class Mail::SmtpEnvelope

def from=(addr)
  if Utilities.blank? addr
    raise ArgumentError, "SMTP From address may not be blank: #{addr.inspect}"
  end
  @from = validate_addr 'From', addr
end

def initialize(mail)
  self.from = mail.smtp_envelope_from
  self.to = mail.smtp_envelope_to
  self.message = mail.encoded
end

def message=(message)
  if Utilities.blank?(message)
    raise ArgumentError, 'SMTP message may not be blank'
  end
  @message = message
end

def to=(addr)
  if Utilities.blank?(addr)
    raise ArgumentError, "SMTP To address may not be blank: #{addr.inspect}"
  end
  @to = Array(addr).map do |addr|
    validate_addr 'To', addr
  end
end

def validate_addr(addr_name, addr)
  if addr.bytesize > MAX_ADDRESS_BYTESIZE
    raise ArgumentError, "SMTP #{addr_name} address may not exceed #{MAX_ADDRESS_BYTESIZE} bytes: #{addr.inspect}"
  end
  if /[\r\n]/ =~ addr
    raise ArgumentError, "SMTP #{addr_name} address may not contain CR or LF line breaks: #{addr.inspect}"
  end
  addr
end