stub in preview for bulk revert

app/logical/google_big_query/post_version.rb

@@ -11,5 +11,35 @@ module GoogleBigQuery
       limit = limit.to_i
       query("select id, post_id, updated_at, updater_id, updater_ip_addr, tags, added_tags, removed_tags, parent_id, rating, source from [#{data_set}.post_versions] where regexp_match(added_tags, \"(?:^| )#{tag}(?:$| )\") order by updated_at desc limit #{limit}")
     end
+
+    def find(user_id, added_tags, removed_tags, limit = 1_000)
+      constraints = []
+
+      constraints << "updater_id = #{user_id.to_i}"
+
+      if added_tags
+        added_tags.scan(/\S+/).each do |tag|
+          escaped = escape(tag)
+          constraints << "regexp_match(added_tags, \"(?:^| )#{escaped}(?:$| )\")"
+        end
+      end
+
+      if removed_tags
+        removed_tags.scan(/\S+/).each do |tag|
+          escaped = escape(tag)
+          constraints << "not regexp_match(added_tags, \"(?:^| )#{escaped}(?:$| )\")"
+        end
+      end
+
+      limit = limit.to_i
+      sql = "select id from [#{data_set}.post_versions] where " + constraints.join(" and ") + " order by updated_at desc limit #{limit}"
+      result = query(sql)
+
+      if result["rows"]
+        result["rows"].map {|x| x["f"][0]["v"].to_i}
+      else
+        []
+      end
+    end
   end
 end