# frozen_string_literal: true
require "graphql/schema/addition"
require "graphql/schema/base_64_encoder"
require "graphql/schema/find_inherited_value"
require "graphql/schema/finder"
require "graphql/schema/invalid_type_error"
require "graphql/schema/introspection_system"
require "graphql/schema/late_bound_type"
require "graphql/schema/null_mask"
require "graphql/schema/timeout"
require "graphql/schema/type_expression"
require "graphql/schema/unique_within_type"
require "graphql/schema/warden"
require "graphql/schema/build_from_definition"

require "graphql/schema/validator"
require "graphql/schema/member"
require "graphql/schema/wrapper"
require "graphql/schema/list"
require "graphql/schema/non_null"
require "graphql/schema/argument"
require "graphql/schema/enum_value"
require "graphql/schema/enum"
require "graphql/schema/field_extension"
require "graphql/schema/field"
require "graphql/schema/input_object"
require "graphql/schema/interface"
require "graphql/schema/scalar"
require "graphql/schema/object"
require "graphql/schema/union"
require "graphql/schema/directive"
require "graphql/schema/directive/deprecated"
require "graphql/schema/directive/include"
require "graphql/schema/directive/one_of"
require "graphql/schema/directive/skip"
require "graphql/schema/directive/feature"
require "graphql/schema/directive/flagged"
require "graphql/schema/directive/transform"
require "graphql/schema/type_membership"

require "graphql/schema/resolver"
require "graphql/schema/mutation"
require "graphql/schema/relay_classic_mutation"
require "graphql/schema/subscription"

module GraphQL
  # A GraphQL schema which may be queried with {GraphQL::Query}.
  #
  # The {Schema} contains:
  #
  #  - types for exposing your application
  #  - query analyzers for assessing incoming queries (including max depth & max complexity restrictions)
  #  - execution strategies for running incoming queries
  #
  # Schemas start with root types, {Schema#query}, {Schema#mutation} and {Schema#subscription}.
  # The schema will traverse the tree of fields & types, using those as starting points.
  # Any undiscoverable types may be provided with the `types` configuration.
  #
  # Schemas can restrict large incoming queries with `max_depth` and `max_complexity` configurations.
  # (These configurations can be overridden by specific calls to {Schema#execute})
  #
  # Schemas can specify how queries should be executed against them.
  # `query_execution_strategy`, `mutation_execution_strategy` and `subscription_execution_strategy`
  # each apply to corresponding root types.
  #  #
  # @example defining a schema
  #   class MySchema < GraphQL::Schema
  #     query QueryType
  #     # If types are only connected by way of interfaces, they must be added here
  #     orphan_types ImageType, AudioType
  #   end
  #
  class Schema
    extend GraphQL::Schema::Member::HasAstNode
    extend GraphQL::Schema::FindInheritedValue

    class DuplicateNamesError < GraphQL::Error
      attr_reader :duplicated_name
      def initialize(duplicated_name:, duplicated_definition_1:, duplicated_definition_2:)
        @duplicated_name = duplicated_name
        super(
          "Found two visible definitions for `#{duplicated_name}`: #{duplicated_definition_1}, #{duplicated_definition_2}"
        )
      end
    end

    class UnresolvedLateBoundTypeError < GraphQL::Error
      attr_reader :type
      def initialize(type:)
        @type = type
        super("Late bound type was never found: #{type.inspect}")
      end
    end

    # Error that is raised when [#Schema#from_definition] is passed an invalid schema definition string.
    class InvalidDocumentError < Error; end;

    class << self
      # Create schema with the result of an introspection query.
      # @param introspection_result [Hash] A response from {GraphQL::Introspection::INTROSPECTION_QUERY}
      # @return [Class<GraphQL::Schema>] the schema described by `input`
      def from_introspection(introspection_result)
        GraphQL::Schema::Loader.load(introspection_result)
      end

