From dd70b09fb1b85a4d1651abfeb96d2e32c2e414d2 Mon Sep 17 00:00:00 2001
From: Dion Moult <dion@thinkmoult.com>
Date: Thu, 12 Oct 2023 22:56:21 +1100
Subject: [PATCH] Representation items panel now shows styles and layers

---
 .../blenderbim/bim/module/geometry/data.py     | 18 +++++++++++++++++-
 .../blenderbim/bim/module/geometry/prop.py     |  1 +
 .../blenderbim/bim/module/geometry/ui.py       | 16 ++++++++++++++--
 .../ifcopenshell/util/element.py               |  2 +-
 4 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/src/blenderbim/blenderbim/bim/module/geometry/data.py b/src/blenderbim/blenderbim/bim/module/geometry/data.py
index bdf7e53a09..d1e3b7fa1e 100644
--- a/src/blenderbim/blenderbim/bim/module/geometry/data.py
+++ b/src/blenderbim/blenderbim/bim/module/geometry/data.py
@@ -99,7 +99,11 @@ class RepresentationItemsData:
 
     @classmethod
     def load(cls):
-        cls.data = {"total_items": cls.total_items()}
+        cls.data = {
+            "total_items": cls.total_items(),
+            "active_surface_style": cls.active_surface_style(),
+            "active_layer": cls.active_layer(),
+        }
         cls.is_loaded = True
 
     @classmethod
@@ -120,6 +124,18 @@ class RepresentationItemsData:
                     result += 1
         return result
 
+    @classmethod
+    def active_surface_style(cls):
+        props = bpy.context.active_object.BIMGeometryProperties
+        if props.active_item_index < len(props.items):
+            return props.items[props.active_item_index].surface_style
+
+    @classmethod
+    def active_layer(cls):
+        props = bpy.context.active_object.BIMGeometryProperties
+        if props.active_item_index < len(props.items):
+            return props.items[props.active_item_index].layer
+
 
 class ConnectionsData:
     data = {}
diff --git a/src/blenderbim/blenderbim/bim/module/geometry/prop.py b/src/blenderbim/blenderbim/bim/module/geometry/prop.py
index ae16daa751..f874172d28 100644
--- a/src/blenderbim/blenderbim/bim/module/geometry/prop.py
+++ b/src/blenderbim/blenderbim/bim/module/geometry/prop.py
@@ -41,6 +41,7 @@ def get_contexts(self, context):
 class RepresentationItem(PropertyGroup):
     name: StringProperty(name="Name")
     surface_style: StringProperty(name="Surface Style")
+    layer: StringProperty(name="Layer")
     ifc_definition_id: IntProperty(name="IFC Definition ID")
 
 
diff --git a/src/blenderbim/blenderbim/bim/module/geometry/ui.py b/src/blenderbim/blenderbim/bim/module/geometry/ui.py
index a824dcf895..c0f5ad5e49 100644
--- a/src/blenderbim/blenderbim/bim/module/geometry/ui.py
+++ b/src/blenderbim/blenderbim/bim/module/geometry/ui.py
@@ -164,6 +164,18 @@ class BIM_PT_representation_items(Panel):
 
         self.layout.template_list("BIM_UL_representation_items", "", props, "items", props, "active_item_index")
 
+        row = self.layout.row()
+        if RepresentationItemsData.data["active_surface_style"]:
+            row.label(text=RepresentationItemsData.data["active_surface_style"], icon="MATERIAL")
+        else:
+            row.label(text="No Surface Style", icon="MESH_UVSPHERE")
+
+        row = self.layout.row()
+        if RepresentationItemsData.data["active_layer"]:
+            row.label(text=RepresentationItemsData.data["active_layer"], icon="STICKY_UVS_LOC")
+        else:
+            row.label(text="No Presentation Layer", icon="STICKY_UVS_LOC")
+
 
 class BIM_PT_connections(Panel):
     bl_label = "Connections"
@@ -423,5 +435,5 @@ class BIM_UL_representation_items(UIList):
             icon = "MATERIAL" if item.surface_style else "MESH_UVSPHERE"
             row = layout.row(align=True)
             row.label(text=item.name, icon=icon)
-            if item.surface_style:
-                row.label(text=item.surface_style)
+            if item.layer:
+                row.label(text="", icon="STICKY_UVS_LOC")
diff --git a/src/ifcopenshell-python/ifcopenshell/util/element.py b/src/ifcopenshell-python/ifcopenshell/util/element.py
index 4852ff067c..7f02dc609b 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/element.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/element.py
@@ -577,7 +577,7 @@ def get_elements_by_layer(ifc_file, layer):
     :rtype: list[ifcopenshell.entity_instance.entity_instance]
     """
     results = set()
-    for item in layer.AssignedItems:
+    for item in layer.AssignedItems or []:
         if item.is_a("IfcShapeRepresentation"):
             results.update(get_elements_by_representation(ifc_file, item))
         elif item.is_a("IfcRepresentationItem"):