module Admin::LeaderboardHelper

  # Turns "SE" into the flag emoji by mapping each letter onto its regional
  # indicator symbol. Cheaper than shipping 34 flag SVGs for one admin screen,
  # and it degrades to the two letters wherever the font has no flag.
  def country_flag(country_code)
    code = country_code.to_s.upcase
    return "" unless code.match?(/\A[A-Z]{2}\z/)

    code.codepoints.map { |c| (c - 65 + 0x1F1E6) }.pack("U*")
  end


  def leaderboard_country_name(country_code)
    t("countries.#{country_code.to_s.downcase}", default: country_code.to_s.upcase)
  end


  # The badge types the API emits, named the way the brief describes them.
  def badge_type_label(type)
    {
      "new_players"   => "New players",
      "encouragement" => "Encouragement",
      "participation" => "Participation"
    }[type.to_s] || type.to_s.humanize
  end


  # How long the published payload still has before the next API call
  # recomputes it. The cache entry carries no expiry we can read back, so this
  # is derived from when it was built.
  def leaderboard_cache_age(updated_at)
    return nil if updated_at.blank?

    Time.current - updated_at
  end
end