path: root/glucometerutils/drivers/otultraeasy.py

# -*- coding: utf-8 -*-
#
# SPDX-License-Identifier: MIT
"""Driver for LifeScan OneTouch Ultra Easy devices.

Also supports OneTouch Ultra Mini devices (different name, same device).

Supported features:
    - get readings;
    - use the glucose unit preset on the device by default;
    - get and set date and time;
    - get serial number and software version;
    - memory reset (caution!)

Expected device path: /dev/ttyUSB0 or similar serial port device.
"""

import binascii
import datetime
import logging

import construct

from glucometerutils import common
from glucometerutils.support import construct_extras
from glucometerutils.support import lifescan
from glucometerutils.support import lifescan_binary_protocol
from glucometerutils.support import serial

_PACKET = lifescan_binary_protocol.LifeScanPacket(True)

_INVALID_RECORD = 501

_COMMAND_SUCCESS = construct.Const(b'\x05\x06')

_VERSION_REQUEST = construct.Const(b'\x05\x0d\x02')

_VERSION_RESPONSE = construct.Struct(
    _COMMAND_SUCCESS,
    'version' / construct.PascalString(construct.Byte, encoding='ascii'),
)

_SERIAL_NUMBER_REQUEST = construct.Const(
    b'\x05\x0B\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00')

_SERIAL_NUMBER_RESPONSE = construct.Struct(
    _COMMAND_SUCCESS,
    'serial_number' / construct.GreedyString(encoding='ascii'),
)

_DATETIME_REQUEST = construct.Struct(
    construct.Const(b'\x05\x20'),  # 0x20 is the datetime
    'request_type' / construct.Enum(construct.Byte, write=0x01, read=0x02),
    'timestamp' / construct.Default(
        construct_extras.Timestamp(construct.Int32ul),  # type: ignore
        datetime.datetime(1970, 1, 1, 0, 0)),
)

_DATETIME_RESPONSE = construct.Struct(
    _COMMAND_SUCCESS,
    'timestamp' / construct_extras.Timestamp(construct.Int32ul),  # type: ignore
)

_GLUCOSE_UNIT_REQUEST = construct.Const(
    b'\x05\x09\x02\x09\x00\x00\x00\x00')


_GLUCOSE_UNIT_RESPONSE = construct.Struct(
    _COMMAND_SUCCESS,
    'unit' / lifescan_binary_protocol.GLUCOSE_UNIT,
    construct.Padding(3),
)

_MEMORY_ERASE_REQUEST = construct.Const(b'\x05\x1A')

_READING_COUNT_RESPONSE = construct.Struct(
    construct.Const(b'\x0f'),
    'count' / construct.Int16ul,
)

_READ_RECORD_REQUEST = construct.Struct(
    construct.Const(b'\x05\x1f'),
    'record_id' / construct.Int16ul,
)

_READING_RESPONSE = construct.Struct(
    _COMMAND_SUCCESS,
    'timestamp' / construct_extras.Timestamp(construct.Int32ul),  # type: ignore
    'value' / construct.Int32ul,
)

def _make_packet(
        message, sequence_number, expect_receive, acknowledge, disconnect):
    return _PACKET.build(
        {'data': {'value': {
            'message': message,
            'link_control': {
                'sequence_number': sequence_number,
                'expect_receive': expect_receive,
                'acknowledge': acknowledge,
                'disconnect': disconnect,
            },
        }}})

class Device(serial.SerialDevice):
    BAUDRATE = 9600
    DEFAULT_CABLE_ID = '067b:2303'  # Generic PL2303 cable.
    TIMEOUT = 0.5

    def __init__(self, device):
        super(Device, self).__init__(device)

        self.sent_counter_ = False
        self.expect_receive_ = False
        self.buffered_reader_ = construct.Rebuffered(
            _PACKET, tailcutoff=1024)

    def connect(self):
        try:
            self._send_packet(b'', disconnect=True)
            self._read_ack()
        except construct.ConstructError as e:
            raise lifescan.MalformedCommand(str(e))

    def disconnect(self):
        self.connect()

    def _send_packet(self, message, acknowledge=False, disconnect=False):
        pkt = _make_packet(
            message,
            self.sent_counter_,
            self.expect_receive_,
            acknowledge,
            disconnect)
        logging.debug('sending packet: %s', binascii.hexlify(pkt))

        self.serial_.write(pkt)
        self.serial_.flush()

    def _read_packet(self):
        raw_pkt = self.buffered_reader_.parse_stream(self.serial_).data
        logging.debug('received packet: %r', raw_pkt)

        # discard the checksum and copy
        pkt = raw_pkt.value

        if not pkt.link_control.disconnect and (
                pkt.link_control.sequence_number != self.expect_receive_):
            raise lifescan.MalformedCommand(
                'at position 2[0b] expected %02x, received %02x' % (
                    self.expect_receive_, pkt.link_connect.sequence_count))

        return pkt

    def _send_ack(self):
        self._send_packet(b'', acknowledge=True, disconnect=False)

    def _read_ack(self):
        pkt = self._read_packet()
        assert pkt.link_control.acknowledge

    def _send_request(self, request_format, request_obj, response_format):
        try:
            request = request_format.build(request_obj)
            self._send_packet(request, acknowledge=False, disconnect=False)

            self.sent_counter_ = not self.sent_counter_
            self._read_ack()

            response_pkt = self._read_packet()
            assert not response_pkt.link_control.acknowledge

            self.expect_receive_ = not self.expect_receive_
            self._send_ack()

            return response_format.parse(response_pkt.message)
        except construct.ConstructError as e:
            raise lifescan.MalformedCommand(str(e))

    def get_meter_info(self):
        return common.MeterInfo(
            'OneTouch Ultra Easy glucometer',
            serial_number=self.get_serial_number(),
            version_info=(
                'Software version: ' + self.get_version(),),
            native_unit=self.get_glucose_unit())

    def get_version(self):
        response = self._send_request(
            _VERSION_REQUEST, None, _VERSION_RESPONSE)

        return response.version

    def get_serial_number(self):
        response = self._send_request(
            _SERIAL_NUMBER_REQUEST, None, _SERIAL_NUMBER_RESPONSE)

        return response.serial_number

    def get_datetime(self):
        response = self._send_request(
            _DATETIME_REQUEST, {'request_type': 'read'},
            _DATETIME_RESPONSE)

        return response.timestamp

    def set_datetime(self, date=datetime.datetime.now()):
        response = self._send_request(
            _DATETIME_REQUEST, {
                'request_type': 'write',
                'timestamp': date,
            }, _DATETIME_RESPONSE)

        return response.timestamp

    def zero_log(self):
        self._send_request(
            _MEMORY_ERASE_REQUEST, None,
            _COMMAND_SUCCESS)

    def get_glucose_unit(self):
        response = self._send_request(
            _GLUCOSE_UNIT_REQUEST, None, _GLUCOSE_UNIT_RESPONSE)

        return response.unit

    def _get_reading_count(self):
        response = self._send_request(
            _READ_RECORD_REQUEST, {'record_id': _INVALID_RECORD},
            _READING_COUNT_RESPONSE)
        return response.count

    def _get_reading(self, record_id):
        response = self._send_request(
            _READ_RECORD_REQUEST, {'record_id': record_id}, _READING_RESPONSE)

        return common.GlucoseReading(
            response.timestamp, float(response.value))

    def get_readings(self):
        record_count = self._get_reading_count()
        for record_id in range(record_count):
            yield self._get_reading(record_id)