#!/usr/bin/env python
# Copyright 2016 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
# Ignore indention messages, since legacy scripts use 2 spaces instead of 4.
# pylint: disable=bad-indentation,docstring-section-indent
# pylint: disable=docstring-trailing-quotes

"""Program to fetch power logging data from a sweetberry device
   or other usb device that exports a USB power logging interface.
"""

# Note: This is a py2/3 compatible file.

from __future__ import print_function
import argparse
import array
from distutils import sysconfig
import json
import logging
import os
import pprint
import struct
import sys
import time
import traceback

import usb

from stats_manager import StatsManager

# Directory where hdctools installs configuration files into.
LIB_DIR = os.path.join(sysconfig.get_python_lib(standard_lib=False), 'servo',
                       'data')

# Potential config file locations: current working directory, the same directory
# as powerlog.py file or LIB_DIR.
CONFIG_LOCATIONS = [os.getcwd(), os.path.dirname(os.path.realpath(__file__)),
                    LIB_DIR]

def logoutput(msg):
  print(msg)
  sys.stdout.flush()

def process_filename(filename):
  """Find the file path from the filename.

  If filename is already the complete path, return that directly. If filename is
  just the short name, look for the file in the current working directory, in
  the directory of the current .py file, and then in the directory installed by
  hdctools. If the file is found, return the complete path of the file.

  Args:
      filename: complete file path or short file name.

  Returns:
      a complete file path.

  Raises:
      IOError if filename does not exist.
  """
  # Check if filename is absolute path.
  if os.path.isabs(filename) and os.path.isfile(filename):
    return filename
  # Check if filename is relative to a known config location.
  for dirname in CONFIG_LOCATIONS:
    file_at_dir = os.path.join(dirname, filename)
    if os.path.isfile(file_at_dir):
      return file_at_dir
  raise IOError('No such file or directory: \'%s\'' % filename)


class Spower(object):
  """Power class to access devices on the bus.

  Usage:
    bus = Spower()

  Instance Variables:
    _dev: pyUSB device object
    _read_ep: pyUSB read endpoint for this interface
    _write_ep: pyUSB write endpoint for this interface
  """

  # INA interface type.
  INA_POWER     = 1
  INA_BUSV      = 2
  INA_CURRENT   = 3
  INA_SHUNTV    = 4
  # INA_SUFFIX is used to differentiate multiple ina types for the same power
  # rail. No suffix for when ina type is 0 (non-existent) and when ina type is 1
  # (power, no suffix for backward compatibility).
  INA_SUFFIX      = ['', '', '_busv', '_cur', '_shuntv']

  # usb power commands
  CMD_RESET   = 0x0000
  CMD_STOP    = 0x0001
  CMD_ADDINA  = 0x0002
  CMD_START   = 0x0003
  CMD_NEXT    = 0x0004
  CMD_SETTIME = 0x0005

  # Map between header channel number (0-47)
  # and INA I2C bus/addr on sweetberry.
  CHMAP = {
	0: (3, 0x40),
	1: (1, 0x40),
	2: (2, 0x40),
	3: (0, 0x40),
	4: (3, 0x41),
	5: (1, 0x41),
	6: (2, 0x41),
	7: (0, 0x41),
	8: (3, 0x42),
	9: (1, 0x42),
	10: (2, 0x42),
	11: (0, 0x42),
	12: (3, 0x43),
	13: (1, 0x43),
	14: (2, 0x43),
	15: (0, 0x43),
	16: (3, 0x44),
	17: (1, 0x44),
	18: (2, 0x44),
	19: (0, 0x44),
	20: (3, 0x45),
	21: (1, 0x45),
	22: (2, 0x45),
	23: (0, 0x45),
	24: (3, 0x46),
	25: (1, 0x46),
	26: (2, 0x46),
	27: (0, 0x46),
	28: (3, 0x47),
	29: (1, 0x47),
	30: (2, 0x47),
	31: (0, 0x47),
	32: (3, 0x48),
	33: (1, 0x48),
	34: (2, 0x48),
	35: (0, 0x48),
	36: (3, 0x49),
	37: (1, 0x49),
	38: (2, 0x49),
	39: (0, 0x49),
	40: (3, 0x4a),
	41: (1, 0x4a),
	42: (2, 0x4a),
	43: (0, 0x4a),
	44: (3, 0x4b),
	45: (1, 0x4b),
	46: (2, 0x4b),
	47: (0, 0x4b),
  }

  def __init__(self, board, vendor=0x18d1,
               product=0x5020, interface=1, serialname=None):
    self._logger = logging.getLogger(__name__)
    self._board = board

