class CwCardUtils::CurveCalculator

def collapsed_curve
  return @collapsed_curve if @collapsed_curve.values.any?
  @collapsed_curve = {
    '0-1' => 0,
    '2'   => 0,
    '3'   => 0,
    '4'   => 0,
    '5'   => 0,
    '6+'  => 0,
  }
  curve.each do |cmc, count|
    case cmc
    when 0..1 then @collapsed_curve['0-1'] += count
    when 2    then @collapsed_curve['2'] += count
    when 3    then @collapsed_curve['3'] += count
    when 4    then @collapsed_curve['4'] += count
    when 5    then @collapsed_curve['5'] += count
    else           @collapsed_curve['6+'] += count
    end
  end
  @collapsed_curve
end