text: import warnings
  from collections import OrderedDict, Iterable
  
  import numpy as np
  import skrf
  import pyvisa
  
  from . import abcvna
  from . import keysight_pna_scpi
  
  
  class PNA(abcvna.VNA):
      """
      Class for modern Keysight/Agilent Performance Network Analyzers
      """
  
      DEFAULT_VISA_ADDRESS = "GPIB::16::INSTR"
      NAME = "Keysight PNA"
      NPORTS = 2
      NCHANNELS = 32
      SCPI_VERSION_TESTED = 'A.09.20.08'
  
      def __init__(self, address=DEFAULT_VISA_ADDRESS, **kwargs):
          """
          initialization of PNA Class
  
          Parameters
          ----------
          address : str
              visa resource string (full string or ip address)
          kwargs : dict
              interface (str), port (int), timeout (int),
          :param address:
          :param kwargs:
          """
          super(PNA, self).__init__(address, **kwargs)
          self.resource.timeout = kwargs.get("timeout", 2000)
          self.scpi = keysight_pna_scpi.SCPI(self.resource)
          # TODO: There is currently no way to change ascii vs binary modes for commands like get_twoport.
          # Because of the update to pyvisa, there are now two commands generated for query commands: an ascii and a binary version.
          # At present all commands which call a query command like this use ascii. 
  
      @property
      def echo(self):
          return self.scpi.echo
  
      @echo.setter
      def echo(self, onoff):
          if onoff in (1, True):
              self.scpi.echo = True
          elif onoff in (0, False):
              self.scpi.echo = False
          else:
              raise warnings.warn("echo must be a boolean")
  
      @property
      def active_channel(self):
          old_timeout = self.resource.timeout
          self.resource.timeout = 500
          try:
              channel = self.scpi.query_active_channel()
          except pyvisa.VisaIOError:
              print("No channel active, using 1")
              channel = 1
          finally:
              self.resource.timeout = old_timeout
          return channel
  
      @active_channel.setter
      def active_channel(self, channel):
          """
          Set the active channel on the analyzer
  
          Parameters
          ----------
          channel : int
  
          Notes
          -----
          There is no specific command to activate a channel, so we ask which channel we want and then activate the first
          trace on that channel.  We do this because if the analyzer gets into a state where it doesn't recognize
          any activated measurements, the get_snp_network method will fail, and possibly others as well.  That is why in
          some methods you will see the following line:
          self.active_channel = channel = kwargs.get("channel", self.active_channel)
          this way we force this property to be set, even if it just resets itself to the same value, but then a trace
          will become active and our get_snp_network method will succeed.
          """
          # TODO: Good chance this will fail if no measurement is on the set channel, need to think about that...
          mnum = self.scpi.query_meas_number_list(channel)[0]
          self.scpi.set_selected_meas_by_number(channel, mnum)
          return
  
      def sweep(self, **kwargs):
          """
          Initialize a fresh sweep of data on the specified channels
  
          Parameters
          ----------
          kwargs : dict
              channel ("all", int or list of channels), timeout (milliseconds)
  
          trigger a fresh sweep on the specified channels (default is "all" if no channel specified)
          Autoset timeout and sweep mode based upon the analyzers current averaging setting,
          and then return to the prior state of continuous trigger or hold.
          """
          self.resource.clear()
          self.scpi.set_trigger_source("IMM")
          original_timeout = self.resource.timeout
  
          # expecting either an int or a list of ints for the channel(s)
          channels_to_sweep = kwargs.get("channels", None)
          if not channels_to_sweep:
              channels_to_sweep = kwargs.get("channel", "all")
          if not type(channels_to_sweep) in (list, tuple):
              channels_to_sweep = [channels_to_sweep]
          channels = self.scpi.query_available_channels()
  
          for i, channel in enumerate(channels):
              sweep_mode = self.scpi.query_sweep_mode(channel)
              was_continuous = "CONT" in sweep_mode.upper()
              sweep_time = self.scpi.query_sweep_time(channel)
              averaging_on = self.scpi.query_averaging_state(channel)
              averaging_mode = self.scpi.query_averaging_mode(channel)
  
