billing

The schema of this module is oriented more toward compatibility with Fiscal Memory Devices, rather than Accounting Software, but it incorporates base Billing and Invoicing standards.
It is suitable for use in Trading Software, Online Shops and provides UFB (Universal Fiscal Basket) for issuing fiscal receipts with Extface module.

This module is currently in development stage

Bill text constructor protocol:

*1                (set operator 1)  
1.2               (charge $1.2)   / default currency or $, default tax group
2*4,5             (2 charges $4.5)
1.2@2             (charge $1.2, tax group 2)
1.2/text          (charge $1.2 with text)
/text             (zero charge with text / comment)
10-50%            (charge $10 with 50% discount)
20-2              (charge $20, discount $2)
#23               (charge PLU by number)
2*#23             (2 qty of PLU by number)
2.5*#23-20%       (2.5 qty of PLU by number, 20% discount)
1.2#4             (charge $1.2 by department 4)
50+2              (charge $50 with $2 surcharge)
-10%              (discount 10% whole bill)
-5                (discount $5)
@2/10             (payment $10 with payment type 2)
@1                (auto calculated payment with payment type 1 / or default payment type if not specified)
@#36              (auto calculated payment and issue invoice for profile 36)         

###Charge

[qty*][price[currency_iso]][#PLU][@tax][+surcharge[%]/-discount[%]][/text]

###Discount/Surcharge

+/-[value[%]][/text]

###Payment

@[type[/value]][#profile]

##Billing schema

Namespace Billing

• Bill - Base billing class.
• Charge - Bill item which increases the total.
• Modilfier - Discount or Surcharge for specified item or global. Can be percent or fixed value.
• Payment - STI model, that defaults to payment with type. Can be extended to payment by external system or with payment gateway.

Nomenclature (STI models):

• TaxGroup - VAT settings

• PaymentType - Cash, Fiscal

• Operator - Fiscal device users

• Department - PLU (Price look-up) groups

• Plu - Price look-up items

• Profile - Invoice infos

• Origin - Billing source categorization and settings

• Report - Daily and periodical finance and fiscal reports

**Instalation

gem 'billing'

bundle install
bundle exec bin/rake billing:install
bundle exec bin/rake db:migrate

Enable billing for an ActiveRecord model by adding macro-like class method:

class MyBillableModel < ActiveRecord::Base
  has_billing
end

The module will add #billing_bills collection to the model.

See http://alexvangelov.wordpress.com/2014/07/20/ruby-on-rails-app-with-billing-and-fiscalization-part1-billing-model/

There are some rules and restrictions in order to maintain the schema universal:

• Charge may have only one modifier (discount or surcharge).
• Bill may have only one global modifier (total discount/surcharge).
• Bill may have only one cash payment
• Bill may not include payments of different payment models (= different origins)
• Bill may not include payments of different fiscal status
• Cascade look-up rule. (Example: If a charge is not initialized with tax group, it looks for tax group in PLU reference. If the PLU doesn't have a tax group, it looks in it's department reference).
• All nomenclature models are STI (Single Table Inheritance) and may be extended by main application.
• Each billing database table has unused integer column master_id, available for global application scopes.

More about Origin

Origin is complex object that is not involved in the billing calculations. By adding first payment to the bill, it allocates bill completition origin. Origin restricts the remaining payments to be of the same origin's payment model. Recommended approach is to have chargable models belonging to Origin. This will allow the system to know where the charges come from. The charges in the bill may come from multiple origins, but at the end of it's life, bill have a single origin.

When extface module is included, it's possible to attach print devices to origin and print store information when a charge is created.

Origin also determines the model of payment and fiscal memory device. That's why this object reflects the physical or virtual locations of administrative units for the billing system. If the application does'n care about the origins, it may work with single default origin.

In contrast to desktop applications, where the operator and the access point to program interface are located at the same place, the cloud based billing system has daily and closure reports per origin, not per operator.

• The schema does not provide direct charge - payment reference. A charge is paid when the bill balance is zero. Explanation: If bill have 3 charges and 2 payments - one by credit card and one in cash, it's not possible to clarify exactly which charge is paid by card.

####Billable, Chargable & Payable* polymorphic associations

Billable is the object to which the module is plugged with has_billing class method. It may be a company, client or the application itself.

Chargable can be any object. According to the explanations above, it should respond to #origin, or the billing module will look for a default origin (cascade look-up rule).

At the moment Payable is only billing bill. Will address deposits and advance payments when they are realized.