      # Create schema from an IDL schema or file containing an IDL definition.
      # @param definition_or_path [String] A schema definition string, or a path to a file containing the definition
      # @param default_resolve [<#call(type, field, obj, args, ctx)>] A callable for handling field resolution
      # @param parser [Object] An object for handling definition string parsing (must respond to `parse`)
      # @param using [Hash] Plugins to attach to the created schema with `use(key, value)`
      # @return [Class] the schema described by `document`
      def from_definition(definition_or_path, default_resolve: nil, parser: GraphQL.default_parser, using: {})
        # If the file ends in `.graphql` or `.graphqls`, treat it like a filepath
        if definition_or_path.end_with?(".graphql") || definition_or_path.end_with?(".graphqls")
          GraphQL::Schema::BuildFromDefinition.from_definition_path(
            self,
            definition_or_path,
            default_resolve: default_resolve,
            parser: parser,
            using: using,
          )
        else
          GraphQL::Schema::BuildFromDefinition.from_definition(
            self,
            definition_or_path,
            default_resolve: default_resolve,
            parser: parser,
            using: using,
          )
        end
      end

      def deprecated_graphql_definition
        graphql_definition(silence_deprecation_warning: true)
      end

      # @return [GraphQL::Subscriptions]
      def subscriptions(inherited: true)
        defined?(@subscriptions) ? @subscriptions : (inherited ? find_inherited_value(:subscriptions, nil) : nil)
      end

      def subscriptions=(new_implementation)
        @subscriptions = new_implementation
      end

      # Returns the JSON response of {Introspection::INTROSPECTION_QUERY}.
      # @see {#as_json}
      # @return [String]
      def to_json(**args)
        JSON.pretty_generate(as_json(**args))
      end

      # Return the Hash response of {Introspection::INTROSPECTION_QUERY}.
      # @param context [Hash]
      # @param only [<#call(member, ctx)>]
      # @param except [<#call(member, ctx)>]
      # @return [Hash] GraphQL result
      def as_json(only: nil, except: nil, context: {})
        execute(Introspection.query(include_deprecated_args: true), only: only, except: except, context: context).to_h
      end

      # Return the GraphQL IDL for the schema
      # @param context [Hash]
      # @param only [<#call(member, ctx)>]
      # @param except [<#call(member, ctx)>]
      # @return [String]
      def to_definition(only: nil, except: nil, context: {})
        GraphQL::Schema::Printer.print_schema(self, only: only, except: except, context: context)
      end

      # Return the GraphQL::Language::Document IDL AST for the schema
      # @return [GraphQL::Language::Document]
      def to_document
        GraphQL::Language::DocumentFromSchemaDefinition.new(self).document
      end

      # @return [String, nil]
      def description(new_description = nil)
        if new_description
          @description = new_description
        elsif defined?(@description)
          @description
        else
          find_inherited_value(:description, nil)
        end
      end

      def find(path)
        if !@finder
          @find_cache = {}
          @finder ||= GraphQL::Schema::Finder.new(self)
        end
        @find_cache[path] ||= @finder.find(path)
      end

      def default_filter
        GraphQL::Filter.new(except: default_mask)
      end

      def default_mask(new_mask = nil)
        if new_mask
          @own_default_mask = new_mask
        else
          @own_default_mask || find_inherited_value(:default_mask, Schema::NullMask)
        end
      end

      def static_validator
        GraphQL::StaticValidation::Validator.new(schema: self)
      end

      def use(plugin, **kwargs)
        if kwargs.any?
          plugin.use(self, **kwargs)
        else
          plugin.use(self)
        end
        own_plugins << [plugin, kwargs]
      end

      def plugins
        find_inherited_value(:plugins, EMPTY_ARRAY) + own_plugins
      end

