# frozen_string_literal: true

require 'rom/types'
require 'rom/associations/abstract'

module ROM
  module Associations
    # Abstract many-to-many association type
    #
    # @api public
    class ManyToMany < Abstract
      # @!attribute [r] join_relation
      #   @return [Relation] Intermediate join relation
      attr_reader :join_relation

      # @api private
      def initialize(*, **)
        super
        @join_relation = relations[through]
      end

      # Adapters should implement this method
      #
      # @abstract
      #
      # @api public
      def call(*)
        raise NotImplementedError
      end

      # Return configured or inferred FK name
      #
      # @return [Symbol]
      #
      # @api public
      def foreign_key
        definition.foreign_key || join_relation.foreign_key(source.name)
      end

      # Return join-relation name
      #
      # @return [Symbol]
      #
      # @api public
      def through
        definition.through
      end

      # Return parent's relation combine keys
      #
      # @return [Hash<Symbol=>Symbol>]
      #
      # @api private
      def parent_combine_keys
        target.associations[source.name].combine_keys.to_a.flatten(1)
      end

      # Associate child tuples with the provided parent
      #
      # @param [Array<Hash>] children An array with child tuples
      # @param [Array,Hash] parent An array with parent tuples or a single tuple
      #
      # @return [Array<Hash>]
      #
      # @api private
      def associate(children, parent)
        ((spk, sfk), (tfk, tpk)) = join_key_map

        case parent
        when Array
          parent.map { |p| associate(children, p) }.flatten(1)
        else
          children.map { |tuple|
            { sfk => tuple.fetch(spk), tfk => parent.fetch(tpk) }
          }
        end
      end

      protected

      # Primary key name on the source side
      #
      # @return [Symbol]
      #
      # @api protected
      def source_key
        source.primary_key
      end

      # Foreign key name on the target side
      #
      # @return [Symbol]
      #
      # @api protected
      def target_key
        foreign_key
      end

      # Return association for many-to-many-through
      #
      # @return [Association]
      #
      # @api protected
      def join_assoc
        if join_relation.associations.key?(through.assoc_name)
          join_relation.associations[through.assoc_name]
        else
          join_relation.associations[through.target]
        end
      end

      # Return a [pk, fk] mapping for source/target relations
      #
      # @return [Array<Symbol>]
      #
      # @api protected
      def join_key_map
        left = super
        right = join_assoc.join_key_map

        [left, right]
      end

      memoize :foreign_key, :join_assoc, :join_key_map
    end
  end
end


# frozen_string_literal: true

require 'rom/array_dataset'

module ROM
  module Memory
    # In-memory dataset
    #
    # This class can be used as a base class for other adapters.
    #
    # @api public
    class Dataset
      include ArrayDataset

      # Join with other datasets
      #
      # @param [Array<Dataset>] args A list of dataset to join with
      #
      # @return [Dataset]
      #
      # @api public
      # rubocop:disable Metrics/AbcSize
      def join(*args)
        left, right = args.size > 1 ? args : [self, args.first]

        join_map = left.each_with_object({}) { |tuple, h|
          others = right.to_a.find_all { |t| tuple.to_a.intersect?(t.to_a) }
          (h[tuple] ||= []).concat(others)
        }

        tuples = left.flat_map { |tuple|
          join_map[tuple].map { |other| tuple.merge(other) }
        }

        self.class.new(tuples, **options)
      end
      # rubocop:enable Metrics/AbcSize

      # Restrict a dataset
      #
      # @param [Hash] criteria A hash with conditions
      #
      # @return [Dataset]
      #
      # @api public
      def restrict(criteria = nil, &)
        return find_all(&) unless criteria

        find_all do |tuple|
          criteria.all? do |k, v|
            case v
            when ::Array then v.include?(tuple[k])
            when ::Regexp then tuple[k].match(v)
            else tuple[k].eql?(v)
            end
          end
        end
      end

      # Project a dataset
      #
      # @param [Array<Symbol>] names A list of attribute names
      #
      # @return [Dataset]
      #
      # @api public
      def project(*names)
        map { |tuple| tuple.select { |key| names.include?(key) } }
      end

      # Sort a dataset
      #
      # @param [Array<Symbol>] fields
      #   Names of fields to order tuples by
      #
      # @option [Boolean] :nils_first (false)
      #   Whether `nil` values should be placed before others
      #
      # @return [Dataset]
      #
      # @api public
      def order(*fields)
        nils_first = fields.pop[:nils_first] if fields.last.is_a?(Hash)

        sort do |a, b|
          fields # finds the first difference between selected fields of tuples
            .map { |n| __compare__ a[n], b[n], nils_first }
            .detect(-> { 0 }) { |r| r != 0 }
        end
      end

      # Insert tuple into a dataset
      #
      # @param [Hash] tuple A new tuple for insertion
      #
      # @api public
      #
      # @return [Dataset]
      def insert(tuple)
        data << tuple
        self
      end
      alias_method :<<, :insert

      # Delete tuples from a dataset
      #
      # @param [Hash] tuple A new tuple for deletion
      #
      # @return [Dataset]
      #
      # @api public
      def delete(tuple)
        data.delete(tuple)
        self
      end

      private

      # Compares two values, that are either comparable, or can be nils
      #
      # @api private
      def __compare__(a, b, nils_first)
        return a <=> b unless a.nil? ^ b.nil?

        nils_first ^ b.nil? ? -1 : 1
      end
    end
  end
end


def restrict(criteria = nil, &)
        return find_all(&) unless criteria

        find_all do |tuple|
          criteria.all? do |k, v|
            case v
            when ::Array then v.include?(tuple[k])
            when ::Regexp then tuple[k].match(v)
            else tuple[k].eql?(v)
            end
          end
        end
      end


# frozen_string_literal: true

require 'rom/relation'
require 'rom/command'

require 'rom/registry'
require 'rom/command_registry'
require 'rom/mapper_registry'

require 'rom/container'
require 'rom/setup/finalize/finalize_commands'
require 'rom/setup/finalize/finalize_relations'
require 'rom/setup/finalize/finalize_mappers'

# temporary
require 'rom/configuration_dsl/relation'

module ROM
  # This giant builds an container using defined classes for core parts of ROM
  #
  # It is used by the setup object after it's done gathering class definitions
  #
  # @private
  class Finalize
    attr_reader :gateways

    attr_reader :repo_adapter

    attr_reader :relation_classes

    attr_reader :mapper_classes

    attr_reader :mapper_objects

    attr_reader :command_classes

    attr_reader :plugins

    attr_reader :config

    attr_reader :notifications

    # @api private
    def initialize(options)
      @gateways = options.fetch(:gateways)

      @relation_classes = options.fetch(:relation_classes)
      @command_classes = options.fetch(:command_classes)

      mappers = options.fetch(:mappers, [])
      @mapper_classes = mappers.select { |mapper| mapper.is_a?(Class) }
      @mapper_objects = (mappers - @mapper_classes).reduce(:merge) || {}

      @config = options.fetch(:config)
      @notifications = options.fetch(:notifications)

      @plugins = options.fetch(:plugins)
    end

    # Return adapter identifier for a given gateway object
    #
    # @return [Symbol]
    #
    # @api private
    def adapter_for(gateway)
      gateways[gateway].adapter
    end

    # Run the finalization process
    #
    # This creates relations, mappers and commands
    #
    # @return [Container]
    #
    # @api private
    def run!
      mappers = load_mappers
      relations = load_relations(mappers)
      commands = load_commands(relations)

      container = Container.new(gateways, relations, mappers, commands)
      container.freeze
      container
    end

    private

    # Build entire relation registry from all known relation subclasses
    #
    # This includes both classes created via DSL and explicit definitions
    #
    # @api private
    def load_relations(mappers)
      global_plugins = plugins.select { |p| p.type == :relation || p.type == :schema }

      FinalizeRelations.new(
        gateways,
        relation_classes,
        mappers: mappers,
        plugins: global_plugins,
        notifications: notifications
      ).run!
    end

    # @api private
    def load_mappers
      FinalizeMappers.new(mapper_classes, mapper_objects).run!
    end

    # Build entire command registries
    #
    # This includes both classes created via DSL and explicit definitions
    #
    # @api private
    def load_commands(relations)
      FinalizeCommands.new(relations, gateways, command_classes, notifications).run!
    end
  end
end


def load_relations(mappers)
      global_plugins = plugins.select { |p| p.type == :relation || p.type == :schema }

      FinalizeRelations.new(
        gateways,
        relation_classes,
        mappers: mappers,
        plugins: global_plugins,
        notifications: notifications
      ).run!
    end


# frozen_string_literal: true

require 'pathname'

require 'rom/support/inflector'

require 'rom/types'
require 'rom/initializer'
require 'rom/setup/auto_registration_strategies/no_namespace'
require 'rom/setup/auto_registration_strategies/with_namespace'
require 'rom/setup/auto_registration_strategies/custom_namespace'

module ROM
  # AutoRegistration is used to load component files automatically from the provided directory path
  #
  # @api public
  class AutoRegistration
    extend Initializer

    NamespaceType = Types::Strict::Bool | Types::Strict::String

    PathnameType = Types.Constructor(Pathname, &Kernel.method(:Pathname))

    DEFAULT_MAPPING = {
      relations: :relations,
      mappers: :mappers,
      commands: :commands
    }.freeze

    # @!attribute [r] directory
    #   @return [Pathname] The root path
    param :directory, type: PathnameType

    # @!attribute [r] namespace
    #   @return [Boolean,String]
    #     The name of the top level namespace or true/false which
    #     enables/disables default top level namespace inferred from the dir name
    option :namespace, type: NamespaceType, default: -> { true }

    # @!attribute [r] component_dirs
    #   @return [Hash] component => dir-name map
    option :component_dirs, type: Types::Strict::Hash, default: -> { DEFAULT_MAPPING }

    # @!attribute [r] globs
    #   @return [Hash] File globbing functions for each component dir
    option :globs, default: lambda {
      component_dirs.transform_values { |path|
        directory.join("#{path}/**/*.rb")
      }
    }

