Add LFRM (Le Mans Arnage) customs form

src/flightforms/fillers/_datetime.py

@@ -0,0 +1,24 @@
+"""Date/time conversion shared by the form fillers.
+
+Requests always carry UTC.  A form that prints the airport's wall clock
+("Heure Locale") declares ``time_reference: "local"`` and a ``time_zone``
+in its mapping.
+"""
+
+from datetime import datetime
+from zoneinfo import ZoneInfo
+
+
+def utc_to_local(date_str: str, time_str: str, tz_name: str) -> tuple[str, str]:
+    """Convert a YYYY-MM-DD / HH:MM pair from UTC to *tz_name*.
+
+    Date and time must convert together: a UTC evening can land on the next
+    day locally (23:50Z on 1 June is 01:50 on 2 June in Paris), so printing a
+    converted time against the original UTC date would misdate the flight by
+    a day on a customs pre-notification.
+
+    The date comes back as YYYY-MM-DD, for the caller to format.
+    """
+    dt = datetime.strptime(f"{date_str} {time_str}", "%Y-%m-%d %H:%M")
+    local = dt.replace(tzinfo=ZoneInfo("UTC")).astimezone(ZoneInfo(tz_name))
+    return local.strftime("%Y-%m-%d"), local.strftime("%H:%M")

src/flightforms/fillers/french_customs_filler.py

@@ -8,27 +8,19 @@
 from datetime import datetime
 from io import BytesIO
 from pathlib import Path
-from zoneinfo import ZoneInfo
 
 from pypdf import PdfReader, PdfWriter
 
 from ..api.models import GenerateRequest
 from ..registry import FormMapping
+from ._datetime import utc_to_local
 
 
 def _parse_date(date_str: str, fmt: str) -> str:
     dt = datetime.strptime(date_str, "%Y-%m-%d")
     return dt.strftime(fmt)
 
 
-def _utc_to_local(time_str: str, date_str: str, tz_name: str) -> str:
-    """Convert HH:MM UTC to local time in the given timezone."""
-    dt = datetime.strptime(f"{date_str} {time_str}", "%Y-%m-%d %H:%M")
-    dt_utc = dt.replace(tzinfo=ZoneInfo("UTC"))
-    dt_local = dt_utc.astimezone(ZoneInfo(tz_name))
-    return dt_local.strftime("%H:%M")
-
-
 def _suffix(index: int) -> str:
     """Row 0 = no suffix, row 1 = '_2', row 2 = '_3', etc."""
     if index == 0:
@@ -51,15 +43,20 @@ def fill_french_customs(
 
     observations = request.observations or mapping.default_observations or ""
 
-    # Use local time conversion only when time_reference is "local"
+    # Use local time conversion only when time_reference is "local".  The date
+    # converts with the time: a late-evening UTC slot falls on the next day
+    # locally, and the form would otherwise print that local time against the
+    # UTC date.
     if mapping.time_reference == "local" and mapping.time_zone:
-        dep_time = _utc_to_local(
-            request.flight.departure_time_utc, request.flight.departure_date, mapping.time_zone
+        dep_date, dep_time = utc_to_local(
+            request.flight.departure_date, request.flight.departure_time_utc, mapping.time_zone
         )
-        arr_time = _utc_to_local(
-            request.flight.arrival_time_utc, request.flight.arrival_date, mapping.time_zone
+        arr_date, arr_time = utc_to_local(
+            request.flight.arrival_date, request.flight.arrival_time_utc, mapping.time_zone
         )
     else:
+        dep_date = request.flight.departure_date
+        arr_date = request.flight.arrival_date
         dep_time = request.flight.departure_time_utc
         arr_time = request.flight.arrival_time_utc
 
@@ -78,8 +75,8 @@ def fill_french_customs(
         "destination": request.flight.destination,
         "registration": request.aircraft.registration,
         "aircraft_type": request.aircraft.type,
-        "departure_date": _parse_date(request.flight.departure_date, mapping.date_format),
-        "arrival_date": _parse_date(request.flight.arrival_date, mapping.date_format),
+        "departure_date": _parse_date(dep_date, mapping.date_format),
+        "arrival_date": _parse_date(arr_date, mapping.date_format),
         "departure_time": dep_time,
         "arrival_time": arr_time,
         "contact": contact,