From d05536bed4697f2ce2b802775b5f799d0d073d82 Mon Sep 17 00:00:00 2001
From: Bill Ferguson <wpferguson@gmail.com>
Date: Sat, 8 Aug 2020 23:21:54 -0400
Subject: [PATCH] Added check to ensure we are in lighttable view prior to
 callling darktable.register_lib.  If darktable was invoked in single image
 (darkroom) mode, then an event handler is registered to detect the change
 from darkroom mode to lighttable mode so that we can then call
 darktable.register_lib.

---
 contrib/AutoGrouper.lua | 65 +++++++++++++++++++++++++++++------------
 1 file changed, 47 insertions(+), 18 deletions(-)

diff --git a/contrib/AutoGrouper.lua b/contrib/AutoGrouper.lua
index 0d92915..18ff103 100644
--- a/contrib/AutoGrouper.lua
+++ b/contrib/AutoGrouper.lua
@@ -45,6 +45,17 @@ local function _(msgid)
     return gettext.dgettext("AutoGrouper", msgid)
 end
 
+local Ag = {}
+Ag.module_installed = false
+Ag.event_registered = false
+
+local GUI = {
+    gap =           {},
+    selected =      {},
+    collection =    {}
+}
+
+
 local function InRange(test, low, high) --tests if test value is within range of low and high (inclusive)
     if test >= low and test <= high then
         return true
@@ -111,12 +122,26 @@ local function main(on_collection)
     end
 end
 
+local function install_module()
+  if not Ag.module_installed then
+    dt.register_lib(
+        'AutoGroup_Lib',    -- Module name
+        _('auto group'),    -- name
+        true,   -- expandable
+        true,   -- resetable
+        {[dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 99}},   -- containers
+        dt.new_widget("box"){
+            orientation = "vertical",
+            GUI.gap,
+            GUI.selected,
+            GUI.collection
+            }
+    )
+    Ag.module_installed = true
+  end
+end
+
 -- GUI --
-GUI = {
-    gap =           {},
-    selected =      {},
-    collection =    {}
-}
 temp = dt.preferences.read(MOD, 'active_gap', 'integer')
 if not InRange(temp, 1, 86400) then temp = 3 end
 GUI.gap = dt.new_widget('slider'){
@@ -143,16 +168,20 @@ GUI.collection = dt.new_widget("button"){
     tooltip =_('auto group the entire collection'),
     clicked_callback = function() main(true) end
 }
-dt.register_lib(
-    'AutoGroup_Lib',    -- Module name
-    _('auto group'),    -- name
-    true,   -- expandable
-    true,   -- resetable
-    {[dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 99}},   -- containers
-    dt.new_widget("box"){
-        orientation = "vertical",
-        GUI.gap,
-        GUI.selected,
-        GUI.collection
-        }
-)
+
+if dt.gui.current_view().name == "lighttable" then
+  install_module()
+else
+  if not Ag.event_registered then
+    dt.register_event(
+      "view-changed",
+      function(event, old_view, new_view)
+        if new_view.name == "lighttable" and old_view.name == "darkroom" then
+          install_module()
+         end
+      end
+    )
+    Ag.event_registered = true
+  end
+end
+