Update model to support financial transactions #367

This change introduces two new data types to group the financial
transactions. Now every transaction has a "type", which itself belongs
to a "class".
Types should be used add structured information to an transaction, instead
of writing it into the notice textfield. E.g. this could be used to have
different types depending on the source of money (cash vs. bank transfer).
Classes are shown as different columns in the tables and will be uses to
group transactions of specific types. They should be used if not the whole
amount of ordergroup should be used to order food. E.g. if there is a
deposit or membership fee, which is independent of the normal credit.
This will allow us to implement additional features based on classes in
the future. E.g. the sum of transactions in the "membership fee" class
must be positive to allow food orders or show a big warning if it is bellow
a certain value.

app/models/financial_transaction.rb

@@ -4,6 +4,7 @@ class FinancialTransaction < ActiveRecord::Base
   belongs_to :ordergroup
   belongs_to :user
   belongs_to :financial_link
+  belongs_to :financial_transaction_type
 
   validates_presence_of :amount, :note, :user_id, :ordergroup_id
   validates_numericality_of :amount, greater_then: -100_000,
@@ -11,8 +12,18 @@ class FinancialTransaction < ActiveRecord::Base
 
   localize_input_of :amount
 
+  after_initialize do
+    initialize_financial_transaction_type
+  end
+
   # Use this save method instead of simple save and after callback
   def add_transaction!
-    ordergroup.add_financial_transaction! amount, note, user
+    ordergroup.add_financial_transaction! amount, note, user, financial_transaction_type
+  end
+
+  protected
+
+  def initialize_financial_transaction_type
+    self.financial_transaction_type ||= FinancialTransactionType.default
   end
 end

app/models/financial_transaction_class.rb

@@ -0,0 +1,6 @@
+class FinancialTransactionClass < ActiveRecord::Base
+  has_many :financial_transaction_types, dependent: :destroy
+
+  validates :name, presence: true
+  validates_uniqueness_of :name
+end

app/models/financial_transaction_type.rb

@@ -0,0 +1,25 @@
+class FinancialTransactionType < ActiveRecord::Base
+  belongs_to :financial_transaction_class
+  has_many :financial_transactions, dependent: :restrict_with_exception
+
+  validates :name, presence: true
+  validates_uniqueness_of :name
+  validates :financial_transaction_class, presence: true
+
+  before_destroy :restrict_deleting_last_financial_transaction_type
+
+  def self.default
+    first
+  end
+
+  def self.has_multiple_types
+    self.count > 1
+  end
+
+  protected
+
+  # check if this is the last financial transaction type and deny
+  def restrict_deleting_last_financial_transaction_type
+    raise I18n.t('model.financial_transaction_type.no_delete_last') if FinancialTransactionType.count == 1
+  end
+end

app/models/order.rb

@@ -231,7 +231,7 @@ class Order < ActiveRecord::Base
   end
 
   # Sets order.status to 'close' and updates all Ordergroup.account_balances
-  def close!(user)
+  def close!(user, transaction_type = nil)
     raise I18n.t('orders.model.error_closed') if closed?
     transaction_note = I18n.t('orders.model.notice_close', :name => name,
                               :ends => ends.strftime(I18n.t('date.formats.default')))
@@ -243,7 +243,7 @@ class Order < ActiveRecord::Base
       for group_order in gos
         if group_order.ordergroup
           price = group_order.price * -1                  # decrease! account balance
-          group_order.ordergroup.add_financial_transaction!(price, transaction_note, user)
+          group_order.ordergroup.add_financial_transaction!(price, transaction_note, user, transaction_type)
         end
       end
 

app/models/ordergroup.rb

@@ -55,9 +55,9 @@ class Ordergroup < Group
 
   # Creates a new FinancialTransaction for this Ordergroup and updates the account_balance accordingly.
   # Throws an exception if it fails.
-  def add_financial_transaction!(amount, note, user, link = nil)
+  def add_financial_transaction!(amount, note, user, transaction_type, link = nil)
     transaction do
-      t = FinancialTransaction.new(ordergroup: self, amount: amount, note: note, user: user, financial_link: link)
+      t = FinancialTransaction.new(ordergroup: self, amount: amount, note: note, user: user, financial_transaction_type: transaction_type, financial_link: link)
       t.save!
       self.account_balance = financial_transactions.sum('amount')
       save!