josephwilk/creative-machine

require 'nokogiri'
require 'open-uri'

module Creative
  module Machine
    module PoetEngine
      class Rhymer
        URL = "http://www.rhymezone.com/r/rhyme.cgi?typeofrhyme=perfect&org1=syl&org2=l&org3=y"
        CACHE_DIR = File.expand_path(File.dirname(__FILE__)) + "/../../../../data/rhythms"

        class << self
          def rhyming_with(word)
            return fetch_from_cache(word) if cached?(word)
            
            rhyming_words = find_rhyming_words_for(word)
          
            cache(word, rhyming_words)

            rhyming_words || []
          end
        
          private
          def find_rhyming_words_for(word)
            doc = Nokogiri::HTML(open("#{URL}&Word=#{URI.escape(word)}"))
            doc.xpath('//a[starts-with(@href, "d=")]').map{|a| a.text}
          end

          def cache(word, rhyming_words)
            File.open("#{CACHE_DIR}/#{word}", "w") do |f|
              f.write(rhyming_words.join(','))
            end
            @rythm_cache ||= {}
            @rythm_cache[word] = rhyming_words
          end
        
          def cached?(word)
            (@rythm_cache||{}).has_key?(word) || File.exists?("#{CACHE_DIR}/#{word}")
          end
        
          def fetch_from_cache(word)
            if (@rythm_cache||{}).has_key?(word)
              @rythm_cache[word]
            else
              data = File.read("#{CACHE_DIR}/#{word}")
              return data.split(",")
            end
          end
        end

      end
    end
  end
end