public override void OnGUI()

in Scripts/Editor/CallbackHandlers/ValuePathMatcherPropertyDrawer.cs [107:222]
105 lines of code
15 McCabe index (conditional complexity)

        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            var rect = new Rect(position)
            {
                height = EditorGUIUtility.singleLineHeight
            };
            var path = property.FindPropertyRelative(Properties.path);

            var valueRefProp = property.FindPropertyRelative(Properties.witValueRef);
            var editIconWidth = 24;
            var pathRect = new Rect(rect);
            pathRect.width -= editIconWidth;
            var pathValue = GetPropertyPath(property);
            if (IsEditingProperty(property))
            {
                if (!valueRefProp.objectReferenceValue)
                {
                    pathRect.width -= WitStyles.IconButtonSize;
                    var value = EditorGUI.TextField(pathRect, path.stringValue);
                    if (value != path.stringValue)
                    {
                        path.stringValue = value;
                    }

                    pathRect.width += WitStyles.IconButtonSize;

                    var pickerRect = new Rect(pathRect)
                    {
                        x = pathRect.x + pathRect.width - 20,
                        width = 20
                    };
                    if (GUI.Button(pickerRect, WitStyles.ObjectPickerIcon, "Label"))
                    {
                        var id = EditorGUIUtility.GetControlID(FocusType.Passive) + 100;
                        EditorGUIUtility.ShowObjectPicker<WitValue>(
                            (WitValue) valueRefProp.objectReferenceValue, false, "", id);
                    }
                }
                else
                {
                    EditorGUI.PropertyField(pathRect, valueRefProp, new GUIContent());
                }

                if (Event.current.commandName == "ObjectSelectorClosed")
                {
                    valueRefProp.objectReferenceValue = EditorGUIUtility.GetObjectPickerObject();
                }

                pathValue = GetPropertyPath(property);
                if (pathValue != currentEditPath && null != currentEditPath)
                {
                    foldouts[currentEditPath] = false;
                    currentEditPath = GetPropertyPath(property);
                    foldouts[currentEditPath] = true;
                }
            }
            else
            {
                if (valueRefProp.objectReferenceValue)
                {
                    EditorGUI.LabelField(pathRect, valueRefProp.objectReferenceValue.name);
                }
                else
                {
                    EditorGUI.LabelField(pathRect, path.stringValue);
                }
            }

            var editRect = new Rect(rect)
            {
                x = pathRect.x + pathRect.width + 8
            };

            if (Foldout(rect, property))
            {
                if (GUI.Button(editRect, WitStyles.EditIcon, "Label"))
                {
                    if (currentEditPath == pathValue)
                    {
                        currentEditPath = null;
                    }
                    else
                    {
                        currentEditPath = pathValue;
                    }
                }

                rect.x += WitStyles.IconButtonSize;
                rect.width -= WitStyles.IconButtonSize;
                rect.y += rect.height;
                EditorGUI.PropertyField(rect, property.FindPropertyRelative(Properties.contentRequired));
                rect.y += rect.height;
                EditorGUI.PropertyField(rect, property.FindPropertyRelative(Properties.matchMethod));

                if (ComparisonMethodsVisible(property))
                {
                    rect.y += rect.height;
                    EditorGUI.PropertyField(rect,
                        property.FindPropertyRelative(Properties.comparisonMethod));
                }

                if (ComparisonValueVisible(property))
                {
                    rect.y += rect.height;
                    EditorGUI.PropertyField(rect,
                        property.FindPropertyRelative(Properties.matchValue));
                }

                if (FloatingToleranceVisible(property))
                {
                    rect.y += rect.height;
                    EditorGUI.PropertyField(rect,
                        property.FindPropertyRelative(Properties.floatingPointComparisonTolerance));
                }
            }
        }