import pyvisa
from time import sleep
# import pkg_resources
import os
from typing import Callable

from ..base import MeasurementDevice
from ...utility.visa import enumerate_devices

import logging
log = logging.getLogger(__name__)

class SR830(MeasurementDevice):
    """
    Wrapper class for the Keithley2700 SMU controlled via pyvisa
    """
    def __init__(self, instr, check_front_switch=True):
        self.instr = instr
        init_script = """
        ' set input A
        ISRC 0
        ' set float
        IGND 0
        ' set AC coupling
        ICPL 0
        ' Enable 1x and 2x Line notch filters
        ILIN 3
        ' Enable synchronous filter < 200Hz
        SYNC 1
        ' Show R and Phase on the displays
        DDEF 1 1 0
        DDEF 2 1 0
        ' Set sample rate to 256 Hz
        12
        ' Set buffer loop mode
        SEND 1
        """
        self.run(init_script)

    def __del__(self):
        """Properly close the instrument connection"""
        self.instr.close()

    # RUN COMMANDS ON THE DEVICE
    def run(self, code, verbose=False):
        """
        Run SCPI code on the device by writing it.
        Empty lines, leading whitespaces and lines starting with ' or # are ignored.
        Parameters
        ----------
        code : str
            SCPI commands
        """
        script = ''
        for line in code.strip(" ").split("\n"):
            l = line.strip(" ")
            if len(l) == 0 or l[0] in "#'": continue
            script += l + "\n"
        if verbose:
            print(f"Running code:\n{script}")
        try:
            ret = self.instr.write(script)
            if ret != 8:
                raise RuntimeError(f"Error while writing command(s):\n'{script}'\n\nDevice returned code {ret}")
        except pyvisa.VisaIOError as e:
            raise RuntimeError(f"VisaIOError raised while writing command(s):\n'{script}'\n\nVisaIOError:\n{e}")

    def get_frequency(self) -> float:
        return float(self.query("FREQ?"))

    def query(self, query):
        return self.instr.query(query).strip("\n")


    @staticmethod
    def enumerate_devices(query="(GPIB)|(USB)?*:INSTR"):
        return enumerate_devices("SR830", query)

    @staticmethod
    def connect_device(name):
        rm = pyvisa.ResourceManager()
        instr = rm.open_resource(name)
        return SR830(instr)

    def __str__(self):
        return "SR830"