# Python Fronius Registers
#
# Copyright 2024, Paul Warren <pwarren@pwarren.id.au>
# Licensed under AGPLv3, See LICENSE.md for terms

class DataType(Enum):
    String8 = 1
    String16 = 2
    String32 = 3
    Int16 = 4
    UInt16 = 5
    Int32 = 6
    UInt32 = 7
    Float32 = 8
    UInt64 = 7

    # Returns the length (amount) of the registers.
    # This corresponds to the value from the Fronius Excel list (column "Size").
    # This refers to how many registers the Mobus function read_holding_registers()
    # must read to get the complete value
    def getRegisterLength(self):

        if (self == DataType.String8) or (self == DataType.UInt64):
            return int(4)
        elif (self == DataType.String16):
            return int(8)
        elif (self == DataType.String32):
            return int(16)
        elif (self == DataType.Int16) or (self == DataType.UInt16):
            return int(1)
        elif (self == DataType.Int32) or (self == DataType.UInt32) or (self == DataType.Float32):
            return int(2)

    def decode(self, value):
        decoder = BinaryPayloadDecoder.fromRegisters(result.registers, byteorder=Endian.Big, wordorder=Endian.Big)

        if (self == DataType.String8) or (self == DataType.String16) or (self == DataType.String32):
            return str(decoder.decode_string(16).decode('utf-8'))

        elif (self == DataType.Int16):
            return decoder.decode_16bit_int()

        elif (self == DataType.UInt16):
            return decoder.decode_16bit_uint()

        elif (self == DataType.Int32):
            return decoder.decode_32bit_int()

        elif (self == DataType.UInt32):
            return decoder.decode_32bit_uint()

        elif (self == DataType.Float32):
            return decoder.decode_32bit_float()

        else:
            return str(decoder.decode_bits())

class FroniusReg:
    def __init__(self, address, datatype, unit, description):
        self.address = address
        self.datatype = DataType(datatype)
        self.unit = unit
        self.description=description

    def getValue(self, modbusClient):
        self.__getRegisterValue(modbusClient,
                              self.address,
                              self.datatype,
                              self.unit)

    def __getRegisterValue(modbusClient, address, dataType, unit):
        modbusValue = modbusClient.read_holding_registers(address-1,
                                                          dataType.getRegisterLength(),
                                                          slave=unit)
        if(modbusValue.isError()):
            raise registerReadError()
        
        return dataType.decode(modbusValue)
                                                          
class ScaledFroniusReg:
    def __init__(self, valueReg, scaleReg):
        self.valueReg=valueReg
        self.scaleReg=scaleReg

    def getValue(self):
        return self.valueReg.getValue() * 10 ** self.scaleReg.getValue()