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

class BK_5491(Multimeter):
    """ BK 5491 multimeter """
    """
    rm = pyvisa.ResourceManager()
    instr=rm.open_resource('ASRL/dev/ttyUSB0::INSTR')
    Make sure to switch off the ECHO at the multimeter communication setup
    """
    def __init__(self, resource, *args, **kwds):
        super().__init__(*args, **kwds)
        self.resource = resource
        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.write = self.resource.write
        self.read = self.resource.read
        self.query = self.resource.query
        self.read_bytes = self.resource.read_bytes
        self.read_binary_values = self.resource.read_binary_values
        self.query_binary_values = self.resource.query_binary_values

        self.switchTime = 0.5 # switch time in seconds for Function/Measurement change 
        self.deviceProperties.update({})

    def isPrompt(self, string):
        if string[1] == '>':
            return True
        return False

    def isPromptGood(self, prompt):
        if prompt[0:2] == '=>':
            return True
        print(f'Error detected {prompt=}')
        return False

    def sendCmd(self, cmd_string, expect_reply=True, Nattemts=5):
        """
        Set command to instrument or query it readings (which is also a command)

        BK_5491 in not SCPI instrument, so we get some replies (prompts *>, =>, etc)
        even if we just send a command not a query. So we have to work around this.
        """
        # print(f"dbg: {cmd_string=}")
        self.write(cmd_string)
        if expect_reply:
            reply = self.read() # this should be result
            # print(f"dbg: {reply=}")
            if self.isPrompt(reply):
                # print(f'Error: we ask {cmd_string=} and got prompt "{reply}" instead of result')
                prompt = reply
                if prompt[0] == '@':
                    if Nattemts >= 2:
                        # print('dbg: numeric reading is not available yet, attempt one more time')
                        time.sleep(self.switchTime)
                        return self.sendCmd(cmd_string, expect_reply=expect_reply, Nattemts=Nattemts-1)
                return None
        else:
            reply = None
        prompt = self.read() # this should be prompt
        self.isPromptGood(prompt)
        # print(f"dbg: {prompt=}")
        return reply

    def getReading(self):
       """ Report current measurement """
       ret_string = self.sendCmd('R1')
       # print(f'dbg: getReading received "{ret_string}"')
       return float(ret_string)

    def setFunction(self, key_string):
        """
        BK_5491 set the measurement functions according to the front panel keys:
            K1 - Vdc
            K2 - Adc
            K3 - Vac
            K4 - Aac
            K5 - Resistance
            K6 - Diode
            K7 - Frequency (Hz)
            K8 - Auto
            K9 - Up key
            K10 - Down key
            K11 - MinMax key
            K12 - Hold key
            K13 - Local (manual does not specify, but it works this way)
            K14 - Rel key
            K15 - Shift key
            K16 - 2nd key
            K17 - Vdc and Vac keys simultaneously
            K18 - Adc and Aac keys simultaneously
            K19 - Shift then Up keys (increasing the intensity of the VFD display)
            K20 - Shift then Down keys (decreasing the intensity of the VFD display)
        """

    def getVdc(self):
        self.sendCmd('K1')
        return self.getReading()
    def getVac(self):
        self.sendCmd('K3')
        return self.getReading()
    def getAdc(self):
        self.sendCmd('K2')
        return self.getReading()
    def getAac(self):
        self.sendCmd('K4')
        return self.getReading()
    def getResistance(self):
        self.sendCmd('K5')
        return self.getReading()
    def getDiode(self):
        self.sendCmd('K6')
        return self.getReading()
    def getFreq(self):
        self.sendCmd('K7')
        return self.getReading()

    def toLocal(self):
        self.sendCmd('K13', expect_reply=False)


if __name__ == '__main__': 
    import pyvisa
    print("testing")
    rm = pyvisa.ResourceManager()
    print(rm.list_resources())    
    instr=rm.open_resource('ASRL/dev/ttyUSB0::INSTR')
    multimeter = BK_5491(instr)
    print('------ Header start -------------')
    print(str.join('\n', multimeter.getHeader()))
    print('------ Header ends  -------------')