module Mail::CheckDeliveryParams

def check(mail)
  envelope = Mail::SmtpEnvelope.new(mail)
  [ envelope.from,
    envelope.to,
    envelope.message ]
end

def check_addr(addr_name, addr)
  mail = Mail.new(from: 'deprecated@example.com', to: 'deprecated@example.com')
  Mail::SmtpEnvelope.new(mail).send(:validate_addr, addr_name, addr)
end

def check_from(addr)
  mail = Mail.new(from: 'deprecated@example.com', to: 'deprecated@example.com')
  Mail::SmtpEnvelope.new(mail).send(:validate_addr, 'From', addr)
end

def check_message(message)
  message = message.encoded if message.respond_to?(:encoded)
  if Utilities.blank?(message)
    raise ArgumentError, 'An encoded message is required to send an email'
  end
  message
end

def check_to(addrs)
  mail = Mail.new(from: 'deprecated@example.com', to: 'deprecated@example.com')
  Array(addrs).map do |addr|
    Mail::SmtpEnvelope.new(mail).send(:validate_addr, 'To', addr)
  end
end

def validate_smtp_addr(addr)
  if addr
    if addr.bytesize > 2048
      yield 'may not exceed 2kB'
    end
    if /[\r\n]/ =~ addr
      yield 'may not contain CR or LF line breaks'
    end
  end
  addr
end