#!/usr/bin/env python
# -*- coding: utf-8 -*-

__author__ = "Franek Łazarewicz-Muradyan"
__copyright__ = "Copyright 2021, Franek Łazarewicz-Muradyan"
__version__ = "0.1"
__status__ = "Beta"
__email__ = "uinarf@autistici.org"

"""
Program intended to be run as daemon reading from sensors and
writing to database.
"""
import signal
import psutil #optional

import sys, os, glob, re
from time import strftime, localtime, sleep
import subprocess
import importlib
import pigpio
import smbus
import configparser
import mysql.connector
from mysql.connector import errorcode
# below installed on my system with custom ebuild, available through pip
import pigpio_dht
# we'll use it for now:

#sys.path.append('..')

#LOCAL_DIR = os.path.dirname(os.path.realpath(__file__)) + "/"
__location__ = os.path.realpath(
        os.path.join(os.getcwd(), os.path.dirname(__file__)))
# here goes our settings file
settings_file = 'settings_config_parser.cfg'
settings_db = 'settings_server.cfg'

# setting up configparser
# so that paths work when script is run from different directory
settings = os.path.join(__location__, settings_file)
settings_db = os.path.join(__location__, settings_db)
cfg = configparser.ConfigParser(interpolation=None)
cfg_db = configparser.ConfigParser(interpolation=None)
cfg.read(settings)
cfg_db.read(settings_db)

class Sensor:
    def __init__(self):
        # read default database name
        try:
            self.dtb = cfg_db['mysql']['database']
        except KeyError:
            self.dtb = 'default.dtb'
        # here we'll defind the elusive NaN
        # needs to be None for database
        self.nan = None
        self.timestamp_format = cfg.get('various', 'timestamp_format')

    def create_connection(self):
        """
        Creates connection to database with credentials provided in
        config file.
        """
        self.conn = None
        try:
            self.conn = mysql.connector.connect(**cfg_db['mysql'])
        except mysql.connector.Error as e:
                if e.errno == errorcode.ER_ACCESS_DENIED_ERROR:
                    print("Something is wrong with your username and password.")
                else:
                    print(e)
        return self.conn

    def create_database(cursor):
        try:
            cursor.execute(
                f"CREATE DATABASE {self.dtb} DEFAULT CHARACTER SET 'utf-8'"
            )
        except mysql.connector.Error as e:
            print(f"Failed creating database: {e}")

    def create_table(self, t_name, dictionary):
        """
        Takes table name (w1, light etc) and data in shape of a dictionary
        and creates database table.
        """
        self.t_name = t_name
        self.data = dictionary
        self.cur = self.create_connection().cursor()
        try:
            self.cur.execute(f"USE {self.dtb}")
        except mysql.connector.Error as e:
            print(f"Database {dtb} does not exist.")
            create_database(self.cur)
            self.cur.execute(f"USE {self.dtb}")
        # Create db statement
        # Achtung: identifiers cannot start with digits!!!
        # Achtung: identifiers cannot contain special characters (-_-)!!!
        # This: row name + data type
        rows_tp= ['timestamp timestamp']
        # This: row name
        self.rows = ['timestamp']
        for i in self.data.keys():
            # skip timestamp
            if i != 'timestamp':
                # digit cannot go first
                if i[0].isdigit():
                    i = 'sens'+i
                # strip of special characters excluding ',' and ' '
                # and remove ', ' at the end
                i  = re.sub('[^A-Za-z0-9, ]+', '', i)
                # all the sensor data is float, ok?
                rows_tp.append(i + ' float')
                self.rows.append(i)
        rows_tp = (', ').join(rows_tp)
        self.rows = (', ').join(self.rows)
        stmt = (
                f"CREATE TABLE IF NOT EXISTS {self.t_name} ("
                f"{rows_tp}"
                ")"
        )
        try:
            self.cur.execute(stmt)
        except mysql.connector.Error as e:
            print(e)

    def db_write(self, t_name, dictionary):
        """
        Write dictionary containing timestamp and sensor values into
        a table in a database.
        """
        self.data = dictionary
        self.cur = self.create_connection().cursor()
        #cur = conn.cursor()
        self.create_table(t_name, dictionary)