    # Load relation files
    #
    # @api private
    def relations
      load_entities(:relations)
    end

    # Load command files
    #
    # @api private
    def commands
      load_entities(:commands)
    end

    # Load mapper files
    #
    # @api private
    def mappers
      load_entities(:mappers)
    end

    private

    # Load given component files
    #
    # @api private
    def load_entities(entity)
      Dir[globs[entity]].map do |file|
        require file
        klass_name =
          case namespace
          when String
            AutoRegistrationStrategies::CustomNamespace.new(
              namespace: namespace, file: file, directory: directory
            ).call
          when TrueClass
            AutoRegistrationStrategies::WithNamespace.new(
              file: file, directory: directory
            ).call
          when FalseClass
            AutoRegistrationStrategies::NoNamespace.new(
              file: file, directory: directory, entity: component_dirs.fetch(entity)
            ).call
          end

        Inflector.constantize(klass_name)
      end
    end
  end
end


# frozen_string_literal: true

require 'rom/initializer'
require 'rom/pipeline'
require 'rom/commands/graph/class_interface'

module ROM
  module Commands
    # Command graph
    #
    # @api private
    class Graph
      extend Initializer
      include Dry::Equalizer(:root, :nodes)

      extend ClassInterface

      include Pipeline
      include Pipeline::Proxy

      # @attr_reader [Command] root The root command
      param :root

      # @attr_reader [Array<Command>] nodes The child commands
      param :nodes

      alias_method :left, :root
      alias_method :right, :nodes

      # @attr_reader [Symbol] root's relation name
      option :name, default: -> { root.name }

      option :mappers, default: -> { MapperRegistry.new }

      # Calls root and all nodes with the result from root
      #
      # Graph results are mappable through `combine` operation in mapper DSL
      #
      # @example
      #   create_user = rom.commands[:users].create
      #   create_task = rom.commands[:tasks].create
      #
      #   command = create_user
      #     .curry(name: 'Jane')
      #     .combine(create_task.curry(title: 'Task'))
      #
      #   command.call
      #
      # @return [Array] nested array with command results
      #
      # @api public
      #
      # rubocop:disable Metrics/PerceivedComplexity
      def call(*args)
        left = root.call(*args)

        right = nodes.map { |node|
          response =
            if node.lazy?
              node.call(args.first, left)
            else
              node.call(left)
            end

          if node.one? && !node.graph?
            [response]
          else
            response
          end
        }

        if one?
          [[left], right]
        else
          [left, right]
        end
      end
      # rubocop:enable Metrics/PerceivedComplexity

      # @api private
      def graph?
        true
      end

      private

      # @api public
      def composite_class
        Command::Composite
      end
    end
  end
end


# frozen_string_literal: true

require 'rom/commands/composite'
require 'rom/commands/graph'

module ROM
  module Commands
    # Lazy command wraps another command and evaluates its input when called
    #
    # @api private
    class Lazy
      include Dry::Equalizer(:command, :evaluator)

      # @attr_reader [Command] command The wrapped command
      attr_reader :command

      alias_method :unwrap, :command

      # @attr_reader [Proc] evaluator The proc that will evaluate the input
      attr_reader :evaluator

      attr_reader :command_proc

      # @api private
      def self.[](command)
        case command
        when Commands::Create then Lazy::Create
        when Commands::Update then Lazy::Update
        when Commands::Delete then Lazy::Delete
        else
          self
        end
      end

      # @api private
      def initialize(command, evaluator, command_proc = nil)
        @command = command
        @evaluator = evaluator
        @command_proc = command_proc || proc { |*| command }
      end

      # Evaluate command's input using the input proc and pass to command
      #
      # @return [Array,Hash]
      #
      # @api public
      def call(*_args)
        raise NotImplementedError
      end

      # Compose a lazy command with another one
      #
      # @see Commands::Abstract#>>
      #
      # @return [Composite]
      #
      # @api public
      def >>(other)
        Composite.new(self, other)
      end

      # Combine with other lazy commands
      #
      # @see Abstract#combine
      #
      # @return [Graph]
      #
      # @api public
      def combine(*others)
        Graph.new(self, others)
      end

      # @api private
      def lazy?
        true
      end

      # @api private
      def respond_to_missing?(name, include_private = false)
        super || command.respond_to?(name)
      end

      private

      # @api private
      def method_missing(name, ...)
        if command.respond_to?(name)
          response = command.public_send(name, ...)

          if response.instance_of?(command.class)
            self.class.new(response, evaluator, command_proc)
          else
            response
          end
        else
          super
        end
      end
    end
  end
end

require 'rom/commands/lazy/create'
require 'rom/commands/lazy/update'
require 'rom/commands/lazy/delete'


# frozen_string_literal: true

require 'rom/pipeline'

module ROM
  module Commands
    # Composite command that consists of left and right commands
    #
    # @api public
    class Composite < Pipeline::Composite
      # Calls the composite command
      #
      # Right command is called with a result from the left one
      #
      # @return [Object]
      #
      # @api public
      #
      # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
      def call(*args)
        response = left.call(*args)

        if response.nil? || (many? && response.empty?)
          return one? ? nil : EMPTY_ARRAY
        end

        if one? && !graph?
          if right.is_a?(Command) || right.is_a?(Commands::Composite)
            right.call([response].first)
          else
            right.call([response]).first
          end
        elsif one? && graph?
          right.call(response).first
        else
          right.call(response)
        end
      end
      alias_method :[], :call
      # rubocop:enable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity

      # @api private
      def graph?
        left.is_a?(Graph)
      end

      # @api private
      def result
        left.result
      end

      # @api private
      def decorate?(response)
        super || response.is_a?(Graph)
      end
    end
  end
end

call

!(response.nil? || (many? && response.empty?))


# frozen_string_literal: true

require 'rom/support/inflector'

module ROM
  # Base command class with factory class-level interface and setup-related logic
  #
  # @private
  class Command
    module ClassInterface
      # This hook sets up default class state
      #
      # @api private
      def inherited(klass)
        super
        klass.instance_variable_set(:@before, before.dup)
        klass.instance_variable_set(:@after, after.dup)
      end

      # Sets up the base class
      #
      # @api private
      def self.extended(klass)
        super
        klass.set_hooks(:before, [])
        klass.set_hooks(:after, [])
      end

      # Return adapter specific sub-class based on the adapter identifier
      #
      # This is a syntax sugar to make things consistent
      #
      # @example
      #   ROM::Commands::Create[:memory]
      #   # => ROM::Memory::Commands::Create
      #
      # @param [Symbol] adapter identifier
      #
      # @return [Class]
      #
      # @api public
      def [](adapter)
        adapter_namespace(adapter).const_get(Inflector.demodulize(name))
      end

      # Return namespaces that contains command subclasses of a specific adapter
      #
      # @param [Symbol] adapter identifier
      #
      # @return [Module]
      #
      # @api private
      def adapter_namespace(adapter)
        ROM.adapters.fetch(adapter).const_get(:Commands)
      rescue KeyError
        raise AdapterNotPresentError.new(adapter, :relation)
      end

      # Build a command class for a specific relation with options
      #
      # @example
      #   class CreateUser < ROM::Commands::Create[:memory]
      #   end
      #
      #   command = CreateUser.build(rom.relations[:users])
      #
      # @param [Relation] relation
      # @param [Hash] options
      #
      # @return [Command]
      #
      # @api public
      def build(relation, **options)
        new(relation, **self.options, **options)
      end

      # Create a command class with a specific type
      #
      # @param [Symbol] name Command name
      # @param [Class] type Command class
      #
      # @yield [Class]
      #
      # @return [Class, Object]
      #
      # @api public
      def create_class(name, type, &)
        klass = Dry::Core::ClassBuilder
          .new(name: "#{Inflector.classify(type)}[:#{name}]", parent: type)
          .call

        if block_given?
          yield(klass)
        else
          klass
        end
      end

      # Use a configured plugin in this relation
      #
      # @example
      #   class CreateUser < ROM::Commands::Create[:memory]
      #     use :pagintion
      #
      #     per_page 30
      #   end
      #
      # @param [Symbol] plugin
      # @param [Hash] options
      # @option options [Symbol] :adapter (:default) first adapter to check for plugin
      #
      # @api public
      def use(plugin, **options)
        ROM.plugin_registry[:command].fetch(plugin, adapter).apply_to(self, **options)
      end

      # Extend a command class with relation view methods
      #
      # @param [Relation] relation
      #
      # @return [Class]
      #
      # @api public
      def extend_for_relation(relation)
        include(relation_methods_mod(relation.class))
      end

      # Set before-execute hooks
      #
      # @overload before(hook)
      #   Set an before hook as a method name
      #
      #   @example
      #     class CreateUser < ROM::Commands::Create[:sql]
      #       relation :users
      #       register_as :create
      #
      #       before :my_hook
      #
      #       def my_hook(tuple, *)
      #         puts "hook called#
      #       end
      #     end
      #
      # @overload before(hook_opts)
      #   Set an before hook as a method name with arguments
      #
      #   @example
      #     class CreateUser < ROM::Commands::Create[:sql]
      #       relation :users
      #       register_as :create
      #
      #       before my_hook: { arg1: 1, arg2: 2 }
      #
      #       def my_hook(tuple, arg1:, arg2:)
      #         puts "hook called with args: #{arg1} and #{arg2}"
      #       end
      #     end
      #
      #   @param [Hash<Symbol=>Hash>] hook Options with method name and pre-set args
      #
      # @return [Array<Hash, Symbol>] A list of all configured before hooks
      #
      # @api public
      def before(*hooks)
        if hooks.empty?
          @before
        else
          set_hooks(:before, hooks)
        end
      end

      # Set after-execute hooks
      #
      # @overload after(hook)
      #   Set an after hook as a method name
      #
      #   @example
      #     class CreateUser < ROM::Commands::Create[:sql]
      #       relation :users
      #       register_as :create
      #
      #       after :my_hook
      #
      #       def my_hook(tuple, *)
      #         puts "hook called#
      #       end
      #     end
      #
      # @overload after(hook_opts)
      #   Set an after hook as a method name with arguments
      #
      #   @example
      #     class CreateUser < ROM::Commands::Create[:sql]
      #       relation :users
      #       register_as :create
      #
      #       after my_hook: { arg1: 1, arg1: 2 }
      #
      #       def my_hook(tuple, arg1:, arg2:)
      #         puts "hook called with args: #{arg1} and #{arg2}"
      #       end
      #     end
      #
      #   @param [Hash<Symbol=>Hash>] hook Options with method name and pre-set args
      #
      # @return [Array<Hash, Symbol>] A list of all configured after hooks
      #
      # @api public
      def after(*hooks)
        if hooks.empty?
          @after
        else
          set_hooks(:after, hooks)
        end
      end