    # Find the stm32.
    dev_g = usb.core.find(idVendor=vendor, idProduct=product, find_all=True)
    dev_list = list(dev_g)
    if dev_list is None:
      raise Exception("Power", "USB device not found")

    # Check if we have multiple stm32s and we've specified the serial.
    dev = None
    if serialname:
      for d in dev_list:
        dev_serial = "PyUSB dioesn't have a stable interface"
        try:
          dev_serial = usb.util.get_string(d, 256, d.iSerialNumber)
        except ValueError:
          # Incompatible pyUsb version.
          dev_serial = usb.util.get_string(d, d.iSerialNumber)
        if dev_serial == serialname:
          dev = d
          break
      if dev is None:
        raise Exception("Power", "USB device(%s) not found" % serialname)
    else:
      try:
        dev = dev_list[0]
      except TypeError:
        # Incompatible pyUsb version.
        dev = dev_list.next()

    self._logger.debug("Found USB device: %04x:%04x", vendor, product)
    self._dev = dev

    # Get an endpoint instance.
    try:
      dev.set_configuration()
    except usb.USBError:
      pass
    cfg = dev.get_active_configuration()

    intf = usb.util.find_descriptor(cfg, custom_match=lambda i: \
        i.bInterfaceClass==255 and i.bInterfaceSubClass==0x54)

    self._intf = intf
    self._logger.debug("InterfaceNumber: %s", intf.bInterfaceNumber)

    read_ep = usb.util.find_descriptor(
      intf,
      # match the first IN endpoint
      custom_match = \
      lambda e: \
          usb.util.endpoint_direction(e.bEndpointAddress) == \
          usb.util.ENDPOINT_IN
    )

    self._read_ep = read_ep
    self._logger.debug("Reader endpoint: 0x%x", read_ep.bEndpointAddress)

    write_ep = usb.util.find_descriptor(
      intf,
      # match the first OUT endpoint
      custom_match = \
      lambda e: \
          usb.util.endpoint_direction(e.bEndpointAddress) == \
          usb.util.ENDPOINT_OUT
    )

    self._write_ep = write_ep
    self._logger.debug("Writer endpoint: 0x%x", write_ep.bEndpointAddress)

    self.clear_ina_struct()

    self._logger.debug("Found power logging USB endpoint.")

  def clear_ina_struct(self):
    """ Clear INA description struct."""
    self._inas = []

  def append_ina_struct(self, name, rs, port, addr,
                        data=None, ina_type=INA_POWER):
    """Add an INA descriptor into the list of active INAs.

    Args:
      name:	Readable name of this channel.
      rs:	Sense resistor value in ohms, floating point.
      port:	I2C channel this INA is connected to.
      addr: 	I2C addr of this INA.
      data:	Misc data for special handling, board specific.
      ina_type: INA function to use, power, voltage, etc.
    """
    ina = {}
    ina['name'] = name
    ina['rs'] = rs
    ina['port'] = port
    ina['addr'] = addr
    ina['type'] = ina_type
    # Calculate INA231 Calibration register
    # (see INA231 spec p.15)
    # CurrentLSB = uA per div = 80mV / (Rsh * 2^15)
    # CurrentLSB uA = 80000000nV / (Rsh mOhm * 0x8000)
    ina['uAscale'] = 80000000. / (rs * 0x8000);
    ina['uWscale'] = 25. * ina['uAscale'];
    ina['mVscale'] = 1.25
    ina['uVscale'] = 2.5
    ina['data'] = data
    self._inas.append(ina)

  def wr_command(self, write_list, read_count=1, wtimeout=100, rtimeout=1000):
    """Write command to logger logic.

    This function writes byte command values list to stm, then reads
    byte status.

    Args:
      write_list: list of command byte values [0~255].
      read_count: number of status byte values to read.

