add specs

app/models/multi_order.rb

@@ -6,11 +6,10 @@ class MultiOrder < ApplicationRecord
   #TODO: diese association lösen
   has_many :group_orders, through: :multi_group_orders
   # has_many :ordergroups, through: :group_orders
-  has_many :ordergroup_invoices, through: :group_orders
+  has_many :ordergroup_invoices, through: :multi_group_orders
 
-  #make sure order has no multi_order_id
-  #make sure orders are not in a multi_order
-  before_create :check_orders
+  validate :check_orders
+  after_create :create_multi_group_orders
 
   def name
     orders.map(&:name).join(', ')
@@ -40,15 +39,38 @@ class MultiOrder < ApplicationRecord
   end
   
   private
+
   def check_orders
-    orders.each do |order|
-      errors.add(:base, "Order #{order.name} is already in a multi order") unless order.multi_order_id.nil?
-      #closed==abgerechnet
-      errors.add(:base, "Order #{order.name} not closed") unless order.closed?
+    unless orders.present?
+      errors.add(:base, "No orders selected")
+      return
     end
-    if errors.any?
-      errors.add(:base, "Cannot create multi order with unfinished orders")
-      raise ActiveRecord::Rollback
+    orders.each do |order|
+      if order.group_orders.blank?
+        errors.add(:base, "Order #{order.name} has no group orders")
+      end
+      unless order.closed? 
+        errors.add(:base, "Order #{order.name} is not closed")
+      end
+      if order.group_orders.any? { |go| go.group_order_invoice.present? }
+        errors.add(:base, "Order #{order.name} has group order invoices")
+      end
+    end
+  end
+
+  def create_multi_group_orders
+    return if orders.empty?
+    all_group_orders = orders.flat_map(&:group_orders)
+    grouped_by_ordergroup = all_group_orders.group_by(&:ordergroup_id)
+
+    grouped_by_ordergroup.each do |ordergroup_id, group_orders|
+      multi_group_order = MultiGroupOrder.create!(
+        multi_order: self, group_orders: group_orders
+      )
+      # Now, associate each group_order with the new multi_group_order
+      group_orders.each do |group_order|
+        group_order.update!(multi_group_order: multi_group_order)
+      end
     end
   end
 end