class LocationOrSchemeDeactivationMailer < NotifyMailer
  DEACTIVATION_TEMPLATE_ID = "8d07a8c3-a4e3-4102-8be7-4ee79e4183fd".freeze

  def send_deactivation_mail(user, log_count, update_logs_url, scheme_name, postcode = nil)
    send_email(
      user.email,
      DEACTIVATION_TEMPLATE_ID,
      {
        log_count:,
        log_or_logs: log_count == 1 ? "log" : "logs",
        update_logs_url:,
        location_or_scheme_description: description(scheme_name, postcode),
      },
    )
  end

  def send_deactivation_mails(logs, update_logs_url, scheme_name, postcode = nil)
    counts_by_user(logs).each do |user, count|
      send_deactivation_mail(user, count, update_logs_url, scheme_name, postcode) if user
    end
  end

private

  def counts_by_user(logs)
    logs.each_with_object(Hash.new(0)) do |log, counts|
      counts[log.created_by] += 1
    end
  end

  def description(scheme_name, postcode)
    if postcode
      "the #{postcode} location from the #{scheme_name} scheme"
    else
      "the #{scheme_name} scheme"
    end
  end
end