# binaural_beta.py

# binaural_beta.py ZZZ this code needs to be verified

'''
Please Note: Binaural beats in the beta pattern are at a frequency of 13 to 30 Hz. This frequency range may help promote concentration and alertness. However, it can also very much increase anxiety when you are in need of rest.
'''

from struct import pack
import math
import wave
import random
import sys
import array

dir='C://py//audio//'

# very basic choice of parameters
channels = 2

hertz = 30 # beta pattern

volume = 100 # percent

def makeSineWaveFile(freq=100, duration=60, bitrate=44100): # took 10 seconds to process 1 minute in length
    freq = int(freq)
    duration = int(duration)
    bitrate = int(bitrate)

    vol=max(0,volume-1)*0.01*32767
    # channel 1 frequency
    freq1=freq-10
    # channel 2 frequency
    freq2=freq
    # duration: 3600 seconds = 1 hour (60 seconds x 60 minutes)
    # freq = 100 # of cycles per second (Hz) (frequency of the sine waves)
    data = array.array('h') # signed short integer (-32768 to 32767) data
    # bitrate = 44100 # of samples per second (standard)
    numChan = 2 # of channels (1: mono, 2: stereo)
    dataSize = 2 # 2 bytes because of using signed short integers => bit depth = 16
    numSamples = (bitrate * duration)
    for i in range(numSamples):
        for hz in (freq1,freq2):
            bit = int((math.sin((hz*i*1.0)/bitrate*2*math.pi)*vol))
            data.append(bit)
    f = wave.open(dir+'wav_binural_stereo.wav', 'w') # .mp3 or .wav
    f.setparams((numChan, dataSize, bitrate, numSamples, "NONE", "Uncompressed"))
    f.writeframes(data.tostring())
    f.close()

makeSineWaveFile(hertz)