Add total amount spent by user

User can see the total amount that he paid for the tickets and total amount spent by him on each ticket

app/controllers/conference_registrations_controller.rb

@@ -27,8 +27,9 @@ class ConferenceRegistrationsController < ApplicationController
   end
 
   def show
-    @total_price = Ticket.total_price(@conference, current_user, paid: true)
+    @total_price = Ticket.total_price_user(@conference, current_user, paid: true)
     @tickets = current_user.ticket_purchases.by_conference(@conference).paid
+    @total_price_per_ticket = @tickets.group(:ticket_id).sum('amount_paid * quantity')
     @ticket_payments = @tickets.group_by(&:ticket_id)
     @total_quantity = @tickets.group(:ticket_id).sum(:quantity)
   end

app/models/ticket.rb

@@ -55,6 +55,11 @@ class Ticket < ActiveRecord::Base
     result ? result : Money.new(0, 'USD')
   end
 
+  def self.total_price_user(conference, user, paid: false)
+    tickets = TicketPurchase.where(conference: conference, user: user, paid: paid)
+    tickets.inject(0){ |sum, ticket| sum + (ticket.amount_paid * ticket.quantity) }
+  end
+
   def tickets_sold
     ticket_purchases.paid.sum(:quantity)
   end

app/views/conference_registrations/show.html.haml

@@ -101,7 +101,7 @@
                 = word_pluralize(@total_quantity[ticket_id], 'Ticket')
                 for
                 = tickets.first.price.symbol
-                = humanized_money tickets.first.price
+                = humanized_money @total_price_per_ticket[ticket_id]
             %br
         - if @tickets.any?
           = link_to 'Get more tickets', conference_tickets_path(@conference.short_title), class: "btn btn-default"

spec/controllers/conference_registration_controller_spec.rb

@@ -252,7 +252,7 @@ describe ConferenceRegistrationsController, type: :controller do
         end
 
         it 'does not assign price of purchased tickets to total_price and purchased tickets to tickets without payment' do
-          expect(assigns(:total_price)).to eq Money.new(0, 'USD')
+          expect(assigns(:total_price)).to eq 0
         end
       end
 
@@ -262,7 +262,7 @@ describe ConferenceRegistrationsController, type: :controller do
         end
 
         it 'assigns 0 dollars to total_price and empty array to tickets variables' do
-          expect(assigns(:total_price)).to eq Money.new(0, 'USD')
+          expect(assigns(:total_price)).to eq 0
           expect(assigns(:tickets)).to match_array []
         end
       end