date Business days functions - can be used in ecommerse for estimating delivery day

fancy_date_functions.py

def get_holidays(year=date.year):
    easter_sunday = easter.easter(year)
    holidays = [
        # These holidays have a fixed date
        date(year,1,1), # New Year
        date(year,5,1), # Labor Day
        date(year,6,5), # Constitution Day (Grundlovsdag)
        date(year,12,24), # Christmas  Night
        date(year,12,25), # 1st Christmas  Day
        date(year,12,26),# 2st Christmas  Day
        date(year, 12, 31), # 31. dec Nytårsaften

        # These days have a date depending on easter
        easter_sunday - timedelta(days=7), # Palmesøndag
        easter_sunday - timedelta(days=3), # Skærtorsdag
        easter_sunday - timedelta(days=2), # Langfredag
        easter_sunday, # Easter Sunday
        easter_sunday + timedelta(days=1), # Easter Monday (2. Påskedag)
        easter_sunday + timedelta(days=26), # Great praior day (St. Bededag)
        easter_sunday + timedelta(days=39), # Kristi Himmelfart
        easter_sunday + timedelta(days=49), # Pentecost Sunday Pinsedag (7th Sunday after Easter)
        easter_sunday + timedelta(days=50), # 1. Pinsedag
    ]
    return holidays


def is_date_a_business_day(current_date=date.today()):
    weekday = current_date.weekday()
    if weekday > 4: # saturday=5, sunday = 6
        return False
    holidays = get_holidays(current_date.year)
    if current_date in holidays:
        return False
    return True


def date_by_adding_business_days(start_date=date.today(), add_days=1):
    current_date = start_date
    business_days_to_add = add_days
    while business_days_to_add > 0:
        current_date += timedelta(days=1)
        if not is_date_a_business_day(current_date):
            continue
        business_days_to_add -= 1
    return current_date


def date_by_substracting_business_days(start_date=date.today(), add_days=1):
    current_date = start_date
    business_days_to_add = add_days
    while business_days_to_add > 0:
        current_date -= timedelta(days=1)
        if not is_date_a_business_day(current_date):
            continue
        business_days_to_add -= 1
    return current_date


def get_next_business_day(current_date=date.today()):
    return date_by_adding_business_days(current_date, 1)


def get_previous_business_day(current_date=date.today()):
    return date_by_substracting_business_days(current_date, 1)