#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2018/12/12 04:44:09 +0900>
"""
Split wav file by 32 samples.
use Pydub.

【Python/pydub】mp3、wavファイルから部分抽出（切り分け、分割） | アルゴリズム雑記
https://algorithm.joho.info/programming/python/pydub-split/

【Python/pydub】mp3、wavのデータをNumPy配列に変換 | アルゴリズム雑記
https://algorithm.joho.info/programming/python/pydub-numpy/

Windows10 x64 + Python 2.7.15 32bit + Pydub 0.23.0 + Numpy 1.15.4
"""

import argparse
import sys
from pydub import AudioSegment
import numpy as np


def dump_table(dt):
    print("pcmtbl={")
    for src in dt:
        d = (src * 0x0f).astype("int16")
        if d.min() < 0 or d.max() > 15:
            print("Error : min(), max() = %f,%f" % (d.min(), d.max()))
            sys.exit()
        s = " {"
        for i in range(0, 32, 2):
            v = ((d[i + 1] & 0x0f) << 4) | (d[i + 0] & 0x0f)
            if i < 30:
                s += "0x%02x," % v
            else:
                s += "0x%02x" % v
        s += "},"
        print(s)
    print("}")


def dump_string(dt):
    print("pcmtbl={")
    for src in dt:
        d = (src * 0x0f).astype("int16")
        if d.min() < 0 or d.max() > 15:
            print("Error : min(), max() = %f,%f" % (d.min(), d.max()))
            sys.exit()
        s = ' "'
        for i in range(0, 32, 2):
            v = ((d[i + 1] & 0x0f) << 4) | (d[i + 0] & 0x0f)
            s += "%02x" % v
        s += '",'
        print(s)
    print("}")


def main():
    """Main."""
    parser = argparse.ArgumentParser()
    parser.add_argument('arg1', metavar='WAVFILE', help='Input wav file')
    parser.add_argument('--table', action='store_true', help='table output')
    args = parser.parse_args()

    infile = args.arg1
    sound = AudioSegment.from_wav(infile)  # read wave file
    data = np.array(sound.get_array_of_samples())
    src = data[::sound.channels]  # get mono channel

    # normlize
    src = (src - src.min()).astype(float) / (src.max() - src.min()).astype(float)

    rate = sound.frame_rate
    sample_len = len(src)

    print("-- Input file : %s" % infile)
    print("-- Channel : %d" % sound.channels)
    print("-- Sampling rate : %d Hz" % rate)
    print("-- Duration : %f msec" % len(sound))
    print("-- Sample length : %d point" % sample_len)

    # divide
    dt = []
    src_len = len(src)
    idx = 0
    while True:
        d = np.array([0.5] * 32)
        for i in range(32):
            if idx + i < src_len:
                d[i] = src[idx + i]
        dt.append(d)
        idx += 32
        if idx >= src_len:
            break

    print("-- N : %d" % len(dt))

    if args.table:
        dump_table(dt)
    else:
        dump_string(dt)


if __name__ == "__main__":
    main()