added related tag query model, fixes to related tag calculator

app/logical/related_tag_query.rb

@@ -0,0 +1,46 @@
+class RelatedTagQuery
+  attr_reader :query, :category
+  
+  def initialize(query, category)
+    @query = query
+    @category = category
+  end
+
+  def tags
+    if query =~ /\*/
+      pattern_matching_tags
+    elsif category.present?
+      related_tags_by_category
+    else
+      related_tags
+    end
+  end
+  
+  def wiki_page_tags
+    wiki_page.try(:tags) || []
+  end
+  
+protected
+  
+  def pattern_matching_tags
+    Tag.name_matches(query).order("post_count desc").limit(50).sort_by {|x| x.name}.map(&:name)
+  end
+  
+  def related_tags
+    tag = Tag.named(query).first
+    
+    if tag
+      tag.related_tag_array.map(&:first)
+    else
+      []
+    end
+  end
+  
+  def related_tags_by_category
+    RelatedTagCalculator.calculate_from_sample_to_array(query, Tag.categories.value_for(category)).map(&:first)
+  end
+
+  def wiki_page
+    WikiPage.titled(query).first
+  end
+end

app/models/tag.rb

@@ -2,7 +2,8 @@ class Tag < ActiveRecord::Base
   attr_accessible :category
   after_save :update_category_cache
   has_one :wiki_page, :foreign_key => "name", :primary_key => "title"
-  scope :name_matches, lambda {|name| where(["name LIKE ? ESCAPE E'\\\\'", name.to_escaped_for_sql_like])}
+  scope :name_matches, lambda {|name| where("name LIKE ? ESCAPE E'\\\\'", name.to_escaped_for_sql_like)}
+  scope :named, lambda {|name| where("name = ?", TagAlias.to_aliased([name]).join(""))}
   search_methods :name_matches
 
   class CategoryMapping
@@ -310,8 +311,9 @@ class Tag < ActiveRecord::Base
   module RelationMethods
     def update_related
       return unless should_update_related?
-      counts = RelatedTagCalculator.calculate_from_sample(Danbooru.config.post_sample_size, name)
-      update_attributes(:related_tags => RelatedTagCalculator.convert_hash_to_string(counts), :related_tags_updated_at => Time.now)
+      self.related_tags = RelatedTagCalculator.calculate_from_sample_to_array(name).join(" ")
+      self.related_tags_updated_at = Time.now
+      save
     end
     
     def update_related_if_outdated

app/models/wiki_page.rb

@@ -88,4 +88,14 @@ class WikiPage < ActiveRecord::Base
   def presenter
     @presenter ||= WikiPagePresenter.new(self)
   end
+  
+  def tags
+    body.scan(/\[\[(.+?)\]\]/).flatten.map do |match|
+      if match =~ /^(.+?)\|(.+)/
+        $1
+      else
+        match
+      end
+    end.map {|x| x.downcase.tr(" ", "_")}
+  end
 end

test/unit/related_tag_query_test.rb

@@ -0,0 +1,74 @@
+require 'test_helper'
+
+class RelatedTagQueryTest < ActiveSupport::TestCase
+  setup do
+    user = Factory.create(:user)
+    CurrentUser.user = user
+    CurrentUser.ip_addr = "127.0.0.1"
+    MEMCACHE.flush_all
+    Delayed::Worker.delay_jobs = false
+  end
+  
+  context "a related tag query without a category constraint" do
+    setup do
+      @post_1 = Factory.create(:post, :tag_string => "aaa bbb")
+      @post_2 = Factory.create(:post, :tag_string => "aaa bbb ccc")
+    end
+
+    context "for a tag that already exists" do
+      setup do
+        Tag.named("aaa").first.update_related
+        @query = RelatedTagQuery.new("aaa", "")
+      end
+      
+      should "work" do
+        assert_equal(["aaa", "bbb", "ccc"], @query.tags)
+      end
+    end
+    
+    context "for a tag that doesn't exist" do
+      setup do
+        @query = RelatedTagQuery.new("zzz", "")
+      end
+      
+      should "work" do
+        assert_equal([], @query.tags)
+      end
+    end
+    
+    context "for a pattern search" do
+      setup do
+        @query = RelatedTagQuery.new("a*", "")
+      end
+      
+      should "work" do
+        assert_equal(["aaa"], @query.tags)
+      end
+    end
+    
+    context "for a tag with a wiki page" do
+      setup do
+        @wiki_page = Factory.create(:wiki_page, :title => "aaa", :body => "[[bbb]] [[ccc]]")
+        @query = RelatedTagQuery.new("aaa", "")
+      end
+      
+      should "find any tags embedded in the wiki page" do
+        assert_equal(["bbb", "ccc"], @query.wiki_page_tags)
+      end
+    end
+  end
+  
+  context "a related tag query with a category constraint" do
+    setup do
+      @post_1 = Factory.create(:post, :tag_string => "aaa bbb")
+      @post_2 = Factory.create(:post, :tag_string => "aaa art:ccc")
+      @post_3 = Factory.create(:post, :tag_string => "aaa copy:ddd")
+      @query = RelatedTagQuery.new("aaa", "artist")
+    end
+    
+    should "find the related tags" do
+      assert_equal(%w(ccc), @query.tags)
+    end
+  end
+end
+