    Interface:
      write: [command, data ... ]
      read: [status ]

    Returns:
      bytes read, or None on failure.
    """
    self._logger.debug("Spower.wr_command(write_list=[%s] (%d), read_count=%s)",
                       list(bytearray(write_list)), len(write_list), read_count)

    # Clean up args from python style to correct types.
    write_length = 0
    if write_list:
      write_length = len(write_list)
    if not read_count:
      read_count = 0

    # Send command to stm32.
    if write_list:
      cmd = write_list
      ret = self._write_ep.write(cmd, wtimeout)

    self._logger.debug("RET: %s ", ret)

    # Read back response if necessary.
    if read_count:
      bytesread = self._read_ep.read(512, rtimeout)
      self._logger.debug("BYTES: [%s]", bytesread)

      if len(bytesread) != read_count:
        pass

      self._logger.debug("STATUS: 0x%02x", int(bytesread[0]))
      if read_count == 1:
        return bytesread[0]
      else:
        return bytesread

    return None

  def clear(self):
    """Clear pending reads on the stm32"""
    try:
      while True:
        ret = self.wr_command(b"", read_count=512, rtimeout=100, wtimeout=50)
        self._logger.debug("Try Clear: read %s",
                           "success" if ret == 0 else "failure")
    except:
      pass

  def send_reset(self):
    """Reset the power interface on the stm32"""
    cmd = struct.pack("<H", self.CMD_RESET)
    ret = self.wr_command(cmd, rtimeout=50, wtimeout=50)
    self._logger.debug("Command RESET: %s",
                       "success" if ret == 0 else "failure")

  def reset(self):
    """Try resetting the USB interface until success.

    Use linear back off strategy when encounter the error with 10ms increment.

    Raises:
      Exception on failure.
    """
    max_reset_retry = 100
    for count in range(1, max_reset_retry + 1):
      self.clear()
      try:
        self.send_reset()
        return
      except Exception as e:
        self.clear()
        self.clear()
        self._logger.debug("TRY %d of %d: %s", count, max_reset_retry, e)
        time.sleep(count * 0.01)
    raise Exception("Power", "Failed to reset")

  def stop(self):
    """Stop any active data acquisition."""
    cmd = struct.pack("<H", self.CMD_STOP)
    ret = self.wr_command(cmd)
    self._logger.debug("Command STOP: %s",
                       "success" if ret == 0 else "failure")

  def start(self, integration_us):
    """Start data acquisition.

    Args:
      integration_us: int, how many us between samples, and
                      how often the data block must be read.

    Returns:
      actual sampling interval in ms.
    """
    cmd = struct.pack("<HI", self.CMD_START, integration_us)
    read = self.wr_command(cmd, read_count=5)
    actual_us = 0
    if len(read) == 5:
      ret, actual_us = struct.unpack("<BI", read)
      self._logger.debug("Command START: %s %dus",
               "success" if ret == 0 else "failure", actual_us)
    else:
      self._logger.debug("Command START: FAIL")

    return actual_us

  def add_ina_name(self, name_tuple):
    """Add INA from board config.

    Args:
      name_tuple:	name and type of power rail in board config.

    Returns:
      True if INA added, False if the INA is not on this board.

    Raises:
      Exception on unexpected failure.
    """
    name, ina_type = name_tuple

    for datum in self._brdcfg:
      if datum["name"] == name:
        rs = int(float(datum["rs"]) * 1000.)
        board = datum["sweetberry"]

        if board == self._board:
          if 'port' in datum and 'addr' in datum:
            port = datum['port']
            addr = datum['addr']
          else:
            channel = int(datum["channel"])
            port, addr = self.CHMAP[channel]
          self.add_ina(port, ina_type, addr, 0, rs, data=datum)
          return True
        else:
          return False
    raise Exception("Power", "Failed to find INA %s" % name)

  def set_time(self, timestamp_us):
    """Set sweetberry time to match host time.

    Args:
      timestamp_us: host timestmap in us.
    """
    # 0x0005 , 8 byte timestamp
    cmd = struct.pack("<HQ", self.CMD_SETTIME, timestamp_us)
    ret = self.wr_command(cmd)

    self._logger.debug("Command SETTIME: %s",
                       "success" if ret == 0 else "failure")

  def add_ina(self, bus, ina_type, addr, extra, resistance, data=None):
    """Add an INA to the data acquisition list.

