using InnovEnergy.Lib.Protocols.Modbus.Clients;
using InnovEnergy.Lib.Protocols.Modbus.Connections;
using InnovEnergy.Lib.Units.Composite;
using static DecimalMath.DecimalEx;

namespace InnovEnergy.Lib.Devices.AMPT;

public class AmptCommunicationUnit
{
    private ModbusTcpClient? Modbus { get; set; }

    private const UInt16 RegistersPerDevice = 16;
    private const UInt16 FirstDeviceOffset  = 85;

    public String Hostname     { get; }
    public UInt16 Port         { get; }
    public Byte   SlaveAddress { get; }

    public AmptCommunicationUnit(String hostname, UInt16 port = 502, Byte slaveAddress = 1)
    {
        Hostname     = hostname;
        Port         = port;
        SlaveAddress = slaveAddress;
    }

    public AmptCommunicationUnitStatus? ReadStatus()
    {
        try
        {
            OpenConnection();
            return TryReadStatus();
        }
        catch
        {
            CloseConnection();
            return null;
        }
    }

    private void CloseConnection()
    {
        try
        {
            Modbus?.CloseConnection();
        }
        catch
        {
            // ignored
        }

        Modbus = null;
    }

    private void OpenConnection()
    {
        if (Modbus is null)
        {
            var connection = new ModbusTcpConnection(Hostname, Port);
            Modbus = new ModbusTcpClient(connection, SlaveAddress);
        }
    }

    private AmptCommunicationUnitStatus TryReadStatus()
    {
        var r = Modbus!.ReadHoldingRegisters(1, 116);

        var currentFactor = Pow(10.0m, r.GetInt16(73));
        var voltageFactor = Pow(10.0m, r.GetInt16(74));
        var energyFactor  = Pow(10.0m, r.GetInt16(76) + 3); // +3 => converted from Wh to kWh
        var nbrOfDevices  = r.GetUInt16(78);

        var devices = Enumerable
                     .Range(0, nbrOfDevices)
                     .Select(ReadDeviceStatus)
                     .ToList();

        return new AmptCommunicationUnitStatus
        {
            Sid           = r.GetUInt32(1),
            IdSunSpec     = r.GetUInt16(3),
            Manufacturer  = r.GetString(5, 16),
            Model         = r.GetString(21, 16),
            Version       = r.GetString(45, 8),
            SerialNumber  = r.GetString(53, 16),
            DeviceAddress = r.GetInt16(69),
            IdVendor      = r.GetUInt16(71),
            Devices       = devices
        };

        AmptStatus ReadDeviceStatus(Int32 deviceNumber)
        {
            var baseAddress = (UInt16)(FirstDeviceOffset + deviceNumber * RegistersPerDevice);  // base address

            return new AmptStatus
            {
                Dc = new DcBus
                {
                    Voltage = r.GetUInt32((UInt16)(baseAddress + 6)) * voltageFactor,
                    Current = r.GetUInt16((UInt16)(baseAddress + 5)) * currentFactor
                },
                Strings = new DcBus[]
                {
                    new()
                    {
                        Voltage = r.GetUInt32((UInt16)(baseAddress + 8)) * voltageFactor,
                        Current = r.GetUInt16((UInt16)(baseAddress + 14)) * currentFactor
                    },
                    new()
                    {
                        Voltage = r.GetUInt32((UInt16)(baseAddress + 9)) * voltageFactor,
                        Current = r.GetUInt16((UInt16)(baseAddress + 15)) * currentFactor
                    }
                },
                ProductionToday = r.GetUInt32((UInt16)(baseAddress + 12)) * energyFactor,
            };
        }
    }
}