      # Build a map of `{ name => type }` and return it
      # @return [Hash<String => Class>] A dictionary of type classes by their GraphQL name
      # @see get_type Which is more efficient for finding _one type_ by name, because it doesn't merge hashes.
      def types(context = GraphQL::Query::NullContext)
        all_types = non_introspection_types.merge(introspection_system.types)
        visible_types = {}
        all_types.each do |k, v|
          visible_types[k] =if v.is_a?(Array)
            visible_t = nil
            v.each do |t|
              if t.visible?(context)
                if visible_t.nil?
                  visible_t = t
                else
                  raise DuplicateNamesError.new(
                    duplicated_name: k, duplicated_definition_1: visible_t.inspect, duplicated_definition_2: t.inspect
                  )
                end
              end
            end
            visible_t
          else
            v
          end
        end
        visible_types
      end

      # @param type_name [String]
      # @return [Module, nil] A type, or nil if there's no type called `type_name`
      def get_type(type_name, context = GraphQL::Query::NullContext)
        local_entry = own_types[type_name]
        type_defn = case local_entry
        when nil
          nil
        when Array
          visible_t = nil
          warden = Warden.from_context(context)
          local_entry.each do |t|
            if warden.visible_type?(t, context)
              if visible_t.nil?
                visible_t = t
              else
                raise DuplicateNamesError.new(
                  duplicated_name: type_name, duplicated_definition_1: visible_t.inspect, duplicated_definition_2: t.inspect
                )
              end
            end
          end
          visible_t
        when Module
          local_entry
        else
          raise "Invariant: unexpected own_types[#{type_name.inspect}]: #{local_entry.inspect}"
        end

        type_defn ||
          introspection_system.types[type_name] || # todo context-specific introspection?
          (superclass.respond_to?(:get_type) ? superclass.get_type(type_name, context) : nil)
      end

      # @api private
      attr_writer :connections

      # @return [GraphQL::Pagination::Connections] if installed
      def connections
        if defined?(@connections)
          @connections
        else
          inherited_connections = find_inherited_value(:connections, nil)
          # This schema is part of an inheritance chain which is using new connections,
          # make a new instance, so we don't pollute the upstream one.
          if inherited_connections
            @connections = Pagination::Connections.new(schema: self)
          else
            nil
          end
        end
      end

      def new_connections?
        !!connections
      end

      def query(new_query_object = nil)
        if new_query_object
          if @query_object
            raise GraphQL::Error, "Second definition of `query(...)` (#{new_query_object.inspect}) is invalid, already configured with #{@query_object.inspect}"
          else
            @query_object = new_query_object
            add_type_and_traverse(new_query_object, root: true)
            nil
          end
        else
          @query_object || find_inherited_value(:query)
        end
      end

      def mutation(new_mutation_object = nil)
        if new_mutation_object
          if @mutation_object
            raise GraphQL::Error, "Second definition of `mutation(...)` (#{new_mutation_object.inspect}) is invalid, already configured with #{@mutation_object.inspect}"
          else
            @mutation_object = new_mutation_object
            add_type_and_traverse(new_mutation_object, root: true)
            nil
          end
        else
          @mutation_object || find_inherited_value(:mutation)
        end
      end

      def subscription(new_subscription_object = nil)
        if new_subscription_object
          if @subscription_object
            raise GraphQL::Error, "Second definition of `subscription(...)` (#{new_subscription_object.inspect}) is invalid, already configured with #{@subscription_object.inspect}"
          else
            @subscription_object = new_subscription_object
            add_subscription_extension_if_necessary
            add_type_and_traverse(new_subscription_object, root: true)
            nil
          end
        else
          @subscription_object || find_inherited_value(:subscription)
        end
      end

      # @see [GraphQL::Schema::Warden] Restricted access to root types
      # @return [GraphQL::ObjectType, nil]
      def root_type_for_operation(operation)
        case operation
        when "query"
          query
        when "mutation"
          mutation
        when "subscription"
          subscription
        else
          raise ArgumentError, "unknown operation type: #{operation}"
        end
      end