    Args:
      bus: which i2c bus the INA is on. Same ordering as Si2c.
      ina_type: Ina interface: INA_POWER/BUSV/etc.
      addr: 7 bit i2c addr of this INA
      extra: extra data for nonstandard configs.
      resistance: int, shunt resistance in mOhm
    """
    # 0x0002, 1B: bus, 1B:INA type, 1B: INA addr, 1B: extra, 4B: Rs
    cmd = struct.pack("<HBBBBI", self.CMD_ADDINA,
                      bus, ina_type, addr, extra, resistance)
    ret = self.wr_command(cmd)
    if ret == 0:
      if data:
        name = data['name']
      else:
        name = "ina%d_%02x" % (bus, addr)
      self.append_ina_struct(name, resistance, bus, addr,
                             data=data, ina_type=ina_type)
    self._logger.debug("Command ADD_INA: %s",
                       "success" if ret == 0 else "failure")

  def report_header_size(self):
    """Helper function to calculate power record header size."""
    result = 2
    timestamp = 8
    return result + timestamp

  def report_size(self, ina_count):
    """Helper function to calculate full power record size."""
    record = 2

    datasize = self.report_header_size() + ina_count * record
    # Round to multiple of 4 bytes.
    datasize = int(((datasize + 3) // 4) * 4)

    return datasize

  def read_line(self):
    """Read a line of data from the setup INAs

    Returns:
      list of dicts of the values read by ina/type tuple, otherwise None.
      [{ts:100, (vbat, power):450}, {ts:200, (vbat, power):440}]
    """
    try:
      expected_bytes = self.report_size(len(self._inas))
      cmd = struct.pack("<H", self.CMD_NEXT)
      bytesread = self.wr_command(cmd, read_count=expected_bytes)
    except usb.core.USBError as e:
      self._logger.error("READ LINE FAILED %s", e)
      return None

    if len(bytesread) == 1:
      if bytesread[0] != 0x6:
        self._logger.debug("READ LINE FAILED bytes: %d ret: %02x",
                           len(bytesread), bytesread[0])
      return None

    if len(bytesread) % expected_bytes != 0:
      self._logger.debug("READ LINE WARNING: expected %d, got %d",
          expected_bytes, len(bytesread))

    packet_count = len(bytesread) // expected_bytes

    values = []
    for i in range(0, packet_count):
      start = i * expected_bytes
      end = (i + 1) * expected_bytes
      record = self.interpret_line(bytesread[start:end])
      values.append(record)

    return values

  def interpret_line(self, data):
    """Interpret a power record from INAs

    Args:
      data: one single record of bytes.

    Output:
      stdout of the record in csv format.

    Returns:
      dict containing name, value of recorded data.
    """
    status, size = struct.unpack("<BB", data[0:2])
    if len(data) != self.report_size(size):
      self._logger.error("READ LINE FAILED st:%d size:%d expected:%d len:%d",
                         status, size, self.report_size(size), len(data))
    else:
      pass

    timestamp = struct.unpack("<Q", data[2:10])[0]
    self._logger.debug("READ LINE: st:%d size:%d time:%dus", status, size,
                       timestamp)
    ftimestamp = float(timestamp) / 1000000.

    record = {"ts": ftimestamp, "status": status, "berry":self._board}

    for i in range(0, size):
      idx = self.report_header_size() + 2*i
      name = self._inas[i]['name']
      name_tuple = (self._inas[i]['name'], self._inas[i]['type'])

      raw_val = struct.unpack("<h", data[idx:idx+2])[0]

      if self._inas[i]['type'] == Spower.INA_POWER:
        val = raw_val * self._inas[i]['uWscale']
      elif self._inas[i]['type'] == Spower.INA_BUSV:
        val = raw_val * self._inas[i]['mVscale']
      elif self._inas[i]['type'] == Spower.INA_CURRENT:
        val = raw_val * self._inas[i]['uAscale']
      elif self._inas[i]['type'] == Spower.INA_SHUNTV:
        val = raw_val * self._inas[i]['uVscale']

      self._logger.debug("READ %d %s: %fs: 0x%04x %f", i, name, ftimestamp,
                         raw_val, val)
      record[name_tuple] = val

    return record

  def load_board(self, brdfile):
    """Load a board config.

