ToString(), response.SlaveAddress);

        var r = ReadHoldingRegistersResponseFrame.Parse(response.Data);

        if (r.RegistersRead.Count != NbToRead)
            throw new UnexpectedResponseFieldException(nameof(r.RegistersRead), NbToRead.ToString(), r.RegistersRead.Count);

        return r;
    }

    public static ReadHoldingRegistersCommandFrame Parse(ArraySegment<Byte> data)
    {
        return new ReadHoldingRegistersCommandFrame(data);
    }
}