class QueryParser
  attr_reader :terms, :exclusions

  def initialize(query)
    @terms = []
    @exclusions = []

    query = query.clone

    while match = query.match(/\-?".+?"/)
      range = match.begin(0)...match.end(0)
      phrase = query[range]
      query[range] = ' '

      negative = phrase.start_with?('-')
      phrase = phrase.gsub(/^\-/, '').gsub(/^"|"$/, '').gsub(/[^\w\-]+/, ' ').strip

      if negative
        @exclusions << phrase
      else
        @terms << phrase
      end
    end

    terms = query.gsub(/[^\w\-]+/, ' ').strip.split(/ +/)
    negative, positive = terms.partition { |x| x.start_with?('-') }

    @terms += positive
    @exclusions += negative.map { |x| x[1..-1] }.reject(&:empty?)
  end
end