# -*- coding: utf-8 -*-
"""
Created on Wed Jun 26 15:54:05 2019

@author: chkarada
"""
import os

import numpy as np
import soundfile as sf


# Function to read audio
def audioread(path, norm=True, start=0, stop=None):
    path = os.path.abspath(path)
    if not os.path.exists(path):
        raise ValueError("[{}] does not exist!".format(path))
    try:
        x, sr = sf.read(path, start=start, stop=stop)
    except RuntimeError:  # fix for sph pcm-embedded shortened v2
        print("WARNING: Audio type not supported")

    if len(x.shape) == 1:  # mono
        if norm:
            rms = (x**2).mean() ** 0.5
            scalar = 10 ** (-25 / 20) / (rms)
            x = x * scalar
        return x, sr
    else:  # multi-channel
        x = x.T
        x = x.sum(axis=0) / x.shape[0]
        if norm:
            rms = (x**2).mean() ** 0.5
            scalar = 10 ** (-25 / 20) / (rms)
            x = x * scalar
        return x, sr


# Funtion to write audio
def audiowrite(data, fs, destpath, norm=False):
    if norm:
        eps = 0.0
        rms = (data**2).mean() ** 0.5
        scalar = 10 ** (-25 / 10) / (rms + eps)
        data = data * scalar
        if max(abs(data)) >= 1:
            data = data / max(abs(data), eps)

    destpath = os.path.abspath(destpath)
    destdir = os.path.dirname(destpath)

    if not os.path.exists(destdir):
        os.makedirs(destdir)

    sf.write(destpath, data, fs)
    return


# Function to mix clean speech and noise at various SNR levels
def snr_mixer(clean, noise, snr):
    # Normalizing to -25 dB FS
    rmsclean = (clean**2).mean() ** 0.5
    scalarclean = 10 ** (-25 / 20) / rmsclean
    clean = clean * scalarclean
    rmsclean = (clean**2).mean() ** 0.5

    rmsnoise = (noise**2).mean() ** 0.5
    scalarnoise = 10 ** (-25 / 20) / rmsnoise
    noise = noise * scalarnoise
    rmsnoise = (noise**2).mean() ** 0.5

    # Set the noise level for a given SNR
    noisescalar = np.sqrt(rmsclean / (10 ** (snr / 20)) / rmsnoise)
    noisenewlevel = noise * noisescalar
    noisyspeech = clean + noisenewlevel
    return clean, noisenewlevel, noisyspeech