Initial commit

backend/app/utils/holidays.py

@@ -0,0 +1,53 @@
+"""Swedish public holiday utilities for leave planning.
+
+Uses the holidays library to get röda dagar (red days) in Sweden.
+Results are cached per year to avoid repeated parsing.
+"""
+
+import datetime
+from typing import Dict
+
+import holidays
+
+_holiday_cache: Dict[int, Dict[datetime.date, str]] = {}
+
+
+def get_swedish_holidays(year: int) -> Dict[datetime.date, str]:
+    """Get all Swedish public holidays (röda dagar) for a given year.
+
+    Returns a mapping of date -> holiday name in Swedish.
+
+    The result is cached per year; subsequent calls with the same year
+    return the cached value without re-parsing.
+
+    Args:
+        year: Calendar year (e.g., 2026)
+
+    Returns:
+        Dict mapping datetime.date to holiday name (e.g. "Juldagen", "Midsommar")
+    """
+    if year in _holiday_cache:
+        return _holiday_cache[year]
+
+    # Get Swedish holidays for the year with Swedish-language names.
+    se_holidays = holidays.Sweden(years=year, language="sv")
+
+    # Convert to our format: date -> name
+    result: Dict[datetime.date, str] = {}
+    for holiday_date, holiday_name in sorted(se_holidays.items()):
+        result[holiday_date] = holiday_name
+
+    _holiday_cache[year] = result
+    return result
+
+
+def is_swedish_holiday(date: datetime.date) -> bool:
+    """Check if a date is a Swedish public holiday."""
+    holidays_for_year = get_swedish_holidays(date.year)
+    return date in holidays_for_year
+
+
+def get_holiday_name(date: datetime.date) -> str | None:
+    """Get the name of a Swedish public holiday, or None if not a holiday."""
+    holidays_for_year = get_swedish_holidays(date.year)
+    return holidays_for_year.get(date)