"""
Micropython module reading data from onewire sensor,
connecting to wifi and sending temperature data to MQTT server.
"""

import ssl
import time
from math import isnan

from ubinascii import hexlify
from ds18x20 import DS18X20
from onewire import OneWire
import rp2
from machine import Pin, PWM, reset, RTC
from network import WLAN, STA_IF

import utime
import usocket
import ustruct

from PID import PID
from umqttsimple import MQTTClient

# Import settings from config.py:
from config import *

# That led is different for different MicroPython versions:
led = Pin("LED", Pin.OUT)

# Blinking communication:

# 1 slow sequence of one: on initializatio
# 2 fast sequences of two: no wifi or ntptime.settime() failed
# 3 fast sequences of two: no mqtt
# 2 fast sequences of three: no certificate files


def blink(n=1, interval=0.5, repeat=0):
    """
    Blink to communicate failures.
    :param n: number of flashes
    :param interval: time interval between flashes
    :param repeat: how many times to repeat sequence
    :return: int
    """
    retval = 1
    r = 0
    try:
        while repeat >= r:
            for i in range(n):
                led.on()
                time.sleep(interval)
                led.off()
                time.sleep(interval)
            r += 1
            time.sleep(1)
        retval = 0
    except:
        pass
    return retval


def create_wifi():
    """
    Create wireless connection. Takes SSID and password from global variables atm.
    :return: wlan object, return value, connection state
    """
    wlan_retval = 1
    wlan = WLAN(STA_IF)
    wlan.active(True)
    rp2.country(COUNTRY)
    try:  # FIXME: this often raises EPERM, find out if it's code or buggy wifi repeater
        wlan.connect(WLAN_NAME, WLAN_PWD)
        time.sleep(0.5)
        wlan_retval = 0
    except Exception as exc:
        print("Failed to connect to wlan: ", exc)
    return wlan, wlan_retval, wlan.isconnected()


def _time():
    """
    Get time from NTP server.
    :return: current time
    """
    cur_time, sock = None, None
    counter = 0
    #  try 5 times to get time from NTP server:
    while counter < 5:
        try:
            NTP_QUERY = bytearray(48)
            NTP_QUERY[0] = 0x1B
            addr = (NTP_SERVER, 123)
            sock = usocket.socket(usocket.AF_INET, usocket.SOCK_DGRAM)
            sock.settimeout(10)  # was 1 second
            res = sock.sendto(NTP_QUERY, addr)
            msg = sock.recv(48)
            val = ustruct.unpack("!I", msg[40:44])[0]
            cur_time = val - NTP_OFFSET
            print("NTP time with offset is: ", cur_time)
            break
        except OSError as exc:
            if exc.args[0] == 110:  # ETIMEDOUT
                print("Timed out getting NTP time.")
                utime.sleep(2)
                counter += 1
                continue
            print("Error from _time(): ", exc)
            counter = 5
        except Exception as exc:
            print("Getting time failed: ", exc)
            counter = 5
        finally:
            if sock:
                sock.close()
    if counter == 5:
        print("Resetting board!!!")
        reset()
    return cur_time


def set_time():
    """
    Set time.
    :return: int
    """
    print("Calling ntptime.time() ...")
    retval = 1
    # t will never be less than zero on success:
    t = -1
    try:
        t = _time()
    except Exception as exc:
        print("Exception calling ntptime.time: ", exc)
    if t == -1:
        # Getting time from NTP failed, return early:
        print("Getting time failed, returning early from set_time()")
        return retval
    try:
        tm = utime.gmtime(t)
    except Exception as exc:
        print("Failed to set tm = utime.gmtime(t)", exc)
    try:
        RTC().datetime((tm[0], tm[1], tm[2], tm[6] + 1, tm[3], tm[4], tm[5], 0))
        retval = 0
    except Exception as exc:
        print("Failed to RTC().datetime ... : ", exc)
    return retval


def connect_wifi(wlan):
    """
    Connect to wifi.
    :return: int
    """
    retcode = 1  # 1 for failure, 0 for success
    r = 0
    while not wlan.isconnected() and r < 3:
        try:
            wlan.connect()
            time.sleep(1)
            r += 1
        except:
            blink(3, 0.2)
            r += 1
    if wlan.isconnected():
        retcode = 0
    return retcode


def load_certs():
    """
    Load certificates from files
    :return: ssl parameters
    """
    try:
        with open(SSL_CERT_FILE, 'rb') as _file:
            SSL_CERT = _file.read()
    except Exception as exc:
        print(f"Reading {SSL_CERT_FILE} failed: {exc}")
        led.off()
    try:
        with open(SSL_KEY_FILE, 'rb') as _file:
            SSL_KEY = _file.read()
    except Exception as exc:
        print(f"Reading {SSL_KEY_FILE} failed: {exc}")
        led.off()
    try:
        with open(SSL_CADATA_FILE, 'rb') as _file:
            SSL_CADATA = _file.read()
    except Exception as exc:
        print(f"Reading {SSL_CADATA_FILE} failed: {exc}")
        led.off()
    ssl_params = {
        "key": SSL_KEY,
        "cert": SSL_CERT,
        "cadata": SSL_CADATA,
        "server_hostname": MQTT_SERVER,
        "server_side": False,
        "cert_reqs": ssl.CERT_REQUIRED,
        "do_handshake": True,
    }
    return ssl_params