              if averaging_on and "SWE" in averaging_mode.upper():
                  sweep_mode = "GROUPS"
                  number_of_sweeps = self.scpi.query_averaging_count(channel)
                  self.scpi.set_groups_count(channel, number_of_sweeps)
                  number_of_sweeps *= self.NPORTS
              else:
                  sweep_mode = "SINGLE"
                  number_of_sweeps = self.NPORTS
              channels[i] = {
                  "cnum": channel,
                  "sweep_time": sweep_time,
                  "number_of_sweeps": number_of_sweeps,
                  "sweep_mode": sweep_mode,
                  "was_continuous": was_continuous
              }
              self.scpi.set_sweep_mode(channel, "HOLD")
          timeout = kwargs.get("timeout", None)  # recommend not setting this variable, as autosetting is preferred
  
          try:
              for channel in channels:
                  import time
                  if "all" not in channels_to_sweep and channel["cnum"] not in channels_to_sweep:
                      continue  # default for sweep is all, else if we specify, then sweep
                  if not timeout:  # autoset timeout based on sweep time
                      sweep_time = channel["sweep_time"] * channel[
                          "number_of_sweeps"] * 1000  # convert to milliseconds, and double for buffer
                      self.resource.timeout = max(sweep_time * 2, 5000)  # give ourselves a minimum 5 seconds for a sweep
                  else:
                      self.resource.timeout = timeout
                  self.scpi.set_sweep_mode(channel["cnum"], channel["sweep_mode"])
                  self.wait_until_finished()
          finally:
              self.resource.clear()
              for channel in channels:
                  if channel["was_continuous"]:
                      self.scpi.set_sweep_mode(channel["cnum"], "CONT")
              self.resource.timeout = original_timeout
          return
  
      def upload_twoport_calibration(self, cal, port1=1, port2=2, **kwargs):
          """
          upload a calibration to the vna, and set correction on all measurements
          
          Parameters
          ----------
          cal : skrf.Calibration
          port1: int
          port2: int
  
          calibration error terms reference
              # forward = (1, 1), reverse = (2, 2)
              "directivity": "EDIR",
              "source match": "ESRM",
              "reflection tracking": "ERFT",
              
              # forward = (2, 1), reverse = (1, 2)
              "load match": "ELDM",
              "transmission tracking": "ETRT"
              "isolation": "EXTLK"
          
          """
          self.active_channel = channel = kwargs.get("channel", self.active_channel)
  
          calname = kwargs.get("calname", "skrf_12term_cal")
          calibrations = self.scpi.query_calset_catalog(cnum=channel, form="NAME")
          if calname in calibrations:
              self.scpi.set_delete_calset(cnum=channel, calset_name=calname)
          self.scpi.set_create_calset(cnum=channel, calset_name=calname)
  
          cfs = dict()
          for coef, data in cal.coefs_12term.items():
              cfs[coef] = skrf.mf.complex2Scalar(data)
  
          for eterm, coef in zip(("EDIR", "ESRM", "ERFT"), ("directivity", "source match", "reflection tracking")):
              self.scpi.set_calset_data(channel, eterm, port1, port1, eterm_data=cfs["forward " + coef])
              self.scpi.set_calset_data(channel, eterm, port2, port2, eterm_data=cfs["reverse " + coef])
          for eterm, coef in zip(("ELDM", "ETRT", "EXTLK"), ("load match", "transmission tracking", "isolation")):
              self.scpi.set_calset_data(channel, eterm, port2, port1, eterm_data=cfs["forward " + coef])
              self.scpi.set_calset_data(channel, eterm, port1, port2, eterm_data=cfs["reverse " + coef])
  
          self.scpi.set_active_calset(1, calname, True)
  
      def get_snp_network(self, ports, **kwargs):
          """
          return n-port network as an Network object
  