    Args:
      brdfile:	Filename of a json file decribing the INA wiring of this board.
    """
    with open(process_filename(brdfile)) as data_file:
        data = json.load(data_file)

    #TODO: validate this.
    self._brdcfg = data;
    self._logger.debug(pprint.pformat(data))


class powerlog(object):
  """Power class to log aggregated power.

  Usage:
    obj = powerlog()

  Instance Variables:
    _data: a StatsManager object that records sweetberry readings and calculates
           statistics.
    _pwr[]: Spower objects for individual sweetberries.
  """

  def __init__(self, brdfile, cfgfile, serial_a=None, serial_b=None,
               sync_date=False, use_ms=False, use_mW=False, print_stats=False,
               stats_dir=None, stats_json_dir=None, print_raw_data=True,
               raw_data_dir=None):
    """Init the powerlog class and set the variables.

    Args:
      brdfile: string name of json file containing board layout.
      cfgfile: string name of json containing list of rails to read.
      serial_a: serial number of sweetberry A.
      serial_b: serial number of sweetberry B.
      sync_date: report timestamps synced with host datetime.
      use_ms: report timestamps in ms rather than us.
      use_mW: report power as milliwatts, otherwise default to microwatts.
      print_stats: print statistics for sweetberry readings at the end.
      stats_dir: directory to save sweetberry readings statistics; if None then
                 do not save the statistics.
      stats_json_dir: directory to save means of sweetberry readings in json
                      format; if None then do not save the statistics.
      print_raw_data: print sweetberry readings raw data in real time, default
                      is to print.
      raw_data_dir: directory to save sweetberry readings raw data; if None then
                    do not save the raw data.
    """
    self._logger = logging.getLogger(__name__)
    self._data = StatsManager()
    self._pwr = {}
    self._use_ms = use_ms
    self._use_mW = use_mW
    self._print_stats = print_stats
    self._stats_dir = stats_dir
    self._stats_json_dir = stats_json_dir
    self._print_raw_data = print_raw_data
    self._raw_data_dir = raw_data_dir

    if not serial_a and not serial_b:
      self._pwr['A'] = Spower('A')
    if serial_a:
      self._pwr['A'] = Spower('A', serialname=serial_a)
    if serial_b:
      self._pwr['B'] = Spower('B', serialname=serial_b)

    with open(process_filename(cfgfile)) as data_file:
      names = json.load(data_file)
    self._names = self.process_scenario(names)

    for key in self._pwr:
      self._pwr[key].load_board(brdfile)
      self._pwr[key].reset()

    # Allocate the rails to the appropriate boards.
    used_boards = []
    for name in self._names:
      success = False
      for key in self._pwr.keys():
        if self._pwr[key].add_ina_name(name):
          success = True
          if key not in used_boards:
            used_boards.append(key)
      if not success:
        raise Exception("Failed to add %s (maybe missing "
                        "sweetberry, or bad board file?)" % name)

    # Evict unused boards.
    for key in list(self._pwr.keys()):
      if key not in used_boards:
        self._pwr.pop(key)

    for key in self._pwr.keys():
      if sync_date:
        self._pwr[key].set_time(time.time() * 1000000)
      else:
        self._pwr[key].set_time(0)

  def process_scenario(self, name_list):
    """Return list of tuples indicating name and type.

    Args:
      json originated list of names, or [name, type]
    Returns:
      list of tuples of (name, type) defaulting to type "POWER"
    Raises: exception, invalid INA type.
    """
    names = []
    for entry in name_list:
      if isinstance(entry, list):
        name = entry[0]
        if entry[1] == "POWER":
          type = Spower.INA_POWER
        elif entry[1] == "BUSV":
          type = Spower.INA_BUSV
        elif entry[1] == "CURRENT":
          type = Spower.INA_CURRENT
        elif entry[1] == "SHUNTV":
          type = Spower.INA_SHUNTV
        else:
          raise Exception("Invalid INA type", "Type of %s [%s] not recognized,"
                    " try one of POWER, BUSV, CURRENT" % (entry[0], entry[1]))
      else:
        name = entry
        type = Spower.INA_POWER

      names.append((name, type))
    return names

  def start(self, integration_us_request, seconds, sync_speed=.8):
    """Starts sampling.

