refactor: prepare for free ticket

app/models/order.rb

@@ -116,6 +116,11 @@ class Order < ApplicationRecord
     promoter_payout_cents / 100.0
   end
 
+  # Check if order contains only free tickets
+  def free?
+    total_amount_cents == 0
+  end
+
   # Create Stripe invoice for accounting records
   #
   # This method creates a post-payment invoice in Stripe for accounting purposes

app/models/ticket.rb

@@ -9,7 +9,7 @@ class Ticket < ApplicationRecord
   validates :qr_code, presence: true, uniqueness: true
   validates :order_id, presence: true
   validates :ticket_type_id, presence: true
-  validates :price_cents, presence: true, numericality: { greater_than: 0 }
+  validates :price_cents, presence: true, numericality: { greater_than_or_equal_to: 0 }
   validates :status, presence: true, inclusion: { in: %w[draft active used expired refunded] }
   validates :first_name, presence: true
   validates :last_name, presence: true

app/models/ticket_type.rb

@@ -6,7 +6,7 @@ class TicketType < ApplicationRecord
   # Validations
   validates :name, presence: true, length: { minimum: 3, maximum: 50 }
   validates :description, presence: true, length: { minimum: 10, maximum: 500 }
-  validates :price_cents, presence: true, numericality: { greater_than: 0 }
+  validates :price_cents, presence: true, numericality: { greater_than_or_equal_to: 0 }
   validates :quantity, presence: true, numericality: { only_integer: true, greater_than: 0 }
   validates :sale_start_at, presence: true
   validates :sale_end_at, presence: true
@@ -48,6 +48,10 @@ class TicketType < ApplicationRecord
     [ quantity - tickets.count, 0 ].max
   end
 
+  def free?
+    price_cents == 0
+  end
+
   def sales_status
     return :draft if sale_start_at.nil? || sale_end_at.nil?
     return :expired if sale_end_at < Time.current