      def root_types
        @root_types
      end

      # @param type [Module] The type definition whose possible types you want to see
      # @return [Hash<String, Module>] All possible types, if no `type` is given.
      # @return [Array<Module>] Possible types for `type`, if it's given.
      def possible_types(type = nil, context = GraphQL::Query::NullContext)
        if type
          # TODO duck-typing `.possible_types` would probably be nicer here
          if type.kind.union?
            type.possible_types(context: context)
          else
            stored_possible_types = own_possible_types[type.graphql_name]
            visible_possible_types = if stored_possible_types && type.kind.interface?
              stored_possible_types.select do |possible_type|
                possible_type.interfaces(context).include?(type)
              end
            else
              stored_possible_types
            end
            visible_possible_types ||
              introspection_system.possible_types[type.graphql_name] ||
              (
                superclass.respond_to?(:possible_types) ?
                  superclass.possible_types(type, context) :
                  EMPTY_ARRAY
              )
          end
        else
          find_inherited_value(:possible_types, EMPTY_HASH)
            .merge(own_possible_types)
            .merge(introspection_system.possible_types)
        end
      end

      def union_memberships(type = nil)
        if type
          own_um = own_union_memberships.fetch(type.graphql_name, EMPTY_ARRAY)
          inherited_um = find_inherited_value(:union_memberships, EMPTY_HASH).fetch(type.graphql_name, EMPTY_ARRAY)
          own_um + inherited_um
        else
          joined_um = own_union_memberships.dup
          find_inherited_value(:union_memberhips, EMPTY_HASH).each do |k, v|
            um = joined_um[k] ||= []
            um.concat(v)
          end
          joined_um
        end
      end

      # @api private
      # @see GraphQL::Dataloader
      def dataloader_class
        @dataloader_class || GraphQL::Dataloader::NullDataloader
      end

      attr_writer :dataloader_class

      def references_to(to_type = nil, from: nil)
        @own_references_to ||= Hash.new { |h, k| h[k] = [] }
        if to_type
          if !to_type.is_a?(String)
            to_type = to_type.graphql_name
          end

          if from
            @own_references_to[to_type] << from
          else
            own_refs = @own_references_to[to_type]
            inherited_refs = find_inherited_value(:references_to, EMPTY_HASH)[to_type] || EMPTY_ARRAY
            own_refs + inherited_refs
          end
        else
          # `@own_references_to` can be quite large for big schemas,
          # and generally speaking, we won't inherit any values.
          # So optimize the most common case -- don't create a duplicate Hash.
          inherited_value = find_inherited_value(:references_to, EMPTY_HASH)
          if inherited_value.any?
            inherited_value.merge(@own_references_to)
          else
            @own_references_to
          end
        end
      end

      def type_from_ast(ast_node, context: nil)
        type_owner = context ? context.warden : self
        GraphQL::Schema::TypeExpression.build_type(type_owner, ast_node)
      end

      def get_field(type_or_name, field_name, context = GraphQL::Query::NullContext)
        parent_type = case type_or_name
        when LateBoundType
          get_type(type_or_name.name, context)
        when String
          get_type(type_or_name, context)
        when Module
          type_or_name
        else
          raise GraphQL::InvariantError, "Unexpected field owner for #{field_name.inspect}: #{type_or_name.inspect} (#{type_or_name.class})"
        end

        if parent_type.kind.fields? && (field = parent_type.get_field(field_name, context))
          field
        elsif parent_type == query && (entry_point_field = introspection_system.entry_point(name: field_name))
          entry_point_field
        elsif (dynamic_field = introspection_system.dynamic_field(name: field_name))
          dynamic_field
        else
          nil
        end
      end

      def get_fields(type, context = GraphQL::Query::NullContext)
        type.fields(context)
      end

      def introspection(new_introspection_namespace = nil)
        if new_introspection_namespace
          @introspection = new_introspection_namespace
          # reset this cached value:
          @introspection_system = nil
        else
          @introspection || find_inherited_value(:introspection)
        end
      end

      def introspection_system
        if !@introspection_system
          @introspection_system = Schema::IntrospectionSystem.new(self)
          @introspection_system.resolve_late_bindings
        end
        @introspection_system
      end