      # Set new or more hooks
      #
      # @api private
      def set_hooks(type, hooks)
        ivar = :"@#{type}"

        if instance_variable_defined?(ivar)
          instance_variable_get(ivar).concat(hooks)
        else
          instance_variable_set(ivar, hooks)
        end
      end

      # Return default name of the command class based on its name
      #
      # During setup phase this is used by defalut as `register_as` option
      #
      # @return [Symbol]
      #
      # @api private
      def default_name
        Inflector.underscore(Inflector.demodulize(name)).to_sym
      end

      # Return default options based on class macros
      #
      # @return [Hash]
      #
      # @api private
      def options
        { input: input, result: result, before: before, after: after }
      end

      # @api private
      def relation_methods_mod(relation_class)
        Module.new do
          relation_class.view_methods.each do |meth|
            module_eval(<<-RUBY, __FILE__, __LINE__ + 1)
              def #{meth}(*args, **kwargs)                                 # def create(*args, **kwargs)
                response = relation.public_send(:#{meth}, *args, **kwargs) #   response = relation.public_send(:create, *args, **kwargs)
                                                                           #
                if response.is_a?(relation.class)                          #   if response.is_a?(relation.class)
                  new(response)                                            #     new(response)
                else                                                       #   else
                  response                                                 #     response
                end                                                        #   end
              end                                                          # end
            RUBY
          end
        end
      end
    end
  end
end


def relation_methods_mod(relation_class)
        Module.new do
          relation_class.view_methods.each do |meth|
            module_eval(<<-RUBY, __FILE__, __LINE__ + 1)
              def #{meth}(*args, **kwargs)                                 # def create(*args, **kwargs)
                response = relation.public_send(:#{meth}, *args, **kwargs) #   response = relation.public_send(:create, *args, **kwargs)
                                                                           #
                if response.is_a?(relation.class)                          #   if response.is_a?(relation.class)
                  new(response)                                            #     new(response)
                else                                                       #   else
                  response                                                 #     response
                end                                                        #   end
              end                                                          # end
            RUBY
          end
        end
      end


# frozen_string_literal: true

require 'rom/support/inflector'

require 'rom/associations/definitions'

module ROM
  class Schema
    # Additional schema DSL for definition SQL associations
    #
    # This DSL is exposed in `associations do .. end` blocks in schema defintions.
    #
    # @api public
    class AssociationsDSL < BasicObject
      # @!attribute [r] source
      #   @return [Relation::Name] The source relation
      attr_reader :source

      # @!attribute [r] registry
      #   @return [RelationRegistry] Relations registry from a rom container
      attr_reader :registry

      # @api private
      def initialize(source, &)
        @source = source
        @registry = {}
        instance_exec(&)
      end

      # Establish a one-to-many association
      #
      # @example using relation identifier
      #   has_many :tasks
      #
      # @example setting custom foreign key name
      #   has_many :tasks, foreign_key: :assignee_id
      #
      # @example with a :through option
      #   # this establishes many-to-many association
      #   has_many :tasks, through: :users_tasks
      #
      # @example using a custom view which overrides default one
      #   has_many :posts, view: :published, override: true
      #
      # @example using aliased association with a custom view
      #   has_many :posts, as: :published_posts, view: :published
      #
      # @example using custom target relation
      #   has_many :user_posts, relation: :posts
      #
      # @example using custom target relation and an alias
      #   has_many :user_posts, relation: :posts, as: :published, view: :published
      #
      # @param [Symbol] target The target relation identifier
      # @param [Hash] options A hash with additional options
      #
      # @return [Associations::OneToMany]
      #
      # @see #many_to_many
      #
      # @api public
      def one_to_many(target, **options)
        if options[:through]
          many_to_many(target, **options)
        else
          add(::ROM::Associations::Definitions::OneToMany.new(source, target, **options))
        end
      end
      alias_method :has_many, :one_to_many

      # Establish a one-to-one association
      #
      # @example using relation identifier
      #   one_to_one :addresses, as: :address
      #
      # @example with an intermediate join relation
      #   one_to_one :tasks, as: :priority_task, through: :assignments
      #
      # @param [Symbol] target The target relation identifier
      # @param [Hash] options A hash with additional options
      #
      # @return [Associations::OneToOne]
      #
      # @see #belongs_to
      #
      # @api public
      def one_to_one(target, **options)
        if options[:through]
          one_to_one_through(target, **options)
        else
          add(::ROM::Associations::Definitions::OneToOne.new(source, target, **options))
        end
      end

      # Establish a one-to-one association with a :through option
      #
      # @example
      #   one_to_one_through :users, as: :author, through: :users_posts
      #
      # @return [Associations::OneToOneThrough]
      #
      # @api public
      def one_to_one_through(target, **options)
        add(::ROM::Associations::Definitions::OneToOneThrough.new(source, target, **options))
      end

      # Establish a many-to-many association
      #
      # @example using relation identifier
      #   many_to_many :tasks, through: :users_tasks
      #
      # @param [Symbol] target The target relation identifier
      # @param [Hash] options A hash with additional options
      #
      # @return [Associations::ManyToMany]
      #
      # @see #one_to_many
      #
      # @api public
      def many_to_many(target, **options)
        add(::ROM::Associations::Definitions::ManyToMany.new(source, target, **options))
      end

      # Establish a many-to-one association
      #
      # @example using relation identifier
      #   many_to_one :users, as: :author
      #
      # @param [Symbol] target The target relation identifier
      # @param [Hash] options A hash with additional options
      #
      # @return [Associations::ManyToOne]
      #
      # @see #one_to_many
      #
      # @api public
      def many_to_one(target, **options)
        add(::ROM::Associations::Definitions::ManyToOne.new(source, target, **options))
      end

      # Shortcut for many_to_one which sets alias automatically
      #
      # @example with an alias (relation identifier is inferred via pluralization)
      #   belongs_to :user
      #
      # @example with an explicit alias
      #   belongs_to :users, as: :author
      #
      # @see #many_to_one
      #
      # @return [Associations::ManyToOne]
      #
      # @api public
      def belongs_to(target, **options)
        many_to_one(dataset_name(target), as: target, **options)
      end

      # Shortcut for one_to_one which sets alias automatically
      #
      # @example with an alias (relation identifier is inferred via pluralization)
      #   has_one :address
      #
      # @example with an explicit alias and a custom view
      #   has_one :posts, as: :priority_post, view: :prioritized
      #
      # @see #one_to_one
      #
      # @return [Associations::OneToOne]
      #
      # @api public
      def has_one(target, **options)
        one_to_one(dataset_name(target), as: target, **options)
      end

      # Return an association set for a schema
      #
      # @return [AssociationSet]
      #
      # @api private
      def call = AssociationSet[source.relation].build(registry)

      private

      # @api private
      def add(association)
        key = association.as || association.name

        if registry.key?(key)
          ::Kernel.raise(
            ::ArgumentError,
            "association #{key.inspect} is already defined for #{source.to_sym.inspect} relation"
          )
        end

        registry[key] = association
      end

      # @api private
      def dataset_name(name) = Inflector.pluralize(name).to_sym
    end
  end
end

add

key?

    def key?(name) = !name.nil? && elements.key?(name.to_sym)

    # @api private
    def fetch(key)
      raise ::ArgumentError, 'key cannot be nil' if key.nil?

      elements.fetch(key.to_sym) do
        return yield if block_given?

        raise self.class.element_not_found_error.new(key, self)
      end
    end


# frozen_string_literal: true

require 'rom/types'
require 'rom/attribute'
require 'rom/schema/associations_dsl'

module ROM
  class Schema
    # Schema DSL exposed as `schema { .. }` in relation classes
    #
    # @api public
    class DSL < ::BasicObject
      KERNEL_METHODS = %i[extend method block_given?].freeze
      KERNEL_METHODS.each { |m| define_method(m, ::Kernel.instance_method(m)) }

      extend Initializer

      # @!attribute [r] relation
      #   @return [Relation::Name] The name of the schema's relation
      param :relation

      # @!attribute [r] inferrer
      #   @return [Inferrer] Optional attribute inferrer
      option :inferrer, default: -> { DEFAULT_INFERRER }

      # @!attribute [r] schema_class
      #   @return [Class] Schema class that should be instantiated
      option :schema_class, default: -> { Schema }

      # @!attribute [r] attr_class
      #   @return [Class] Attribute class that should be used
      option :attr_class, default: -> { Attribute }

      # @!attribute [r] adapter
      #   @return [Symbol] The adapter identifier used in gateways
      option :adapter, default: -> { :default }

      # @!attribute [r] attributes
      #   @return [Hash<Symbol, Hash>] A hash with attribute names as
      #   keys and attribute representations as values.
      #
      #   @see [Schema.build_attribute_info]
      attr_reader :attributes

      # @!attribute [r] plugins
      #   @return [Hash] A hash with schema plugins enabled in a schema
      attr_reader :plugins

      # @!attribute [r] definition
      #   @return [Proc] Definition block passed to DSL
      attr_reader :definition

      # @!attribute [r] associations_dsl
      #   @return [AssociationDSL] Associations defined within a block
      attr_reader :associations_dsl

      # @api private
      def initialize(*, **, &block)
        super

        @attributes = {}
        @plugins = {}

        @definition = block
      end

      # Defines a relation attribute with its type and options.
      #
      # When only options are given, type is left as nil. It makes
      # sense when it is used alongside an schema inferrer, which will
      # populate the type.
      #
      # @see Relation.schema
      #
      # @api public
      def attribute(name, type_or_options, options = EMPTY_HASH)
        if attributes.key?(name)
          ::Kernel.raise ::ROM::AttributeAlreadyDefinedError,
                         "Attribute #{name.inspect} already defined"
        end

        attributes[name] = build_attribute_info(name, type_or_options, options)
      end

      # Define associations for a relation
      #
      # @example
      #   class Users < ROM::Relation[:sql]
      #     schema(infer: true) do
      #       associations do
      #         has_many :tasks
      #         has_many :posts
      #         has_many :posts, as: :priority_posts, view: :prioritized
      #         belongs_to :account
      #       end
      #     end
      #   end
      #
      #   class Posts < ROM::Relation[:sql]
      #     schema(infer: true) do
      #       associations do
      #         belongs_to :users, as: :author
      #       end
      #     end
      #
      #     view(:prioritized) do
      #       where { priority <= 3 }
      #     end
      #   end
      #
      # @return [AssociationDSL]
      #
      # @api public
      def associations(&)
        @associations_dsl = AssociationsDSL.new(relation, &)
      end

