"""Logic for max available date."""

import datetime

from sound_recordings.constants.parameters import ALL_TIME
from sound_recordings.models import data_availability

HIGHWATERMARK_DATE = "HIGHWATERMARK"


def _get_max_available_date(downloads):
    if downloads:
        return data_availability.get_downloads_max_available_date()
    return data_availability.get_max_available_date()


def get_date_range(start_date, days, downloads=False):
    """Return date range based on start date, highwatermark and days.

    Args:
        start_date (string): Start date or highwatermark key word
        days (int): number of days
        downloads (bool): get max available date for downloads
        videos (bool): get max available date for video views

    Returns:
        start_date (datetime.date): Start date
        end_date (datetime.date): End date

    """
    is_highwater_mark = start_date == HIGHWATERMARK_DATE
    is_all_time = is_highwater_mark and days == 0

    abs_start_date = datetime.datetime.strptime(
        _get_max_available_date(downloads) if is_highwater_mark else start_date,
        "%Y-%m-%d",
    ).date()

    if is_all_time:
        abs_end_date = abs_start_date
        abs_start_date = ALL_TIME
    elif days < 0:
        abs_end_date = abs_start_date
        abs_start_date += datetime.timedelta(days=days + 1)
    elif is_highwater_mark:
        abs_end_date = abs_start_date
        abs_start_date -= datetime.timedelta(days=days - 1)
    else:
        abs_end_date = abs_start_date + datetime.timedelta(days=days - 1)

    return abs_start_date, abs_end_date


def get_max_available_date():
    """Return max available date for all stores.

    Returns:
        max_available_date (datetime.date): Max available date

    """
    return datetime.datetime.strptime(
        data_availability.get_max_available_date(), "%Y-%m-%d"
    ).date()


def get_downloads_max_available_date():
    """Return max available date for all download stores.

    Returns:
        max_available_date (datetime.date): Max available date

    """
    return datetime.datetime.strptime(
        data_availability.get_downloads_max_available_date(), "%Y-%m-%d"
    ).date()