class RuboCop::Cop::Rails::MailerName


end
class UserMailer < ApplicationMailer
end
class UserMailer < ActionMailer::Base
# good
end
class User < ApplicationMailer
end
class User < ActionMailer::Base
# bad
@example
always an unsafe operation.
This cop’s autocorrection is unsafe because renaming a constant is
@safety
and which views are related to the mailer.
Without the ‘Mailer` suffix it isn’t immediately apparent what’s a mailer
Enforces that mailer names end with ‘Mailer` suffix.

def autocorrect(corrector, node) 

def autocorrect(corrector, node)
  if node.casgn_type?
    name = node.children[1]
    corrector.replace(node.loc.name, "#{name}Mailer")
  else
    name = node.children.last
    corrector.replace(node, "#{name}Mailer")
  end
end

def mailer_suffix?(mailer_name) 

def mailer_suffix?(mailer_name)
  mailer_name.to_s.end_with?('Mailer')
end

def on_class(node) 

def on_class(node)
  class_definition?(node) do |name_node|
    add_offense(name_node) do |corrector|
      autocorrect(corrector, name_node)
    end
  end
end

def on_send(node) 

def on_send(node)
  return unless class_new_definition?(node)
  casgn_parent = node.each_ancestor(:casgn).first
  return unless casgn_parent
  name = casgn_parent.children[1]
  return if mailer_suffix?(name)
  add_offense(casgn_parent.loc.name) do |corrector|
    autocorrect(corrector, casgn_parent)
  end
end