# -*- coding: utf-8 -*-
#
# SPDX-License-Identifier: MIT
"""Driver for FreeStyle Libre devices.
Supported features:
- get readings (sensor, flash and blood glucose), including comments;
- get and set date and time;
- get serial number and software version;
- get and set patient name.
Expected device path: /dev/hidraw9 or similar HID device. Optional when using
HIDAPI.
Further information on the device protocol can be found at
https://protocols.glucometers.tech/abbott/freestyle-libre
"""
import datetime
from glucometerutils import common
from glucometerutils.support import freestyle
# Fields of the records returned by both $history and $arresult?
# Tuple of pairs of idx and field name
_BASE_ENTRY_MAP = (
(0, 'device_id'),
(1, 'type'),
(2, 'month'),
(3, 'day'),
(4, 'year'), # 2-digits
(5, 'hour'),
(6, 'minute'),
(7, 'second'),
)
# Fields of the records returned by $history?
_HISTORY_ENTRY_MAP = _BASE_ENTRY_MAP + (
(13, 'value'),
(15, 'errors'),
)
# Fields of the results returned by $arresult? where type = 2
_ARRESULT_TYPE2_ENTRY_MAP = (
(9, 'reading-type'), # 0 = glucose blood strip,
# 1 = ketone blood strip,
# 2 = glucose sensor
(12, 'value'),
(15, 'sport-flag'),
(16, 'medication-flag'),
(17, 'rapid-acting-flag'), # see _ARRESULT_RAPID_INSULIN_ENTRY_MAP
(18, 'long-acting-flag'),
(19, 'custom-comments-bitfield'),
(23, 'double-long-acting-insulin'),
(25, 'food-flag'),
(26, 'food-carbs-grams'),
(28, 'errors'),
)
_ARRESULT_TIME_ADJUSTMENT_ENTRY_MAP = (
(9, 'old_month'),
(10, 'old_day'),
(11, 'old_year'),
(12, 'old_hour'),
(13, 'old_minute'),
(14, 'old_second'),
)
# Fields only valid when rapid-acting-flag is "1"
_ARRESULT_RAPID_INSULIN_ENTRY_MAP = (
(43, 'double-rapid-acting-insulin'),
)
def _parse_record(record, entry_map):
"""Parses a list of string fields into a dictionary of integers."""
if not record:
return {}
try:
return {
key: int(record[idx]) for idx, key in entry_map
}
except IndexError:
return {}
def _extract_timestamp(parsed_record, prefix=''):
"""Extract the timestamp from a parsed record.
This leverages the fact that all the records have the same base structure.
"""
return datetime.datetime(
parsed_record[prefix + 'year'] + 2000,
parsed_record[prefix + 'month'],
parsed_record[prefix + 'day'],
parsed_record[prefix + 'hour'],
parsed_record[prefix + 'minute'],
parsed_record[prefix + 'second'])
def _parse_arresult(record):
"""Takes an array of string fields as input and parses it into a Reading."""
parsed_record = _parse_record(record, _BASE_ENTRY_MAP)
# There are other record types, but we don't currently need to expose these.
if not parsed_record:
return None
elif parsed_record['type'] == 2:
parsed_record.update(_parse_record(record, _ARRESULT_TYPE2_ENTRY_MAP))
elif parsed_record['type'] == 5:
parsed_record.update(_parse_record(record, _ARRESULT_TIME_ADJUSTMENT_ENTRY_MAP))
return common.TimeAdjustment(
_extract_timestamp(parsed_record),
_extract_timestamp(parsed_record, 'old_'),
extra_data={'device_id': parsed_record['device_id']},
)
else:
return None
# Check right away if we have rapid insulin
if parsed_record['rapid-acting-flag']:
parsed_record.update(
_parse_record(record, _ARRESULT_RAPID_INSULIN_ENTRY_MAP))
if parsed_record['errors']:
return None
comment_parts = []
measure_method = None
cls = None
value = None
if parsed_record['reading-type'] == 2:
comment_parts.append('(Scan)')
measure_method = common.MeasurementMethod.CGM
cls = common.GlucoseReading
value = parsed_record['value']
elif parsed_record['reading-type'] == 0:
comment_parts.append('(Blood)')
measure_method = common.MeasurementMethod.BLOOD_SAMPLE
cls = common.GlucoseReading
value = parsed_record['value']
elif parsed_record['reading-type'] == 1:
comment_parts.append('(Ketone)')
measure_method = common.MeasurementMethod.BLOOD_SAMPLE
cls = common.KetoneReading
# automatically convert the raw value in mmol/L
value = freestyle.convert_ketone_unit(parsed_record['value'])
else:
# unknown reading
return None
custom_comments = record[29:35]
for comment_index in range(6):
if parsed_record['custom-comments-bitfield'] & (1 << comment_index):
comment_parts.append(custom_comments[comment_index][1:-1])
if parsed_record['sport-flag']:
comment_parts.append('Sport')
if parsed_record['medication-flag']:
comment_parts.append('Medication')
if parsed_record['food-flag']:
if parsed_record['food-carbs-grams']:
comment_parts.append(
'Food (%d g)' % parsed_record['food-carbs-grams'])
else:
comment_parts.append('Food')
if parsed_record['long-acting-flag']:
if parsed_record['double-long-acting-insulin']:
comment_parts.append(
'Long-acting insulin (%.1f)' %
(parsed_record['double-long-acting-insulin']/2.))
else:
comment_parts.append('Long-acting insulin')
if parsed_record['rapid-acting-flag']:
# provide default value, as this record does not always exist
# (even if rapid-acting-flag is set)
if parsed_record.get('double-rapid-acting-insulin', 0):
comment_parts.append(
'Rapid-acting insulin (%.1f)' %
(parsed_record['double-rapid-acting-insulin']/2.))
else:
comment_parts.append('Rapid-acting insulin')
return cls(
_extract_timestamp(parsed_record),
value,
comment='; '.join(comment_parts),
measure_method=measure_method,
extra_data={'device_id': parsed_record['device_id']},
)
class Device(freestyle.FreeStyleHidDevice):
"""Glucometer driver for FreeStyle Libre devices."""
USB_PRODUCT_ID = 0x3650
def get_meter_info(self):
"""Return the device information in structured form."""
return common.MeterInfo(
'FreeStyle Libre',
serial_number=self.get_serial_number(),
version_info=(
'Software version: ' + self._get_version(),),
native_unit=self.get_glucose_unit(),
patient_name=self.get_patient_name())
def get_serial_number(self):
"""Overridden function as the command is not compatible."""
return self._send_text_command(b'$sn?').rstrip('\r\n')
def get_glucose_unit(self): # pylint: disable=no-self-use
"""Returns the glucose unit of the device."""
# TODO(Flameeyes): figure out how to identify the actual unit on the
# device.
return common.Unit.MG_DL
def get_readings(self):
# First of all get the usually longer list of sensor readings, and
# convert them to Readings objects.
for record in self._get_multirecord(b'$history?'):
parsed_record = _parse_record(record, _HISTORY_ENTRY_MAP)
if not parsed_record or parsed_record['errors'] != 0:
# The reading is considered invalid, so ignore it.
continue
yield common.GlucoseReading(
_extract_timestamp(parsed_record),
parsed_record['value'],
comment='(Sensor)',
measure_method=common.MeasurementMethod.CGM,
extra_data={'device_id': parsed_record['device_id']},
)
# Then get the results of explicit scans and blood tests (and other
# events).
for record in self._get_multirecord(b'$arresult?'):
reading = _parse_arresult(record)
if reading:
yield reading
