#!/usr/bin/python
# Author: Zion Orent <zorent@ics.com>
# Copyright (c) 2015 Intel Corporation.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

from __future__ import print_function
import time, sys, signal, atexit

# Load alcohol sensor module
from upm import pyupm_mq303a as upmMq303a

def main():
    # Instantiate an mq303a sensor on analog pin A0
    # This device uses a heater powered from an analog I/O pin.
    # If using A0 as the data pin, then you need to use A1, as the heater
    # pin (if using a grove mq303a).  For A1, we can use the D15 gpio,
    # setup as an output, and drive it low to power the heater.
    myAlcoholSensor = upmMq303a.MQ303A(0, 15)

    ## Exit handlers ##
    # This function stops python from printing a stacktrace when you hit control-C
    def SIGINTHandler(signum, frame):
        raise SystemExit

    # This function lets you run code on exit, including functions from myAlcoholSensor
    def exitHandler():
        print("Exiting")
        sys.exit(0)

    # Register exit handlers
    atexit.register(exitHandler)
    signal.signal(signal.SIGINT, SIGINTHandler)

    print("Enabling heater and waiting 2 minutes for warmup.")

    # give time updates every 30 seconds until 2 minutes have passed
    # for the alcohol sensor to warm up
    def warmup(iteration):
        totalSeconds = (30 * iteration)
        time.sleep(30)
        print(totalSeconds, "seconds have passed")
    warmup(1)
    warmup(2)
    warmup(3)
    warmup(4)

    notice = ("This sensor may need to warm "
    "until the value drops below about 450.")
    print(notice)

    # Print the detected alcohol value every second
    while(1):
        val = myAlcoholSensor.value()
        msg = "Alcohol detected "
        msg += "(higher means stronger alcohol): "
        print(msg + str(val))
        time.sleep(1)

if __name__ == '__main__':
    main()