        vals = [*self.data.values()]
        # placeholder length
        pl_hd = ('%s,'*len(self.data))[:-1]
        sql = (
            f"INSERT INTO {self.t_name} ("
            f"{self.rows})"
            "VALUES ("
            f"{pl_hd}"
            ")"
        )
        try:
            #cur.execute(sql, vals)
            self.cur.execute(sql, vals)
        except mysql.connector.Error as e:
            print(e)
        self.conn.commit()
        self.cur.close()
        self.conn.close()


    def write(self, data, log_file):
        """
        Takes data in form of dictionary and writes to a log file.
        Data in dictionary takes form of sensor name : value pairs.
        In case of sensors returning multiple values each sensor name
        is followed by data type (i.e. 'tsl_0-infrared').
        """
        # Since I'm replacing it with db_write it has been abandoned,
        # variables passed from dictionary need stringification (sic!)
        # employed one hasn't been checked.
        # leaving it here, may get used as a fallback option.
        self.data = data
        self.log_file = log_file
        while True:
            with open(self.log_file, 'a') as f:
                [_data.extend(str(x)) for x in self.data.items()]
                data = ' '.join(_data)
                f.write(f'{data}\n')
                break

class Temperature(Sensor):
    """
    Dealing with 1 wire temperature sensors.
    """
    w1_path = '/sys/bus/w1/devices'
    the_line = w1_path + '/28-*/w1_slave'
    sens_files = glob.glob(the_line)

    def __init__(self):
        """
        Check if w1_gpio and w1_therm kernel modules are loaded.
        """
        # implement writing warnings and such into a log file
        super().__init__()
        cmd = ['lsmod']
        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        output, error = proc.communicate()
        if 'w1_gpio' in output.decode():
            pass
        else:
            print('Module w1-gpio not found.')
            # write that to a log file
        if 'w1_therm' in output.decode():
            pass
        else:
            print('Module w1-therm not found.')
            # write that to a log file

    def check_w1(self):
        """
        Checks consistency of w1 sensor mapping. Need to have access to the
        database already
        """
        conn = self.create_connection()
        cur = conn.cursor()
        try:
            dtb = cfg_db['mysql']['database']
        except KeyError:
            print("You have not defined database. Check your settings file.")
            sys.exit()
        cur.execute(f"USE {dtb};")
        sql = (
            "SELECT * FROM temperature;"
        )
        cur.execute(sql)
        # checking actual number of w1 sensors detected:
        act_sens_list = []
        [[act_sens_list.append(i) for i in x if i.__contains__('28-')] \
            for z, x, y in os.walk(self.w1_path)]
        # checking number of sensors in database:
        db_sens_list = [i[0] for i in cur.description][1:]
        # checking for no mapping defined in config file:
        if len(cfg['w1_mapping']) == 0:
            print("Info: you have no mapping for w1 temperature sensors "
                "defined, assigning default mapping. You can reassing them "
                "in settings file."
            )
            map_list = ['Inside ground', 'Inside', 'Outside ground', 'Outside']
            cfg['w1_mapping'] = dict(zip(db_sens_list , map_list))
            with open(settings_file, 'w') as f:
                cfg.write(f)
        elif len(cfg['w1_mapping']) != 0 and len(db_sens_list) > len(act_sens_list):
            print("Warning: Number of w1 temperature sensors detected is "
                f"({len(act_sens_list)}), smaller than number of sensors in "
                f"the database ({len(db_sens_list)}). "
                "Perhaps a sensor has detached/malfunctioned?"
            )
            sys.exit()
        elif len(db_sens_list) < len(act_sens_list):
            print("Warning: number of w1 temperature sensors detected is "
                "greater than that in a database."
            )
            sys.exit()

    def read(self):
        """
        Returns dictionary of available sensor names as keys and readings in
        Celcius as values.
        """

        sens_list = ['timestamp']
        [[sens_list.append(i) for i in x if i.__contains__('28-')] \
                for z, x, y in os.walk(self.w1_path)]
        temp_list = [strftime(self.timestamp_format, localtime())]
        for i in self.sens_files:
            with open(i, 'r') as f:
                tries=0
                _crc = f.readline()[-4:-1]
                if _crc !='YES':
                    reading = self.nan
                else:
                    reading = f.readline().split('t=')[1]
                try:
                    temp = str(round(float(reading)/1000, 1))
                except ValueError:
                    temp = self.nan
                temp_list.append(temp)

