[#4420] Display per period Retainer values on the Contract details page.

app/models/deliverable.rb

@@ -38,6 +38,11 @@ class Deliverable < ActiveRecord::Base
     ''
   end
 
+  # Deliverable's aren't dated. Subclasses may override this for period behavior.
+  def current_date
+    nil
+  end
+
   def to_s
     title
   end

app/models/fixed_deliverable.rb

@@ -29,8 +29,8 @@ class FixedDeliverable < Deliverable
 
   # The amount of money remaining after expenses have been taken out
   # Profit left = Total - Labor spent - Overhead spent
-  def profit_left
-    total_spent - labor_budget_spent - overhead_spent
+  def profit_left(date=nil)
+    total_spent(date) - labor_budget_spent(date) - overhead_spent(date)
   end
   
   # Hardcoded value used as a wrapper for the old Budget plugin API.

app/models/retainer_deliverable.rb

@@ -19,8 +19,12 @@ class RetainerDeliverable < HourlyDeliverable
     'R'
   end
 
+  def current_date
+    Date.today
+  end
+  
   def current_period
-    Date.today.strftime("%B %Y")
+    current_date.strftime("%B %Y")
   end
 
   def beginning_date
@@ -32,7 +36,11 @@ class RetainerDeliverable < HourlyDeliverable
   end
 
   def date_range
-    (beginning_date..ending_date)
+    if beginning_date && ending_date && beginning_date <= ending_date
+      (beginning_date..ending_date)
+    else
+      []
+    end
   end
 
   def within_date_range?(date)