      # Builds a representation of the information needed to create an
      # attribute. It returns a hash with `:type` and `:options` keys.
      #
      # @return [Hash]
      #
      # @see [Schema.build_attribute_info]
      #
      # @api private
      def build_attribute_info(name, type_or_options, options = EMPTY_HASH)
        type, options = if type_or_options.is_a?(::Hash)
                          [nil, type_or_options]
                        else
                          [build_type(type_or_options, options), options]
                        end
        Schema.build_attribute_info(
          type, **options, name: name
        )
      end

      # Builds a type instance from base type and meta options
      #
      # @return [Dry::Types::Type] Type instance
      #
      # @api private
      # rubocop:disable Metrics/AbcSize
      def build_type(type, options = EMPTY_HASH)
        if options[:read]
          type.meta(source: relation, read: options[:read])
        elsif type.optional? && type.meta[:read]
          type.meta(source: relation, read: type.meta[:read].optional)
        else
          type.meta(source: relation)
        end.meta(Attribute::META_OPTIONS.map { |opt|
                   [opt, options[opt]] if options.key?(opt)
                 }.compact.to_h)
      end
      # rubocop:enable Metrics/AbcSize

      # Specify which key(s) should be the primary key
      #
      # @api public
      def primary_key(*names)
        names.each do |name|
          attributes[name][:type] =
            attributes[name][:type].meta(primary_key: true)
        end
        self
      end

      # Enables for the schema
      #
      # @param [Symbol] plugin_name Plugin name
      # @param [Hash] options Plugin options
      #
      # @api public
      def use(plugin_name, options = ::ROM::EMPTY_HASH)
        plugin = ::ROM.plugin_registry[:schema].fetch(plugin_name, adapter)
        app_plugin(plugin, options)
      end

      # @api private
      def app_plugin(plugin, options = ::ROM::EMPTY_HASH)
        plugin.extend_dsl(self)
        @plugins[plugin.name] = [plugin, plugin.config.to_hash.merge(options)]
      end

      # @api private
      def call(&)
        instance_exec(&) if block_given?
        instance_exec(&definition) if definition

        schema_class.define(relation, **opts) do |schema|
          plugins.each_value do |plugin, options|
            plugin.apply_to(schema, **options)
          end
        end
      end

      # @api private
      def plugin_options(plugin) = @plugins[plugin][1]

      private

      # Return schema opts
      #
      # @return [Hash]
      #
      # @api private
      def opts
        opts = { attributes: attributes.values, inferrer: inferrer, attr_class: attr_class }

        if associations_dsl
          { **opts, associations: associations_dsl.call }
        else
          opts
        end
      end
    end
  end
end

    def self.build_attribute_info(type, **options)
      {
        type: type,
        options: options
      }
    end


def build_type(type, options = EMPTY_HASH)
        if options[:read]
          type.meta(source: relation, read: options[:read])
        elsif type.optional? && type.meta[:read]
          type.meta(source: relation, read: type.meta[:read].optional)
        else
          type.meta(source: relation)
        end.meta(Attribute::META_OPTIONS.map { |opt|
                   [opt, options[opt]] if options.key?(opt)
                 }.compact.to_h)
      end


# frozen_string_literal: true

module ROM
  class Schema
    # @api private
    class Inferrer
      extend Dry::Core::ClassAttributes
      extend Initializer

      # @!method self.attributes_inferrer
      #   @overload attributes_inferrer
      #     @return [Proc]
      #
      #   @overload attributes_inferrer(value)
      #     @param value [Proc]
      #     @return [Proc]
      #
      # @!method self.attr_class
      #   @overload attr_class
      #     @return [Class(ROM::Attribute)]
      #
      #   @overload attr_class(value)
      #     @param value [Class(ROM::Attribute)]
      #     @return [Class(ROM::Attribute)]
      defines :attributes_inferrer, :attr_class

      MissingAttributesError = ::Class.new(::StandardError) do
        def initialize(name, attributes)
          super(
            "Following attributes in #{Relation::Name[name].relation.inspect} schema cannot " \
            "be inferred and have to be defined explicitly: #{attributes.map(&:inspect).join(', ')}"
          )
        end
      end

      DEFAULT_ATTRIBUTES = [EMPTY_ARRAY, EMPTY_ARRAY].freeze

      attributes_inferrer -> * { DEFAULT_ATTRIBUTES }

      attr_class Attribute

      include ::Dry::Equalizer(:options)

      # @!attribute [r] attr_class
      #   @return [Class(ROM::Attribute)]
      option :attr_class, default: -> { self.class.attr_class }

      # @!attribute [r] enabled
      #   @return [Boolean]
      option :enabled, default: -> { true }

      alias_method :enabled?, :enabled

      # @!attribute [r] attributes_inferrer
      #   @return [ROM::Schema::AttributesInferrer]
      option :attributes_inferrer, default: -> { self.class.attributes_inferrer }

      # @api private
      def call(schema, gateway)
        if enabled?
          inferred, missing = attributes_inferrer.(schema, gateway, options)
        else
          inferred, missing = DEFAULT_ATTRIBUTES
        end

        attributes = merge_attributes(schema.attributes, inferred)

        check_all_attributes_defined(schema, attributes, missing)

        { attributes: attributes }
      end

      # @api private
      def check_all_attributes_defined(schema, all_known, not_inferred)
        not_defined = not_inferred - all_known.map(&:name)

        raise MissingAttributesError.new(schema.name, not_defined) unless not_defined.empty?
      end

      # @api private
      # rubocop:disable Metrics/AbcSize
      def merge_attributes(defined, inferred)
        type_lookup = lambda do |attrs, name|
          attrs.find { |a| a.name == name }.type
        end
        defined_with_type, defined_names =
          defined.each_with_object([[], []]) do |attr, (attrs, names)|
            attrs << if attr.type.nil?
                       attr.class.new(
                         type_lookup.(inferred, attr.name),
                         **attr.options
                       )
                     else
                       attr
                     end
            names << attr.name
          end

        defined_with_type + inferred.reject do |attr|
          defined_names.include?(attr.name)
        end
      end
      # rubocop:enable Metrics/AbcSize
    end
  end
end


def merge_attributes(defined, inferred)
        type_lookup = lambda do |attrs, name|
          attrs.find { |a| a.name == name }.type
        end
        defined_with_type, defined_names =
          defined.each_with_object([[], []]) do |attr, (attrs, names)|
            attrs << if attr.type.nil?
                       attr.class.new(
                         type_lookup.(inferred, attr.name),
                         **attr.options
                       )
                     else
                       attr
                     end
            names << attr.name
          end

        defined_with_type + inferred.reject do |attr|
          defined_names.include?(attr.name)
        end
      end


# frozen_string_literal: true

module ROM
  # This extension is only used for environment objects to configure arbitrary options, each
  # adapter can use them according to what they need.
  #
  # @api private
  module Configurable
    class Config
      WRITER_REGEXP = /=$/

      # @!attribute [r] settings
      #   @return [Hash] A hash with defined settings
      attr_reader :settings

      # @api private
      def initialize(settings = {})
        @settings = settings
      end

      # Return a setting
      #
      # @return [Mixed]
      #
      # @api public
      def [](name) = public_send(name)

      # @api private
      def key?(name) = settings.key?(name)

      def to_hash = settings

      # @api private
      def respond_to_missing?(_name, _include_private = false) = true

      # @api private
      def dup = self.class.new(dup_settings(settings))

      private

      def dup_settings(settings)
        settings.to_h do |key, value|
          if value.is_a?(self.class)
            [key, value.dup]
          else
            [key, value]
          end
        end
      end

      # @api private
      def method_missing(meth, *args, &)
        return settings.fetch(meth, nil) if frozen?

        name = meth.to_s
        key = name.gsub(WRITER_REGEXP, '').to_sym

        if writer?(name)
          settings[key] = args.first
        else
          settings.fetch(key) { settings[key] = self.class.new }
        end
      end

      # @api private
      def writer?(name)
        !WRITER_REGEXP.match(name).nil?
      end
    end

    # Return config instance
    #
    # @return [Config]
    #
    # @api private
    def config
      @config ||= Config.new
    end

    # Yield config instance
    #
    # @return [self]
    #
    # @api public
    def configure
      yield(config)
      self
    end
  end
end


# frozen_string_literal: true

module ROM
  # @api private
  module Memoizable
    MEMOIZED_HASH = {}.freeze

    module ClassInterface
      # @api private
      def memoize(*names)
        prepend(Memoizer.new(self, names))
      end

      def new(*, **, &)
        obj = super
        obj.instance_variable_set(:@__memoized__, MEMOIZED_HASH.dup)
        obj
      end
    end

    def self.included(klass)
      super
      klass.extend(ClassInterface)
    end

    attr_reader :__memoized__

    # @api private
    class Memoizer < ::Module
      attr_reader :klass

      attr_reader :names

      # @api private
      def initialize(klass, names)
        super()
        @names = names
        @klass = klass
        define_memoizable_names!
      end

      private

      # @api private
      def define_memoizable_names!
        names.each do |name|
          meth = klass.instance_method(name)

          if meth.parameters.empty?
            define_method(name) do
              __memoized__[name] ||= super()
            end
          else
            define_method(name) do |*args|
              __memoized__[:"#{name}_#{args.hash}"] ||= super(*args)
            end
          end
        end
      end
    end
  end
end


# frozen_string_literal: true

require 'rom/support/inflector'

module ROM
  module ConfigurationDSL
    # Setup DSL-specific command extensions
    #
    # @private
    class Command
      # Generate a command subclass
      #
      # This is used by Setup#commands DSL and its `define` block
      #
      # @api private
      def self.build_class(name, relation, options = EMPTY_HASH, &)
        type = options.fetch(:type) { name }
        command_type = Inflector.classify(type)
        adapter = options.fetch(:adapter)
        parent = ROM::Command.adapter_namespace(adapter).const_get(command_type)
        class_name = generate_class_name(adapter, command_type, relation)

        Dry::Core::ClassBuilder.new(name: class_name, parent: parent).call do |klass|
          klass.register_as(name)
          klass.relation(relation)
          klass.class_eval(&) if block_given?
        end
      end