def create_mqtt():
    """
    Instantiate MQTT client
    :return: mqtt client
    """
    mqtt_client = None
    try:
        ssl_params = load_certs()
    except Exception as exc:
        print("failed to create mqtt client: ", exc)
        blink(3, 0.3, 2)
        ssl_params = None
    if ssl_params:
        try:
            mqtt_client = MQTTClient(
                client_id=MQTT_CLIENT_ID,
                server=MQTT_SERVER_IP,
                port=MQTT_PORT,
                keepalive=60,
                ssl=True,
                ssl_params=ssl_params,
            )
        except:
            blink()
    return mqtt_client


def connect_mqtt(client):
    """
    Connect MQTT client.
    :return: int
    """
    retval = 1
    try:
        client.connect()
        retval = 0
    # reset to clear memory on OSError:
    except OSError as exc:
        print("OSError: ", exc)
        if exc == 'Exception in thread rx':
            pass
        print("OSError repr: ", repr(exc))
        print("OSError encountered, reseting ...")
        reset()
    except Exception as exc:
        print("Failed to connect to mqtt: ", exc)
        blink(2, 0.2, 3)
    return retval


def get_temperature():
    """
    Get temperatures and ids from one wire sensors.
    :return: (id: str, temperature: float)
    """
    sensor = DS18X20(OneWire(Pin(ONEWIRE_PIN)))
    sensor.convert_temp()
    roms = sensor.scan()
    _temperatures = None
    time.sleep(1)
    try:
        _temperatures = [(hexlify(_id).decode(), str(round(float(sensor.read_temp(_id)), 1))) for _id in roms]
    except Exception as exc:
        print("Failed to get temperatures: ", exc)
    return _temperatures


class Mosfet:
    """
    Mosfet class.
    """
    def __init__(self):
        self.mosfet_pin = Pin(MOSFET_PIN, Pin.OUT)
        self.mosfet = PWM(self.mosfet_pin)

    @staticmethod
    def pid_value(
            cur_temp
    ):
        """
        Calculate PID value.
        :param cur_temp: float
        :return: float
        """
        if isnan(cur_temp):
            retval = 0
        else:
            pid = PID(
                KP,
                KI,
                KD,
                setpoint=TARGET_TEMPERATURE,
                output_limits=(0, 65535),
                sample_time=SAMPLE_TIME,
            )
            retval = pid(cur_temp)
        return retval

    def set(
            self,
            value,
    ):
        """
        Set mosfet value.
        """
        if value not in range(0, 65535):
            print('Mosfet value not in range.')
        try:
            # Valid values in range 0-65535:
            self.mosfet.duty_u16(value)
        except Exception as exc:
            led.off()
            print(f"Setting mosfet value failed: {exc}")
            raise


WLAN_UNINITIALISED = CLIENT_UNINITIALISED = WLAN_RETVAL = TIME_RETVAL = MQTT_RETVAL = 1
temperatures, client, wlan = None, None, None
WLAN_CONNECTED = False
while True:
    # Create connection object only once:
    if WLAN_UNINITIALISED:
        print("Creating wlan... ")
        blink(1, 1, 1)
        wlan, WLAN_UNINITIALISED, WLAN_CONNECTED = create_wifi()
        if WLAN_CONNECTED:
            WLAN_RETVAL = 0
    if wlan and not WLAN_UNINITIALISED and not WLAN_CONNECTED:
        try:
            print("Connecting to wifi ...")
            WLAN_RETVAL = connect_wifi(wlan)
            print("WLAN_RETVAL: ", WLAN_RETVAL)
            print("Wlan connected: ", wlan.isconnected())
        except Exception as exc:
            print('Failed to connect to wifi: ', exc)
    if TIME_RETVAL and wlan.isconnected():
        print("Setting time: ...")
        TIME_RETVAL = set_time()
        print("TIME_RETVAL: ", TIME_RETVAL)
    if CLIENT_UNINITIALISED and not WLAN_RETVAL and not TIME_RETVAL:
        print("Creating client ...")
        try:
            client = create_mqtt()
            CLIENT_UNINITIALISED = 0
        except Exception as exc:
            print("Won't be any client: ", exc)
    if MQTT_RETVAL and not WLAN_RETVAL and not TIME_RETVAL and client:
        try:
            print("Connecting to mqtt broker ...")
            MQTT_RETVAL = connect_mqtt(client)
            print("MQTT_RETVAL: ", MQTT_RETVAL)
        except Exception as exc:
            print("Failed to connect to mqtt broker: ", exc)
        if MQTT_RETVAL:
            print("Failed to connect to mqtt broker: ", MQTT_RETVAL)
    try:
        temperatures = get_temperature()
        print("Temperatures: ", temperatures)
    except Exception as exc:
        print("Failed to get temperature(s): ", exc)
    if not WLAN_RETVAL and not MQTT_RETVAL and not TIME_RETVAL and temperatures:
        try:
            for _id, temp in temperatures:
                print(f"Publishing temperature: sensor id: {_id} - {temp} ...")
                client.publish(f'temperature/{_id}', temp)
                client.check_msg()
        except Exception as exc:
            print("Exception publishing: ", exc)
            blink(3, 0.2, 1)
    else:
        print(f"Failed to publish:\nWLAN_RETVAL: {WLAN_RETVAL}\nMQTT_RETVAL: {MQTT_RETVAL}\nTIME_RETVAL: {TIME_RETVAL}\n")
    print("Going to sleep for 10")
    time.sleep(10)
# ntptime.settime() kills the board. Check out solutions at:
# https://forum.micropython.org/viewtopic.php?f=20&t=10221&start=10
#     try:
#         pid_val = mft.pid_value(temp)
#         mft.set(pid_val)
#     except Exception as exc:
#         led.off()
#         print(f"Setting mosfet value failed: {exc}")
#         pass
#    time.sleep(10)