limit events fetched for calendar to month requested

app/controllers/events_controller.rb

@@ -34,11 +34,15 @@ def calendar
     # include expired results so we also fill past pages
     params[:per_page] ||= 200
     params[:include_expired] ||= 'true'
+    @start_date = Date.parse(params.fetch(:start_date, Date.today.to_s)).beginning_of_month
+
     set_params
+    # override @facet_params to get only events relevant for the current month view
+    @facet_params[:running_during] = "#{@start_date.to_s}/#{(@start_date + 1.month).to_s}"
+
     fetch_resources
     # now customize the list by moving all events longer than 3 days into a separate array
     @long_events, @events = @events.partition { |e| e.end.nil? || e.start.nil? || e.start + TeSS::Config.site.fetch(:calendar_event_maxlength, 5).to_i.days < e.end }
-    @start_date = params[:start_date]
 
     respond_to do |format|
       format.js

lib/facets.rb

@@ -6,6 +6,7 @@ module Facets
       elixir: -> (c) { ['Event', 'Material', 'ContentProvider'].include?(c.name) },
       max_age: -> (c) { ['Event', 'Material'].include?(c.name) },
       start: -> (c) { c.name == 'Event' },
+      running_during: -> (c) { c.name == 'Event' },
       include_hidden: -> (c) { c.method_defined?(:user_requires_approval?) }
   }.with_indifferent_access.freeze
 
@@ -15,6 +16,7 @@ module Facets
       include_archived: -> (value) { value == 'true'},
       max_age: -> (value) { Subscription::FREQUENCY.detect { |f| f[:title] == value }.try(:[], :period) },
       start: -> (value) { value&.split('/')&.map {|d| Date.parse(d) rescue nil } },
+      running_during: -> (value) { value&.split('/')&.map {|d| Date.parse(d) rescue nil } },
       include_hidden: -> (value) { value == 'true'}
   }
 
@@ -56,6 +58,20 @@ def start(scope, bounds, _)
       end
     end
 
+    def running_during(scope, bounds, _)
+      lb, ub = bounds
+
+      sunspot_scoped(scope) do
+        if lb && ub
+          with(:end).between(lb..(ub + TeSS::Config.site.fetch(:calendar_event_maxlength, 5).to_i.days))
+        elsif lb
+          with(:end).greater_than_or_equal_to(lb)
+        elsif ub
+          with(:start).less_than_or_equal_to(ub)
+        end
+      end
+    end
+
     def include_expired(scope, value, _)
       sunspot_scoped(scope) { with('end').greater_than(Time.zone.now) } unless value
     end