pools: allow searching pools by post tags.

Find all pools containing at least one post tagged 'translated':

    https://danbooru.donmai.us/pools?search[post_tags_match]=translated

app/models/pool.rb

@@ -50,6 +50,11 @@ class Pool < ApplicationRecord
       where_ilike(:name, name)
     end
 
+    def post_tags_match(query)
+      posts = Post.tag_match(query).select(:id).reorder(nil)
+      joins("CROSS JOIN unnest(post_ids) AS post_id").group(:id).where("post_id IN (?)", posts)
+    end
+
     def default_order
       order(updated_at: :desc)
     end
@@ -60,6 +65,10 @@ class Pool < ApplicationRecord
       q = q.search_attributes(params, :creator, :is_active, :is_deleted, :name, :description, :post_ids)
       q = q.text_attribute_matches(:description, params[:description_matches])
 
+      if params[:post_tags_match]
+        q = q.post_tags_match(params[:post_tags_match])
+      end
+
       if params[:name_matches].present?
         q = q.name_matches(params[:name_matches])
       end

app/views/pools/_search.html.erb

@@ -19,6 +19,15 @@
         </td>
       </tr>
 
+      <tr>
+        <th><label for="search_post_tags">Post Tags</th>
+        <td>
+          <div class="input">
+            <%= text_field "search", "post_tags_match", :value => params[:search][:post_tags_match], :data => { autocomplete: "tag-query" } %>
+          </div>
+        </td>
+      </tr>
+
       <tr>
         <th><label for="search_creator_name">Creator</th>
         <td>

test/unit/pool_test.rb

@@ -78,6 +78,18 @@ class PoolTest < ActiveSupport::TestCase
 
       assert_equal([@pool1.id], Pool.search(post_id_count: 2).pluck(:id))
     end
+
+    should "find pools by post tags" do
+      @pool1 = create(:pool, name: "pool1")
+      @pool2 = create(:pool, name: "pool2")
+      @post1 = create(:post, tag_string: "pool:pool1 bkub")
+      @post2 = create(:post, tag_string: "pool:pool1 fumimi")
+      @post3 = create(:post, tag_string: "pool:pool2 bkub fumimi")
+
+      assert_equal([@pool2.id, @pool1.id], Pool.search(post_tags_match: "bkub").pluck(:id))
+      assert_equal([@pool2.id, @pool1.id], Pool.search(post_tags_match: "fumimi").pluck(:id))
+      assert_equal([@pool2.id], Pool.search(post_tags_match: "bkub fumimi").pluck(:id))
+    end
   end
 
   context "Creating a pool" do