      # Create a command subclass name based on adapter, type and relation
      #
      # @api private
      def self.generate_class_name(adapter, command_type, relation)
        pieces = ['ROM']
        pieces << Inflector.classify(adapter)
        pieces << 'Commands'
        pieces << "#{command_type}[#{Inflector.classify(relation)}s]"
        pieces.join('::')
      end
    end
  end
end

      def adapter_namespace(adapter)
        ROM.adapters.fetch(adapter).const_get(:Commands)
      rescue KeyError
        raise AdapterNotPresentError.new(adapter, :relation)
      end


# frozen_string_literal: true

require 'rom/support/inflector'

module ROM
  module ConfigurationDSL
    # Setup DSL-specific relation extensions
    #
    # @private
    class Relation
      # Generate a relation subclass
      #
      # This is used by Setup#relation DSL
      #
      # @api private
      def self.build_class(name, options = EMPTY_HASH)
        class_name = "ROM::Relation[#{Inflector.camelize(name)}]"
        adapter = options.fetch(:adapter)

        ::Dry::Core::ClassBuilder.new(
          name: class_name, parent: ::ROM::Relation[adapter]
        ).call do |klass|
          klass.gateway(options.fetch(:gateway, :default))
          klass.schema(name) { nil }
        end
      end
    end
  end
end


# frozen_string_literal: true

require 'concurrent/map'

module ROM
  class Relation
    # Relation name container
    #
    # This is a simple struct with two fields.
    # It handles both relation registration name (i.e. Symbol) and dataset name.
    # The reason we need it is a simplification of passing around these two objects.
    # It is quite common to have a dataset named differently from a relation
    # built on top if you are dealing with a legacy DB and often you need both
    # to support things such as associations (rom-sql as an example).
    #
    # @api private
    class Name
      include ::Dry::Equalizer(:relation, :dataset, :key)

      # Coerce an object to a Name instance
      #
      # @return [ROM::Relation::Name]
      #
      # @api private
      def self.[](*args)
        cache.fetch_or_store(args.hash) do
          relation, dataset, aliaz = args

          if relation.is_a?(Name)
            relation
          else
            new(relation, dataset, aliaz)
          end
        end
      end

      # @api private
      def self.cache
        @cache ||= Concurrent::Map.new
      end

      # Relation registration name
      #
      # @return [Symbol]
      #
      # @api private
      attr_reader :relation

      # Underlying dataset name
      #
      # @return [Symbol]
      #
      # @api private
      attr_reader :dataset

      attr_reader :aliaz
      attr_reader :key

      # @api private
      def initialize(relation, dataset = relation, aliaz = nil)
        @relation = relation
        @dataset = dataset || relation
        @key = aliaz || relation
        @aliaz = aliaz
      end

      # @api private
      def as(aliaz) = self.class[relation, dataset, aliaz]

      # @api private
      def aliased? = aliaz && aliaz != relation

      # Return relation name
      #
      # @return [String]
      #
      # @api private
      def to_s
        if aliased?
          "#{relation} on #{dataset} as #{aliaz}"
        elsif relation == dataset
          relation.to_s
        else
          "#{relation} on #{dataset}"
        end
      end

      # Alias for registration key implicitly called by ROM::Registry
      #
      # @return [Symbol]
      #
      # @api private
      def to_sym = relation

      # Return inspected relation
      #
      # @return [String]
      #
      # @api private
      def inspect = "#{self.class.name}(#{self})"
    end
  end
end


# frozen_string_literal: true

module ROM
  class Relation
    # Extensions for relation classes which provide access to commands
    #
    # @api public
    module Commands
      # Return a command for the relation
      #
      # This method can either return an existing custom command identified
      # by `type` param, or generate a command dynamically based on relation
      # AST.
      #
      # @example build a simple :create command
      #   users.command(:create)
      #
      # @example build a command which returns multiple results
      #   users.command(:create, result: many)
      #
      # @example build a command which uses a specific plugin
      #   users.command(:create, use: :timestamps)
      #
      # @example build a command which sends results through a custom mapper
      #   users.command(:create, mapper: :my_mapper_identifier)
      #
      # @example return an existing custom command
      #   users.command(:my_custom_command_identifier)
      #
      # @param type [Symbol] The command type (:create, :update or :delete)
      # @param opts [Hash] Additional options
      # @option opts [Symbol] :mapper (nil) An optional mapper applied to the command result
      # @option opts [Array<Symbol>] :use ([]) A list of command plugins
      # @option opts [Symbol] :result (:one) Set how many results the command should return.
      #                                       Can be `:one` or `:many`
      #
      # @return [ROM::Command]
      #
      # @api public
      def command(type, mapper: nil, use: EMPTY_ARRAY, plugins_options: EMPTY_HASH, **opts)
        base_command =
          if commands.key?(type)
            commands[type]
          else
            commands[type, adapter, to_ast, use, plugins_options, opts]
          end

        command =
          if mapper
            base_command >> mappers[mapper]
          elsif auto_map?
            base_command >> self.mapper
          else
            base_command
          end

        if command.restrictible?
          command.new(self)
        else
          command
        end
      end
    end
  end
end


# frozen_string_literal: true

require 'rom/types'
require 'rom/initializer'
require 'rom/pipeline'
require 'rom/relation/name'
require 'rom/relation/materializable'
require 'rom/relation/graph'
require 'rom/relation/wrap'
require 'rom/relation/composite'

module ROM
  class Relation
    # Curried relation is a special relation proxy used by auto-curry mechanism.
    #
    # When a relation view method is called without all arguments, a curried proxy
    # is returned that can be fully applied later on.
    #
    # Curried relations are typically used for relation composition
    #
    # @api public
    class Curried
      extend Initializer

      WRAPS = [Relation, Graph, Wrap, Composite].freeze

      include Dry::Equalizer(:relation, :options)
      include Materializable
      include Pipeline

      undef :map_with

      # @!attribute [r] relation
      #   @return [Relation] The source relation that is curried
      param :relation

      # @!attribute [r] view
      #   @return [Symbol] The name of relation's view method
      option :view, type: Types::Strict::Symbol

      # @!attribute [r] arity
      #   @return [Integer] View's arity
      option :arity, type: Types::Strict::Integer

      # @!attribute [r] curry_args
      #   @return [Array] Arguments that will be passed to curried view
      option :curry_args, default: -> { EMPTY_ARRAY }

      # Load relation if args match the arity
      #
      # @return [Loaded,Curried]
      #
      # @api public
      def call(*args)
        all_args = curry_args + args

        if all_args.empty?
          raise ArgumentError,
                "curried #{relation.class}##{view} relation was called without any arguments"
        end

        if args.empty?
          self
        elsif arity == all_args.size
          Loaded.new(relation.__send__(view, *all_args))
        else
          __new__(relation, curry_args: all_args)
        end
      end
      alias_method :[], :call

      # Relations are coercible to an array but a curried relation cannot be coerced
      # When something tries to do this, an exception will be raised
      #
      # @raise ArgumentError
      #
      # @api public
      def to_a
        raise(
          ArgumentError,
          "#{relation.class}##{view} arity is #{arity} " \
          "(#{curry_args.size} args given)"
        )
      end
      alias_method :to_ary, :to_a

      # Return if this lazy relation is curried
      #
      # @return [true]
      #
      # @api private
      def curried? = true

      # @api private
      def respond_to_missing?(name, include_private = false)
        super || relation.respond_to?(name, include_private)
      end

      private

      # @api private
      def __new__(relation, **new_opts)
        self.class.new(relation, **options, **new_opts)
      end

      # @api private
      def composite_class = Relation::Composite

      # @api private
      def method_missing(meth, ...)
        if relation.respond_to?(meth)
          response = relation.__send__(meth, ...)

          super if response.is_a?(self.class)

          if WRAPS.any? { |klass| response.is_a?(klass) }
            __new__(response)
          else
            response
          end
        else
          super
        end
      end
    end
  end
end


def method_missing(meth, ...)
        if relation.respond_to?(meth)
          response = relation.__send__(meth, ...)

          super if response.is_a?(self.class)

          if WRAPS.any? { |klass| response.is_a?(klass) }
            __new__(response)
          else
            response
          end
        else
          super
        end
      end

!(WRAPS.any? { |klass| response.is_a?(klass) })


# frozen_string_literal: true

require 'set'

require 'rom/support/inflector'

require 'rom/constants'
require 'rom/relation/name'
require 'rom/relation/view_dsl'
require 'rom/schema'
require 'rom/support/notifications'

module ROM
  class Relation
    # Global class-level API for relation classes
    #
    # @api public
    # rubocop:disable Metrics/ModuleLength
    module ClassInterface
      extend Notifications::Listener

      subscribe('configuration.relations.object.registered') do |event|
        relation = event[:relation]
        registry = event[:registry]

        schemas = relation.schemas.reduce({}) do |h, (a, e)|
          h.update(a => e.is_a?(Proc) ? relation.class.instance_exec(registry, &e) : e)
        end

        relation.schemas.update(schemas)
        relation
      end

      DEFAULT_DATASET_PROC = -> * { self }.freeze
      INVALID_RELATIONS_NAMES = [
        :relations
      ].freeze

      # Return adapter-specific relation subclass
      #
      # @example
      #   ROM::Relation[:memory]
      #   # => ROM::Memory::Relation
      #
      # @return [Class]
      #
      # @api public
      def [](adapter)
        ROM.adapters.fetch(adapter).const_get(:Relation)
      rescue KeyError
        raise AdapterNotPresentError.new(adapter, :relation)
      end

      # Set or get custom dataset block
      #
      # This block will be evaluated when a relation is instantiated and registered
      # in a relation registry.
      #
      # @example
      #   class Users < ROM::Relation[:memory]
      #     dataset { sort_by(:id) }
      #   end
      #
      # @api public
      def dataset(&block)
        if defined?(@dataset)
          @dataset
        else
          @dataset = block || DEFAULT_DATASET_PROC
        end
      end

      # Specify canonical schema for a relation
      #
      # With a schema defined commands will set up a type-safe input handler
      # automatically
      #
      # @example
      #   class Users < ROM::Relation[:sql]
      #     schema do
      #       attribute :id, Types::Serial
      #       attribute :name, Types::String
      #     end
      #   end
      #
      #   # access schema from a finalized relation
      #   users.schema
      #
      # @return [Schema]
      #
      # @param [Symbol] dataset An optional dataset name
      # @param [Boolean] infer Whether to do an automatic schema inferring
      #
      # @api public
      # rubocop:disable Metrics/AbcSize, Metrics/PerceivedComplexity
      def schema(dataset = nil, as: nil, infer: false, &)
        if defined?(@schema) && !block_given? && !infer
          @schema
        elsif block_given? || infer
          raise MissingSchemaClassError, self unless schema_class

          ds_name = dataset || schema_opts.fetch(:dataset, default_name.dataset)
          relation = as || schema_opts.fetch(:relation, ds_name)

          raise InvalidRelationName, relation if invalid_relation_name?(relation)

