require 'riak/search'

module Riak::Search

  # A collection of Riak Search 2 ("Yokozuna") results. Provides direct access
  # to the {Riak::RObject} instances found, and access through the #docs method
  # to the results as returned by Solr.
  class ResultCollection
    # @return [Riak::Client]
    attr_reader :client

    # @return [Hash] the de-serialzed hash returned from Solr
    attr_reader :raw

    # @return [Numeric] the maximum score found by Solr
    attr_reader :max_score

    # @return [Integer] the number of documents in this collection
    attr_reader :length

    # @return [Integer] the total number of documents matched, including ones
    #   not returned due to row-limiting
    attr_reader :num_found

    # Initialize a {ResultCollection} with the client queried and the raw
    # JSON returned from the search API.
    #
    # This is automatically called by {Riak::Search::Query}#results
    #
    # @api private
    def initialize(client, raw_results)
      @client = client
      @raw = raw_results
      @max_score = raw['max_score']
      @num_found = raw['num_found']
      @length = raw['docs'].length
    end

    # Access the individual documents from the search results. The document
    # metadata are each wrapped in a {Riak::Search::ResultDocument}.
    #
    # @return [Array<Riak::Search::ResultDocument>] individual documents
    def docs
      @docs ||= raw['docs'].map do |result|
        ResultDocument.new client, result
      end
    end

    # @return [Boolean] does this collection contain any documents?
    def empty?
      length == 0
    end

    # @param [Integer] index the index of the [Riak::RObject] to load and return
    # @return [Riak::RObject,NilClass] the found object, or nil if the index
    #   is out of range
    def [](index)
      doc = docs[index]
      return nil if doc.nil?

      doc.object
    end

    # @return [Riak::RObject,NilClass] the first found object, or nil if the
    #   index is out of range
    def first
      self[0]
    end

    # Materializes and returns an array of objects from search results.
    # You'll probably need to type inspect its members.
    #
    # @return [Array] materialized objects
    def objects
      @objects ||= docs.map do |doc|
        next doc.crdt if doc.crdt?
        doc.robject
      end
    end

    # Materializes [Riak::RObject]s from any key-value results. Refuses to
    # return RObjects for any CRDT results.
    #
    # @return [Array<Riak::RObject>] key-value objects
    def robjects
      @robjects ||= docs.reject(&:crdt?).map(&:robject)
    end

    # Materializes [Riak::Crdt::Base] subclasses from any CRDT results.
    #
    # @return [Array<Riak::Crdt::Base>] CRDT objects
    def crdts
      @crdts ||= docs.select(&:crdt?).map(&:crdt)
    end

    # Materializes [Riak::Crdt::Counter] results.
    #
    # @return [Array<Riak::Crdt::Counter] counter objects
    def counters
      @counters ||= docs.
                  select{ |d| d.type_class == Riak::Crdt::Counter }.
                  map(&:counter)
    end

    # Materializes [Riak::Crdt::Map] results.
    #
    # @return [Array<Riak::Crdt::Map] map objects
    def maps
      @maps ||= docs.
              select{ |d| d.type_class == Riak::Crdt::Map }.
              map(&:map)
    end

    # Materializes [Riak::Crdt::Set] results.
    #
    # @return [Array<Riak::Crdt::Set>]
    def sets
      @sets ||= docs.
              select{ |d| d.type_class == Riak::Crdt::Set }.
              map(&:set)
    end

    # {Enumerable}-compatible iterator method. If a block is given, yields with
    # each {Riak::RObject} in the collection. If no block is given, returns an
    # {Enumerator} over each {Riak::RObject in the collection.
    # @yieldparam robject [Riak::RObject]
    # @return [Enumerator<Riak::RObject>]
    def each_robject
      enum = docs.each_with_index

      if block_given?
        enum.each do |doc, idx|
          yield self[idx]
        end
      else
        Enumerator.new do |yielder|
          enum.each do |doc, idx|
            yielder << self[idx]
          end
        end
      end
    end
  end
end