sortcollection.rb

# SortCollectionRelevancy
#
# Sort any collection (array), with specific methods based on the word frequency
class SortCollectionRelevancy
  def initialize(query, collection, methods = [])
    @query = query
    @collection = collection
    @methods = Array(methods)
  end

  def sort
    sort_collection(@query, @collection, @methods)
  end

  protected

  def sort_collection(query, collection, methods)
    query_words = normalize_words(query).uniq
    collection.sort_by.with_index do |record, i|
      word_count = methods.flat_map do |method|
        normalize_words(record.send(method))
      end.inject(Hash.new(0)) { |h, v| h.tap { h[v] += 1 }}
      -word_count.values_at(*query_words).sum
    end
  end

  def normalize_words(value)
    value.split(/\W+/).map(&:downcase)
  end
end