Adding a Mention model, test stubs

app/services/process_mentions_service.rb

@@ -0,0 +1,33 @@
+class ProcessMentionsService < BaseService
+  # Scan status for mentions and fetch remote mentioned users, create
+  # local mention pointers, send Salmon notifications to mentioned
+  # remote users
+  # @param [Status] status
+  def call(status)
+    status.text.scan(Account::MENTION_RE).each do |match|
+      username, domain = match.first.split('@')
+      local_account = Account.find_by(username: username, domain: domain)
+
+      if local_account.nil?
+        local_account = follow_remote_account_service.("acct:#{match.first}")
+      end
+
+      local_account.mentions.first_or_create(status: status)
+    end
+
+    status.mentions.each do |mentioned_account|
+      next if mentioned_account.local?
+      send_interaction_service.(status.stream_entry, mentioned_account)
+    end
+  end
+
+  private
+
+  def follow_remote_account_service
+    @follow_remote_account_service ||= FollowRemoteAccountService.new
+  end
+
+  def send_interaction_service
+    @send_interaction_service ||= SendInteractionService.new
+  end
+end