          Parameters
          ----------
          ports : Iterable
              a iterable of integers designating the ports to query
          kwargs : dict
              channel(int) [ default 'self.active_channel' ]
              sweep(bool) [default True]
              name(str) [default \"\"]
              f_unit(str) [ default \"GHz\" ]
              raw_data(bool)  [default False]
  
          Returns
          -------
          Network
  
          general function to take in a list of ports and return the full snp network as a Network object
          """
          self.resource.clear()
  
          # force activate channel to avoid possible errors:
          self.active_channel = channel = kwargs.get("channel", self.active_channel)
  
          sweep = kwargs.get("sweep", True)
          name = kwargs.get("name", "")
          f_unit = kwargs.get("f_unit", "GHz")
          raw_data = kwargs.get("raw_data", False)
  
          ports = [int(port) for port in ports] if type(ports) in (list, tuple) else [int(ports)]
          if not name:
              name = "{:}Port Network".format(len(ports))
          if sweep:
              self.sweep(channel=channel)
  
          npoints = self.scpi.query_sweep_n_points(channel)
  
          snp_fmt = self.scpi.query_snp_format()
          self.scpi.set_snp_format("RI")
          if raw_data is True:
              if self.scpi.query_channel_correction_state(channel):
                  self.scpi.set_channel_correction_state(channel, False)
                  data = self.scpi.query_snp_data_ascii(channel, ports)
                  self.scpi.set_channel_correction_state(channel, True)
              else:
                  data = self.scpi.query_snp_data_ascii(channel, ports)
          else:
              data = self.scpi.query_snp_data_ascii(channel, ports)
          self.scpi.set_snp_format(snp_fmt)  # restore the value before we got the RI data
          self.scpi.set_snp_format(snp_fmt)  # restore the value before we got the RI data
  
          data = np.array(data)
          nrows = int(len(data) / npoints)
          nports = int(np.sqrt((nrows - 1)/2))
          data = data.reshape([nrows, -1])
  
          fdata = data[0]
          sdata = data[1:]
          ntwk = skrf.Network()
          ntwk.frequency = skrf.Frequency.from_f(fdata, unit="Hz")
          ntwk.s = np.empty(shape=(sdata.shape[1], nports, nports), dtype=complex)
          for n in range(nports):
              for m in range(nports):
                  i = n * nports + m
                  ntwk.s[:, m, n] = sdata[i * 2] + 1j * sdata[i * 2 + 1]
          ntwk.frequency.unit = f_unit
          ntwk.name = name
          return ntwk
  
      def get_list_of_traces(self, **kwargs):
          self.resource.clear()
          traces = []
          channels = self.scpi.query_available_channels()
          for channel in channels:
              meas_list = self.scpi.query_meas_name_list(channel)
              if len(meas_list) == 1:
                  continue  # if there isnt a single comma, then there aren't any measurements
              parameters = dict([(meas_list[k], meas_list[k + 1]) for k in range(0, len(meas_list) - 1, 2)])
  
              meas_numbers = self.scpi.query_meas_number_list()
              for mnum in meas_numbers:
                  name = self.scpi.query_meas_name_from_number(mnum)
                  item = {"name": name, "channel": channel, "measurement number": mnum,
                          "parameter": parameters.get(name, name)}
                  item["label"] = "{:s} - Chan{:},Meas{:}".format(
                      item["parameter"], item["channel"], item["measurement number"])
                  traces.append(item)
          return traces
  
      def get_traces(self, traces, **kwargs):
          """
          retrieve traces as 1-port networks from a list returned by get_list_of_traces
  
          Parameters
          ----------
          traces : list
              list of type that is exported by self.get_list_of_traces
          kwargs : dict
              sweep (bool), name_prefix (str)
  
          Returns
          -------
          list
              a list of 1-port networks representing the desired traces
  
