Include aliased tags in autocomplete

app/assets/javascripts/autocomplete.js

@@ -173,11 +173,9 @@
     }
 
     $.ajax({
-      url: "/tags.json",
+      url: "/tags/autocomplete.json",
       data: {
-        "search[order]": "count",
         "search[name_matches]": term + "*",
-        "limit": 10
       },
       method: "get",
       success: function(data) {
@@ -185,6 +183,7 @@
           return {
             type: "tag",
             label: tag.name.replace(/_/g, " "),
+            antecedent: tag.antecedent_name,
             value: tag.name,
             category: tag.category,
             post_count: tag.post_count
@@ -202,7 +201,16 @@
   }
 
   Danbooru.Autocomplete.render_item = function(list, item) {
-    var $link = $("<a/>").text(item.label);
+    var $link = $("<a/>");
+
+    if (item.antecedent) {
+      var antecedent = item.antecedent.replace(/_/g, " ");
+      var arrow = $("<span/>").html(" &rarr; ").addClass("autocomplete-arrow");
+      $link.append(document.createTextNode(antecedent));
+      $link.append(arrow);
+    }
+
+    $link.append(document.createTextNode(item.label));
     $link.attr("href", "/posts?tags=" + encodeURIComponent(item.value));
     $link.click(function(e) {
       e.preventDefault();

app/assets/stylesheets/common/autocomplete.css.scss

@@ -5,4 +5,8 @@
   .ui-menu-item a {
     padding: 1px .2em;
   }
+
+  .autocomplete-arrow {
+    color: black;
+  }
 }

app/controllers/tags_controller.rb

@@ -17,6 +17,16 @@ class TagsController < ApplicationController
     end
   end
 
+  def autocomplete
+    @tags = Tag.names_matches_with_aliases(params[:search][:name_matches])
+
+    respond_with(@tags) do |format|
+      format.xml do
+        render :xml => @tags.to_xml(:root => "tags")
+      end
+    end
+  end
+
   def search
   end
 

app/logical/daily_maintenance.rb

@@ -12,5 +12,6 @@ class DailyMaintenance
     TagSubscription.process_all
     ApiCacheGenerator.new.generate_tag_cache
     ForumSubscription.process_all!
+    TagAlias.update_cached_post_counts_for_all
   end
 end

app/models/tag.rb

@@ -673,6 +673,23 @@ class Tag < ActiveRecord::Base
 
       q
     end
+
+    def names_matches_with_aliases(name)
+      query1 = Tag.select("tags.name, tags.post_count, tags.category, null AS antecedent_name")
+        .search(:name_matches => name, :order => "count").limit(10)
+
+      name = name.mb_chars.downcase.to_escaped_for_sql_like
+      query2 = TagAlias.select("tags.name, tag_aliases.post_count, tags.category, tag_aliases.antecedent_name")
+        .joins("INNER JOIN tags ON tags.name = tag_aliases.consequent_name")
+        .where("tag_aliases.antecedent_name LIKE ? ESCAPE E'\\\\'", name)
+        .where("tags.name NOT LIKE ? ESCAPE E'\\\\'", name)
+        .where("tag_aliases.post_count > 0")
+        .order("tag_aliases.post_count desc")
+        .limit(20) # Get 20 records even though only 10 will be displayed in case some duplicates get filtered out.
+
+      sql_query = "((#{query1.to_sql}) UNION ALL (#{query2.to_sql})) AS unioned_query"
+      Tag.select("DISTINCT ON (name, post_count) *").from(sql_query).order("post_count desc").limit(10)
+    end
   end
 
   def editable_by?(user)

app/models/tag_alias.rb

@@ -254,4 +254,8 @@ class TagAlias < ActiveRecord::Base
     update_forum_topic_for_reject
     destroy
   end
+
+  def self.update_cached_post_counts_for_all
+    execute_sql("UPDATE tag_aliases SET post_count = tags.post_count FROM tags WHERE tags.name = tag_aliases.consequent_name")
+  end
 end

config/routes.rb

@@ -213,6 +213,9 @@ Rails.application.routes.draw do
   resource :source, :only => [:show]
   resources :tags do
     resource :correction, :only => [:new, :create, :show], :controller => "tag_corrections"
+    collection do
+      get :autocomplete
+    end
   end
   resources :tag_aliases do
     resource :correction, :controller => "tag_alias_corrections"

db/migrate/20150403224949_add_antecedent_name_pattern_index_and_post_count_to_tag_aliases.rb

@@ -0,0 +1,14 @@
+class AddAntecedentNamePatternIndexAndPostCountToTagAliases < ActiveRecord::Migration
+  def up
+    execute "set statement_timeout = 0"
+    execute "create index index_tag_aliases_on_antecedent_name_pattern on tag_aliases (antecedent_name text_pattern_ops)"
+    add_column :tag_aliases, :post_count, :integer, :null => false, :default => 0
+    add_index :tag_aliases, :post_count
+  end
+
+  def down
+    execute "set statement_timeout = 0"
+    execute "drop index index_tag_aliases_on_antecedent_name_pattern"
+    remove_column :tag_aliases, :post_count
+  end
+end