Fix manual time entry timezone (Issue #471)

Manual time entries were interpreted in the application timezone instead of the user's timezone, so users in a different timezone (e.g. GMT+1) saw times adjusted to the server timezone (e.g. GMT+0) on the calendar.

- Add parse_user_local_datetime() in timezone utils to parse form date/time as the user's local time and return naive datetime in app timezone for storage.
- Use parse_user_local_datetime() in the manual entry form so submitted times are stored correctly and display at the right slot in the calendar.

Calendar events and drag-created entries were already correct; only the manual entry form path is changed. Other callers of parse_local_datetime are unchanged.

app/routes/timer.py

@@ -3,7 +3,7 @@ from flask_babel import gettext as _
 from flask_login import login_required, current_user
 from app import db, socketio, log_event, track_event
 from app.models import User, Project, TimeEntry, Task, Settings, Activity, Client
-from app.utils.timezone import parse_local_datetime, utc_to_local
+from app.utils.timezone import parse_local_datetime, parse_user_local_datetime, utc_to_local
 from datetime import datetime, timedelta
 import json
 from app.utils.db import safe_commit
@@ -1068,10 +1068,10 @@ def manual_entry():
                 prefill_end_time=end_time,
             )
 
-        # Parse datetime with timezone awareness
+        # Parse datetime: treat form input as user's local time, store in app timezone
         try:
-            start_time_parsed = parse_local_datetime(start_date, start_time)
-            end_time_parsed = parse_local_datetime(end_date, end_time)
+            start_time_parsed = parse_user_local_datetime(start_date, start_time, current_user)
+            end_time_parsed = parse_user_local_datetime(end_date, end_time, current_user)
         except ValueError:
             flash(_("Invalid date/time format"), "error")
             return render_template(

app/utils/timezone.py

@@ -222,6 +222,26 @@ def parse_local_datetime(date_str, time_str):
         raise ValueError(f"Invalid date/time format: {e}")
 
 
+def parse_user_local_datetime(date_str, time_str, user=None):
+    """Parse date and time strings as user's local time; return naive datetime in app timezone for storage.
+
+    Use this for manual time entry forms where the user enters a time in their local timezone.
+    When user has no timezone set, falls back to app timezone (same as parse_local_datetime input semantics).
+    """
+    try:
+        datetime_str = f"{date_str} {time_str}"
+        naive_dt = datetime.strptime(datetime_str, "%Y-%m-%d %H:%M")
+
+        # Treat input as user's timezone (or app timezone if no user / no user TZ)
+        user_tz = get_timezone_for_user(user)
+        app_tz = get_timezone_obj()
+        localized_in_user_tz = _localize_with_timezone(naive_dt, user_tz)
+        in_app_tz = localized_in_user_tz.astimezone(app_tz)
+        return in_app_tz.replace(tzinfo=None)
+    except ValueError as e:
+        raise ValueError(f"Invalid date/time format: {e}")
+
+
 def format_local_datetime(utc_dt, format_str="%Y-%m-%d %H:%M"):
     """Format UTC datetime in local application timezone."""
     if utc_dt is None: