little-bobby-tables/elasticfusion

# frozen_string_literal: true
require 'elasticfusion/search/builder'
require 'elasticfusion/search/peeker'
require 'elasticfusion/search/errors'
require 'elasticfusion/search/query/parser'
require 'elasticfusion/search/query/visitors/elasticsearch'

# An instance of this class represents a single search.
# It encapsulates all custom search features (advanced query parsing,
# query building, etc.)
module Elasticfusion
  module Search
    class Wrapper
      def initialize(model, query, &block)
        @search_runner      = model.method(:search)

        @searchable_mapping = model.elasticfusion[:searchable_mapping]
        @searchable_fields  = model.elasticfusion[:searchable_fields]
        @keyword_field      = model.elasticfusion[:keyword_field]

        @builder = Search::Builder.new(model.elasticfusion)
        @builder.instance_eval(&block) if block_given?

        # The subset of queries that is currently supported can be executed
        # in the filter context, which does not compute _score and can be cached.
        # It cannot be used for relevance sorting, though.
        @builder.filter parse_query(query) if query.present?
      end

      delegate :next_record, :previous_record, to: :peeker

      def perform(request = elasticsearch_request)
        @search_runner.call(request)
      end

      def elasticsearch_request
        { query: { bool: { must: @builder.queries,
                           filter: @builder.filters } },
          sort: @builder.sorts }
      end

      def peeker
        Peeker.new(self)
      end

      private

      def parse_query(query)
        ast = Query::Parser.new(query, @searchable_fields).ast
        visitor = Query::Visitors::Elasticsearch.new(@keyword_field,
                                                     @searchable_mapping)
        visitor.accept(ast)
      end
    end
  end
end