Refactor: Extract constants and reduce code duplication

- Extract DEFAULT_EVENT_SHAPE constant to replace 'square' magic string
- Create _index_event_refs() helper method to reduce duplication in _build_event_to_person_index()
- Use DEFAULT_EVENT_SHAPE constant in _draw_shape() default parameter

These changes improve maintainability by reducing code duplication and
replacing magic strings with named constants.

MyTimeline.py

@@ -129,6 +129,7 @@ FONT_SIZE_LARGE = 24
 # Visual Effect Constants
 MARKER_HOVER_SIZE_MULTIPLIER = 1.3
 MARKER_SELECTED_SIZE_MULTIPLIER = 1.2
+DEFAULT_EVENT_SHAPE = 'square'  # Default shape for events without specific shape mapping
 GRADIENT_BRIGHTNESS_OFFSET = 0.2
 GRADIENT_DARKNESS_OFFSET = 0.1
 SHADOW_OFFSET_X = 1
@@ -1826,24 +1827,30 @@ class MyTimelineView(NavigationView):
                         continue
                     
                     # Check primary events first (these take precedence)
-                    for event_ref in person.get_primary_event_ref_list():
+                    self._index_event_refs(person.get_primary_event_ref_list(), person)
-                        event_handle = event_ref.ref
-                        # Only store if not already mapped (primary events take priority)
-                        if event_handle not in self._event_to_person_cache:
-                            self._event_to_person_cache[event_handle] = person
                     
                     # Check all events (for events not in primary list)
-                    for event_ref in person.get_event_ref_list():
+                    self._index_event_refs(person.get_event_ref_list(), person)
-                        event_handle = event_ref.ref
-                        # Only store if not already mapped
-                        if event_handle not in self._event_to_person_cache:
-                            self._event_to_person_cache[event_handle] = person
                             
                 except (AttributeError, KeyError):
                     continue
         except (AttributeError, KeyError) as e:
             logger.warning(f"Error building event-to-person index from database: {e}", exc_info=True)
 
+    def _index_event_refs(self, event_ref_list: List[Any], person: 'Person') -> None:
+        """
+        Index event references from a list, mapping event handles to person.
+        
+        Args:
+            event_ref_list: List of event references from a person object.
+            person: The person object to associate with the events.
+        """
+        for event_ref in event_ref_list:
+            event_handle = event_ref.ref
+            # Only store if not already mapped (to preserve priority of primary events)
+            if event_handle not in self._event_to_person_cache:
+                self._event_to_person_cache[event_handle] = person
+
     def _find_person_for_event(self, event: 'Event') -> Optional['Person']:
         """
         Find a primary person associated with an event using the cached index.
@@ -3107,7 +3114,7 @@ class MyTimelineView(NavigationView):
         
         # Get color and shape
         color = EVENT_COLORS.get(event_type_value, DEFAULT_EVENT_COLOR)
-        shape = EVENT_SHAPES.get(event_type_value, 'square')
+        shape = EVENT_SHAPES.get(event_type_value, DEFAULT_EVENT_SHAPE)
         marker_size = EVENT_MARKER_SIZE
         
         # Increase size if hovered or selected
@@ -3206,7 +3213,7 @@ class MyTimelineView(NavigationView):
             'hexagon': self._draw_hexagon,
         }
         
-        drawer = shape_drawers.get(shape, self._draw_square)  # Default to square
+        drawer = shape_drawers.get(shape, shape_drawers[DEFAULT_EVENT_SHAPE])
         drawer(context, x, y, size)
 
     def draw_event_label(self, context: cairo.Context, x: float, y: float,