          @relation_name = Name[relation, ds_name]

          @schema_proc = proc do |*args, &inner_block|
            schema_dsl.new(
              relation_name,
              schema_class: schema_class,
              attr_class: schema_attr_class,
              inferrer: schema_inferrer.with(enabled: infer),
              &
            ).call(*args, &inner_block)
          end
        end
      end
      # rubocop:enable Metrics/AbcSize, Metrics/PerceivedComplexity

      # Assign a schema to a relation class
      #
      # @param [Schema] schema
      #
      # @return [Schema]
      #
      # @api private
      def set_schema!(schema)
        @schema = schema
      end

      # @api private
      attr_reader :schema_proc

      # @!attribute [r] relation_name
      #   @return [Name] Qualified relation name
      def relation_name
        raise MissingSchemaError, self unless defined?(@relation_name)

        @relation_name
      end

      # Define a relation view with a specific schema
      #
      # This method should only be used in cases where a given adapter doesn't
      # support automatic schema projection at run-time.
      #
      # **It's not needed in rom-sql**
      #
      # @overload view(name, schema, &block)
      #   @example View with the canonical schema
      #     class Users < ROM::Relation[:sql]
      #       view(:listing, schema) do
      #         order(:name)
      #       end
      #     end
      #
      #   @example View with a projected schema
      #     class Users < ROM::Relation[:sql]
      #       view(:listing, schema.project(:id, :name)) do
      #         order(:name)
      #       end
      #     end
      #
      # @overload view(name, &block)
      #   @example View with the canonical schema and arguments
      #     class Users < ROM::Relation[:sql]
      #       view(:by_name) do |name|
      #         where(name: name)
      #       end
      #     end
      #
      #   @example View with projected schema and arguments
      #     class Users < ROM::Relation[:sql]
      #       view(:by_name) do
      #         schema { project(:id, :name) }
      #         relation { |name| where(name: name) }
      #       end
      #     end
      #
      #   @example View with a schema extended with foreign attributes
      #     class Users < ROM::Relation[:sql]
      #       view(:index) do
      #         schema { append(relations[:tasks][:title]) }
      #         relation { |name| where(name: name) }
      #       end
      #     end
      #
      # @return [Symbol] view method name
      #
      # @api public
      # rubocop:disable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity
      def view(*args, &block)
        if args.size == 1 && block.arity.positive?
          raise ArgumentError, 'schema attribute names must be provided as the second argument'
        end

        name, new_schema_fn, relation_block =
          if args.size == 1
            ViewDSL.new(*args, schema, &block).call
          else
            [*args, block]
          end

        schemas[name] =
          if args.size == 2
            -> _ { schema.project(*args[1]) }
          else
            new_schema_fn
          end

        if relation_block.arity.positive?
          auto_curry_guard do
            define_method(name, &relation_block)

            auto_curry(name) do
              schemas[name].(self)
            end
          end
        else
          define_method(name) do
            schemas[name].(instance_exec(&relation_block))
          end
        end

        name
      end
      # rubocop:enable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity

      # Dynamically define a method that will forward to the dataset and wrap
      # response in the relation itself
      #
      # @example
      #   class SomeAdapterRelation < ROM::Relation
      #     forward :super_query
      #   end
      #
      # @api public
      def forward(*methods)
        methods.each do |method|
          class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
            def #{method}(...)                        # def super_query(...)
              new(dataset.__send__(:#{method}, ...))  #   new(dataset.__send__(:super_query, ...))
            end                                       # end
          RUBY
        end
      end

      # Include a registered plugin in this relation class
      #
      # @param [Symbol] plugin
      # @param [Hash] options
      # @option options [Symbol] :adapter (:default) first adapter to check for plugin
      #
      # @api public
      def use(plugin, **options)
        ROM.plugin_registry[:relation].fetch(plugin, adapter).apply_to(self, **options)
      end

      # Build default mapper registry
      #
      # @return [MapperRegistry]
      #
      # @api private
      def mapper_registry(opts = EMPTY_HASH)
        adapter_ns = ROM.adapters[adapter]

        compiler =
          if adapter_ns&.const_defined?(:MapperCompiler)
            adapter_ns.const_get(:MapperCompiler)
          else
            MapperCompiler
          end

        MapperRegistry.new({}, compiler: compiler.new(**opts), **opts)
      end

      # @api private
      def curried = Curried

      # @api private
      def view_methods
        ancestor_methods = ancestors.reject { |klass| klass == self }
          .map(&:instance_methods).flatten(1)

        instance_methods - ancestor_methods + auto_curried_methods.to_a
      end

      # @api private
      def schemas
        @schemas ||= {}
      end

      # Return default relation name used in schemas
      #
      # @return [Name]
      #
      # @api private
      def default_name
        Name[Inflector.underscore(name).tr('/', '_').to_sym]
      end

      # @api private
      def default_schema(klass = self)
        klass.schema ||
          if klass.schema_proc
            klass.set_schema!(klass.schema_proc.call)
          else
            klass.schema_class.define(klass.default_name)
          end
      end

      # @api private
      def name = super || superclass.name

      private

      def invalid_relation_name?(relation)
        INVALID_RELATIONS_NAMES.include?(relation.to_sym)
      end
    end
    # rubocop:enable Metrics/ModuleLength
  end
end

schema

!(defined?(@schema) && !block_given? && !infer)


def view(*args, &block)
        if args.size == 1 && block.arity.positive?
          raise ArgumentError, 'schema attribute names must be provided as the second argument'
        end

        name, new_schema_fn, relation_block =
          if args.size == 1
            ViewDSL.new(*args, schema, &block).call
          else
            [*args, block]
          end

        schemas[name] =
          if args.size == 2
            -> _ { schema.project(*args[1]) }
          else
            new_schema_fn
          end

        if relation_block.arity.positive?
          auto_curry_guard do
            define_method(name, &relation_block)

            auto_curry(name) do
              schemas[name].(self)
            end
          end
        else
          define_method(name) do
            schemas[name].(instance_exec(&relation_block))
          end
        end

        name
      end

view

size

!(args.size == 1 && block.arity.positive?)

project

    def project(*names)
      new(names.map { |name| name.is_a?(Symbol) ? self[name] : name })
    end


def mapper_registry(opts = EMPTY_HASH)
        adapter_ns = ROM.adapters[adapter]

        compiler =
          if adapter_ns&.const_defined?(:MapperCompiler)
            adapter_ns.const_get(:MapperCompiler)
          else
            MapperCompiler
          end

        MapperRegistry.new({}, compiler: compiler.new(**opts), **opts)
      end


# frozen_string_literal: true

module ROM
  class Relation
    # Materializes a relation and exposes interface to access the data.
    #
    # This relation type is returned when a lazy relation is called
    #
    # @api public
    class Loaded
      include ::Enumerable
      include ::Dry::Equalizer(:source, :collection)

      # Coerce loaded relation to an array
      #
      # @return [Array]
      #
      # @api public
      alias_method :to_ary, :to_a

      # Source relation
      #
      # @return [Relation]
      #
      # @api private
      attr_reader :source

      # Materialized relation
      #
      # @return [Object]
      #
      # @api private
      attr_reader :collection

      # @api private
      def initialize(source, collection = source.to_a)
        @source = source
        @collection = collection
      end

      # Yield relation tuples
      #
      # @yield [Hash]
      #
      # @api public
      def each(&)
        return to_enum unless block_given?

        collection.each(&)
      end

      # Returns a single tuple from the relation if there is one.
      #
      # @raise [ROM::TupleCountMismatchError] if the relation contains more than
      #   one tuple
      #
      # @api public
      def one
        if collection.count > 1
          raise(
            TupleCountMismatchError,
            'The relation consists of more than one tuple'
          )
        else
          collection.first
        end
      end

      # Like [one], but additionally raises an error if the relation is empty.
      #
      # @raise [ROM::TupleCountMismatchError] if the relation does not contain
      #   exactly one tuple
      #
      # @api public
      def one!
        one || raise(
          TupleCountMismatchError,
          'The relation does not contain any tuples'
        )
      end

      # Return a list of values under provided key
      #
      # @example
      #   all_users = rom.relations[:users].call
      #   all_users.pluck(:name)
      #   # ["Jane", "Joe"]
      #
      # @param [Symbol] key The key name
      #
      # @return [Array]
      #
      # @raise KeyError when provided key doesn't exist in any of the tuples
      #
      # @api public
      def pluck(key) = map { |tuple| tuple.fetch(key) }

      # Pluck primary key values
      #
      # This method *may not work* with adapters that don't provide relations
      # that have primary key configured
      #
      # @example
      #   users = rom.relations[:users].call
      #   users.primary_keys
      #   # [1, 2, 3]
      #
      # @return [Array]
      #
      # @api public
      def primary_keys = pluck(source.primary_key)

      # Return if loaded relation is empty
      #
      # @return [TrueClass,FalseClass]
      #
      # @api public
      def empty? = collection.empty?

      # Return a loaded relation with a new collection
      #
      # @api public
      def new(collection) = self.class.new(source, collection)
    end
  end
end

one

count

collection.count > 1
!(collection.count > 1)


# frozen_string_literal: true

require 'rom/relation/graph'
require 'rom/relation/commands'

module ROM
  class Relation
    # Represents a relation graphs which combines root relation
    # with other relation nodes
    #
    # @api public
    class Combined < Graph
      include Commands

      # Create a new relation combined with others
      #
      # @param [Relation] relation
      # @param [Array<Relation>] nodes
      #
      # @return [Combined]
      #
      # @api public
      def self.new(relation, nodes)
        struct_ns = relation.options[:struct_namespace]
        new_nodes = nodes.uniq(&:name).map { |node| node.struct_namespace(struct_ns) }

        root =
          if relation.is_a?(self)
            new_nodes.concat(relation.nodes)
            relation.root
          else
            relation
          end

        super(root, new_nodes)
      end

      # Combine this graph with more nodes
      #
      # @param [Array<Relation>] others A list of relations
      #
      # @return [Graph]
      #
      # @api public
      def combine_with(*others)
        self.class.new(root, nodes + others)
      end

      # Combine with other relations
      #
      # @see Relation#combine
      #
      # @return [Combined]
      #
      # @api public
      def combine(*args)
        self.class.new(root, nodes + root.combine(*args).nodes)
      end

      # Materialize combined relation
      #
      # @return [Loaded]
      #
      # @api public
      def call(*args)
        left = root.with(auto_map: false, auto_struct: false).call(*args)

        right =
          if left.empty?
            nodes.map { |node| Loaded.new(node, EMPTY_ARRAY) }
          else
            nodes.map { |node| node.call(left) }
          end

        if auto_map?
          Loaded.new(self, mapper.([left, right]))
        else
          Loaded.new(self, [left, right])
        end
      end

      # Return a new combined relation with adjusted node returned from a block
      #
      # @example with a node identifier
      #   combine(:tasks).node(:tasks) { |tasks| tasks.prioritized }
      #
      # @example with a nested path
      #   combine(tasks: :tags).node(tasks: :tags) { |tags| tags.where(name: 'red') }
      #
      # @param [Symbol] name The node relation name
      #
      # @yieldparam [Relation] relation The relation node
      # @yieldreturn [Relation] The new relation node
      #
      # @return [Relation]
      #
      # @api public
      # rubocop:disable Metrics/AbcSize, Metrics/PerceivedComplexity
      def node(name, &)
        if name.is_a?(Symbol) && !nodes.map { |n| n.name.key }.include?(name)
          raise ArgumentError, "#{name.inspect} is not a valid aggregate node name"
        end

        new_nodes = nodes.map { |node|
          case name
          when Symbol
            name == node.name.key ? yield(node) : node
          when Hash
            other, *rest = name.flatten(1)
            if other == node.name.key
              nodes.detect { |n| n.name.key == other }.node(*rest, &)
            else
              node
            end
          else
            node
          end
        }

        with_nodes(new_nodes)
      end
      # rubocop:enable Metrics/AbcSize, Metrics/PerceivedComplexity

      # Return a `:create` command that can insert data from a nested hash.
      #
      # This is limited to `:create` commands only, because automatic restriction
      # for `:update` commands would be quite complex. It's possible that in the
      # future support for `:update` commands will be added though.
      #
      # Another limitation is that it can only work when you're composing
      # parent and its child(ren), which follows canonical hierarchy from your
      # database, so that parents are created first, then their PKs are set
      # as FKs in child tuples. It should be possible to make it work with
      # both directions (parent => child or child => parent), and it would
      # require converting input tuples based on how they depend on each other,
      # which we could do in the future.
      #
      # Expanding functionality of this method is planned for rom 5.0.
      #
      # @see Relation#command
      #
      # @raise NotImplementedError when type is not `:create`
      #
      # @api public
      def command(type, **)
        if type == :create
          super
        else
          raise NotImplementedError,
                "#{self.class}#command doesn't work with #{type.inspect} command type yet"
        end
      end

      private

      # @api private
      def decorate?(other)
        super || other.is_a?(self.class) || other.is_a?(Wrap)
      end
    end
  end
end

new

relation

  class Relation
    # Global class-level API for relation classes
    #
    # @api public
    # rubocop:disable Metrics/ModuleLength
    module ClassInterface
      extend Notifications::Listener

      subscribe('configuration.relations.object.registered') do |event|
        relation = event[:relation]
        registry = event[:registry]

        schemas = relation.schemas.reduce({}) do |h, (a, e)|
          h.update(a => e.is_a?(Proc) ? relation.class.instance_exec(registry, &e) : e)
        end

        relation.schemas.update(schemas)
        relation
      end

      DEFAULT_DATASET_PROC = -> * { self }.freeze
      INVALID_RELATIONS_NAMES = [
        :relations
      ].freeze

      # Return adapter-specific relation subclass
      #
      # @example
      #   ROM::Relation[:memory]
      #   # => ROM::Memory::Relation
      #
      # @return [Class]
      #
      # @api public
      def [](adapter)
        ROM.adapters.fetch(adapter).const_get(:Relation)
      rescue KeyError
        raise AdapterNotPresentError.new(adapter, :relation)
      end

      # Set or get custom dataset block
      #
      # This block will be evaluated when a relation is instantiated and registered
      # in a relation registry.
      #
      # @example
      #   class Users < ROM::Relation[:memory]
      #     dataset { sort_by(:id) }
      #   end
      #
      # @api public
      def dataset(&block)
        if defined?(@dataset)
          @dataset
        else
          @dataset = block || DEFAULT_DATASET_PROC
        end
      end

      # Specify canonical schema for a relation
      #
      # With a schema defined commands will set up a type-safe input handler
      # automatically
      #
      # @example
      #   class Users < ROM::Relation[:sql]
      #     schema do
      #       attribute :id, Types::Serial
      #       attribute :name, Types::String
      #     end
      #   end
      #
      #   # access schema from a finalized relation
      #   users.schema
      #
      # @return [Schema]
      #
      # @param [Symbol] dataset An optional dataset name
      # @param [Boolean] infer Whether to do an automatic schema inferring
      #
      # @api public
      # rubocop:disable Metrics/AbcSize, Metrics/PerceivedComplexity
      def schema(dataset = nil, as: nil, infer: false, &)
        if defined?(@schema) && !block_given? && !infer
          @schema
        elsif block_given? || infer
          raise MissingSchemaClassError, self unless schema_class

          ds_name = dataset || schema_opts.fetch(:dataset, default_name.dataset)
          relation = as || schema_opts.fetch(:relation, ds_name)

          raise InvalidRelationName, relation if invalid_relation_name?(relation)

          @relation_name = Name[relation, ds_name]

          @schema_proc = proc do |*args, &inner_block|
            schema_dsl.new(
              relation_name,
              schema_class: schema_class,
              attr_class: schema_attr_class,
              inferrer: schema_inferrer.with(enabled: infer),
              &
            ).call(*args, &inner_block)
          end
        end
      end
      # rubocop:enable Metrics/AbcSize, Metrics/PerceivedComplexity

      # Assign a schema to a relation class
      #
      # @param [Schema] schema
      #
      # @return [Schema]
      #
      # @api private
      def set_schema!(schema)
        @schema = schema
      end

      # @api private
      attr_reader :schema_proc

      # @!attribute [r] relation_name
      #   @return [Name] Qualified relation name
      def relation_name
        raise MissingSchemaError, self unless defined?(@relation_name)

        @relation_name
      end

      # Define a relation view with a specific schema
      #
      # This method should only be used in cases where a given adapter doesn't
      # support automatic schema projection at run-time.
      #
      # **It's not needed in rom-sql**
      #
      # @overload view(name, schema, &block)
      #   @example View with the canonical schema
      #     class Users < ROM::Relation[:sql]
      #       view(:listing, schema) do
      #         order(:name)
      #       end
      #     end
      #
      #   @example View with a projected schema
      #     class Users < ROM::Relation[:sql]
      #       view(:listing, schema.project(:id, :name)) do
      #         order(:name)
      #       end
      #     end
      #
      # @overload view(name, &block)
      #   @example View with the canonical schema and arguments
      #     class Users < ROM::Relation[:sql]
      #       view(:by_name) do |name|
      #         where(name: name)
      #       end
      #     end
      #
      #   @example View with projected schema and arguments
      #     class Users < ROM::Relation[:sql]
      #       view(:by_name) do
      #         schema { project(:id, :name) }
      #         relation { |name| where(name: name) }
      #       end
      #     end
      #
      #   @example View with a schema extended with foreign attributes
      #     class Users < ROM::Relation[:sql]
      #       view(:index) do
      #         schema { append(relations[:tasks][:title]) }
      #         relation { |name| where(name: name) }
      #       end
      #     end
      #
      # @return [Symbol] view method name
      #
      # @api public
      # rubocop:disable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity
      def view(*args, &block)
        if args.size == 1 && block.arity.positive?
          raise ArgumentError, 'schema attribute names must be provided as the second argument'
        end

        name, new_schema_fn, relation_block =
          if args.size == 1
            ViewDSL.new(*args, schema, &block).call
          else
            [*args, block]
          end

        schemas[name] =
          if args.size == 2
            -> _ { schema.project(*args[1]) }
          else
            new_schema_fn
          end

        if relation_block.arity.positive?
          auto_curry_guard do
            define_method(name, &relation_block)

            auto_curry(name) do
              schemas[name].(self)
            end
          end
        else
          define_method(name) do
            schemas[name].(instance_exec(&relation_block))
          end
        end

        name
      end
      # rubocop:enable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity

      # Dynamically define a method that will forward to the dataset and wrap
      # response in the relation itself
      #
      # @example
      #   class SomeAdapterRelation < ROM::Relation
      #     forward :super_query
      #   end
      #
      # @api public
      def forward(*methods)
        methods.each do |method|
          class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
            def #{method}(...)                        # def super_query(...)
              new(dataset.__send__(:#{method}, ...))  #   new(dataset.__send__(:super_query, ...))
            end                                       # end
          RUBY
        end
      end

      # Include a registered plugin in this relation class
      #
      # @param [Symbol] plugin
      # @param [Hash] options
      # @option options [Symbol] :adapter (:default) first adapter to check for plugin
      #
      # @api public
      def use(plugin, **options)
        ROM.plugin_registry[:relation].fetch(plugin, adapter).apply_to(self, **options)
      end

      # Build default mapper registry
      #
      # @return [MapperRegistry]
      #
      # @api private
      def mapper_registry(opts = EMPTY_HASH)
        adapter_ns = ROM.adapters[adapter]

        compiler =
          if adapter_ns&.const_defined?(:MapperCompiler)
            adapter_ns.const_get(:MapperCompiler)
          else
            MapperCompiler
          end

        MapperRegistry.new({}, compiler: compiler.new(**opts), **opts)
      end

      # @api private
      def curried = Curried

      # @api private
      def view_methods
        ancestor_methods = ancestors.reject { |klass| klass == self }
          .map(&:instance_methods).flatten(1)

        instance_methods - ancestor_methods + auto_curried_methods.to_a
      end

      # @api private
      def schemas
        @schemas ||= {}
      end

      # Return default relation name used in schemas
      #
      # @return [Name]
      #
      # @api private
      def default_name
        Name[Inflector.underscore(name).tr('/', '_').to_sym]
      end

