import subprocess
import typing

import numpy as np

import audeer
import audmath


MAX_CHANNELS = {
    'wav': 65535,
    'ogg': 255,
    'flac': 8,
}
r"""Maximum number of channels per format."""

SNDFORMATS = ['wav', 'flac', 'ogg']
r"""File formats handled by soundfile"""


def binary_missing_error(binary: str) -> Exception:
    r"""Missing binary error message.

    Args:
        binary: name of binary

    Returns:
        error message

    """
    return FileNotFoundError(
        f'{binary} cannot be found.\n'
        'Please make sure it is installed.\n'
        'For further instructions visit: '
        'https://audeering.github.io/audiofile/installation.html'
    )


def broken_file_error(file: str) -> Exception:
    r"""Broken file error message.

    If we encounter a broken file,
    we raise the same error for non SND files
    as soundfile does for SND files

    Args:
        file: file name

    Returns:
        error message

    """
    return RuntimeError(
        f'Error opening {file}: '
        'File contains data in an unknown format.'
    )


def duration_in_seconds(
        duration: typing.Union[float, int, str, np.timedelta64],
        sampling_rate: typing.Union[float, int],
) -> np.floating:
    r"""Duration in seconds.

    This mirrors the behavior of audmath.duration_in_seconds()
    but handles only string values without unit,
    e.g. ``'2000'`` as representing samples.

    """
    if isinstance(duration, str):
        duration = audmath.duration_in_seconds(duration, sampling_rate)
    else:
        duration = audmath.duration_in_seconds(duration)
    return duration


def file_extension(path):
    """Lower case file extension."""
    return audeer.file_extension(path).lower()


def run(shell_command):
    """Return the output of a shell command provided as string."""
    out = subprocess.check_output(
        shell_command,
        stderr=subprocess.STDOUT
    )
    try:
        return out.split()[0]
    except IndexError:
        return ''


def run_ffmpeg(infile, outfile, offset, duration):
    """Convert audio file to WAV file."""
    if duration:
        cmd = [
            'ffmpeg',
            '-ss', str(offset),
            '-i', infile,
            '-t', str(duration),
            outfile
        ]
    else:
        cmd = [
            'ffmpeg',
            '-ss', str(offset),
            '-i', infile,
            outfile,
        ]
    run(cmd)


def run_sox(infile, outfile, offset, duration):
    """Convert audio file to WAV file."""
    if duration:
        cmd = [
            'sox',
            infile,
            outfile,
            'trim', str(offset),
            str(duration),
        ]
    else:
        cmd = [
            'sox',
            infile,
            outfile,
            'trim', str(offset),
        ]
    run(cmd)