import configparser
import sys
import os
from pprint import pprint


DEFAULT_INI=\
"""\
[server]
; base URL of the server
URL = http://dados.cta.if.ufrgs.br/emm

; board identification number (auto generated when a new board is created)
BOARD_ID =

; authentication token for the board's user
USER_HASH =


[reading]
; CSV list of sensor names/nicknames (order reflect columns on datalog files)
SENSORS = DHT22_TEMP, DHT22_AH, BMP085_PRESSURE, LDR

; time between logger cycles -- format:   hours:minutes:seconds
INTERVAL = 0:5:0

; true for read board clock; if fail, or false, system's time will be used
RTC_DS1307 = true


[datalog]
; CSV delimiter for local log files (sugestions: ',' or ';' or '\t')
CSV_SEP = '\t'

; format of the datetime column (see Python docs on datetime module)
DATETIME_FORMAT = %Y-%m-%d-%H-%M-%S


[arduino]
; CSV list of ports to attempt or blank for automatic search on
; /dev/ttyACM* and /dev/ttyUSB* (where * varies from 0 to 10)
SERIAL_PORT =
"""


def make_path_here(filename):
    ''' Append filename to the current __file__ path. '''
    return os.path.join(os.path.abspath(os.path.dirname(__file__)), filename)


class RTCDateTime:
    SENSOR_NAME = 'RTC_DS1307'
    READ_TIMESTAMP = '%Y-%m-%d %H:%M:%S'
    __qualname__ = "RTCDateTime fmt='{}'".format(READ_TIMESTAMP)

    def __init__(self, s):
        self.dt = datetime.strptime(s, self.RTC_DT_FMT)

    def __str__(self):
        return self.dt.strftime('%Y%m%d%H%M%S')


class Config:
    SETTINGS_FILENAME = make_path_here('../../settings.ini')
    DATALOG_PATH = make_path_here('../../data/')
    EXECUTION_LOG_PATH = make_path_here('../logs/')
    OUTGOING_FILENAME = make_path_here('../../data/outgoing.json')

    URL_API_POST_RAWSENSORDATA = '{base}api/post/rawsensordata/{bid}'
    SERIAL_CSV_SEP = ','

    def __init__(self):
        super().__init__()
        self.default = configparser.ConfigParser()
        self.default.read_string(DEFAULT_INI)
        try:
            self.load_settings()
        except Exception as e:
            print('\nConfigurationError:', e)


    def __getitem__(self, key):
        return self._parser._sections[key]


    def ask_restore_settings_file(self):
        a = input("\nRestore default file now and overwrite all"
                  "current values? [y/N] ")
        if 'y' in a.lowercase():
            try:
                with open(self.SETTINGS_FILENAME, 'w') as f:
                    f.write(DEFAULT_SETTINGS)
                print("Done! Restart the application!")
                sys.exit(0)
            except:
                print("Unable to write on file\n    {}\n\nTry to run this "
                      "program from another location!".format(
                          self.SETTINGS_FILENAME))
                sys.exit(1)


    def load_settings(self):
        '''
        Load the INI configuration file onto the self._parser attribute.
        '''
        self._parser = configparser.ConfigParser()
        try:
            self._parser.read(self.SETTINGS_FILENAME)
        except:
            print("Unable to open configuration file at\n    {}".format(
                  self.SETTINGS_FILENAME))

        pprint(self._parser._sections)

        self.validate_server_url()
        self.validate_reading_sensors()
        self.validate_reading_interval()
        self.validate_datalog_csv_sep()
        self.validate_arduino_serial_port()

        pprint(self._parser._sections)


    def validate_server_url(self):
        try:
            bid = int(self['server']['board_id'])
        except:
            raise Exception(
                "Invalid numeric value for the server/BOARD_ID key.\n"
                "Expected to be of type integer.\n"
                "Was given:\n   {}".format(self['server']['board_id']))

        self['server']['api_post_url'] = self.URL_API_POST_RAWSENSORDATA\
            .format(base=self['server']['url'] +
                        ('' if self['server']['url'].endswith('/') else '/'),
                    bid=bid)

    def validate_reading_sensors(self):
        self['reading']['sensors'] = [x.strip() for x in
            self['reading']['sensors'].split(',') if x.strip() != '']

        if len(self['reading']['sensors']) == 0:
            raise Exception(
                    "At least one sensor must be present on the reading/"
                    "SENSORS key.")

        if 'true' in self['reading']['rtc_ds1307'].lower():
            self['reading']['sensors'].append(RTCDateTime.SENSOR_NAME)

        self['reading']['command'] = 'readSensors,' + ','.join(
            self['reading']['sensors'])


    def validate_reading_interval(self):
        try:
            numbers = self['reading']['interval'].split(':')
            if len(numbers) != 3: raise Exception
            self['reading']['interval'] = {k: int(v) for k, v in
                zip(['H', 'M', 'S'], numbers)}
            self['reading']['interval_seconds'] =\
                3600 * self['reading']['interval']['H'] + \
                  60 * self['reading']['interval']['M'] + \
                       self['reading']['interval']['S']
        except:
            raise Exception(
                "Invalid time value for the reading/INTERVAL key.\n"
                "Expected format:\n"
                "    hours:minutes:seconds  (integer numbers)\n"
                "Was given:\n    {}".format(self['reading']['interval']))


    def validate_datalog_csv_sep(self):
        value = self['datalog']['csv_sep']
        self['datalog']['csv_sep'] = bytes(value, 'utf8').decode(
                                           'unicode_escape')
        if not value in (',', ';', r'\t'):
            raise Exception(
                "Invalid character value for the datalog/CSV_SEP key.\n"
                "Supported values:\n    ','   ';'   '\\t'\n"
                "Was given:\n    {}".format(value))

    def validate_arduino_serial_port(self):

        self['arduino']['serial_port'] = [x.strip() for x in
            self['arduino']['serial_port'].split(',') if x.strip() != '']

        if len(self['arduino']['serial_port']) == 0:
            self['arduino']['serial_port'] = []

            for i in range(5):
                self['arduino']['serial_port'].append('/dev/ttyACM{}'.format(i))
                self['arduino']['serial_port'].append('/dev/ttyUSB{}'.format(i))