# morphing into a dict so that we knew which sensor is which
        temp_dict = dict(zip(sens_list, temp_list))
        return temp_dict

class Humidity(Sensor):
    """
    This part deals with a DHT11 temperature and humidity sensor.
    Using pigpio-dht module so not much to do here
    """
    def __init__(self):
        super().__init__()
        self.pin = cfg.getint('hardware_settings','dht_pin_1')
        self.dht = pigpio_dht.DHT11(self.pin)

    def read(self, n=0):
        """
        Reading from dht11 sensor, tries to read 10x on bad read then passes.
        """
        n=0
        now = strftime(self.timestamp_format, localtime())
        reading = {'timestamp': now}
        try:
            reading.update(self.dht.read())
        except TimeoutError:
                reading.update({'temp_c': self.nan, 'humidity': self.nan})
                return reading
        while True:
            if reading['valid'] == True:
                del reading['temp_f']
                del reading['valid']
                for i in list(reading):
                    reading[i] = str(reading[i])
                return reading
                break
            if reading['valid'] == False and n >=3:
                del reading['temp_f']
                del reading['valid']
                reading.update({'temp_c': self.nan, 'humidity': self.nan})
                return reading
                break
            else:
                n+=1
                sleep(0.17)

class Light(Sensor):
    """
    This part deals with tsl2561 sensor using smbus.
    """
    # at the moment I find changing gain and exposure time to not be reliable
    # and/or usefull. May try to reimplement it at a later date.
    _SMBUSADDR = 1

    tsls = [
        ('_TSLADDR', 0x39), # default
        ('_TSLADDR_LOW', 0x29),
        ('_TSLADDR_HIGH', 0x49)
    ]

    # controls
    # this first is for on/of only
    _REG_CONTR = 0x00
    # this is for any other commands we'll use here
    _CONTR = 0x01
    # command option
    _CMD = 0x80

    # max reading a channel can hold
    # on exposure 402ms:
    max_read = 65535
    # on exposure 100ms:
    max_read_1 = 37177
    # on exposure 13.7ms:
    max_read_2 = 5047

    # commands
    _ON = 0x03
    _OF = 0x00
    # set gain
    _CMD_GN = 0x81

    # registers
    _regs = {
        '_CH_0' : 0xAC, # visible + infra red
        '_CH_1' : 0xAE # infra red
    }
    # gain and exposure
    _gain = [
        ('_GN_VLOW', 0x00), # gain 1x, exposure : 13.7ms
        ('_GN_LOW', 0x01), # gain 1x, exposure : 100ms
        ('_GN_DEF', 0x02), # gain 1x, exposure : 402ms
        ('_GN_HI', 0x10),  # gain 16x, exposure : 13.7ms
        ('_GN_VHI', 0x11), # gain 16x, exposure : 100ms
        ('_GN_UHI', 0x12) # gain 16x, exposure : 402ms
    ]

    def __init__(self, tsl):
        super().__init__()
        self.tsl = tsl
        if self.tsl > 2:
            print('We can only adress 3 TSL2561 sensors on this bus, aborting')
            sys.exit()
        # since default gain is always _gain[2][1]
        self.n = 2
        # initiate bus
        self.bus = smbus.SMBus(self._SMBUSADDR)
        # turn on sensor
        self.tsl_addr = self.tsls[self.tsl][1]
        self.bus.write_byte_data(self.tsl_addr, self._REG_CONTR | self._CMD, self._ON)

    def setGain(self, gain):
        """
        To be used from within read function.
        """
        self.gain = gain
        self.bus.write_byte_data(self.tsl_addr, self._CMD_GN | self._CMD, gain)

