module Picky

  module Sources

    # Important note: We're not sure if this works already.
    #
    # A Mongo database source.
    #
    # Options:
    # * url, db
    # Example:
    #   Sources::Mongo.new(:collection1, :collection2, :url => 'localhost:28017', :db => 'testdatabase')
  	# Be sure to escape the URL properly, e.g. # => %23 in the databasename if needed
  	#
    # and all the options of a <tt>RestClient::Resource</tt>.
    # See http://github.com/archiloque/rest-client.
    #
    class Mongo < Base

      # Raised when a Mongo source is instantiated without a valid uri.
    	#
    	# Important!
      # You have to start your mongodb with --rest in order to use
      # the rest / http interface
    	#
      class NoDBGiven < StandardError; end

  		@@id_key = '_id'
      #
      #
      def initialize *category_names, options
        check_gem

  			unless options[:url] && options[:db]
  				raise_no_db_given(category_names)
  			end

  		  @db         = RestClient::Resource.new options.delete(:url), options
  			@database   = options.delete(:db)
  		  @key_format = options[:key_format] && options[:key_format].to_sym || :to_sym
  		end

      # Tries to require the rest_client gem.
      #
      def check_gem # :nodoc:
        require 'rest_client'
      rescue LoadError
        warn_gem_missing 'rest-client', 'the MongoDB source'
        exit 1
      end

  		# Fetches the data, @limit=0 will return all records
  		#
  		# Limit is set to 0 by default - all collection entries will be send
  		# If want to limit the results, set to to any other number, e.g. limit=15
  		# to return only 15 entries
  		#
  		def harvest category
  			collection = (category.from || category.index_name).to_s
  			resp = @db["/#{@database}/#{category.index_name}/?@limit=0"].get
  			JSON.parse(resp)['rows'].each do |row|
  			  text = row[collection].to_s
  			  next unless text
  				index_key = row.delete(@@id_key) # TODO Still works, I removed .values
  				yield index_key, text
  			end
  		end

      def raise_no_db_given category_names # :nodoc:
        raise NoDBGiven.new(category_names.join(', '))
      end

      def to_s
        self.class.name
      end

    end
  end

end