      def cursor_encoder(new_encoder = nil)
        if new_encoder
          @cursor_encoder = new_encoder
        end
        @cursor_encoder || find_inherited_value(:cursor_encoder, Base64Encoder)
      end

      def default_max_page_size(new_default_max_page_size = nil)
        if new_default_max_page_size
          @default_max_page_size = new_default_max_page_size
        else
          @default_max_page_size || find_inherited_value(:default_max_page_size)
        end
      end

      def default_page_size(new_default_page_size = nil)
        if new_default_page_size
          @default_page_size = new_default_page_size
        else
          @default_page_size || find_inherited_value(:default_page_size)
        end
      end

      def query_execution_strategy(new_query_execution_strategy = nil)
        if new_query_execution_strategy
          @query_execution_strategy = new_query_execution_strategy
        else
          @query_execution_strategy || find_inherited_value(:query_execution_strategy, self.default_execution_strategy)
        end
      end

      def mutation_execution_strategy(new_mutation_execution_strategy = nil)
        if new_mutation_execution_strategy
          @mutation_execution_strategy = new_mutation_execution_strategy
        else
          @mutation_execution_strategy || find_inherited_value(:mutation_execution_strategy, self.default_execution_strategy)
        end
      end

      def subscription_execution_strategy(new_subscription_execution_strategy = nil)
        if new_subscription_execution_strategy
          @subscription_execution_strategy = new_subscription_execution_strategy
        else
          @subscription_execution_strategy || find_inherited_value(:subscription_execution_strategy, self.default_execution_strategy)
        end
      end

      attr_writer :validate_timeout

      def validate_timeout(new_validate_timeout = nil)
        if new_validate_timeout
          @validate_timeout = new_validate_timeout
        elsif defined?(@validate_timeout)
          @validate_timeout
        else
          find_inherited_value(:validate_timeout)
        end
      end

      # Validate a query string according to this schema.
      # @param string_or_document [String, GraphQL::Language::Nodes::Document]
      # @return [Array<GraphQL::StaticValidation::Error >]
      def validate(string_or_document, rules: nil, context: nil)
        doc = if string_or_document.is_a?(String)
          GraphQL.parse(string_or_document)
        else
          string_or_document
        end
        query = GraphQL::Query.new(self, document: doc, context: context)
        validator_opts = { schema: self }
        rules && (validator_opts[:rules] = rules)
        validator = GraphQL::StaticValidation::Validator.new(**validator_opts)
        res = validator.validate(query, timeout: validate_timeout, max_errors: validate_max_errors)
        res[:errors]
      end

      attr_writer :validate_max_errors

      def validate_max_errors(new_validate_max_errors = nil)
        if new_validate_max_errors
          @validate_max_errors = new_validate_max_errors
        elsif defined?(@validate_max_errors)
          @validate_max_errors
        else
          find_inherited_value(:validate_max_errors)
        end
      end

      attr_writer :max_complexity

      def max_complexity(max_complexity = nil)
        if max_complexity
          @max_complexity = max_complexity
        elsif defined?(@max_complexity)
          @max_complexity
        else
          find_inherited_value(:max_complexity)
        end
      end

      attr_writer :analysis_engine

      def analysis_engine
        @analysis_engine || find_inherited_value(:analysis_engine, self.default_analysis_engine)
      end

      def using_ast_analysis?
        true
      end

      def interpreter?
        true
      end

      attr_writer :interpreter

      def error_bubbling(new_error_bubbling = nil)
        if !new_error_bubbling.nil?
          @error_bubbling = new_error_bubbling
        else
          @error_bubbling.nil? ? find_inherited_value(:error_bubbling) : @error_bubbling
        end
      end

      attr_writer :error_bubbling

      attr_writer :max_depth

      def max_depth(new_max_depth = nil)
        if new_max_depth
          @max_depth = new_max_depth
        elsif defined?(@max_depth)
          @max_depth
        else
          find_inherited_value(:max_depth)
        end
      end

      def disable_introspection_entry_points
        @disable_introspection_entry_points = true
        # TODO: this clears the cache made in `def types`. But this is not a great solution.
        @introspection_system = nil
      end

