import numpy as np
import sounddevice as sd
import time
from collections import defaultdict

# Set this to your sound card as appropriate
sd.default.device = "Focusrite USB ASIO"
 
sample_rates=[44100,48000]
wave_tables = defaultdict(dict)

def generate_wavetables():
    """
    Generate a series of 32bit floating point sine waves
    with a fade in and fade out to avoid pops and clicks
    40% of full scale, which translates to ~ -15dB on meter reading
    <function truncated for brevity>
    :return:
    """
    duration = 2
    volume = 0.4  # 0.4 Should give ~ -15dB reading at zero gain
    
    for sample_rate in sample_rates:
        fade_time = int(sample_rate / 10)
        fade_in = np.arange(0., 1., 1 / fade_time)
        fade_out = np.arange(1., 0., -1 / fade_time)

        sine_wave = (volume * np.sin(2 * np.pi * np.arange(sample_rate * duration) * 997 / sample_rate)).astype(
            np.float32)
        sine_wave[:fade_time] = np.multiply(sine_wave[:fade_time], fade_in)
        sine_wave[-fade_time:] = np.multiply(sine_wave[-fade_time:], fade_out)

        wave_tables[sample_rate][997] = sine_wave

def play_and_get_level(sample_rate=44100, freq=997, channels=2, inputs=2, check_locked=False):    
    sd.default.channels = 1
    sd.default.latency = 'low'    
    out_channels = np.linspace(1, channels, channels, dtype=int)    
    note = wave_tables[sample_rate][freq]
    
    print("About to play a sound of {}Hz at sample rate {}Hz".format(freq, sample_rate))    
    try:        
        sd.play(note, mapping=out_channels, blocking = True)        
    except Exception as e:
        print ("bang {}".format(e))        
        return None
    
    print ("Getting levels")
    # this is where subprocess would launch external exe
    #readings = get_levels(1, inputs)
    readings = [-20,-20]    
    return readings

generate_wavetables()

for i in range(100):
    levels = play_and_get_level()
    if levels is not None:
        for level in levels:
            print ("Loop {} {}".format(i, level))