"""Acoustic Echo Cancellation for wav files."""

import wave
import sys
from speexdsp import EchoCanceller


if len(sys.argv) < 4:
    print('Usage: {} near.wav far.wav out.wav'.format(sys.argv[0]))
    sys.exit(1)


frame_size = 256

near = wave.open(sys.argv[1], 'rb')
far = wave.open(sys.argv[2], 'rb')

if near.getnchannels() > 1 or far.getnchannels() > 1:
    print('Only support mono channel')
    sys.exit(2)

out = wave.open(sys.argv[3], 'wb')
out.setnchannels(near.getnchannels())
out.setsampwidth(near.getsampwidth())
out.setframerate(near.getframerate())


print('near - rate: {}, channels: {}, length: {}'.format(
        near.getframerate(),
        near.getnchannels(),
        near.getnframes() / near.getframerate()))
print('far - rate: {}, channels: {}'.format(far.getframerate(), far.getnchannels()))



echo_canceller = EchoCanceller.create(frame_size, 2048, near.getframerate())

in_data_len = frame_size
in_data_bytes = frame_size * 2
out_data_len = frame_size
out_data_bytes = frame_size * 2

while True:
    in_data = near.readframes(in_data_len)
    out_data = far.readframes(out_data_len)
    if len(in_data) != in_data_bytes or len(out_data) != out_data_bytes:
        break

    in_data = echo_canceller.process(in_data, out_data)

    out.writeframes(in_data)

near.close()
far.close()
out.close()
