use Twitter::Extractor for creating links (#2502)

app/lib/extractor.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Extractor
+  extend Twitter::Extractor
+
+  module_function
+
+  def extract_mentions_or_lists_with_indices(text) # :yields: username, list_slug, start, end
+    return [] unless text =~ Twitter::Regex[:at_signs]
+
+    possible_entries = []
+
+    text.to_s.scan(Account::MENTION_RE) do |screen_name, _|
+      match_data = $LAST_MATCH_INFO
+      after = $'
+      unless after =~ Twitter::Regex[:end_mention_match]
+        start_position = match_data.char_begin(1) - 1
+        end_position = match_data.char_end(1)
+        possible_entries << {
+          screen_name: screen_name,
+          indices: [start_position, end_position],
+        }
+      end
+    end
+
+    if block_given?
+      possible_entries.each do |mention|
+        yield mention[:screen_name], mention[:indices].first, mention[:indices].last
+      end
+    end
+    possible_entries
+  end
+end