import pyaudio
import wave
import audioop
from collections import deque
import os
import urllib2
import urllib
import time


def handleText(text):
    print text;


def listen_for_speech():

    chunk = 1024
    FORMAT = pyaudio.paInt16
    CHANNELS = 1
    RATE = 16000
    THRESHOLD = 180 #The threshold intensity that defines silence signal (lower than).
    SILENCE_LIMIT = 2 #Silence limit in seconds. The max ammount of seconds where only silence is recorded. When this time passes the recording finishes and the file is delivered.

    #open stream
    p = pyaudio.PyAudio()

    stream = p.open(format = FORMAT,
        channels = CHANNELS,
        rate = RATE,
        input = True,
        frames_per_buffer = chunk)

    print "* listening. CTRL+C to finish."
    all_m = []
    data = ''
    SILENCE_LIMIT = 2
    rel = RATE/chunk
    slid_win = deque(maxlen=SILENCE_LIMIT*rel)
    started = False

    while (True):
        data = stream.read(chunk)
        slid_win.append (abs(audioop.avg(data, 2)))

        if(True in [ x>THRESHOLD for x in slid_win]):
            if(not started):
                print "starting record"
            started = True
            all_m.append(data)
        elif (started==True):
            print "finished"
            #the limit was reached, finish capture and deliver
            filename = save_speech(all_m,p)
            handleText(stt_google_wav(filename))
            #reset all
            started = False
            slid_win = deque(maxlen=SILENCE_LIMIT*rel)
            all_m= []
            print "listening ..."

    print "* done recording"
    stream.close()
    p.terminate()


def save_speech(data, p):
    filename = 'output_'+str(int(time.time()))
    # write data to WAVE file
    data = ''.join(data)
    wf = wave.open(filename+'.wav', 'wb')
    wf.setnchannels(1)
    wf.setsampwidth(p.get_sample_size(pyaudio.paInt16))
    wf.setframerate(16000)
    wf.writeframes(data)
    wf.close()
    return filename


def stt_google_wav(filename):
    #Convert to flac
    os.system('ffmpeg -loglevel panic -i ' + filename + '.wav -ab 192k -y ' + filename + '.flac')
    f = open(filename+'.flac','rb')
    flac_cont = f.read()
    f.close()
    #post it
    lang_code='en-US'
    googl_speech_url = 'https://www.google.com/speech-api/v1/recognize?xjerr=1&client=chromium&pfilter=2&lang=%s&maxresults=6'%(lang_code)
    hrs = {"User-Agent": "Mozilla/5.0 (X11; Linux i686) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.63 Safari/535.7",'Content-type': 'audio/x-flac; rate=16000'}
    req = urllib2.Request(googl_speech_url, data=flac_cont, headers=hrs)
    p = urllib2.urlopen(req)

    res = eval(p.read())['hypotheses']
    map(os.remove, (filename+'.flac', filename+'.wav'))
    return res

if(__name__ == '__main__'):
    listen_for_speech()