"""Custom methods for validation of audio metadata."""

import trafaret as t

from src.constants import errors
from src.constants import validation_const


"""For any changes that are made to audio metadata requirements, please update:
https://github.com/theorchard/frontend-distribution/blob/b0f7ea92b0a2df8df145777abdb1b04b2c59c547/src/selectors/track-audio-validation-errors.js
"""  # noqa: E501


def sample_rate_validation(audio_meta):
    """Validate sample_rate value for default schema.

    Args:
        audio_meta (dict): input audio metadata.
        {
            'sample_rate': 44100,
            'bits_per_sample': 16
        }
    Returns:
        dict: sample_rate value or trafaret.DataError exception.

    """
    bits_per_sample = audio_meta.get('bits_per_sample')
    sample_rate = audio_meta.get('sample_rate')

    if not bits_per_sample or not sample_rate:
        return {'sample_rate': sample_rate}

    if bits_per_sample not in (
        validation_const.BITS_PER_SAMPLE_TO_ALLOWED_SAMPLE_RATES
    ):
        return {'sample_rate': sample_rate}

    available_sample_rates = (
        validation_const.BITS_PER_SAMPLE_TO_ALLOWED_SAMPLE_RATES[
            bits_per_sample
        ]
    )
    if sample_rate not in available_sample_rates:
        error_message = errors.INVALID_INPUT_VALUE_ERROR_MESSAGE.format(
            name='sample_rate',
            expected=available_sample_rates,
            value=sample_rate
        )
        return {'sample_rate': t.DataError(error_message)}

    return {'sample_rate': sample_rate}