# -*- coding: utf-8 -*-
#
# SPDX-License-Identifier: MIT
"""Driver for Accu-Chek Mobile devices with reports mode.

Supported features:
    - get readings, including comments;
    - use the glucose unit preset on the device by default;
    - get serial number.

Expected device path: /mnt/ACCUCHEK, the mountpoint of the block device.

The Accu-Chek Mobile meters should be set to "Reports" mode.

"""

import csv
import datetime
import glob
import os

from glucometerutils import common
from glucometerutils import exceptions

_UNIT_MAP = {
    'mmol/l': common.Unit.MMOL_L,
    'mg/dl': common.Unit.MG_DL,
}

_DATE_CSV_KEY = 'Date'
_TIME_CSV_KEY = 'Time'
_RESULT_CSV_KEY = 'Result'
_UNIT_CSV_KEY = 'Unit'
_TEMPWARNING_CSV_KEY = 'Temperature warning' # ignored
_OUTRANGE_CSV_KEY = 'Out of target range' # ignored
_OTHER_CSV_KEY = 'Other' # ignored
_BEFORE_MEAL_CSV_KEY = 'Before meal'
_AFTER_MEAL_CSV_KEY = 'After meal'
# Control test has extra whitespace which is not ignored.
_CONTROL_CSV_KEY = 'Control test' + ' '*197

_DATE_FORMAT = '%d.%m.%Y'
_TIME_FORMAT = '%H:%M'

_DATETIME_FORMAT = ' '.join((_DATE_FORMAT, _TIME_FORMAT))

class Device:
    def __init__(self, device):
        if not device or not os.path.isdir(device):
            raise exceptions.CommandLineError(
                '--device parameter is required, should point to mount path '
                'for the meter.')

        reports_path = os.path.join(device, '*', 'Reports', '*.csv')
        report_files = glob.glob(reports_path)
        if not report_files:
            raise exceptions.ConnectionFailed(
                'No report file found in path "%s".' % reports_path)

        self.report_file = report_files[0]

    def _get_records_reader(self):
        self.report.seek(0)
        # Skip the first two lines
        next(self.report)
        next(self.report)

        return csv.DictReader(
            self.report,
            delimiter=';',
            skipinitialspace=True,
            quoting=csv.QUOTE_NONE)

    def connect(self):
        self.report = open(
            self.report_file, 'r', newline='\r\n', encoding='utf-8')

    def disconnect(self):
        self.report.close()

    def get_meter_info(self):
        return common.MeterInfo(
            '%s glucometer' % self.get_model(),
            serial_number=self.get_serial_number(),
            native_unit=self.get_glucose_unit())

    def get_model(self):
        # $device/MODEL/Reports/*.csv
        return os.path.basename(
            os.path.dirname(os.path.dirname(self.report_file)))

    def get_serial_number(self):
        self.report.seek(0)
        # ignore the first line.
        next(self.report)
        # The second line of the CSV is serial-no;report-date;report-time;;;;;;;
        return next(self.report).split(';')[0]

    def get_glucose_unit(self):
        # Get the first record available and parse that.
        record = next(self._get_records_reader())
        return _UNIT_MAP[record[_UNIT_CSV_KEY]]

    def get_datetime(self):
        raise NotImplementedError

    def set_datetime(self, date=None):
        raise NotImplementedError

    def zero_log(self):
        raise NotImplementedError

    def _extract_datetime(self, record):  # pylint: disable=no-self-use
        # Date and time are in separate column, but we want to parse them
        # together.
        date_and_time = ' '.join((record[_DATE_CSV_KEY], record[_TIME_CSV_KEY]))
        return datetime.datetime.strptime(date_and_time, _DATETIME_FORMAT)

    def _extract_meal(self, record):  # pylint: disable=no-self-use
        if record[_AFTER_MEAL_CSV_KEY] and record[_BEFORE_MEAL_CSV_KEY]:
            raise exceptions.InvalidResponse(
                'Reading cannot be before and after meal.')
        elif record[_AFTER_MEAL_CSV_KEY]:
            return common.Meal.AFTER
        elif record[_BEFORE_MEAL_CSV_KEY]:
            return common.Meal.BEFORE
        else:
            return common.Meal.NONE

    def get_readings(self):
        for record in self._get_records_reader():
            if record[_RESULT_CSV_KEY] is None:
                continue

            yield common.GlucoseReading(
                self._extract_datetime(record),
                common.convert_glucose_unit(
                    float(record[_RESULT_CSV_KEY]),
                    _UNIT_MAP[record[_UNIT_CSV_KEY]],
                    common.Unit.MG_DL),
                meal=self._extract_meal(record))