From 9afa74df42ee54e444c6f99227f069e52c1f566a Mon Sep 17 00:00:00 2001
From: Antonio Terceiro <terceiro@colivre.coop.br>
Date: Thu, 16 Dec 2010 11:41:27 -0300
Subject: [PATCH] Smarter way of sorting profiles randomly

---
 app/models/profile_list_block.rb     |  8 ++++++--
 lib/noosfero/sql.rb                  | 15 ---------------
 test/unit/profile_list_block_test.rb | 13 ++++++++++---
 3 files changed, 16 insertions(+), 20 deletions(-)
 delete mode 100644 lib/noosfero/sql.rb

diff --git a/app/models/profile_list_block.rb b/app/models/profile_list_block.rb
index b372e2d..a2224db 100644
--- a/app/models/profile_list_block.rb
+++ b/app/models/profile_list_block.rb
@@ -12,12 +12,16 @@ class ProfileListBlock < Block
   end
 
   def profile_list
-    random = Noosfero::SQL.random_function
+    random = randomizer
     profiles.visible.all(:limit => limit, :select => 'DISTINCT profiles.*, ' + random, :order => random)
   end
 
   def profile_count
-    profiles.visible.count
+    profiles.visible.count('DISTINCT(profiles.id)')
+  end
+
+  def randomizer
+    @randomizer ||= "(profiles.id % #{rand(profile_count)})"
   end
 
   # the title of the block. Probably will be overriden in subclasses.
diff --git a/lib/noosfero/sql.rb b/lib/noosfero/sql.rb
deleted file mode 100644
index ca3585b..0000000
--- a/lib/noosfero/sql.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-module Noosfero
-  module SQL
-    class << self
-
-      def random_function()
-        default = 'random()'
-        adapter = ActiveRecord::Base.configurations[Rails.env]['adapter']
-        {
-          'mysql' => 'rand()'
-        }[adapter] || default
-      end
-
-    end
-  end
-end
diff --git a/test/unit/profile_list_block_test.rb b/test/unit/profile_list_block_test.rb
index 59b6a52..1eb8a39 100644
--- a/test/unit/profile_list_block_test.rb
+++ b/test/unit/profile_list_block_test.rb
@@ -141,13 +141,20 @@ class ProfileListBlockTest < Test::Unit::TestCase
     p2 = fast_create(Person, :environment_id => env.id)
     p3 = fast_create(Person, :environment_id => env.id)
 
-    # force the "random" function to be something we know
-    Noosfero::SQL.stubs(:random_function).returns('-id')
-
     block = ProfileListBlock.new
     block.stubs(:owner).returns(env)
 
+    # force the "random" function to return something we know
+    block.stubs(:randomizer).returns('-id')
+
     assert_equal [p3.id, p2.id, p1.id], block.profile_list.map(&:id)
   end
 
+  should 'randomize using modulo operator and random number' do
+    block = ProfileListBlock.new
+    block.expects(:profile_count).returns(10)
+    block.expects(:rand).with(10).returns(5)
+    assert_match /profiles.id % 5/, block.randomizer
+  end
+
 end
--
libgit2 0.21.2