autocomplete: make number of results configurable (partly).

Add `Danbooru.Autocomplete.MAX_RESULTS` param that controls the number
of results returned by autocomplete.

This does not work with tag autocomplete for Builders. Builder
autocomplete still needs to be refactored and unified with Member
autocomplete.

Also fix a bug in the /saved_searches/labels endpoint where the limit
param wasn't respected.

app/controllers/saved_searches_controller.rb

@@ -7,7 +7,7 @@ class SavedSearchesController < ApplicationController
   end
 
   def labels
-    @labels = SavedSearch.search_labels(CurrentUser.id, params[:search])
+    @labels = SavedSearch.search_labels(CurrentUser.id, params[:search]).take(params[:limit].to_i || 10)
     respond_with(@labels)
   end
 

app/controllers/tags_controller.rb

@@ -18,7 +18,7 @@ class TagsController < ApplicationController
       # limit rollout
       @tags = TagAutocomplete.search(params[:search][:name_matches])
     else
-      @tags = Tag.names_matches_with_aliases(params[:search][:name_matches])
+      @tags = Tag.names_matches_with_aliases(params[:search][:name_matches], limit: params[:limit])
     end
 
     # XXX

app/javascript/src/javascripts/autocomplete.js.erb

@@ -11,6 +11,7 @@ Autocomplete.ORDER_METATAGS = <%= Tag::ORDER_METATAGS.to_json.html_safe %>;
 Autocomplete.TAG_PREFIXES = "-|~|" + Object.keys(Autocomplete.TAG_CATEGORIES).map(category => category + ":").join("|");
 Autocomplete.METATAGS_REGEX = Autocomplete.METATAGS.concat(Object.keys(Autocomplete.TAG_CATEGORIES)).join("|");
 Autocomplete.TERM_REGEX = new RegExp(`([-~]*)(?:(${Autocomplete.METATAGS_REGEX}):)?(\\S*)$`, "i");
+Autocomplete.MAX_RESULTS = 10;
 
 Autocomplete.initialize_all = function() {
   if (CurrentUser.data("enable-auto-complete")) {
@@ -288,7 +289,7 @@ Autocomplete.static_metatag_source = function(term, metatag) {
   var sub_metatags = this.static_metatags[metatag];
 
   var matches = sub_metatags.filter(sub_metatag => sub_metatag.startsWith(term.toLowerCase()));
-  matches = matches.map(sub_metatag => `${metatag}:${sub_metatag}`).sort().slice(0, 10);
+  matches = matches.map(sub_metatag => `${metatag}:${sub_metatag}`).sort().slice(0, Autocomplete.MAX_RESULTS);
 
   return matches;
 }
@@ -300,6 +301,7 @@ Autocomplete.tag_source = async function(term) {
 
   let tags = await $.getJSON("/tags/autocomplete", {
     "search[name_matches]": term,
+    "limit": Autocomplete.MAX_RESULTS,
     "expiry": 7
   });
 
@@ -322,7 +324,7 @@ Autocomplete.artist_source = async function(term) {
     "search[name_like]": term.trim().replace(/\s+/g, "_") + "*",
     "search[is_active]": true,
     "search[order]": "post_count",
-    "limit": 10,
+    "limit": Autocomplete.MAX_RESULTS,
     "expiry": 7
   });
 
@@ -341,7 +343,7 @@ Autocomplete.wiki_source = async function(term) {
     "search[title]": term + "*",
     "search[hide_deleted]": "Yes",
     "search[order]": "post_count",
-    "limit": 10,
+    "limit": Autocomplete.MAX_RESULTS,
     "expiry": 7
   });
 
@@ -360,7 +362,7 @@ Autocomplete.user_source = async function(term, prefix = "") {
     "search[order]": "post_upload_count",
     "search[current_user_first]": "true",
     "search[name_matches]": term + "*",
-    "limit": 10
+    "limit": Autocomplete.MAX_RESULTS
   });
 
   return users.map(function(user) {
@@ -378,7 +380,7 @@ Autocomplete.pool_source = async function(term, prefix = "") {
     "search[name_matches]": term,
     "search[is_deleted]": false,
     "search[order]": "post_count",
-    "limit": 10
+    "limit": Autocomplete.MAX_RESULTS
   });
 
   return pools.map(function(pool) {
@@ -395,7 +397,7 @@ Autocomplete.pool_source = async function(term, prefix = "") {
 Autocomplete.favorite_group_source = async function(term, prefix = "") {
   let favgroups = await $.getJSON("/favorite_groups", {
     "search[name_matches]": term,
-    "limit": 10
+    "limit": Autocomplete.MAX_RESULTS
   });
 
   return favgroups.map(function(favgroup) {
@@ -410,7 +412,7 @@ Autocomplete.favorite_group_source = async function(term, prefix = "") {
 Autocomplete.saved_search_source = async function(term, prefix = "") {
   let labels = await $.getJSON("/saved_searches/labels", {
     "search[label]": term + "*",
-    "limit": 10
+    "limit": Autocomplete.MAX_RESULTS
   });
 
   return labels.map(function(label) {

app/models/tag.rb

@@ -895,12 +895,12 @@ class Tag < ApplicationRecord
       q
     end
 
-    def names_matches_with_aliases(name)
+    def names_matches_with_aliases(name, limit: 10)
       name = normalize_name(name)
       wildcard_name = name + '*'
 
       query1 = Tag.select("tags.name, tags.post_count, tags.category, null AS antecedent_name")
-        .search(:name_matches => wildcard_name, :order => "count").limit(10)
+        .search(:name_matches => wildcard_name, :order => "count").limit(limit)
 
       query2 = TagAlias.select("tags.name, tags.post_count, tags.category, tag_aliases.antecedent_name")
         .joins("INNER JOIN tags ON tags.name = tag_aliases.consequent_name")
@@ -909,13 +909,13 @@ class Tag < ApplicationRecord
         .where("tags.name NOT LIKE ? ESCAPE E'\\\\'", wildcard_name.to_escaped_for_sql_like)
         .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.
+        .limit(limit * 2) # Get extra records in case some duplicates get filtered out.
 
       sql_query = "((#{query1.to_sql}) UNION ALL (#{query2.to_sql})) AS unioned_query"
-      tags = Tag.select("DISTINCT ON (name, post_count) *").from(sql_query).order("post_count desc").limit(10)
+      tags = Tag.select("DISTINCT ON (name, post_count) *").from(sql_query).order("post_count desc").limit(limit)
 
       if tags.empty?
-        tags = Tag.select("tags.name, tags.post_count, tags.category, null AS antecedent_name").fuzzy_name_matches(name).order_similarity(name).nonempty.limit(10)
+        tags = Tag.select("tags.name, tags.post_count, tags.category, null AS antecedent_name").fuzzy_name_matches(name).order_similarity(name).nonempty.limit(limit)
       end
 
       tags