coding_test.rb

# fullfill_orders_job.rb

...

class FulfillOrdersJob < ApplicationJob
  queue_as :default

  def perform(*args)
      Order.pending.each do |order|
        Order.transaction do
          fulfill_order(order)
        end
      end
    end
  end

  private

    def fulfill_order(order)
      Rails.logger.info "Fulfilling to fulfill order for #{order.id}"
    
      fulfilling_supplier = check_suppliers(order)

      if fulfilling_supplier
        reference = fulfilling_supplier.api_client.fulfill(product_name: order.product.name)
        begin
          order.update!(
            supplier: fulfilling_supplier,
            supplier_reference: reference,
            state: 'completed'
          )
          Rails.logger.info "Order fulfilled successfully."
        rescue ActiveRecord::RecordInvalid => e
          Rails.logger.error "Error updating order: #{e.message}"
        end
      else
        Rails.logger.info "Could not find a supplier with stock to fulfill order for #{order.id}".alarmify
      end
  end
  
  def check_suppliers(order)
    found_supplier = nil
    Supplier.find_each do |supplier|
      stock_available = check_stock_for_order_at_supplier(order, supplier)
    
      if stock_available
         found_supplier = supplier
         break
      end
    end
    found_supplier
  end


  def check_stock_for_order_at_supplier(order, supplier)
    begin
      stock = supplier.api_client.fetch_stock(product_name: order.product.name)
      stock.positive?
    rescue
      Rails.logger.info "There was an error when checking for available stock for #{order.id} and #{supplier.name}".alarmify
    end
  end
...

# supplier.rb

class Supplier < ApplicationRecord
  has_many :orders
  validates :name, presence: true, uniqueness: true

  def api_client
    api_clients = {
      'supplier_foo' => SupplierFooApi::Client,
      'supplier_bar' => SupplierBarApi::Client
      # Add other suppliers here
    }

    api_clients[self.name]
  end
end