"""Support utilities for COMP28512.

Place this in the same directory you use for COMP28512 notebooks.

Import it with:
>>> from comp28512_utils import Audio

Use as:
>>> Audio(data, sampling_rate, filename)
To save the given data as a wav file and then load it
into the notebook.

(C) University of Manchester 2015
Author: Andrew Mundy
"""
from __future__ import print_function

import base64
from IPython import display
import numpy as np
from scipy.io import wavfile


def Audio(data, rate, filename=None):
    """Save data to a file then play."""
    # Get a filename
    if filename is None:
        filename = "{:x}.wav".format(id(data))

    # Check the data type
    if data.dtype.kind == 'f':
        # Data is floating point, assume that we can scale to 16 bits and save
        data = np.int16(data * 2**15)

    # Write the data
    wavfile.write(filename, rate, data)
    print("Data written to {}.".format(filename))

    # Read the data back in
    return audio_from_file(filename)


def get_audio_from_file(filename):
    with open(filename, 'rb') as f:
        return "data:audio/wav;base64," + base64.encodestring(f.read())


def audio_from_file(filename):
    """Play the data from a file"""
    # Return an HTML audio object with base64 encoded audio data included.
    # If file:// could return correct MIMEtypes this would be much nicer.
    with open(filename, 'rb') as f:
        return display.HTML(
            "<p><audio controls=\"controls\">"
            "<source src=\"{}\" type=\"audio/wav\" />"
            "Your browser does not support the AUDIO element. "
            "Open the relevant file to listen."
            "</audio></p>".format(get_audio_from_file(filename)))