module TrackingNumber

def self.detect(tracking_number, match: :carrier)
  all_matches = search(tracking_number, match: match)
  if all_matches.empty?
    Unknown.new(tracking_number)
  else
    all_matches.max_by(&:confidence)
  end
end

def self.detect_all(tracking_number)
  matches = []
  (TYPES + [Unknown]).each do |test_klass|
    tn = test_klass.new(tracking_number)
    matches << tn if tn.valid?
  end
  matches
end

def self.new(tracking_number)
  detect(tracking_number)
end

def self.search(body, match: :carrier)
  matches = TYPES.collect { |type| type.search(body) }.flatten
  # Some tracking numbers (e.g. Fedex Smartpost) are partnerships between two parties, where one party is the shipper (e.g. Fedex)
  # and the other party is the [last mile] carrier (e.g. USPS). We're probably interested in the last mile aspect of
  # the partnership, so by default we'll show those
  # Tracking numbers without a partnership are both the shipper and carrier.
  case match
  when :carrier
    matches.filter(&:carrier?)
  when :shipper
    matches.filter(&:shipper?)
  when :all
    matches
  else
    matches
  end
end