using System.Reflection;
using InnovEnergy.Lib.Protocols.Modbus.Protocol.Frames.Accessors;
using InnovEnergy.Lib.Protocols.Modbus.Reflection.Attributes;
using InnovEnergy.Lib.Utils;
using static System.Reflection.BindingFlags;

namespace InnovEnergy.Lib.Protocols.Modbus.Reflection;

#pragma warning disable CS8509

internal record ModbusMember
(
    UInt16                 StartAddress,
    UInt16                 EndAddress,
    ModbusAttribute        Attribute,
    Action<MbData, Object> ModbusToRecord,
    Action<Object, MbData> RecordToModbus
);

internal static class ModbusMembers
{
    private static readonly (Double scale, Double offset) NoTransform = (scale:1, offset:0);

    internal static IEnumerable<ModbusMember> From<R>(Int32 addressOffset) 
    {
        return GetDataMembers<R>()
              .Where(HasAttribute<ModbusAttribute>)
              .Select(m => m.CreateModbusMember(addressOffset));
    }


    private static ModbusMember CreateModbusMember(this MemberInfo info, Int32 addressOffset) 
    {
        var attribute    = info.GetCustomAttributes<ModbusAttribute>().Single();
        var startAddress = (UInt16)(attribute.Address + addressOffset);
        var endAddress   = (UInt16)(startAddress + attribute.Size);
        var modbusType   = attribute.ModbusType;
        var transform    = attribute is ModbusRegisterAttribute mra
                         ? (mra.Scale, mra.Offset)
                         : NoTransform;
        
        var modbusToRecord = info.ModbusToRecord(startAddress, modbusType, transform);
        var recordToModbus = info.RecordToModbus(startAddress, modbusType, transform);
        
        return new ModbusMember
        (
            startAddress,
            endAddress,
            attribute, 
            modbusToRecord, 
            recordToModbus
        );
    }

    private static Action<MbData, Object> ModbusToRecord(this MemberInfo info, UInt16 address, TypeCode modbusType, (Double scale, Double offset) transform) 
    {
        var decode = ConvertModbusToRecord(transform);
        
        Func<MbData, IConvertible> readFromMbData = modbusType switch
        {
            TypeCode.Boolean => d => d.GetInput  (address),
            TypeCode.UInt16  => d => d.GetUInt16 (address),
            TypeCode.Int16   => d => d.GetInt16  (address),
            TypeCode.UInt32  => d => d.GetUInt32 (address),
            TypeCode.Int32   => d => d.GetInt32  (address),
            TypeCode.Single  => d => d.GetFloat32(address),
            TypeCode.UInt64  => d => d.GetUInt64 (address),
            TypeCode.Int64   => d => d.GetInt64  (address),
            TypeCode.Double  => d => d.GetFloat64(address),
            _                => throw new ArgumentException(nameof(modbusType))
        };
        
        Action<Object, IConvertible> set = info switch
        {
            FieldInfo    fi => (rec, value) => fi.SetValue(rec, value.ConvertTo(fi.FieldType)),
            PropertyInfo pi => (rec, value) => pi.SetValue(rec, value.ConvertTo(pi.PropertyType)),
        };


        return (mbData, rec) =>
        {
            var rawModbusValue = readFromMbData(mbData);
            var decoded        = decode(rawModbusValue);
            
            set(rec, decoded);
        };
    }

    private static Func<IConvertible, IConvertible> ConvertModbusToRecord((Double scale, Double offset) transform)
    {
        if (transform == NoTransform)
            return Nop;
        
        var scale  = transform.scale.ConvertTo<Decimal>();
        var offset = transform.offset.ConvertTo<Decimal>();
        
        return c =>
        {
            var value = c.ConvertTo<Decimal>();
            
            return (value + offset) * scale;
        };
    }


    private static Action<Object, MbData> RecordToModbus(this MemberInfo info, UInt16 addr, TypeCode modbusType, (Double scale, Double offset) transform) 
    {
        var encode = ConvertRecordToModbus(transform);
        
        Func<Object, IConvertible> get = info switch
        {
            FieldInfo    fi => rec => (IConvertible)fi.GetValue(rec)!,
            PropertyInfo pi => rec => (IConvertible)pi.GetValue(rec)!,
        };

        Action<IConvertible, MbData> writeToMbData = modbusType switch
        {
            TypeCode.Boolean => (value, mbData) => mbData.SetCoil   (addr, value.ConvertTo<Boolean>()),
            TypeCode.UInt16  => (value, mbData) => mbData.SetUInt16 (addr, value.ConvertTo<UInt16>()),
            TypeCode.Int16   => (value, mbData) => mbData.SetInt16  (addr, value.ConvertTo<Int16>()),
            TypeCode.UInt32  => (value, mbData) => mbData.SetUInt32 (addr, value.ConvertTo<UInt32>()),
            TypeCode.Int32   => (value, mbData) => mbData.SetInt32  (addr, value.ConvertTo<Int32>()),
            TypeCode.Single  => (value, mbData) => mbData.SetFloat32(addr, value.ConvertTo<Single>()),
            TypeCode.UInt64  => (value, mbData) => mbData.SetUInt64 (addr, value.ConvertTo<UInt64>()),
            TypeCode.Int64   => (value, mbData) => mbData.SetInt64  (addr, value.ConvertTo<Int64>()),
            TypeCode.Double  => (value, mbData) => mbData.SetFloat64(addr, value.ConvertTo<Double>()),
            _                => throw new ArgumentException(nameof(modbusType))
        };

        return (rec, mbData) =>
        {
            var memberValue = get(rec);
            var encoded = encode(memberValue);

            writeToMbData(encoded, mbData);
        };
    }

    private static Func<IConvertible, IConvertible> ConvertRecordToModbus((Double scale, Double offset) transform)
    {
        if (transform == NoTransform)
            return Nop;

        var scale  = transform.scale.ConvertTo<Decimal>();
        var offset = transform.offset.ConvertTo<Decimal>();
        
        return c =>
        {
            var value = c.ConvertTo<Decimal>();

            return value / scale - offset;
        };
    }


    private static T Nop<T>(T c) => c;


    private static IEnumerable<MemberInfo> GetDataMembers<R>()
    {
        var recordType = typeof(R);
                
        const BindingFlags bindingFlags = Instance 
                                        | Public 
                                        | NonPublic 
                                        | FlattenHierarchy;

        var fields = recordType.GetFields(bindingFlags);
        var props  = recordType.GetProperties(bindingFlags);

        return fields.Concat<MemberInfo>(props);
    }
    
    private static Boolean HasAttribute<T>(MemberInfo i) where T : Attribute
    {
        return i.GetCustomAttributes<T>().Any();
    }
}