Add method to return correct price for an operation #2741

app/models/pricelist.rb

@@ -1,6 +1,8 @@
 class Pricelist < ActiveRecord::Base
   include Versions # version/pricelist_version.rb
 
+  scope :valid, -> { where("valid_from <= ? AND valid_to >= ? OR valid_to IS NULL", Time.zone.now, Time.zone.now) }
+
   monetize :price_cents
 
   validates :price_cents, :price_currency, :price,
@@ -13,10 +15,18 @@ class Pricelist < ActiveRecord::Base
   after_initialize :init_values
   def init_values
     return unless new_record?
-    self.valid_from = Time.zone.now.beginning_of_year
+    self.valid_from = Time.zone.now.beginning_of_year unless valid_from
   end
 
   def name
     "#{operation_category} #{category}"
   end
+
+  class << self
+    def price_for(category, operation, duration)
+      lists = valid.where(category: category, operation_category: operation, duration: duration)
+      return lists.first.price if lists.count == 1
+      lists.where('valid_to IS NOT NULL').order(valid_from: :desc).first.price
+    end
+  end
 end

spec/models/pricelist_spec.rb

@@ -15,8 +15,8 @@ describe Pricelist do
     it 'should not be valid' do
       @pricelist.valid?
       @pricelist.errors.full_messages.should match_array([
-        "Category is missing", 
+        "Category is missing",
-        "Duration is missing", 
+        "Duration is missing",
         "Operation category is missing"
       ])
     end
@@ -36,7 +36,6 @@ describe Pricelist do
     it 'should not have name' do
       @pricelist.name.should == ' '
     end
-
   end
 
   context 'with valid attributes' do
@@ -69,4 +68,94 @@ describe Pricelist do
       end
     end
   end
+
+  it 'should return correct price' do
+    Fabricate(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.50,
+      valid_from: Time.zone.parse('2198-01-01'),
+      valid_to: Time.zone.parse('2199-01-01')
+    })
+
+    expect { Pricelist.price_for('ee', 'create', '1year') }.to raise_error(NoMethodError)
+
+    Fabricate(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.50,
+      valid_from: Time.zone.parse('2015-01-01'),
+      valid_to: nil
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.50
+
+    Fabricate(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.30,
+      valid_from: Time.zone.parse('2015-01-01'),
+      valid_to: Time.zone.parse('2999-01-01')
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.30
+
+    Fabricate.create(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.20,
+      valid_from: Time.zone.parse('2015-06-01'),
+      valid_to: Time.zone.parse('2999-01-01')
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.20
+
+    Fabricate.create(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.10,
+      valid_from: Time.zone.parse('2014-01-01'),
+      valid_to: Time.zone.parse('2999-01-01')
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.20
+
+    Fabricate.create(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.10,
+      valid_from: Time.zone.parse('2999-02-01'),
+      valid_to: Time.zone.parse('2999-01-01')
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.20
+
+    Fabricate.create(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.10,
+      valid_from: Time.zone.parse('2015-06-02'),
+      valid_to: nil
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.20
+
+    Fabricate.create(:pricelist, {
+      category: 'ee',
+      operation_category: 'create',
+      duration: '1year',
+      price: 1.10,
+      valid_from: Time.zone.parse('2015-07-01'),
+      valid_to: Time.zone.parse('2999-01-01')
+    })
+
+    Pricelist.price_for('ee', 'create', '1year').should == 1.10
+  end
 end