from qolab.hardware.basic import BasicInstrument
from qolab.hardware.multimeter import MultimeterSCPI
from qolab.hardware.scpi  import SCPI_PROPERTY
from pyvisa import constants as pyvisa_constants
import time

class HP_34401(MultimeterSCPI):
    """ HP 34401 multimeter (same as Agilent) """
    """
    rm = pyvisa.ResourceManager()
    instr=rm.open_resource('ASRL/dev/ttyUSB0::INSTR')
    """
    def __init__(self, resource, *args, **kwds):
        super().__init__(resource, *args, **kwds)
        self.config['Device model']='HP 34401'
        self.resource.read_termination = '\r\n'
        self.resource.baud_rate = 9600
        self.resource.data_bits = 8
        self.resource.parity = pyvisa_constants.Parity.none
        self.resource.stop_bits = pyvisa_constants.StopBits.one
        self.resource.timeout = 5000
        self.switchTime = 0.5 # switch time in seconds for Function/Measurement change 
        self.deviceProperties.update({'Function'})

    Function = SCPI_PROPERTY(scpi_prfx='SENSe:FUNCtion', ptype=str, doc="""
        Current measurement function (Voltmeter DC/AC, Currentmeter DC/AC, etc.
        Important! When assigning, string should be quoted, i.e. use:
            Function=\'"VOLT:DC"\'

        Possible values:
            "VOLTage:DC", same as "VOLT"
            "VOLTage:DC:RATio"
            "VOLTage:AC"
            "CURRent:DC", same as "CURR"
            "CURRent:AC"
            "RESistance" (2-wire ohms)
            "FRESistance" (4-wire ohms)
            "FREQuency"
            "PERiod"
            "CONTinuity"
            "DIODe"
        """
     )

    def toRemote(self):
        self.write("SYSTem:REMote")

    def toLocal(self):
        self.write("SYSTem:LOCal")

    def isSensing(self, test):
        return test == self.Function

    Reading = SCPI_PROPERTY(scpi_prfx='SYSTem:REMote; :READ', ptype=float, doc='Report current measurement', no_setter=True)

    # HP 34401 is tricky
    # when reading over serial interface the value of measurement/function,
    # the device need to be switched to REMOTE mode, but this leaves screen blank and unusable
    # so we have to do the dance with toRemote and toLocal
    def getReadingWithSettingFunction(self, desired_function_string, function_internal_name):
        """
        Get the reading but first check if we are set to do specific function/measurement.
        If the instrument set to do different function, set to desired one
        Note: the function name should be in quotes, i.e. '"Volt"'
        """
        if not self.isSensing(function_internal_name):
            # print(f"function {self.Function} switching function to {desired_function_string}")
            self.Function=desired_function_string
            time.sleep(self.switchTime)
        # self.toRemote() # this is done inside of Reading
        ret = self.Reading
        self.toLocal()
        return ret

    def getVdc(self):
        return self.getReadingWithSettingFunction('"VOLTage:DC"', '"VOLT"')
    def getVac(self):
        return self.getReadingWithSettingFunction('"VOLTage:AC"', '"VOLT:AC"')
    def getAdc(self):
        return self.getReadingWithSettingFunction('"CURRent:DC"', '"CURR"')
    def getAac(self):
        return self.getReadingWithSettingFunction('"CURRent:AC"', '"CURR:AC"')
    def getResistance(self):
        return self.getReadingWithSettingFunction('"RESistance"', '"RES"')
    def getDiode(self):
        return self.getReadingWithSettingFunction('"DIODe"', '"DIOD"')
    def getFreq(self):
        return self.getReadingWithSettingFunction('"FREQuency"', '"FREQ"')


if __name__ == '__main__': 
    import pyvisa
    print("testing")
    rm = pyvisa.ResourceManager()
    print(rm.list_resources())    
    instr=rm.open_resource('ASRL/dev/ttyUSB0::INSTR')
    multimeter = HP_34401(instr)
    print('------ Header start -------------')
    print(str.join('\n', multimeter.getHeader()))
    print('------ Header ends  -------------')