#!/usr/bin/env 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
from upm import pyupm_gas as upmGas

def main():
    # Attach gas sensor to AIO0
    myMQ9 = upmGas.MQ9(0)

    ## 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 myMQ9
    def exitHandler():
        print("Exiting")
        sys.exit(0)

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

    threshContext = upmGas.thresholdContext()
    threshContext.averageReading = 0
    threshContext.runningAverage = 0
    threshContext.averagedOver = 2

    # Infinite loop, ends when script is cancelled
    # Repeatedly, take a sample every 2 microseconds;
    # find the average of 128 samples; and
    # print a running graph of dots as averages
    mybuffer = upmGas.uint16Array(128)
    while(1):
        samplelen = myMQ9.getSampledWindow(2, 128, mybuffer)
        if samplelen:
            thresh = myMQ9.findThreshold(threshContext, 30, mybuffer, samplelen)
            myMQ9.printGraph(threshContext, 5)
            if(thresh):
                print("Threshold is ", thresh)

if __name__ == '__main__':
    main()
