fix(importing): normalize non-breaking spaces in CSV datetime fields

Google Sheets embeds \xa0 (non-breaking space) in 12-hour time values
(e.g. "3:00\xa0PM") and when date/time columns are combined. This caused
MariaDB datetime INSERTs to fail with an OperationalError.

Adds _clean_datetime() which strips \xa0, normalizes whitespace, and
parses common import formats (M/D/YYYY H:MM AM/PM, etc.) into
YYYY-MM-DD HH:MM:SS before the DB write. Applied to all four datetime
fields: session and presentation start/end.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/routers/event_importing.py

@@ -28,6 +28,21 @@ from app.models.response_models import Resp_Body_Base, mk_resp
 router = APIRouter()
 
 
+def _clean_datetime(value) -> str | None:
+    """Normalize datetime strings from CSV imports (handles \xa0 from Excel, 12-hour format)."""
+    if not value:
+        return None
+    cleaned = str(value).replace('\xa0', ' ').strip()
+    if not cleaned:
+        return None
+    for fmt in ('%m/%d/%Y %I:%M %p', '%m/%d/%Y %H:%M', '%Y-%m-%d %H:%M:%S', '%Y-%m-%d %H:%M'):
+        try:
+            return datetime.datetime.strptime(cleaned, fmt).strftime('%Y-%m-%d %H:%M:%S')
+        except ValueError:
+            continue
+    return cleaned
+
+
 # No longer needed? 2024-08-15
 # Based on the program import template the clients are given.
 # Ideally the import file should only contain records with new External IDs. Old records will be checked and only updated if needed.
@@ -332,7 +347,10 @@ router = APIRouter()
 # ### BEGIN ### Event Importing ### event_importing_program_data() ###
 # Based on the program import template the clients are given.
 # Create and update locations, sessions, presentations, and presenters as needed.
-# Updated 2024-03-25
+# Careful with how date and time fields are combined
+# This should work: =TEXT(G2,"M/D/YYYY")&" "&TEXT(H2,"H:MM AM/PM")
+# Simply adding the fields (=D264+E264) sort of works. This produces non breaking spaces but clean up on import.
+# Updated 2026-05-15
 @router.post('/event/{event_id}/importing/program_data', response_model=Resp_Body_Base)
 async def event_importing_program_data(
         event_id: str = Path(min_length=11, max_length=22),
@@ -656,13 +674,8 @@ async def event_importing_program_data(
         if record.get('session_description'):
             event_session_data['description'] = record.get('session_description', '').strip()
 
-        event_session_data['start_datetime'] = record.get('session_start_datetime', '').strip()
-        # event_session_start_datetime = record.get('event_session_start_date', '') + ' ' + record.get('event_session_start_time', '')
-        # event_session_data['start_datetime'] = event_session_start_datetime
-
-        event_session_data['end_datetime'] = record.get('session_end_datetime', '').strip()
-        # event_session_end_datetime = record.get('event_session_end_date', '') + ' ' + record.get('event_session_end_time', '')
-        # event_session_data['end_datetime'] = event_session_end_datetime
+        event_session_data['start_datetime'] = _clean_datetime(record.get('session_start_datetime'))
+        event_session_data['end_datetime'] = _clean_datetime(record.get('session_end_datetime'))
 
         event_session_data['sort'] = record.get('session_sort')
 
@@ -736,19 +749,11 @@ async def event_importing_program_data(
         if record.get('presentation_description'):
             event_presentation_data['description'] = record.get('presentation_description', '').strip()
 
-        if record.get('presentation_start_datetime'):
-            event_presentation_data['start_datetime'] = record.get('presentation_start_datetime', '').strip()
-            data['presentation_start_datetime'] = event_presentation_data['start_datetime']
-        else:
-            event_presentation_data['start_datetime'] = None
-            data['presentation_start_datetime'] = None
+        event_presentation_data['start_datetime'] = _clean_datetime(record.get('presentation_start_datetime'))
+        data['presentation_start_datetime'] = event_presentation_data['start_datetime']
 
-        if record.get('presentation_end_datetime'):
-            event_presentation_data['end_datetime'] = record.get('presentation_end_datetime', '').strip()
-            data['presentation_end_datetime'] = event_presentation_data['end_datetime']
-        else:
-            event_presentation_data['end_datetime'] = None
-            data['presentation_end_datetime'] = None
+        event_presentation_data['end_datetime'] = _clean_datetime(record.get('presentation_end_datetime'))
+        data['presentation_end_datetime'] = event_presentation_data['end_datetime']
 
         if record.get('presentation_abstract_code'):
             event_presentation_data['abstract_code'] = record.get('presentation_abstract_code', '').strip()