Number of plans can no be incremented or decremented

app/models/job.rb

@@ -5,18 +5,23 @@ class Job < ApplicationRecord
   has_one_attached :pdf, dependent: :purge
 
   validates_presence_of :costumer_firstname, :costumer_lastname, :privacy_policy_accepted, :pdf
+  # validates_numericality_of  {:number_of_plans_a0,:number_of_plans_a1, :number_of_plans_a2, :number_of_plans_a3},  greater_than_or_equal_to: 0
+  validates :number_of_plans_a0, :number_of_plans_a1, :number_of_plans_a2, :number_of_plans_a3, numericality: { greater_than_or_equal_to: 0 }
+
+
   validate :acceptable_pdf
 
   before_save :update_printed_at, if: :will_save_change_to_status?
   before_save :update_paid_at, if: :will_save_change_to_status?
   before_save :update_status_changed_at, if: :will_save_change_to_status?
   before_save :set_cost_qm
+  before_save :calc_cost, if: :printed_pages_changes?
 
   # TODO: works only when job is created. Should move analyzer to activestorage :https://discuss.rubyonrails.org/t/active-storage-in-production-lessons-learned-and-in-depth-look-at-how-it-works/83289
   after_create_commit :analyze_pdf
 
   # NOTE: Multiple status if paing before brinting?
-  enum status: {
+  enum :status, {
     open: 0,
     printing: 1,
     pickup: 2,
@@ -24,6 +29,8 @@ class Job < ApplicationRecord
     canceled: 4
   }
 
+  AVAILABLE_PAGE_FORMATS = [ :a0, :a1, :a2, :a3 ]
+
   # NOTE: only named status are returned because of WHERE/IN clause for the enum values
   scope :in_status_order, -> { in_order_of(:status, %w[open printing pickup paid canceled]) }
 
@@ -86,8 +93,24 @@ class Job < ApplicationRecord
     end
   end
 
+  def increment_page(din)
+    return false unless AVAILABLE_PAGE_FORMATS.include?(din.to_sym)
+    public_send("number_of_plans_#{din}=", public_send("number_of_plans_#{din}") + 1) if respond_to? "number_of_plans_#{din}="
+    save
+  end
+
+  def decrement_page(din)
+    return false unless AVAILABLE_PAGE_FORMATS.include?(din.to_sym)
+    public_send("number_of_plans_#{din}=", public_send("number_of_plans_#{din}") - 1) if respond_to? "number_of_plans_#{din}="
+    save
+  end
+
   private
 
+  def printed_pages_changes?
+    costum_qm_plan_previously_changed? || number_of_plans_a0_changed? || number_of_plans_a1_changed? || number_of_plans_a2_changed? || number_of_plans_a3_changed?
+  end
+
   def update_printed_at
     self.printed_at = Time.now if pickup? || (paid? && printed_at.nil?)
   end