import configparser
import math
import smtplib
import time
from datetime import datetime
from email.mime.text import MIMEText

import requests
from microstacknode.hardware.accelerometer.mma8452q import MMA8452Q


EMAIL_USERNAME = 'noreply@ianonavy.com'
EMAIL_PASSWORD = 'S2PENjQbO6=cHgchw@CXs.bJ'
RECIPIENT_EMAILS = ['ianonavy@gmail.com']
ALERT_EMAIL_TEXT = """Hi,

Your laundry is done. Or maybe your roomate's. I don't know.

Regretfully,
Ianonavy Bot
"""
G_RANGE = 2
INTERVAL = 0.005  # seconds
WINDOW_SIZE = 400  # intervals
THRESHOLD = 0.025  # G's
MAX_NOTIFICATION_FREQUENCY = 60  # seconds
CONFIG_FILE_PATH = '/home/pi/laundry-notifier/laundry_notifier/laundry_notifier.conf'


def average(s):
    return sum(s) * 1.0 / len(s)


def stdev(s):
    if not s:
        return 0
    avg = average(list(s))
    variance = map(lambda x: (x - avg) ** 2, s)
    return math.sqrt(average(list(variance)))


def notify_user(recipient_email_address):
    log("Alerting " + recipient_email_address)

    msg = MIMEText(ALERT_EMAIL_TEXT)

    # me == the sender's email address
    # you == the recipient's email address
    msg['Subject'] = 'Laundry Finished'
    msg['From'] = 'pi@localhost'
    msg['To'] = recipient_email_address

    # Send the message via our own SMTP server.
    username = EMAIL_USERNAME
    password = EMAIL_PASSWORD
    server = smtplib.SMTP('smtp.gmail.com:587')
    server.starttls()
    server.login(username, password)
    server.send_message(msg)
    server.quit()


def enqueue(sliding_window, item):
    if len(sliding_window) == WINDOW_SIZE:
        sliding_window.pop(0)
    sliding_window.append(item)


def amplitude_stdev(sliding_window):
    standard_deviations = {}
    for key in ('x', 'y', 'z'):
        values = [measurement[key] for measurement in sliding_window]
        standard_deviations[key] = stdev(values)
    return standard_deviations


def send_notifications(last_notification_sent_at, iftttkey):
    seconds_since_last_notification = \
        (datetime.now() - last_notification_sent_at).seconds
    # Log the time notifications were sent
    log("Sending notification after %ds" % seconds_since_last_notification)
    # limit frequency of notifications
    if seconds_since_last_notification > MAX_NOTIFICATION_FREQUENCY:
        [notify_user(email) for email in RECIPIENT_EMAILS]
        # Notify if this, then that
        requests.get(
            'https://maker.ifttt.com/trigger/laundry_done/with/key/%s'
            % iftttkey)
        return datetime.now()
    return last_notification_sent_at


def main():
    log('started laundry notifier')
    config = configparser.ConfigParser()
    config.read(CONFIG_FILE_PATH)
    iftttkey = config['notifications']['ifttt_key']
    with MMA8452Q() as accelerometer:
        # Configure accelerometer
        accelerometer.standby()
        accelerometer.set_g_range(G_RANGE)
        accelerometer.activate()

        # Settle
        time.sleep(INTERVAL)

        sliding_window = []
        dryer_state = 'off'
        last_notification_sent_at = datetime(1970, 1, 1, 0, 0, 0)

        while True:
            g_values = accelerometer.get_xyz()
            enqueue(sliding_window, g_values)
            sliding_stdev = amplitude_stdev(sliding_window)
            if g_values:
                if sliding_stdev['x'] < THRESHOLD:
                    # Notify recipients on state transitions from 'on' to 'off'
                    if dryer_state == 'on':
                        log('Dryer turned off; sliding stdev is %f' % sliding_stdev['x'])
                        last_notification_sent_at = send_notifications(
                            last_notification_sent_at,
                            iftttkey)
                    dryer_state = 'off'
                else:
                    # Log state transitions from 'off' to 'on'
                    if dryer_state == 'off':
                        log('Dryer turned on; sliding stdev is %f' % sliding_stdev['x'])
                    dryer_state = 'on'

            time.sleep(INTERVAL)


def log(message):
    print('%s\t%s' % (datetime.isoformat(datetime.now()), message))


if __name__ == '__main__':
    main()