"""Media metadata extraction module."""

from functools import reduce
import subprocess

from . import common_config
from .common_config import logger
from .constants import errors
from .constants import mediainfo_const


def get_audio_asset_media_info(file_path):
    """Collect all information about audio media file using mediainfo.

    Args:
        file_path (str): path to file or url.

    Returns:
        dict: dictionary with full mediainfo output.
    """
    info = []
    for cli_filter in mediainfo_const.CLI_FILTERS:
        mediainfo_result_by_flag = get_media_info(file_path, cli_filter)
        info.append(mediainfo_result_by_flag)
    # extract all dictionaries key/values pairs to one dictionary
    result_dict = reduce((lambda x, y: dict(x, **y)), info)
    return result_dict


def get_media_info(file_path, filter_pattern):
    """Get mediainfo output for file by filter pattern.

    Args:
        file_path (str): File path or url.
        filter_pattern (str): String pattern for grabbing mediainfo results.

    Returns:
        dict: Mediainfo output parsed by filter_pattern.

    Raises:
        RuntimeError: Unable to read asset file technical and tag data.
        OSError: Any error occurred during meadiainfo work.

    """
    try:
        media_info_binary_data = subprocess.check_output(
            [common_config.MEDIAINFO_PATH, filter_pattern, file_path])
    except OSError as e:
        logger.exception(str(e))
        raise

    if not media_info_binary_data:
        raise RuntimeError(errors.ERROR_MEDIAINFO_EMPTY_OUTPUT_MESSAGE)

    media_info = (
        media_info_binary_data.decode('utf-8').replace('\n', ''))

    # split info unit by key and value
    split_data = map(lambda s: s.split(' ', 1), media_info.split(' * '))
    # type casting
    unready_res = {ld[0].lower(): ld[1].lower() if len(ld) > 1 else None for ld in split_data}
    result_dict = {k: type_cast(k, v) for k, v in unready_res.items()}
    return result_dict


def type_cast(key, value):
    """Cast type of output value from mediainfo.

    Args:
        key (str): result key for mediainfo cli output
        value (str): result value

    Returns:
        str or int: return casted value

    """
    if key in mediainfo_const.NUMERIC_FIELDS:
        if '/' in value:
            value = value.split('/')[0]
        if value == '':
            value = 0
        return int(value)
    return value