Fix access to context variables in UI rules

Signed-off-by: Jimmy Tanagra <[email protected]>

lib/openhab/core.rb

@@ -98,6 +98,29 @@ def import_scope_values(scope_values)
           eval("#{key} = value unless defined?(#{key})", nil, __FILE__, __LINE__) # rubocop:disable Security/Eval
         end
       end
+
+      #
+      # Returns a hash of global context variable `$ctx` injected into UI based scripts.
+      #
+      # The keys in $ctx are prefixed with the trigger module id.
+      # This method strips them off and symbolizes them so they are accessible without the module id prefix.
+      #
+      # @!visibility private
+      # @return [Hash<Symbol, Object>, nil]
+      #
+      def ui_context
+        # $ctx is a java.util.HashMap and its #to_h doesn't take a block like Ruby's
+        @ui_context ||= $ctx&.to_hash&.to_h do |key, value|
+          [
+            key.split(".", 2).last.to_sym,
+            case value
+            when Items::Item then Items::Proxy.new(value)
+            when Things::Thing then Things::Proxy.new(value)
+            else value
+            end
+          ]
+        end.freeze
+      end
     end
 
     import_default_presets unless defined?($ir)

lib/openhab/core/events/item_event.rb

@@ -32,7 +32,7 @@ def item
         # @since openHAB 4.1 for UI rules
         #
         def group
-          triggering_group = inputs&.[]("triggeringGroup") || $ctx&.[]("triggeringGroup")
+          triggering_group = inputs&.[]("triggeringGroup") || Core.ui_context&.[](:triggeringGroup)
           Items::Proxy.new(triggering_group) if triggering_group
         end
       end

lib/openhab/dsl.rb

@@ -1094,15 +1094,20 @@ def try_parse_time_like(string)
     # @!visibility private
     ruby2_keywords def method_missing(method, *args)
       return super unless args.empty? && !block_given?
-      return super unless (context = Thread.current[:openhab_context]) && context.key?(method)
 
-      logger.trace("DSL#method_missing found context variable: '#{method}'")
-      context[method]
+      if (context = Thread.current[:openhab_context]) && context.key?(method)
+        logger.trace("DSL#method_missing found context variable: '#{method}'")
+        return context[method]
+      elsif Core.ui_context&.key?(method)
+        logger.trace("DSL#method_missing found UI context variable: '#{method}'")
+        return Core.ui_context[method]
+      end
+      super
     end
 
     # @!visibility private
     def respond_to_missing?(method, include_private = false)
-      Thread.current[:openhab_context]&.key?(method) || super
+      Thread.current[:openhab_context]&.key?(method) || Core.ui_context&.key?(method) || super
     end
   end
 end