      # @api private
      def default_schema(klass = self)
        klass.schema ||
          if klass.schema_proc
            klass.set_schema!(klass.schema_proc.call)
          else
            klass.schema_class.define(klass.default_name)
          end
      end

      # @api private
      def name = super || superclass.name

      private

      def invalid_relation_name?(relation)
        INVALID_RELATIONS_NAMES.include?(relation.to_sym)
      end
    end
    # rubocop:enable Metrics/ModuleLength
  end

    # @!attribute [r] struct_namespace
    #   @return [Module] Custom struct namespace
    #   @api private
    option :struct_namespace, reader: false, default: -> { self.class.struct_namespace }

    # @!attribute [r] mappers
    #   @return [MapperRegistry] an optional mapper registry (empty by default)
    option :mappers, default: -> { self.class.mapper_registry }

    # @!attribute [r] commands
    #   @return [CommandRegistry] Command registry
    #   @api private
    option :commands, default: -> { CommandRegistry.new({}, relation_name: name.relation) }

    # @!attribute [r] meta
    #   @return [Hash] Meta data stored in a hash
    #   @api private
    option :meta, reader: true, default: -> { EMPTY_HASH }

    # Return schema attribute
    #
    # @example accessing canonical attribute
    #   users[:id]
    #   # => #<ROM::SQL::Attribute[Integer] primary_key=true
    #   #     name=:id source=ROM::Relation::Name(users)>
    #
    # @example accessing joined attribute
    #   tasks_with_users = tasks.join(users).select_append(tasks[:title])
    #   tasks_with_users[:title, :tasks]
    #   # => #<ROM::SQL::Attribute[String] primary_key=false
    #   #     name=:title source=ROM::Relation::Name(tasks)>
    #
    # @return [Attribute]
    #
    # @api public
    def [](name) = schema[name]

    # Yields relation tuples
    #
    # Every tuple is processed through Relation#output_schema, it's a no-op by default
    #
    # @yield [Hash]
    #
    # @return [Enumerator] if block is not provided
    #
    # @api public
    def each(&)
      return to_enum unless block_given?

      if auto_map?
        mapper.(dataset.map { |tuple| output_schema[tuple] }).each(&)
      else
        dataset.each { |tuple| yield(output_schema[tuple]) }
      end
    end


def call(*args)
        left = root.with(auto_map: false, auto_struct: false).call(*args)

        right =
          if left.empty?
            nodes.map { |node| Loaded.new(node, EMPTY_ARRAY) }
          else
            nodes.map { |node| node.call(left) }
          end

        if auto_map?
          Loaded.new(self, mapper.([left, right]))
        else
          Loaded.new(self, [left, right])
        end
      end

call

with

    def with(opts)
      new_options =
        if opts.key?(:meta)
          opts.merge(meta: meta.merge(opts[:meta]))
        else
          opts
        end

      new(dataset, **options, **new_options)
    end

call

    def call = Loaded.new(self)

    # Materializes a relation into an array
    #
    # @return [Array<Hash>]
    #
    # @api public
    def to_a = to_enum.to_a

    # Returns if this relation is curried
    #
    # @return [false]
    #
    # @api private
    def curried? = false

    # Returns if this relation is a graph
    #
    # @return [false]
    #
    # @api private
    def graph? = false

    # Return if this is a wrap relation
    #
    # @return [false]
    #
    # @api private
    def wrap? = false

    # Returns true if a relation has schema defined
    #
    # @return [TrueClass, FalseClass]
    #
    # @api private
    def schema? = !schema.empty?

    # Return a new relation with provided dataset and additional options
    #
    # Use this method whenever you need to use dataset API to get a new dataset
    # and you want to return a relation back. Typically relation API should be
    # enough though. If you find yourself using this method, it might be worth
    # to consider reporting an issue that some dataset functionality is not available
    # through relation API.
    #
    # @example with a new dataset
    #   users.new(users.dataset.some_method)
    #
    # @example with a new dataset and options
    #   users.new(users.dataset.some_method, other: 'options')
    #
    # @param [Object] dataset
    # @param [Hash] new_opts Additional options
    #
    # @api public
    def new(dataset, **new_opts)
      opts =
        if new_opts.empty?
          options
        elsif new_opts.key?(:schema)
          options.merge(new_opts).except(:input_schema, :output_schema)
        else
          options.merge(new_opts)
        end

      self.class.new(dataset, **opts)
    end


def node(name, &)
        if name.is_a?(Symbol) && !nodes.map { |n| n.name.key }.include?(name)
          raise ArgumentError, "#{name.inspect} is not a valid aggregate node name"
        end

        new_nodes = nodes.map { |node|
          case name
          when Symbol
            name == node.name.key ? yield(node) : node
          when Hash
            other, *rest = name.flatten(1)
            if other == node.name.key
              nodes.detect { |n| n.name.key == other }.node(*rest, &)
            else
              node
            end
          else
            node
          end
        }

        with_nodes(new_nodes)
      end

node

map

!(name.is_a?(Symbol) && !nodes.map { |n| n.name.key }.include?(name))

name

    # @!attribute [r] name
    #   @return [Object] The relation name
    #   @api public
    option :name, default: lambda {
      self.class.schema ? self.class.schema.name : self.class.default_name
    }

    # @!attribute [r] input_schema
    #   @return [Object#[]] tuple processing function, uses schema or defaults to Hash[]
    #   @api private
    option :input_schema, default: -> { schema.to_input_hash }

    # @!attribute [r] output_schema
    #   @return [Object#[]] tuple processing function, uses schema or defaults to NOOP_OUTPUT_SCHEMA
    #   @api private
    option :output_schema, default: lambda {
      schema.any?(&:read?) ? schema.to_output_hash : NOOP_OUTPUT_SCHEMA
    }

    # @!attribute [r] auto_map
    #   @return [true, false] Whether or not a relation and its
    #                         compositions should be auto-mapped
    #   @api private
    option :auto_map, default: -> { self.class.auto_map }

    # @!attribute [r] auto_struct
    #   @return [true, false] Whether or not tuples should be auto-mapped to structs
    #   @api private
    option :auto_struct, default: -> { self.class.auto_struct }

    # @!attribute [r] struct_namespace
    #   @return [Module] Custom struct namespace
    #   @api private
    option :struct_namespace, reader: false, default: -> { self.class.struct_namespace }

    # @!attribute [r] mappers
    #   @return [MapperRegistry] an optional mapper registry (empty by default)
    option :mappers, default: -> { self.class.mapper_registry }

    # @!attribute [r] commands
    #   @return [CommandRegistry] Command registry
    #   @api private
    option :commands, default: -> { CommandRegistry.new({}, relation_name: name.relation) }

    # @!attribute [r] meta
    #   @return [Hash] Meta data stored in a hash
    #   @api private
    option :meta, reader: true, default: -> { EMPTY_HASH }

    # Return schema attribute
    #
    # @example accessing canonical attribute
    #   users[:id]
    #   # => #<ROM::SQL::Attribute[Integer] primary_key=true
    #   #     name=:id source=ROM::Relation::Name(users)>
    #
    # @example accessing joined attribute
    #   tasks_with_users = tasks.join(users).select_append(tasks[:title])
    #   tasks_with_users[:title, :tasks]
    #   # => #<ROM::SQL::Attribute[String] primary_key=false
    #   #     name=:title source=ROM::Relation::Name(tasks)>
    #
    # @return [Attribute]
    #
    # @api public
    def [](name) = schema[name]

    # Yields relation tuples
    #
    # Every tuple is processed through Relation#output_schema, it's a no-op by default
    #
    # @yield [Hash]
    #
    # @return [Enumerator] if block is not provided
    #
    # @api public
    def each(&)
      return to_enum unless block_given?

      if auto_map?
        mapper.(dataset.map { |tuple| output_schema[tuple] }).each(&)
      else
        dataset.each { |tuple| yield(output_schema[tuple]) }
      end
    end

node

    def node(name)
      assoc = associations[name]
      other = assoc.node
      other.eager_load(assoc)
    end

      def with_nodes(nodes) = self.class.new(root, nodes)

      # Return if this is a graph relation
      #
      # @return [true]
      #
      # @api private
      def graph? = true

      # Map graph tuples via custom mappers
      #
      # @see Relation#map_with
      #
      # @return [Relation::Composite]
      #
      # @api public
      def map_with(*names, **opts)
        names.reduce(self.class.new(root.with(opts), nodes)) { |a, e| a >> mappers[e] }
      end


# frozen_string_literal: true

require 'pathname'

require 'rom/support/inflector'
require 'rom/types'
require 'rom/setup/auto_registration_strategies/base'

module ROM
  module AutoRegistrationStrategies
    # Custom namespace strategy loads components and assumes they are defined
    # within the provided namespace
    #
    # @api private
    class CustomNamespace < Base
      # @!attribute [r] directory
      #   @return [Pathname] The path to dir with components
      option :directory, type: PathnameType

      # @!attribute [r] namespace
      #   @return [String] Name of a namespace
      option :namespace, type: Types::Strict::String

      # Loads components
      #
      # @api private
      def call
        parts = path_arr.map { |part| Inflector.camelize(part) }
        potential = parts.map.with_index do |_, i|
          parts[(i - parts.size)..parts.size]
        end
        attempted = []

        potential.map do |path|
          const_fragment = path.join('::')

          constant = "#{namespace}::#{const_fragment}"

          return constant if ns_const.const_defined?(const_fragment)

          attempted << constant
        end

        # If we have reached this point, its means constant is not defined and
        # NameError will be thrown if we attempt to camelize something like:
        # `"#{namespace}::#{Inflector.camelize(filename)}"`
        # so we can assume naming convention was not respected in required
        # file.

        raise NameError, name_error_message(attempted)
      end

      private

      # @api private
      def name_error_message(attempted)
        'required file does not define expected constant name; either ' \
          'register your constant explicitly of try following the path' \
          "naming convention like:\n\n\t- #{attempted.join("\n\t- ")}\n"
      end

      # @api private
      def filename = Pathname(file).basename('.rb')

      # @api private
      def ns_const
        @namespace_constant ||= Inflector.constantize(namespace)
      end

      # @api private
      def path_arr = file_path << filename

      # @api private
      def file_path
        File.dirname(file).split('/') - directory.to_s.split('/')
      end
    end
  end
end