module Internals

  module Indexed # :nodoc:all

    # TODO Rewrite.
    #
    # A Bundle is a number of indexes
    # per [index, category] combination.
    #
    # At most, there are three indexes:
    # * *core* index (always used)
    # * *weights* index (always used)
    # * *similarity* index (used with similarity)
    #
    # In Picky, indexing is separated from the index
    # handling itself through a parallel structure.
    #
    # Both use methods provided by this base class, but
    # have very different goals:
    #
    # * *Indexing*::*Bundle* is just concerned with creating index files
    #   and providing helper functions to e.g. check the indexes.
    #
    # * *Index*::*Bundle* is concerned with loading these index files into
    #   memory and looking up search data as fast as possible.
    #
    module Bundle

      class Base

        attr_reader   :identifier, :configuration
        attr_accessor :similarity_strategy
        attr_accessor :index, :weights, :similarity, :configuration

        delegate :[], :to => :configuration
        delegate :size, :to => :index

        def initialize name, configuration, similarity_strategy
          @identifier = "#{configuration.identifier}:#{name}"

          @index         = {}
          @weights       = {}
          @similarity    = {}

          @similarity_strategy = similarity_strategy
        end

        # Get a list of similar texts.
        #
        # Note: Does not return itself.
        #
        def similar text
          code = similarity_strategy.encoded text
          similar_codes = code && @similarity[code]
          similar_codes.delete text if similar_codes
          similar_codes || []
        end

        # Loads all indexes.
        #
        def load
          load_index
          load_weights
          load_similarity
          load_configuration
        end

        # Loads the core index.
        #
        def load_index
          # No loading needed.
        end
        # Loads the weights index.
        #
        def load_weights
          # No loading needed.
        end
        # Loads the similarity index.
        #
        def load_similarity
          # No loading needed.
        end
        # Loads the configuration.
        #
        def load_configuration
          # No loading needed.
        end

        # Loads the core index.
        #
        def clear_index
          # No loading needed.
        end
        # Loads the weights index.
        #
        def clear_weights
          # No loading needed.
        end
        # Loads the similarity index.
        #
        def clear_similarity
          # No loading needed.
        end
        # Loads the configuration.
        #
        def clear_configuration
          # No loading needed.
        end

      end

    end

  end

end