    def read(self, idx=0):
        # Upon testing sensor I've come to the conclusion that all that
        # setting gain and timing gives me nothing, sensor reports limits
        # on those instead.
        self.idx = idx
        _vals = []
        _iter = 0
        for i in self._regs.keys():
            _vals.append(self.bus.read_word_data(self.tsl_addr, self._regs.get(i)))
        #for i in _vals:
        #    if self.safe_read < i < max_read:
        #        pass
        #    elif i >= max_read and self.idx < 3:
        #        idx+=1
        #        # if excessive reading decrease gain/exposure
        #        self.n -=1
        #        try:
        #            gain = self._gain[self.n][1]
        #            self.setGain(gain) # increment gain position by one
        #            self.read(self.idx)
        #        except IndexError:
        #            _vals = [self.nan, self.nan]
        #    elif 0 <= i <= self.safe_read:
        #        # attempt to increase gain/exposure to optimal
        #        idx+=1
        #        if idx >= 3:
        #            pass
        #        else:
        #            try:
        #                self.n +=1
        #                gain = self._gain[self.n][1]
        #                self.setGain(gain)
        #                self.read(self.idx)
        #            except IndexError:
        #                pass
        #    else:
        #        _vals = ['Nan', 'Nan']
        lux = self.calculate_lux(_vals)
        now = strftime(self.timestamp_format, localtime())
        reading = {
            'timestamp': now,
            f'tsl_{self.tsl}-Broadband': _vals[0],
            f'tsl_{self.tsl}-Infrared': _vals[1],
            f'tsl_{self.tsl}-Lux': lux
        }
        return reading

    def calculate_lux(self, _vals):
        """
        Calculate lux from tuple 'visible+infrared'/'infrared' as returned
        by read() function. From datasheet for FN package sensor version.
        """
        ch0, ch1 = _vals
        if ch0 == 0:
            lux = 0
        elif ch0 == self.nan or ch1 == self.nan:
            lux = self.nan
        # normally broadband maxes out before infrared which makes visible
        # drop which is clearly wrong hence:
        elif ch0 == self.max_read or ch1 == self.max_read:
            lux = self.nan
        else:
            ratio = ch1/ch0
            if 0 < ratio <= 0.52:
                lux = 0.0304 * ch0 - 0.062 * ch0 * (ratio ** 1.4)
            elif 0.5 < ratio <= 0.61:
                lux = 0.0224 * ch0 - 0.031 * ch1
            elif 0.61 < ratio <= 0.8:
                lux = 0.0128 * ch0 - 0.0153 * ch1
            elif 0.8 < ratio <= 1.3:
                lux = 0.00146 * ch0 - 0.00112 * ch1
            else:
                lux = 0
            lux = round(lux, 4)
        return lux

class Rain(Sensor):

    def __init__(self):
        super().__init__()
        self.pin = cfg.getint('hardware_settings', 'rain_pin')
        self.pi = pigpio.pi()
        self.pi.set_pull_up_down(self.pin, pigpio.PUD_UP)
        self.rain = self.pi.callback(self.pin)
        self.bucket = cfg.getfloat('hardware_settings', 'bucket_size')

    def read(self):
        """
        Read and return rain data.
        """
        amount = str(round(self.rain.tally() * self.bucket, 4))
        now = strftime(self.timestamp_format, localtime())
        data = {
                'timestamp': now,
                'amount' : amount
        }
        self.rain.reset_tally()

        return data

#    GPIO.add_event_detect(self.pin, GPIO.FALLING, callback=self.read(),
#    bouncetime=300)


if __name__ == '__main__':
    fq = cfg.getint('hardware_settings', 'read_frequency')
    print("Instantiating gpio connection")
    dht = Humidity()
    tmp = Temperature()
    tsl = Light(0)
#    tsl_sensors = []
#       tsl_no = cfg.getint('hardware_settings', 'tsl2561_number')
#    for i in range(tsl_no):
#        tsl_sensors.append(Light(i))
    rain = Rain()
    while True:
        #if not pi.connected:
        #    try:
        #        print('Attempting to reconnect to pigpiod ...')
        #        pi = pigpio.pi()
        #    except:
        #        print("Pigpio couldn't connect to pi on port 8888")
        #        exit()
        #else:
        #    pass
        tmp.check_w1()
        tmp.db_write('temperature', tmp.read())
        dht.db_write('humidity', dht.read())
        tsl.db_write('light', tsl.read())
        rain.db_write('rain', rain.read())
        #for i in tsl_sensors:
        #    i.log = f'{log_files[light_log]}_{i}'
        #    i.write(i.read(), i.log)
        #pi.stop()
        sleep(fq)

    sys.exit()