toptal/chewy

Dir.glob(File.join(File.dirname(__FILE__), 'parameters', 'concerns', '*.rb')).each { |f| require f }
Dir.glob(File.join(File.dirname(__FILE__), 'parameters', '*.rb')).each { |f| require f }

module Chewy
  module Search
    # This class is basically a compound storage of the request
    # parameter storages. It encapsulates some storage-collection-handling
    # logic.
    #
    # @see Chewy::Search::Request#parameters
    # @see Chewy::Search::Parameters::Storage
    class Parameters
      QUERY_STRING_STORAGES = %i[indices preference search_type request_cache allow_partial_search_results ignore_unavailable].freeze

      # Default storage classes warehouse. It is probably possible to
      # add your own classes here if necessary, but I'm not sure it will work.
      #
      # @return [{Symbol => Chewy::Search::Parameters::Storage}]
      def self.storages
        @storages ||= Hash.new do |hash, name|
          hash[name] = "Chewy::Search::Parameters::#{name.to_s.camelize}".constantize
        end
      end

      # @return [{Symbol => Chewy::Search::Parameters::Storage}]
      attr_accessor :storages

      delegate :[], :[]=, to: :storages

      # Accepts an initial hash as basic values or parameter storages.
      #
      # @example
      #   Chewy::Search::Parameters.new(limit: 10, offset 10)
      #   Chewy::Search::Parameters.new(
      #     limit: Chewy::Search::Parameters::Limit.new(10),
      #     limit: Chewy::Search::Parameters::Offset.new(10)
      #   )
      # @param initial [{Symbol => Object, Chewy::Search::Parameters::Storage}]
      def initialize(initial = {}, **kinitial)
        @storages = Hash.new do |hash, name|
          hash[name] = self.class.storages[name].new
        end
        initial = initial.deep_dup.merge(kinitial)
        initial.each_with_object(@storages) do |(name, value), result|
          storage_class = self.class.storages[name]
          storage = value.is_a?(storage_class) ? value : storage_class.new(value)
          result[name] = storage
        end
      end

      # Compares storages by their values.
      #
      # @param other [Object] any object
      # @return [true, false]
      def ==(other)
        super || (other.is_a?(self.class) && compare_storages(other))
      end

      # Clones the specified storage, performs the operation
      # defined by block on the clone.
      #
      # @param name [Symbol] parameter name
      # @yield the block is executed in the cloned storage instance binding
      # @return [Chewy::Search::Parameters::Storage]
      def modify!(name, &block)
        @storages[name] = @storages[name].clone.tap do |s|
          s.instance_exec(&block)
        end
      end

      # Removes specified storages from the storages hash.
      #
      # @param names [Array<String, Symbol>]
      # @return [{Symbol => Chewy::Search::Parameters::Storage}] removed storages hash
      def only!(names)
        @storages.slice!(*assert_storages(names))
      end

      # Keeps only specified storages removing everything else.
      #
      # @param names [Array<String, Symbol>]
      # @return [{Symbol => Chewy::Search::Parameters::Storage}] kept storages hash
      def except!(names)
        @storages.except!(*assert_storages(names))
      end

      # Takes all the storages and merges them one by one using
      # {Chewy::Search::Parameters::Storage#merge!} method. Merging
      # is implemented in different ways for different storages: for
      # limit, offset and other single-value classes it is a simple
      # value replacement, for boolean storages (explain, none) it uses
      # a disjunction result, for compound values - merging and
      # concatenation, for query, filter, post_filter - it is the
      # "and" operation.
      #
      # @see Chewy::Search::Parameters::Storage#merge!
      # @return [{Symbol => Chewy::Search::Parameters::Storage}] storages from other parameters
      def merge!(other)
        other.storages.each do |name, storage|
          modify!(name) { merge!(storage) }
        end
      end

      # Renders and merges all the parameter storages into a single hash.
      #
      # @return [Hash] request body
      def render
        render_query_string_params.merge(render_body)
      end

    protected

      def initialize_clone(origin)
        @storages = origin.storages.clone
      end

      def compare_storages(other)
        keys = (@storages.keys | other.storages.keys)
        @storages.values_at(*keys) == other.storages.values_at(*keys)
      end

      def assert_storages(names)
        raise ArgumentError, 'No storage names were specified' if names.empty?

        names = names.map(&:to_sym)
        self.class.storages.values_at(*names)
        names
      end

      def render_query_string_params
        query_string_storages = @storages.select do |storage_name, _|
          QUERY_STRING_STORAGES.include?(storage_name)
        end

        query_string_storages.values.inject({}) do |result, storage|
          result.merge!(storage.render || {})
        end
      end

      def render_body
        exceptions = %i[filter query none] + QUERY_STRING_STORAGES
        body = @storages.except(*exceptions).values.inject({}) do |result, storage|
          result.merge!(storage.render || {})
        end
        body.merge!(render_query || {})
        {body: body}
      end

      def render_query
        none = @storages[:none].render

        return none if none

        filter = @storages[:filter].render
        query = @storages[:query].render

        return query unless filter

        if query && query[:query][:bool]
          query[:query][:bool].merge!(filter)
          query
        elsif query
          {query: {bool: {must: query[:query]}.merge!(filter)}}
        else
          {query: {bool: filter}}
        end
      end
    end
  end
end