Mostly working sequence_usage_report + remove N+1 from sequence index

app/controllers/api/sequences_controller.rb

@@ -33,10 +33,7 @@ module Api
     end
 
     def sequences
-      puts "TODO- maybe I need to do a raw SQL query here ? Hmmm..."
-      @sequences ||= Sequence
-                      .includes(:primary_nodes, :edge_nodes)
-                      .where(device: current_device)
+      @sequences ||= Sequence.with_usage_reports.where(device: current_device)
     end
 
     def sequence

app/lib/celery_script/fetch_celery.rb

@@ -86,11 +86,12 @@ module CeleryScript
     def misc_fields
       return {
         id:         sequence.id,
-        name:       sequence.name,
-        color:      sequence.color,
         created_at: sequence.created_at,
         updated_at: sequence.updated_at,
-        args:       Sequence::DEFAULT_ARGS
+        args:       Sequence::DEFAULT_ARGS,
+        color:      sequence.color,
+        in_use:     sequence.in_use?,
+        name:       sequence.name,
       }
     end
 
@@ -110,12 +111,6 @@ module CeleryScript
 
     def execute
       canonical_form = misc_fields.merge!(recurse_into_node(entry_node))
-      # N+1 AHEAD:
-      canonical_form[:in_use] = \
-        EdgeNode.where(kind: "sequence_id", value: sequence.id).exists? ||
-        RegimenItem.where(sequence_id: sequence.id).exists? ||
-        FarmEvent.where(executable: sequence).exists?
-      raise "Eager load sequence_usage_report" if !sequence.association(:sequence_usage_report).loaded?
       s = canonical_form.with_indifferent_access
       # HISTORICAL NOTE:
       #   When I prototyped the variables declaration stuff, a few (failed)

app/models/sequence.rb

@@ -63,6 +63,20 @@ class Sequence < ApplicationRecord
     false unless destroyed?
   end
 
+  # Determines if the current sequence is used by any farmevents, regimens or
+  # sequences.
+  def in_use?
+    [sequence_usage_report.edge_node_count,
+     sequence_usage_report.farm_event_count,
+     sequence_usage_report.regimen_items_count].max != 0
+  end
+
+  # Eagerly load edge_node, primary_node and usage_report. This is a big deal
+  # for performance when serializing sequences.
+  def self.with_usage_reports
+    self.includes(:sequence_usage_report, :edge_nodes, :primary_nodes)
+  end
+
   # THIS IS AN OVERRIDE - Special serialization required for auto sync.
   # When a sequence is created, we save it to the database to create a primary
   # key, then we iterate over `EdgeNode` and `PrimaryNode`s, assigning that