class ActionMailer::Preview

def all
  load_previews if descendants.empty?
  descendants
end

def call(email, params = {})
  preview = new(params)
  message = preview.public_send(email)
  inform_preview_interceptors(message)
  message
end

def email_exists?(email)
  emails.include?(email)
end

def emails
  public_instance_methods(false).map(&:to_s).sort
end

def exists?(preview)
  all.any? { |p| p.preview_name == preview }
end

def find(preview)
  all.find { |p| p.preview_name == preview }
end

def inform_preview_interceptors(message)
  Base.preview_interceptors.each do |interceptor|
    interceptor.previewing_email(message)
  end
end

def initialize(params = {})
  @params = params
end

def load_previews
  if preview_path
    Dir["#{preview_path}/**/*_preview.rb"].sort.each { |file| require_dependency file }
  end
end

def preview_name
  name.delete_suffix("Preview").underscore
end

def preview_path
  Base.preview_path
end

def show_previews
  Base.show_previews
end