"""Functionality for preparing the data and writig the CSV reports."""

import csv

from ioda import const


CSV_FIELDS = [
    const.FILENAME, const.CUSTOM_ID, const.ASSET_ID, const.ISRC,
    const.ADD_ASSET_LABELS, const.UPC, const.GRID, const.SONG_TITLE,
    const.ARTIST, const.ALBUM, const.GENRE, const.LABEL,
    const.ORIGINAL_RELEASE_DATE, const.OWNERSHIP, const.MATCH_POLICY,
    const.AUDIOSWAP
]

YOUTUBE_CSV_FIELDS = [
    const.ASSET_ID, const.UPC, const.ISRC, const.CUSTOM_ID
]


def create_csv_row(row):
    """Map row from dataset into dict for writing a CSV row.

    Args:
        row (dict): row from dataset

    Returns:
        dict: dictionary to be written to CSV
    """
    csv_row = {
        const.FILENAME: const.EMPTY,
        const.CUSTOM_ID: get_custom_id(row),
        const.ASSET_ID: str(row[const.ASSET_ID]).strip(),
        const.ISRC: row.get(const.ORCHARD_ISRC, row[const.ISRC]),
        const.ADD_ASSET_LABELS: const.EMPTY,
        const.UPC: row.get(const.ORCHARD_UPC, row[const.UPC]),
        const.GRID: row[const.GRID],
        const.SONG_TITLE: row[const.SONG_TITLE],
        const.ARTIST: row[const.ARTIST],
        const.ALBUM: row[const.ALBUM],
        const.GENRE: const.EMPTY,
        const.LABEL: row[const.LABEL],
        const.ORIGINAL_RELEASE_DATE: const.EMPTY,
        const.OWNERSHIP: const.EMPTY,
        const.MATCH_POLICY: const.EMPTY,
        const.AUDIOSWAP: const.EMPTY
    }
    return csv_row


def create_csv_row_from_asset(asset):
    """Map row from YouTube asset metadata into dict for writing a CSV row.

    Args:
        asset (dict): asset metadata from YouTube API

    Returns:
        dict: dictionary to be written to CSV
    """
    csv_row = {
        const.ASSET_ID: asset[const.ID],
        const.UPC: asset[const.METADATA][const.UPC],
        const.ISRC: asset[const.METADATA][const.ISRC],
        const.CUSTOM_ID: asset[const.METADATA][const.YT_CUSTOM_ID],
    }
    return csv_row


def save_csv(
        data, file_name, fields=CSV_FIELDS, row_mapper=create_csv_row,
        write_header=True):
    """Save CSV file.

    Args:
        data (list): data to write
        file_name (str): name of the file
        fields (list): list of fields in CSV
        row_mapper (func): function that should generate a dict for CSV row
            from source data
        write_header (bool): should CSV contain header row
    """
    with open(file_name, 'w', encoding='utf8') as csv_file:
        writer = csv.DictWriter(csv_file, fields, lineterminator='\n')
        if write_header:
            writer.writeheader()
        for row in data:
            csv_row = row_mapper(row)
            writer.writerow(csv_row)


def get_custom_id(row):
    """Get valid custom_id.

    If existing custom_id contains '_', then use it, otherwise construct
    the custom_custom using columns from joined IODA mapping tables.

    Args:
        row (dict): Row from dataset

    Returns:
        str: custom_id
    """
    custom_id = row[const.CUSTOM_ID]
    if const.SEPARATOR not in custom_id:
        custom_id = '{}_{}_{}'.format(
            row[const.ORCHARD_UPC],
            row[const.ORCHARD_ISRC],
            row[const.ORCHARD_TUID])
    return custom_id