          Notes
          -----
          There is no current way to distinguish between traces and 1-port networks within skrf
          """
          self.resource.clear()
          sweep = kwargs.get("sweep", False)
  
          name_prefix = kwargs.get("name_prefix", "")
          if name_prefix:
              name_prefix += " - "
  
          channels = OrderedDict()
          for trace in traces:
              ch = trace["channel"]
              if ch not in channels.keys():
                  channels[ch] = {
                      "frequency": None,
                      "traces": list()}
              channels[ch]["traces"].append(trace)
  
          if sweep is True:
              self.sweep(channels=list(channels.keys()))
  
          traces = []
          for ch, ch_data in channels.items():
              frequency = ch_data["frequency"] = self.get_frequency()
              for trace in ch_data["traces"]:
                  self.scpi.set_selected_meas_by_number(trace["channel"], trace["measurement number"])
                  sdata = np.array(self.scpi.query_data_ascii(trace["channel"], "SDATA"))
                  s = sdata[::2] + 1j * sdata[1::2]
                  ntwk = skrf.Network()
                  ntwk.s = s
                  ntwk.frequency = frequency
                  ntwk.name = name_prefix + trace.get("parameter", "trace")
                  traces.append(ntwk)
          return traces
  
      def get_frequency(self, **kwargs):
          """
          get an skrf.Frequency object for the current channel
  
          Parameters
          ----------
          kwargs : dict
              channel (int), f_unit (str)
  
          Returns
          -------
          skrf.Frequency
          """
          self.resource.clear()
          channel = kwargs.get("channel", self.active_channel)
          sweep_type = self.scpi.query_sweep_type(channel)
          if sweep_type in ["LIN", "LOG", "SEGM"]:
              freqs = self.scpi.query_sweep_data_ascii(channel)
          else:
              freqs = np.array([self.scpi.query_f_start_ascii(channel)])
  
          frequency = skrf.Frequency.from_f(freqs, unit="Hz")
          frequency.unit = kwargs.get("f_unit", "Hz")
          return frequency
  
      def set_frequency_sweep(self, f_start, f_stop, f_npoints, **kwargs):
          f_unit = kwargs.get("f_unit", "hz").lower()
          if f_unit != "hz":
              f_start = self.to_hz(f_start, f_unit)
              f_stop = self.to_hz(f_stop, f_unit)
          channel = kwargs.get("channel", self.active_channel)
          self.scpi.set_f_start(channel, f_start)
          self.scpi.set_f_stop(channel, f_stop)
          self.scpi.set_sweep_n_points(f_npoints)
  
      def get_switch_terms(self, ports=(1, 2), **kwargs):
          self.resource.clear()
          p1, p2 = ports
  
          self.active_channel = channel = kwargs.get("channel", self.active_channel)
  
          measurements = self.get_meas_list()
          max_trace = len(measurements)
          for meas in measurements:  # type: str
              try:
                  trace_num = int(meas[0][-2:].replace("_", ""))
                  if trace_num > max_trace:
                      max_trace = trace_num
              except ValueError:
                  pass
  
          forward_name = "CH{:}_FS_P{:d}_{:d}".format(channel, p1, max_trace + 1)
          reverse_name = "CH{:}_RS_P{:d}_{:d}".format(channel, p2, max_trace + 2)
  
          self.create_meas(forward_name, 'a{:}b{:},{:}'.format(p2, p2, p1))
          self.create_meas(reverse_name, 'a{:}b{:},{:}'.format(p1, p1, p2))
  
          self.sweep(channel=channel)
  
          forward = self.get_measurement(mname=forward_name, sweep=False)  # type: skrf.Network
          forward.name = "forward switch terms"
          reverse = self.get_measurement(mname=reverse_name, sweep=False)  # type: skrf.Network
          reverse.name = "reverse switch terms"
  
          self.scpi.set_delete_meas(channel, forward_name)
          self.scpi.set_delete_meas(channel, reverse_name)
          return forward, reverse
  
      def get_measurement(self, mname=None, mnum=None, **kwargs):
          """
          get a measurement trace from the analyzer, specified by either name or number
  
          Parameters
          ----------
          mname : str
              the name of the measurement, e.g. 'CH1_S11_1'
          mnum : int
              the number of number of the measurement
          kwargs : dict
              channel (int), sweep (bool)
  
