gistfile1.txt

diff --git a/Gemfile b/Gemfile
index da92010..2218160 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,3 +5,4 @@ gem 'reek'
 gem 'rake'
 gem 'rspec', '~> 3.1.0'
 gem 'pry'
+gem "ruby-prof"
diff --git a/Gemfile.lock b/Gemfile.lock
index eb603bf..067cae2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -57,6 +57,7 @@ GEM
     rspec-mocks (3.1.3)
       rspec-support (~> 3.1.0)
     rspec-support (3.1.2)
+    ruby-prof (0.15.9)
     slop (3.6.0)
     thread_safe (0.3.5)
     unparser (0.2.4)
@@ -82,6 +83,7 @@ DEPENDENCIES
   rake
   reek
   rspec (~> 3.1.0)
+  ruby-prof
 
 BUNDLED WITH
    1.10.6
diff --git a/lib/invoice_repository.rb b/lib/invoice_repository.rb
index f34b834..d24e97b 100644
--- a/lib/invoice_repository.rb
+++ b/lib/invoice_repository.rb
@@ -1,11 +1,12 @@
 require_relative "invoice"
 
 class InvoiceRepository
-  attr_reader :invoices, :engine
+  attr_reader :invoices, :engine, :by_merchant_id
 
   def initialize(engine, raw_invoices)
     @engine = engine
     @invoices = load_data(raw_invoices)
+    @by_merchant_id = all.group_by(&:merchant_id)
   end
 
   def inspect
@@ -13,29 +14,39 @@ class InvoiceRepository
   end
 
   def load_data(raw_invoices)
-    raw_invoices.reduce([]) do |invoices, row|
-      invoices << Invoice.new(self, row.to_h)
+    # raw_invoices.reduce([]) do |invoices, row|
+    #   invoices << Invoice.new(self, row.to_h)
+    # end
+
+    invoices = {}
+    raw_invoices.each do |row|
+      i = Invoice.new(self, row.to_h)
+      invoices[i.id] = i
     end
+
+    invoices
   end
 
   def all
-    invoices
+    invoices.values
   end
 
   def find_by_id(id)
-    invoices.detect { |i| i.id == id }
+    invoices[id]
   end
 
   def find_all_by_customer_id(customer_id)
-    invoices.select { |i| i.customer_id == customer_id }
+    all.select { |i| i.customer_id == customer_id }
   end
 
   def find_all_by_merchant_id(merchant_id)
-    invoices.select { |i| i.merchant_id == merchant_id }
+    # "indexing"
+    by_merchant_id[merchant_id] || []
+    # invoices.select { |i| i.merchant_id == merchant_id }
   end
 
   def find_all_by_status(status)
-    invoices.select { |i| i.status == status }
+    all.select { |i| i.status == status }
   end
 
   def find_merchant_by_id(merchant_id)
diff --git a/lib/item_repository.rb b/lib/item_repository.rb
index 3973145..b3f96c9 100644
--- a/lib/item_repository.rb
+++ b/lib/item_repository.rb
@@ -1,11 +1,12 @@
 require_relative "item"
 
 class ItemRepository
-  attr_reader :items, :engine
+  attr_reader :items, :engine, :grouped_by_merchant_id
 
   def initialize(engine, raw_items)
     @engine = engine
     @items = load_data(raw_items)
+    @grouped_by_merchant_id = items.group_by(&:merchant_id)
   end
 
   def load_data(raw_items)
@@ -35,7 +36,9 @@ class ItemRepository
   end
 
   def find_all_by_merchant_id(merchant_id)
-    items.select { |item| item.merchant_id == merchant_id }
+    grouped_by_merchant_id[merchant_id] || []
+    # [Item1, Item2, Item3, Item4]
+    # items.select { |item| item.merchant_id == merchant_id }
   end
 
   def find_all_with_description(description)
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 2f59b40..366b265 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -25,10 +25,14 @@ module BlackThursdaySpecHelpers
   end
 end
 
+require "ruby-prof"
+
 RSpec.configure do |config|
   config.disable_monkey_patching!
 
   config.before(:suite) do
+    RubyProf.start
+
     BlackThursdaySpecHelpers.engine = SalesEngine.from_csv({
       items: File.join('data', 'items.csv'),
       merchants: File.join('data', 'merchants.csv'),
@@ -39,6 +43,16 @@ RSpec.configure do |config|
     })
   end
 
+  config.after(:suite) do
+    puts "AFTER THE TESTSSS"
+
+    result = RubyProf.stop
+
+    # printer = RubyProf::FlatPrinter.new(result)
+    printer = RubyProf::GraphHtmlPrinter.new(result)
+    printer.print(File.open("./profile.html", "w"))
+  end
+
   # File.join 'data'
   config.include BlackThursdaySpecHelpers
 end