    Args:
      integration_us_request: requested interval between sample values.
      seconds: time until exit, or None to run until cancel.
      sync_speed: A usb request is sent every [.8] * integration_us.
    """
    # We will get back the actual integration us.
    # It should be the same for all devices.
    integration_us = None
    for key in self._pwr:
      integration_us_new = self._pwr[key].start(integration_us_request)
      if integration_us:
        if integration_us != integration_us_new:
          raise Exception("FAIL",
              "Integration on A: %dus != integration on B %dus" % (
              integration_us, integration_us_new))
      integration_us = integration_us_new

    # CSV header
    title = "ts:%dus" % integration_us
    for name_tuple in self._names:
      name, ina_type = name_tuple

      if ina_type == Spower.INA_POWER:
        unit = "mW" if self._use_mW else "uW"
      elif ina_type == Spower.INA_BUSV:
        unit = "mV"
      elif ina_type == Spower.INA_CURRENT:
        unit = "uA"
      elif ina_type == Spower.INA_SHUNTV:
        unit = "uV"

      title += ", %s %s" % (name, unit)
      name_type = name + Spower.INA_SUFFIX[ina_type]
      self._data.SetUnit(name_type, unit)
    title += ", status"
    if self._print_raw_data:
      logoutput(title)

    forever = False
    if not seconds:
      forever = True
    end_time = time.time() + seconds
    try:
      pending_records = []
      while forever or end_time > time.time():
        if (integration_us > 5000):
          time.sleep((integration_us / 1000000.) * sync_speed)
        for key in self._pwr:
          records = self._pwr[key].read_line()
          if not records:
            continue

          for record in records:
            pending_records.append(record)

        pending_records.sort(key=lambda r: r['ts'])

        aggregate_record = {"boards": set()}
        for record in pending_records:
          if record["berry"] not in aggregate_record["boards"]:
            for rkey in record.keys():
              aggregate_record[rkey] = record[rkey]
            aggregate_record["boards"].add(record["berry"])
          else:
            self._logger.info("break %s, %s", record["berry"],
                              aggregate_record["boards"])
            break

          if aggregate_record["boards"] == set(self._pwr.keys()):
            csv = "%f" % aggregate_record["ts"]
            for name in self._names:
              if name in aggregate_record:
                multiplier = 0.001 if (self._use_mW and
                    name[1]==Spower.INA_POWER) else 1
                value = aggregate_record[name] * multiplier
                csv += ", %.2f" % value
                name_type = name[0] + Spower.INA_SUFFIX[name[1]]
                self._data.AddSample(name_type, value)
              else:
                csv += ", "
            csv += ", %d" % aggregate_record["status"]
            if self._print_raw_data:
              logoutput(csv)

            aggregate_record = {"boards": set()}
            for r in range(0, len(self._pwr)):
              pending_records.pop(0)

    except KeyboardInterrupt:
      self._logger.info('\nCTRL+C caught.')

    finally:
      for key in self._pwr:
        self._pwr[key].stop()
      self._data.CalculateStats()
      if self._print_stats:
        print(self._data.SummaryToString())
      save_dir = 'sweetberry%s' % time.time()
      if self._stats_dir:
        stats_dir = os.path.join(self._stats_dir, save_dir)
        self._data.SaveSummary(stats_dir)
      if self._stats_json_dir:
        stats_json_dir = os.path.join(self._stats_json_dir, save_dir)
        self._data.SaveSummaryJSON(stats_json_dir)
      if self._raw_data_dir:
        raw_data_dir = os.path.join(self._raw_data_dir, save_dir)
        self._data.SaveRawData(raw_data_dir)


