refactors

backend/utils/date_queries.py

@@ -0,0 +1,27 @@
+"""Utilities for date/time query operations."""
+
+from datetime import UTC, date, datetime, time
+
+
+def date_to_start_datetime(d: date) -> datetime:
+    """Convert a date to datetime at start of day (00:00:00) in UTC."""
+    return datetime.combine(d, time.min, tzinfo=UTC)
+
+
+def date_to_end_datetime(d: date) -> datetime:
+    """Convert a date to datetime at end of day (23:59:59.999999) in UTC."""
+    return datetime.combine(d, time.max, tzinfo=UTC)
+
+
+def date_range_to_datetime_range(
+    start_date: date, end_date: date
+) -> tuple[datetime, datetime]:
+    """
+    Convert a date range to datetime range.
+
+    Returns:
+        Tuple of (start_datetime, end_datetime) where:
+        - start_datetime is start_date at 00:00:00 UTC
+        - end_datetime is end_date at 23:59:59.999999 UTC
+    """
+    return date_to_start_datetime(start_date), date_to_end_datetime(end_date)