UX: suspend forever time period messages (#13776)

When the Forever option is selected for suspending a user, the user is suspended for 1000 years. Without customizing the site’s text, this time period is displayed to the user in the suspension email that is sent to the user, and if the user attempts to log back into the site. Telling someone that they have been suspended for 1000 years seems likely to come across as a bad attempt at humour.

This PR special case messages when a user suspended or silenced forever.

app/models/user.rb

@@ -958,6 +958,10 @@ class User < ActiveRecord::Base
     silenced_record.try(:created_at) if silenced?
   end
 
+  def silenced_forever?
+    silenced_till > 100.years.from_now
+  end
+
   def suspend_record
     UserHistory.for(self, :suspend_user).order('id DESC').first
   end
@@ -974,6 +978,27 @@ class User < ActiveRecord::Base
     nil
   end
 
+  def suspended_message
+    return nil unless suspended?
+
+    message = "login.suspended"
+    if suspend_reason
+      if suspended_forever?
+        message = "login.suspended_with_reason_forever"
+      else
+        message = "login.suspended_with_reason"
+      end
+    end
+
+    I18n.t(message,
+           date: I18n.l(suspended_till, format: :date_only),
+           reason: Rack::Utils.escape_html(suspend_reason))
+  end
+
+  def suspended_forever?
+    suspended_till > 100.years.from_now
+  end
+
   # Use this helper to determine if the user has a particular trust level.
   # Takes into account admin, etc.
   def has_trust_level?(level)