WIP: Basic structure for daily job to update user invoices

app/jobs/update_user_invoices.rb

@@ -0,0 +1,59 @@
+UpdateUserInvoices = Struct.new("UpdateUserInvoices") do
+  def perform
+    # If it is the first of the month, update invoices for the previous month up until midnight last night
+    # Otherwise, update invoices for the current month
+    start_date = (Time.now - 1.day).beginning_of_month
+    end_date = Time.now.beginning_of_day
+
+    # Find all users that have owned an enterprise at some point in the current billing period (this month)
+    enterprise_users = Spree::User.joins(:billable_periods)
+    .where('billable_periods.begins_at >= (?) AND billable_periods.ends_at <= (?)', start_date, end_date)
+    .select('DISTINCT spree_users.*')
+
+    enterprise_users.each do |user|
+      update_invoice_for(user, user.billable_periods.where('begins_at >= (?) AND ends_at <= (?)', start_date, end_date))
+    end
+  end
+
+  def update_invoice_for(user, billable_periods)
+    invoice = user.current_invoice
+
+    billable_periods.each do |billable_period|
+      adjustment = invoice.adjustments.where(source: billable_period).first
+      adjustment ||= invoice.adjustments.new( adjustment_attrs_from(billable_period) )
+      adjustment.label = adjustment_label_from(billable_period)
+      adjustment.amount = billable_period.bill
+      adjustment.save
+    end
+
+    finalize(invoice)
+  end
+
+  def adjustment_attrs_from(billable_period)
+    { :source => billable_period,
+      :originator => billable_period,
+      :mandatory => mandatory,
+      :locked => true }
+  end
+
+  def adjustment_label_from(billable_period)
+    category = enterprise.version_at(billable_period.begins_at).reify.category.to_s.titleize
+    category += (billable_period.trial ? " Trial" : "")
+    begins = billable_period.begins_at.strftime("%d/%m")
+    ends = billable_period.begins_at.strftime("%d/%m")
+
+    "#{enterprise.name} (#{category}) [#{begins}-#{ends}]"
+  end
+
+  def finalize(invoice)
+    if Date.today.day == 1
+      while @order.state != "complete"
+        @order.next
+      end
+      user.current_invoice.process
+      # Mark current invoice as completed
+      # Create a new invoice
+      user.current_invoice = new_invoice_for(user)
+    end
+  end
+end

app/models/spree/user_decorator.rb

@@ -7,6 +7,7 @@ Spree.user_class.class_eval do
   has_many :enterprises, through: :enterprise_roles
   has_many :owned_enterprises, class_name: 'Enterprise', foreign_key: :owner_id, inverse_of: :owner
   has_many :owned_groups, class_name: 'EnterpriseGroup', foreign_key: :owner_id, inverse_of: :owner
+  has_many :billable_periods, foreign_key: :owner_id, inverse_of: :owner
   has_one :cart
   has_many :customers
 

spec/jobs/update_user_invoices_spec.rb

@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+def travel_to(time)
+  around { |example| Timecop.travel(start_of_july + time) { example.run } }
+end
+
+describe UpdateUserInvoices do
+  describe "units specs" do
+    let!(:start_of_july) { Time.now.beginning_of_year + 6.months }
+
+    let!(:updater) { UpdateUserInvoices.new }
+
+    describe "perform" do
+      let!(:user) { create(:user) }
+      let!(:old_billable_period) { create(:billable_period, owner: user, begins_at: start_of_july - 1.month, ends_at: start_of_july) }
+      let!(:billable_period1) { create(:billable_period, owner: user, begins_at: start_of_july, ends_at: start_of_july + 12.days) }
+      let!(:billable_period2) { create(:billable_period, owner: user, begins_at: start_of_july + 12.days, ends_at: start_of_july + 20.days) }
+
+      before do
+        allow(updater).to receive(:update_invoice_for)
+      end
+
+      context "on the first of the month" do
+        travel_to(3.hours)
+
+        it "updates the user's current invoice with billable_periods from the previous month" do
+          updater.perform
+          expect(updater).to have_received(:update_invoice_for).once
+          .with(user, [old_billable_period])
+        end
+      end
+
+      context "on other days" do
+        travel_to(20.days)
+
+        it "updates the user's current invoice with billable_periods from the current month" do
+          updater.perform
+          expect(updater).to have_received(:update_invoice_for).once
+          .with(user, [billable_period1, billable_period2])
+        end
+      end
+    end
+
+    describe "update_invoice_for" do
+      let!(:user) { create(:user) }
+      let!(:billable_period1) { create(:billable_period, owner: user, begins_at: start_of_july, ends_at: start_of_july + 12.days) }
+      let!(:billable_period2) { create(:billable_period, owner: user, begins_at: start_of_july + 12.days, ends_at: start_of_july + 20.days) }
+
+
+    end
+  end
+end