From aceb2140ad3409a1f9fb94ed799d8b31299905dd Mon Sep 17 00:00:00 2001
From: Dion Moult <dion@thinkmoult.com>
Date: Tue, 9 Mar 2021 12:50:50 +1100
Subject: [PATCH] Fix #1361. You can now unlink objects and styles of elements
 that you've lost the IFC of to recover them.

---
 .../blenderbim/bim/module/root/operator.py       |  2 ++
 .../blenderbim/bim/module/root/ui.py             |  9 +++++++--
 .../blenderbim/bim/module/style/__init__.py      |  1 +
 .../blenderbim/bim/module/style/operator.py      | 16 ++++++++++++++--
 .../blenderbim/bim/module/style/ui.py            |  4 +++-
 5 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/ifcblenderexport/blenderbim/bim/module/root/operator.py b/src/ifcblenderexport/blenderbim/bim/module/root/operator.py
index 7eda7f3a96..299ed6aeaf 100644
--- a/src/ifcblenderexport/blenderbim/bim/module/root/operator.py
+++ b/src/ifcblenderexport/blenderbim/bim/module/root/operator.py
@@ -215,6 +215,8 @@ class UnlinkObject(bpy.types.Operator):
         for obj in objects:
             if obj.BIMObjectProperties.ifc_definition_id:
                 obj.BIMObjectProperties.ifc_definition_id = 0
+            if "Ifc" in obj.name and "/" in obj.name:
+                obj.name = "/".join(obj.name.split("/")[1:])
         return {"FINISHED"}
 
 
diff --git a/src/ifcblenderexport/blenderbim/bim/module/root/ui.py b/src/ifcblenderexport/blenderbim/bim/module/root/ui.py
index 88053fedf8..058de8afe7 100644
--- a/src/ifcblenderexport/blenderbim/bim/module/root/ui.py
+++ b/src/ifcblenderexport/blenderbim/bim/module/root/ui.py
@@ -19,7 +19,12 @@ class BIM_PT_class(Panel):
         props = context.active_object.BIMObjectProperties
         if props.ifc_definition_id:
             if props.ifc_definition_id not in Data.products:
-                Data.load(props.ifc_definition_id)
+                try:
+                    Data.load(props.ifc_definition_id)
+                except:
+                    row = self.layout.row(align=True)
+                    row.label(text="IFC Element Not Found")
+                    row.operator("bim.unlink_object", icon="UNLINKED", text="")
             if props.is_reassigning_class:
                 row = self.layout.row(align=True)
                 row.operator("bim.reassign_class", icon="CHECKMARK")
@@ -35,7 +40,7 @@ class BIM_PT_class(Panel):
                 row = self.layout.row(align=True)
                 row.label(text=name)
                 row.operator("bim.copy_class", icon="DUPLICATE", text="").obj = context.active_object.name
-                row.operator("bim.unlink_object", icon="UNLINKED", text="").obj = context.active_object.name
+                row.operator("bim.unlink_object", icon="UNLINKED", text="")
                 row.operator("bim.enable_reassign_class", icon="GREASEPENCIL", text="")
                 row.operator("bim.unassign_class", icon="X", text="").obj = context.active_object.name
         else:
diff --git a/src/ifcblenderexport/blenderbim/bim/module/style/__init__.py b/src/ifcblenderexport/blenderbim/bim/module/style/__init__.py
index bd340a126a..590bb7d66e 100644
--- a/src/ifcblenderexport/blenderbim/bim/module/style/__init__.py
+++ b/src/ifcblenderexport/blenderbim/bim/module/style/__init__.py
@@ -4,6 +4,7 @@ from . import ui, operator
 classes = (
     operator.AddStyle,
     operator.EditStyle,
+    operator.UnlinkStyle,
     ui.BIM_PT_style,
 )
 
diff --git a/src/ifcblenderexport/blenderbim/bim/module/style/operator.py b/src/ifcblenderexport/blenderbim/bim/module/style/operator.py
index 204a4e4385..62cce46f0b 100644
--- a/src/ifcblenderexport/blenderbim/bim/module/style/operator.py
+++ b/src/ifcblenderexport/blenderbim/bim/module/style/operator.py
@@ -3,8 +3,6 @@ import blenderbim.bim.module.style.add_style as add_style
 import blenderbim.bim.module.style.edit_style as edit_style
 from blenderbim.bim.ifc import IfcStore
 
-# from blenderbim.bim.module.spatial.data import Data
-
 
 def get_colour_settings(material):
     transparency = material.diffuse_color[3]
@@ -48,3 +46,17 @@ class AddStyle(bpy.types.Operator):
         style = add_style.Usecase(self.file, settings).execute()
         material.BIMMaterialProperties.ifc_style_id = int(style.id())
         return {"FINISHED"}
+
+
+class UnlinkStyle(bpy.types.Operator):
+    bl_idname = "bim.unlink_style"
+    bl_label = "Unlink Style"
+    material: bpy.props.StringProperty()
+
+    def execute(self, context):
+        self.file = IfcStore.get_file()
+        material = bpy.data.materials.get(self.material)
+        material.BIMMaterialProperties.ifc_style_id = 0
+        if "Ifc" in material.name and "/" in material.name:
+            material.name = "/".join(material.name.split("/")[1:])
+        return {"FINISHED"}
diff --git a/src/ifcblenderexport/blenderbim/bim/module/style/ui.py b/src/ifcblenderexport/blenderbim/bim/module/style/ui.py
index 408e42a846..b34f4595fb 100644
--- a/src/ifcblenderexport/blenderbim/bim/module/style/ui.py
+++ b/src/ifcblenderexport/blenderbim/bim/module/style/ui.py
@@ -19,8 +19,10 @@ class BIM_PT_style(Panel):
 
     def draw(self, context):
         props = context.active_object.active_material.BIMMaterialProperties
-        row = self.layout.row()
+        row = self.layout.row(align=True)
         if props.ifc_style_id:
             row.operator("bim.edit_style", icon="GREASEPENCIL")
+            op = row.operator("bim.unlink_style", icon="UNLINKED", text="")
+            op.material = context.active_object.active_material.name
         else:
             row.operator("bim.add_style", icon="ADD")