      def disable_schema_introspection_entry_point
        @disable_schema_introspection_entry_point = true
        # TODO: this clears the cache made in `def types`. But this is not a great solution.
        @introspection_system = nil
      end

      def disable_type_introspection_entry_point
        @disable_type_introspection_entry_point = true
        # TODO: this clears the cache made in `def types`. But this is not a great solution.
        @introspection_system = nil
      end

      def disable_introspection_entry_points?
        if instance_variable_defined?(:@disable_introspection_entry_points)
          @disable_introspection_entry_points
        else
          find_inherited_value(:disable_introspection_entry_points?, false)
        end
      end

      def disable_schema_introspection_entry_point?
        if instance_variable_defined?(:@disable_schema_introspection_entry_point)
          @disable_schema_introspection_entry_point
        else
          find_inherited_value(:disable_schema_introspection_entry_point?, false)
        end
      end

      def disable_type_introspection_entry_point?
        if instance_variable_defined?(:@disable_type_introspection_entry_point)
          @disable_type_introspection_entry_point
        else
          find_inherited_value(:disable_type_introspection_entry_point?, false)
        end
      end

      def orphan_types(*new_orphan_types)
        if new_orphan_types.any?
          new_orphan_types = new_orphan_types.flatten
          add_type_and_traverse(new_orphan_types, root: false)
          own_orphan_types.concat(new_orphan_types.flatten)
        end

        find_inherited_value(:orphan_types, EMPTY_ARRAY) + own_orphan_types
      end

      def default_execution_strategy
        if superclass <= GraphQL::Schema
          superclass.default_execution_strategy
        else
          @default_execution_strategy ||= GraphQL::Execution::Interpreter
        end
      end

      def default_analysis_engine
        if superclass <= GraphQL::Schema
          superclass.default_analysis_engine
        else
          @default_analysis_engine ||= GraphQL::Analysis::AST
        end
      end

      def context_class(new_context_class = nil)
        if new_context_class
          @context_class = new_context_class
        else
          @context_class || find_inherited_value(:context_class, GraphQL::Query::Context)
        end
      end

      def rescue_from(*err_classes, &handler_block)
        err_classes.each do |err_class|
          Execution::Errors.register_rescue_from(err_class, error_handlers[:subclass_handlers], handler_block)
        end
      end

      NEW_HANDLER_HASH = ->(h, k) {
        h[k] = {
          class: k,
          handler: nil,
          subclass_handlers: Hash.new(&NEW_HANDLER_HASH),
         }
      }

      def error_handlers
        @error_handlers ||= {
          class: nil,
          handler: nil,
          subclass_handlers: Hash.new(&NEW_HANDLER_HASH),
        }
      end

      # @api private
      def handle_or_reraise(context, err)
        handler = Execution::Errors.find_handler_for(self, err.class)
        if handler
          obj = context[:current_object]
          args = context[:current_arguments]
          args = args && args.keyword_arguments
          field = context[:current_field]
          if obj.is_a?(GraphQL::Schema::Object)
            obj = obj.object
          end
          handler[:handler].call(err, obj, args, context, field)
        else
          raise err
        end
      end

      # rubocop:disable Lint/DuplicateMethods
      module ResolveTypeWithType
        def resolve_type(type, obj, ctx)
          maybe_lazy_resolve_type_result = if type.is_a?(Module) && type.respond_to?(:resolve_type)
            type.resolve_type(obj, ctx)
          else
            super
          end

          after_lazy(maybe_lazy_resolve_type_result) do |resolve_type_result|
            if resolve_type_result.is_a?(Array) && resolve_type_result.size == 2
              resolved_type = resolve_type_result[0]
              resolved_value = resolve_type_result[1]
            else
              resolved_type = resolve_type_result
              resolved_value = obj
            end

