require "base64"

class MailOpensController < ActionController::Base
  PIXEL = Base64.decode64("R0lGODlhAQABAPAAAAAAAAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==").freeze

  def show
    record_open
    expires_now
    response.set_header("Cache-Control", "no-store, no-cache, must-revalidate, private, max-age=0")
    response.set_header("Pragma", "no-cache")
    send_data PIXEL, type: "image/gif", disposition: "inline", filename: "o.gif"
  end

  private

  def record_open
    token = params[:token].to_s
    recipient = MailingRecipient.find_by(tracking_token: token)
    recipient&.record_open!
  rescue StandardError => e
    Rails.logger.warn("[mail_open] #{e.class}: #{e.message}")
    raise if Rails.env.test?
  end
end