def main(argv=None):
  if argv is None:
    argv = sys.argv[1:]
  # Command line argument description.
  parser = argparse.ArgumentParser(
      description="Gather CSV data from sweetberry")
  parser.add_argument('-b', '--board', type=str,
      help="Board configuration file, eg. my.board", default="")
  parser.add_argument('-c', '--config', type=str,
      help="Rail config to monitor, eg my.scenario", default="")
  parser.add_argument('-A', '--serial', type=str,
      help="Serial number of sweetberry A", default="")
  parser.add_argument('-B', '--serial_b', type=str,
      help="Serial number of sweetberry B", default="")
  parser.add_argument('-t', '--integration_us', type=int,
      help="Target integration time for samples", default=100000)
  parser.add_argument('-s', '--seconds', type=float,
      help="Seconds to run capture", default=0.)
  parser.add_argument('--date', default=False,
      help="Sync logged timestamp to host date", action="store_true")
  parser.add_argument('--ms', default=False,
      help="Print timestamp as milliseconds", action="store_true")
  parser.add_argument('--mW', default=False,
      help="Print power as milliwatts, otherwise default to microwatts",
      action="store_true")
  parser.add_argument('--slow', default=False,
      help="Intentionally overflow", action="store_true")
  parser.add_argument('--print_stats', default=False, action="store_true",
      help="Print statistics for sweetberry readings at the end")
  parser.add_argument('--save_stats', type=str, nargs='?',
      dest='stats_dir', metavar='STATS_DIR',
      const=os.path.dirname(os.path.abspath(__file__)), default=None,
      help="Save statistics for sweetberry readings to %(metavar)s if "
           "%(metavar)s is specified, %(metavar)s will be created if it does "
           "not exist; if %(metavar)s is not specified but the flag is set, "
           "stats will be saved to where %(prog)s is located; if this flag is "
           "not set, then do not save stats")
  parser.add_argument('--save_stats_json', type=str, nargs='?',
      dest='stats_json_dir', metavar='STATS_JSON_DIR',
      const=os.path.dirname(os.path.abspath(__file__)), default=None,
      help="Save means for sweetberry readings in json to %(metavar)s if "
           "%(metavar)s is specified, %(metavar)s will be created if it does "
           "not exist; if %(metavar)s is not specified but the flag is set, "
           "stats will be saved to where %(prog)s is located; if this flag is "
           "not set, then do not save stats")
  parser.add_argument('--no_print_raw_data',
      dest='print_raw_data', default=True, action="store_false",
      help="Not print raw sweetberry readings at real time, default is to "
           "print")
  parser.add_argument('--save_raw_data', type=str, nargs='?',
      dest='raw_data_dir', metavar='RAW_DATA_DIR',
      const=os.path.dirname(os.path.abspath(__file__)), default=None,
      help="Save raw data for sweetberry readings to %(metavar)s if "
           "%(metavar)s is specified, %(metavar)s will be created if it does "
           "not exist; if %(metavar)s is not specified but the flag is set, "
           "raw data will be saved to where %(prog)s is located; if this flag "
           "is not set, then do not save raw data")
  parser.add_argument('-v', '--verbose', default=False,
      help="Very chatty printout", action="store_true")

  args = parser.parse_args(argv)

  root_logger = logging.getLogger(__name__)
  if args.verbose:
    root_logger.setLevel(logging.DEBUG)
  else:
    root_logger.setLevel(logging.INFO)

  # if powerlog is used through main, log to sys.stdout
  if __name__ == "__main__":
    stdout_handler = logging.StreamHandler(sys.stdout)
    stdout_handler.setFormatter(logging.Formatter('%(levelname)s: %(message)s'))
    root_logger.addHandler(stdout_handler)

  integration_us_request = args.integration_us
  if not args.board:
    raise Exception("Power", "No board file selected, see board.README")
  if not args.config:
    raise Exception("Power", "No config file selected, see board.README")

  brdfile = args.board
  cfgfile = args.config
  seconds = args.seconds
  serial_a = args.serial
  serial_b = args.serial_b
  sync_date = args.date
  use_ms = args.ms
  use_mW = args.mW
  print_stats = args.print_stats
  stats_dir = args.stats_dir
  stats_json_dir = args.stats_json_dir
  print_raw_data = args.print_raw_data
  raw_data_dir = args.raw_data_dir

  boards = []

  sync_speed = .8
  if args.slow:
    sync_speed = 1.2

  # Set up logging interface.
  powerlogger = powerlog(brdfile, cfgfile, serial_a=serial_a, serial_b=serial_b,
      sync_date=sync_date, use_ms=use_ms, use_mW=use_mW,
      print_stats=print_stats, stats_dir=stats_dir,
      stats_json_dir=stats_json_dir,
      print_raw_data=print_raw_data,raw_data_dir=raw_data_dir)

  # Start logging.
  powerlogger.start(integration_us_request, seconds, sync_speed=sync_speed)


if __name__ == "__main__":
  main()
