toptal/chewy

module Chewy
  class Config
    include Singleton

    attr_accessor :settings, :logger,
                  # The first strategy in stack. `:base` by default.
                  # If you need to return to the previous chewy behavior -
                  # just set it to `:bypass`
                  #
                  :root_strategy,
                  # Default request strategy middleware, used in e.g
                  # Rails controllers. See Chewy::Railtie::RequestStrategy
                  # for more info.
                  #
                  :request_strategy,
                  # Rails console strategy, `:urgent` by default.
                  #
                  :console_strategy,
                  # Use after_commit callbacks for RDBMS instead of
                  # after_save and after_destroy. True by default. Useful
                  # in tests with transactional fixtures or transactional
                  # DatabaseCleaner strategy.
                  #
                  :use_after_commit_callbacks,
                  # Where Chewy expects to find index definitions
                  # within a Rails app folder.
                  :indices_path,
                  # Set index refresh_interval setting to -1 before reset and put the original value after.
                  # If setting not present, put back to default 1s
                  # https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-update-settings.html
                  :reset_disable_refresh_interval,
                  # Set number_of_replicas to 0 before reset and put the original value after
                  # https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-update-settings.html
                  :reset_no_replicas,
                  # Refresh or not when import async (sidekiq, lazy_sidekiq, activejob)
                  :disable_refresh_async,
                  # Default options for root of Chewy type. Allows to set default options
                  # for type mappings like `_all`.
                  :default_root_options,
                  # Default field type for any field in any Chewy type. Defaults to 'text'.
                  :default_field_type,
                  # Callback called on each search request to be done into ES
                  :before_es_request_filter,
                  # Behavior when import scope for index includes order, offset or limit.
                  # Can be :ignore, :warn, :raise. Defaults to :warn
                  :import_scope_cleanup_behavior

    attr_reader :transport_logger, :transport_tracer,
                # Chewy search request DSL base class, used by every index.
                :search_class

    def self.delegated
      public_instance_methods - superclass.public_instance_methods - Singleton.public_instance_methods
    end

    def initialize
      @settings = {}
      @root_strategy = :base
      @request_strategy = :atomic
      @console_strategy = :urgent
      @use_after_commit_callbacks = true
      @reset_disable_refresh_interval = false
      @reset_no_replicas = false
      @disable_refresh_async = false
      @indices_path = 'app/chewy'
      @default_root_options = {}
      @default_field_type = 'text'.freeze
      @import_scope_cleanup_behavior = :warn
      @search_class = build_search_class(Chewy::Search::Request)
    end

    def transport_logger=(logger)
      Chewy.client.transport.logger = logger
      @transport_logger = logger
    end

    def transport_tracer=(tracer)
      Chewy.client.transport.tracer = tracer
      @transport_tracer = tracer
    end

    # Chewy core configurations. There is two ways to set it up:
    # use `Chewy.settings=` method or, for Rails application,
    # create `config/chewy.yml` file. Btw, `config/chewy.yml` supports
    # ERB the same way as ActiveRecord's config.
    #
    # Configuration options:
    #
    #   1. Chewy client options. All the options Elasticsearch::Client
    #      supports.
    #
    #        test:
    #          host: 'localhost:9250'
    #
    #   2. Chewy self-configuration:
    #
    #      :prefix - used as prefix for any index created.
    #
    #        test:
    #          host: 'localhost:9250'
    #          prefix: test<%= ENV['TEST_ENV_NUMBER'] %>
    #
    #      Then UsersIndex.index_name will be "test42_users"
    #      in case TEST_ENV_NUMBER=42
    #
    #      :wait_for_status - if this option set - chewy actions such
    #      as creating or deleting index, importing data will wait for
    #      the status specified. Extremely useful for tests under heavy
    #      indexes manipulations.
    #
    #        test:
    #          host: 'localhost:9250'
    #          wait_for_status: green
    #
    #   3. Index settings. All the possible ElasticSearch index settings.
    #      Will be merged as defaults with index settings on every index
    #      creation.
    #
    #        test: &test
    #          host: 'localhost:9250'
    #          index:
    #            number_of_shards: 1
    #            number_of_replicas: 0
    #
    def configuration
      yaml_settings.merge(settings.deep_symbolize_keys).tap do |configuration|
        configuration[:logger] = transport_logger if transport_logger
        configuration[:indices_path] ||= indices_path if indices_path
        configuration.merge!(tracer: transport_tracer) if transport_tracer
      end
    end

  private

    def yaml_settings
      @yaml_settings ||= build_yaml_settings || {}
    end

    def build_yaml_settings
      return unless defined?(Rails::VERSION)

      file = Rails.root.join('config', 'chewy.yml')

      return unless File.exist?(file)

      yaml = ERB.new(File.read(file)).result
      hash = YAML.unsafe_load(yaml)
      hash[Rails.env].try(:deep_symbolize_keys) if hash
    end

    def build_search_class(base)
      Class.new(base).tap do |search_class|
        search_class.send :include, Chewy::Search::Pagination::Kaminari if defined?(::Kaminari)
      end
    end
  end
end