module ActiveStorage
  class Service::Configurator #:nodoc:
    attr_reader :configurations

    def self.build(service_name, configurations)
      new(configurations).build(service_name)
    end

    def initialize(configurations)
      @configurations = configurations.deep_symbolize_keys
    end

    def build(service_name)
      config = config_for(service_name.to_sym)
      resolve(config.fetch(:service)).build(**config, configurator: self)
    end

    private
      def config_for(name)
        configurations.fetch name do
          raise "Missing configuration for the #{name.inspect} Active Storage service. Configurations available for #{configurations.keys.inspect}"
        end
      end

      def resolve(class_name)
        require "active_storage/service/#{class_name.to_s.underscore}_service"
        ActiveStorage::Service.const_get(:"#{class_name}Service")
      end
  end
end