added rudimentary support for belongs_to ordering

lib/forty_facets/facet_search.rb

@@ -120,8 +120,10 @@ def result(skip_ordering: false)
         filter.build_scope.call(previous)
       end
 
-      unless skip_ordering
-        query = query.order(order.definition.clause) if order
+      if order && !skip_ordering
+        query = order.apply(query)
+      else
+        query = query.distinct
       end
       query
     end

lib/forty_facets/filter/facet_filter_definition.rb

@@ -64,7 +64,7 @@ def build_scope
       def facet
         my_column = definition.qualified_column_name
         query = "#{my_column} AS facet_value, count(#{my_column}) AS occurrences"
-        counts = without.result(skip_ordering: true).reorder('').joins(definition.joins).select(query).group(my_column)
+        counts = without.result(skip_ordering: true).distinct.joins(definition.joins).select(query).group(my_column)
         counts.includes_values = []
         facet = counts.map do |c|
           is_selected = selected.include?(c.facet_value)
@@ -102,7 +102,7 @@ def build_scope
       def facet
         my_column = definition.qualified_column_name
         query = "#{my_column} AS foreign_id, count(#{my_column}) AS occurrences"
-        counts = without.result(skip_ordering: true).reorder('').joins(definition.joins).select(query).group(my_column)
+        counts = without.result(skip_ordering: true).distinct.joins(definition.joins).select(query).group(my_column)
         counts.includes_values = []
         entities_by_id = definition.association.klass.find(counts.map(&:foreign_id)).group_by(&:id)
 
@@ -136,7 +136,7 @@ def facet
         foreign_id_col = definition.association.name.to_s.singularize + '_id'
         my_column = join_name + '.' + foreign_id_col
         counts = without.result(skip_ordering: true)
-                  .reorder('')
+                  .distinct
                   .joins(definition.joins)
                   .select("#{my_column} as foreign_id, count(#{my_column}) as occurrences")
                   .group(my_column)

lib/forty_facets/order.rb

@@ -11,6 +11,38 @@ def by
       new_params[:order] = definition.request_value
       search.class.new_unwrapped(new_params, search.root)
     end
+
+    def apply(query)
+      if [Symbol, String, Hash].include? definition.clause.class
+        query.order(definition.clause)
+      elsif definition.clause.is_a? Array # [:person, :first_name]
+        # new and unelegant handling of ordering by columns from joined tables
+        root_table = search.class.root_class.table_name
+        primary_key = search.class.root_class.primary_key
+        just_ids = query.select("#{root_table}.#{primary_key}")
+        path_to_order_property = definition.clause
+        order_class = path_to_order_property
+                      .take(path_to_order_property.length - 1)
+                      .inject(search.class.root_class) do |prev_class, assoc_name|
+                        prev_class.reflect_on_association(assoc_name).klass
+                      end
+        joins = path_to_order_property
+                  .reverse
+                  .drop(1)
+                  .inject(nil) do |sum, elem|
+                    if sum
+                      {elem => sum}
+                    else
+                      elem
+                    end
+                  end
+        search.root
+          .joins(joins)
+          .where(search.class.root_class.primary_key => just_ids)
+          .order("#{order_class.table_name}.#{path_to_order_property.last}")
+      end
+
+    end
   end
 end