import pyaudio
import numpy as np
import pygame
import multiprocessing as mp

CHUNK = 8192
FORMAT = pyaudio.paInt16
CHANNELS = 1
RATE = 48000
NP_FORMAT = np.int16
DELAY_LENGTH = 8


def delay_modification(data, buffer, index):
    start_index = index
    buffer_len = len(buffer)
    was_filled = buffer[buffer_len-1] != 0

    if was_filled:
        for i in range(len(data) - 1, -1, -1):
            start_index -= 1
            if start_index < 0:
                start_index = buffer_len - 1
            data[i] = data[i] // 2 + buffer[start_index] // 2

    for i in range(len(data)):
        if index == buffer_len:
            index = 0
            was_filled = True

        buffer[index] = data[i]
        index += 1

    return index

def feed_queue(q):

    buffer = np.zeros(CHUNK * DELAY_LENGTH)
    index = 0

    p = pyaudio.PyAudio()
    stream = p.open(format=FORMAT,
                    channels=CHANNELS,
                    rate=RATE,
                    input=True,
                    output=False,
                    frames_per_buffer=CHUNK)

    while True:
        data = stream.read(CHUNK, exception_on_overflow=False)
        data = np.fromstring(data, dtype=NP_FORMAT)

        index = delay_modification(data, buffer, index)
        if q.full():
            q.get_nowait()
        q.put(data)

def main():
    np.set_printoptions(threshold=np.nan)

    queue = mp.Queue(maxsize=RATE // CHUNK)
    p = mp.Process(target=feed_queue, args=(queue,))
    p.start()

    pygame.mixer.init()
    S = pygame.mixer.Sound

    while True:
        d = queue.get()
        S(d).play()


if __name__ == "__main__":
    main()