From d90fe8cd2196985384b873e656404a0bef56d929 Mon Sep 17 00:00:00 2001
From: Luke Baker <lukebaker@gmail.com>
Date: Wed, 19 Jan 2011 15:18:32 -0500
Subject: [PATCH] make updates to simple random choose prompt

---
 app/models/question.rb       | 26 +++++++++++++++++---------
 spec/models/question_spec.rb | 21 ++++++++++++++++++---
 2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/app/models/question.rb b/app/models/question.rb
index 0b8cf45..d17a6a4 100644
--- a/app/models/question.rb
+++ b/app/models/question.rb
@@ -57,7 +57,7 @@ class Question < ActiveRecord::Base
         next_prompt = self.pop_prompt_queue
         if next_prompt.nil?
           logger.info("DEBUG Catchup prompt cache miss! Nothing in prompt_queue")
-          next_prompt = self.picked_prompt
+          next_prompt = self.simple_random_choose_prompt
           record_prompt_cache_miss
         else
           record_prompt_cache_hit
@@ -66,16 +66,16 @@ class Question < ActiveRecord::Base
         return next_prompt
     else
         #Standard choose prompt at random
-        return self.picked_prompt
+        return self.simple_random_choose_prompt
     end
           
   end
 
   #TODO: generalize for prompts of rank > 2
-  def picked_prompt(rank = 2)
-    logger.info "inside Question#picked_prompt"
+  def simple_random_choose_prompt(rank = 2)
+    logger.info "inside Question#simple_random_choose_prompt"
     raise NotImplementedError.new("Sorry, we currently only support pairwise prompts.  Rank of the prompt must be 2.") unless rank == 2
-    choice_id_array = distinct_array_of_choice_ids(rank, true)
+    choice_id_array = distinct_array_of_choice_ids(:rank => rank, :only_active => true)
     prompts.find_or_create_by_left_choice_id_and_right_choice_id(choice_id_array[0], choice_id_array[1], :include => [:left_choice ,:right_choice ])
   end
 
@@ -334,13 +334,20 @@ class Question < ActiveRecord::Base
  end
 
    
-  def distinct_array_of_choice_ids(rank = 2, only_active = true)
+  def distinct_array_of_choice_ids(params={})
+    params = {
+      :rank => 2,
+      :only_active => true
+    }.merge(params)
+    rank = params[:rank]
+    only_active = params[:only_active]
     count = (only_active) ? choices.active.count : choices.count
     
     found_choices = []
+    # select only active choices?
+    conditions = (only_active) ? ['active = ?', true] : ['1=1']
+
     rank.times do 
-      # select only active choices?
-      conditions = (only_active) ? ['active = ?', true] : ['']
       # if we've already found some, make sure we don't find them again
       if found_choices.count > 0
         conditions[0] += ' AND id NOT IN (?)'
@@ -350,13 +357,14 @@ class Question < ActiveRecord::Base
       found_choices.push choices.find(:first,
           :select => 'id',
           :conditions => conditions,
+          # rand generates value >= 0 and < param
           :offset => rand(count - found_choices.count)).id
     end
     return found_choices
   end
  
    def picked_prompt_id
-     picked_prompt.id
+     simple_random_choose_prompt.id
    end
  
    def self.voted_on_by(u)
diff --git a/spec/models/question_spec.rb b/spec/models/question_spec.rb
index 4901ce6..ce79d0c 100644
--- a/spec/models/question_spec.rb
+++ b/spec/models/question_spec.rb
@@ -37,10 +37,23 @@ describe Question do
   #end
 
   it "should choose an active prompt randomly" do
-    prompt = @question.picked_prompt
+    prompt = @question.simple_random_choose_prompt
     prompt.active?.should == true
   end
 
+  it "should randomly choose two active choices" do
+    50.times do
+      choice_ids = @question.distinct_array_of_choice_ids(:rank => 2, :only_active => true)
+      choice_ids.count.should == 2
+      choice_ids.uniq.count.should == 2
+      choice_ids.each do |choice_id|
+        c = Choice.find(choice_id)
+        c.active?.should == true
+      end
+    end
+    
+  end
+
   it "should choose an active prompt using catchup algorithm" do 
     prompt = @question.catchup_choose_prompt
     prompt.active?.should == true
@@ -321,7 +334,8 @@ describe Question do
       end
 
       200.times.each do |num|
-        @p = @aoi_question.picked_prompt
+        @p = @aoi_question.simple_random_choose_prompt
+        @p.active?.should == true
 
         @a = user.record_appearance(visitor, @p)
 
@@ -454,7 +468,8 @@ describe Question do
           {:data => "foo'bar", :local_identifier => "example creator"})
 
       40.times.each do |num|
-        @p = @aoi_question.picked_prompt
+        @p = @aoi_question.simple_random_choose_prompt
+        @p.active?.should == true
 
         @a = user.record_appearance(visitor, @p)
 
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