isholidays.py

"""
Look at the split of non-working-day windows for each year

Produces something like this:

2020 - 117 frídagar (119 í frígluggum sem hefjast á árinu)
- 1x fimm daga frí       - 9.4 (Holy Thursday)
- 2x fjögurra daga frí   - 24.12 (Christmas Eve), 31.12 (New Year's Eve)
- 3x þriggja daga frí    - 1.5 (Labour Day), 3.5 (Whit Monday), 1.8 (Commerce Day)
- 47x tveggja daga frí
- 3x eins daga frí       - 23.4 (First day of summer), 21.5 (Ascension Thursday), 17.6 (Icelandic National Day)

2021 - 115 frídagar (114 í frígluggum sem hefjast á árinu)
- 1x fimm daga frí       - 1.4 (Holy Thursday)
- 4x þriggja daga frí    - 22.5 (Whit Monday), 31.7 (Commerce Day), 24.12 (Christmas Eve), 31.12 (New Year's Eve)
- 47x tveggja daga frí
- 3x eins daga frí       - 22.4 (First day of summer), 13.5 (Ascension Thursday), 17.6 (Icelandic National Day)

2022 - 114 frídagar (113 í frígluggum sem hefjast á árinu)
- 1x fimm daga frí       - 14.4 (Holy Thursday)
- 4x þriggja daga frí    - 4.6 (Whit Monday), 17.6 (Icelandic National Day), 3.7 (Commerce Day), 24.12 (Christmas Eve)
- 47x tveggja daga frí
- 2x eins daga frí       - 21.4 (First day of summer), 26.5 (Ascension Thursday)

2023 - 115 frídagar (115 í frígluggum sem hefjast á árinu)
- 1x fimm daga frí       - 6.4 (Holy Thursday)
- 1x fjögurra daga frí   - 23.12 (Christmas Eve)
- 4x þriggja daga frí    - 29.4 (Labour Day), 27.5 (Whit Monday), 5.8 (Commerce Day), 3.12 (New Year's Eve)
- 46x tveggja daga frí
- 2x eins daga frí       - 2.4 (First day of summer), 18.5 (Ascension Thursday)


"""


import datetime as dt
from collections import defaultdict
from workalendar.europe import Iceland

cal = Iceland()

this_year = dt.date.today().year

wordize = {
    1: "eins",
    2: "tveggja",
    3: "þriggja",
    4: "fjögurra",
    5: "fimm",
    6: "sex",
}

for year in range(this_year, this_year + 21):

    holidays = dict(cal.holidays(year))

    day = dt.date(year, 1, 1)
    total = 0
    while day.year == year:
        if not cal.is_working_day(day):
            total += 1
        day += dt.timedelta(days=1)

    windows = defaultdict(list)
    day = dt.date(year, 1, 1)

    # Always start with the first working day of the year
    while not cal.is_working_day(day):
        day += dt.timedelta(days=1)

    while day.year == year:
        # we want to find each non-working day window
        if not cal.is_working_day(day):
            length = 0
            start = day
            holiday = None
            while not cal.is_working_day(day):
                length += 1
                if holiday is None:
                    holiday = holidays.get(day)
                day = day + dt.timedelta(days=1)
            windows[length].append((start, day, holiday))
        day = day + dt.timedelta(days=1)

    window_total = sum(i * len(j) for i, j in windows.items())
    shifts = window_total - total
    header = (
        f"{year} - {total} frídagar ({window_total} í frígluggum sem hefjast á árinu)"
    )
    print(header)

    for length, instances in sorted(
        windows.items(), key=lambda pair: pair[0], reverse=True
    ):
        occurances = len(instances)

        message = f"- {occurances}x {wordize[length]} daga frí"
        # add a date preview for non weekend windows
        preview = ", ".join(
            "{}{}".format(
                i[0].strftime("%d.%m").replace("0", ""),
                " ({})".format(i[2]) if i[2] else "",
            )
            for i in instances[:4]
            if i[0].weekday() < 5 or length != 2
        )
        if len(instances) > 4 and preview:
            preview += "..."

        if preview:
            message = f"{message.ljust(24)} - {preview}"

        print(message)

    print()