          Returns
          -------
          skrf.Network
          """
          if mname is None and mnum is None:
              raise ValueError("must provide either a measurement mname or a mnum")
  
          channel = kwargs.get("channel", self.active_channel)
  
          if type(mname) is str:
              self.scpi.set_selected_meas(channel, mname)
          else:
              self.scpi.set_selected_meas_by_number(channel, mnum)
          return self.get_active_trace_as_network(**kwargs)
  
      def get_active_trace_as_network(self, **kwargs):
          """
          get the active trace as a network object
  
          Parameters
          ----------
          kwargs : dict
              channel (int), sweep (bool)
  
          Returns
          -------
          skrf.Network
          """
          channel = self.active_channel
          sweep = kwargs.get("sweep", False)
          if sweep:
              self.sweep(channel=channel)
  
          ntwk = skrf.Network()
          sdata = np.array(self.scpi.query_data_ascii(channel))
          ntwk.s = sdata[::2] + 1j * sdata[1::2]
          ntwk.frequency = self.get_frequency(channel=channel)
          return ntwk
  
      def create_meas(self, mname, param, **kwargs):
          """
          Create a new measurement trace on the analyzer
  
          Parameters
          ----------
          mname: str
              name of the measurement  **WARNING**, not all names behave well
          param: str
              analyzer parameter, e.g.: S11 ; a1/b1,1 ; A/R1,1
          kwargs : dict
              channel(int)
          """
          channel = kwargs.get("channel", self.active_channel)
          self.scpi.set_create_meas(channel, mname, param)
          self.display_trace(mname)
  
      def display_trace(self, mname, **kwargs):
          """
          Display measurement name on the analyzer display window
  
          Parameters:
          mname : str
              the name of the measurement, e.g. 'CH1_S11_1'
          kwargs : dict
              channel(int), window_n(int), trace_n(int), display_format(str)
  
          Keyword Arguments
          ----------------
          display_format : str
              must be one of: MLINear, MLOGarithmic, PHASe, UPHase, IMAGinary, REAL, POLar, SMITh,
                              SADMittance, SWR, GDELay, KELVin, FAHRenheit, CELSius
          """
          channel = kwargs.get('channel', self.active_channel)
          window_n = kwargs.get("window_n", '')
          trace_n = kwargs.get("trace_n",
                               max(self.scpi.query_window_trace_numbers(window_n)) + 1)
          display_format = kwargs.get('display_format', 'MLOG')
  
          self.scpi.set_display_trace(window_n, trace_n, mname)
  
          self.scpi.set_selected_meas(channel, mname)
          self.scpi.set_display_format(channel, display_format)
  
      def get_meas_list(self, **kwargs):
          """
          Convenience function to return a nicely arranged list of the measurement, parameter catalogue
  
          Parameters
          ----------
          kwargs : dict
              channel : int
  
          Returns
          -------
          list
              list of tuples of the form: (name, measurement)
  
          Return a list of measurement names on all channels.
          If channel is provided to kwargs, then only measurements for that channel are queried
          """
          channel = kwargs.get("channel", self.active_channel)
          meas_list = self.scpi.query_meas_name_list(channel)
          if len(meas_list) == 1:
              return None  # if there isnt a single comma, then there arent any measurements
          return [(meas_list[k], meas_list[k + 1]) for k in range(0, len(meas_list) - 1, 2)]
  
      @property
      def ntraces(self):
          """
          Get the number of traces on the active channel
  
          Returns
          -------
          int
              The number of measurement traces that exist on the current channel
  
          Notes
          -----
          Note that this may not be the same as the number of traces displayed because a measurement may exist,
          but not be associated with a trace.
          """
          meas_list = self.scpi.query_meas_number_list(self.active_channel)
          return 0 if meas_list is None else len(meas_list)
  
  
  class PNAX(PNA):
      NAME = "Keysight PNA-X"
      NPORTS = 4
      NCHANNELS = 32
  