cache dossiers count

app/models/procedure.rb

@@ -15,10 +15,12 @@
 #  closed_at                                 :datetime
 #  declarative_with_state                    :string
 #  description                               :string
+#  dossiers_count_computed_at                :datetime
 #  duree_conservation_dossiers_dans_ds       :integer
 #  duree_conservation_etendue_par_ds         :boolean          default(FALSE)
 #  encrypted_api_particulier_token           :string
 #  estimated_duration_visible                :boolean          default(TRUE), not null
+#  estimated_dossiers_count                  :integer
 #  euro_flag                                 :boolean          default(FALSE)
 #  experts_require_administrateur_invitation :boolean          default(FALSE)
 #  for_individual                            :boolean          default(FALSE)
@@ -71,6 +73,8 @@ class Procedure < ApplicationRecord
 
   MIN_WEIGHT = 350000
 
+  DOSSIERS_COUNT_EXPIRING = 1.hour
+
   attr_encrypted :api_particulier_token
 
   has_many :revisions, -> { order(:id) }, class_name: 'ProcedureRevision', inverse_of: :procedure
@@ -836,7 +840,13 @@ class Procedure < ApplicationRecord
     self.connection.query(query.to_sql).flatten
   end
 
-  private
+  def compute_dossiers_count
+    now = Time.zone.now
+    if now > (self.dossiers_count_computed_at || self.created_at) + DOSSIERS_COUNT_EXPIRING
+      self.update(estimated_dossiers_count: self.dossiers.visible_by_administration.count,
+                dossiers_count_computed_at: now)
+    end
+  end
 
   def move_new_children_to_new_parent_coordinate(new_draft)
     children = new_draft.revision_types_de_champ

db/migrate/20230217094119_add_estimated_dossiers_count_and_dossiers_count_computed_at_to_procedures.rb

@@ -0,0 +1,6 @@
+class AddEstimatedDossiersCountAndDossiersCountComputedAtToProcedures < ActiveRecord::Migration[6.1]
+  def change
+    add_column :procedures, :estimated_dossiers_count, :integer
+    add_column :procedures, :dossiers_count_computed_at, :datetime
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2023_02_16_141558) do
+ActiveRecord::Schema.define(version: 2023_02_17_094119) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
@@ -703,12 +703,14 @@ ActiveRecord::Schema.define(version: 2023_02_16_141558) do
     t.string "declarative_with_state"
     t.string "description"
     t.string "direction"
+    t.datetime "dossiers_count_computed_at"
     t.bigint "draft_revision_id"
     t.integer "duree_conservation_dossiers_dans_ds"
     t.boolean "duree_conservation_etendue_par_ds", default: false
     t.boolean "durees_conservation_required", default: true
     t.string "encrypted_api_particulier_token"
     t.boolean "estimated_duration_visible", default: true, null: false
+    t.integer "estimated_dossiers_count"
     t.boolean "euro_flag", default: false
     t.boolean "experts_require_administrateur_invitation", default: false
     t.boolean "for_individual", default: false

spec/models/procedure_spec.rb

@@ -9,6 +9,20 @@ describe Procedure do
     it { expect(subject.without_continuation_mail_template).to be_a(Mails::WithoutContinuationMail) }
   end
 
+  describe 'compute_dossiers_count' do
+    let(:procedure) { create(:procedure_with_dossiers, dossiers_count: 2, dossiers_count_computed_at: Time.zone.now - Procedure::DOSSIERS_COUNT_EXPIRING) }
+
+    it 'caches estimated_dossiers_count' do
+      procedure.dossiers.each(&:passer_en_construction!)
+      expect { procedure.compute_dossiers_count }.to change(procedure, :estimated_dossiers_count).from(nil).to(2)
+      expect { create(:dossier, procedure: procedure).passer_en_construction! }.not_to change(procedure, :estimated_dossiers_count)
+
+      Timecop.freeze(Time.zone.now + Procedure::DOSSIERS_COUNT_EXPIRING)
+      expect { procedure.compute_dossiers_count }.to change(procedure, :estimated_dossiers_count).from(2).to(3)
+      Timecop.return
+    end
+  end
+
   describe 'initiated_mail' do
     let(:procedure) { create(:procedure) }