            if resolved_type.nil? || (resolved_type.is_a?(Module) && resolved_type.respond_to?(:kind))
              if resolved_value
                [resolved_type, resolved_value]
              else
                resolved_type
              end
            else
              raise ".resolve_type should return a type definition, but got #{resolved_type.inspect} (#{resolved_type.class}) from `resolve_type(#{type}, #{obj}, #{ctx})`"
            end
          end
        end
      end

      def resolve_type(type, obj, ctx)
        if type.kind.object?
          type
        else
          raise GraphQL::RequiredImplementationMissingError, "#{self.name}.resolve_type(type, obj, ctx) must be implemented to use Union types or Interface types (tried to resolve: #{type.name})"
        end
      end
      # rubocop:enable Lint/DuplicateMethods

      def inherited(child_class)
        if self == GraphQL::Schema
          child_class.directives(default_directives.values)
        end
        child_class.singleton_class.prepend(ResolveTypeWithType)
        super
      end

      def object_from_id(node_id, ctx)
        raise GraphQL::RequiredImplementationMissingError, "#{self.name}.object_from_id(node_id, ctx) must be implemented to load by ID (tried to load from id `#{node_id}`)"
      end

      def id_from_object(object, type, ctx)
        raise GraphQL::RequiredImplementationMissingError, "#{self.name}.id_from_object(object, type, ctx) must be implemented to create global ids (tried to create an id for `#{object.inspect}`)"
      end

      def visible?(member, ctx)
        member.visible?(ctx)
      end

      def accessible?(member, ctx)
        member.accessible?(ctx)
      end

      def schema_directive(dir_class, **options)
        @own_schema_directives ||= []
        Member::HasDirectives.add_directive(self, @own_schema_directives, dir_class, options)
      end

      def schema_directives
        Member::HasDirectives.get_directives(self, @own_schema_directives, :schema_directives)
      end

      # This hook is called when a client tries to access one or more
      # fields that fail the `accessible?` check.
      #
      # By default, an error is added to the response. Override this hook to
      # track metrics or return a different error to the client.
      #
      # @param error [InaccessibleFieldsError] The analysis error for this check
      # @return [AnalysisError, nil] Return an error to skip the query
      def inaccessible_fields(error)
        error
      end

      # This hook is called when an object fails an `authorized?` check.
      # You might report to your bug tracker here, so you can correct
      # the field resolvers not to return unauthorized objects.
      #
      # By default, this hook just replaces the unauthorized object with `nil`.
      #
      # Whatever value is returned from this method will be used instead of the
      # unauthorized object (accessible as `unauthorized_error.object`). If an
      # error is raised, then `nil` will be used.
      #
      # If you want to add an error to the `"errors"` key, raise a {GraphQL::ExecutionError}
      # in this hook.
      #
      # @param unauthorized_error [GraphQL::UnauthorizedError]
      # @return [Object] The returned object will be put in the GraphQL response
      def unauthorized_object(unauthorized_error)
        nil
      end

      # This hook is called when a field fails an `authorized?` check.
      #
      # By default, this hook implements the same behavior as unauthorized_object.
      #
      # Whatever value is returned from this method will be used instead of the
      # unauthorized field . If an error is raised, then `nil` will be used.
      #
      # If you want to add an error to the `"errors"` key, raise a {GraphQL::ExecutionError}
      # in this hook.
      #
      # @param unauthorized_error [GraphQL::UnauthorizedFieldError]
      # @return [Field] The returned field will be put in the GraphQL response
      def unauthorized_field(unauthorized_error)
        unauthorized_object(unauthorized_error)
      end

      def type_error(type_error, ctx)
        case type_error
        when GraphQL::InvalidNullError
          ctx.errors << type_error
        when GraphQL::UnresolvedTypeError, GraphQL::StringEncodingError, GraphQL::IntegerEncodingError
          raise type_error
        when GraphQL::IntegerDecodingError
          nil
        end
      end

      # A function to call when {#execute} receives an invalid query string
      #
      # The default is to add the error to `context.errors`
      # @param err [GraphQL::ParseError] The error encountered during parsing
      # @param ctx [GraphQL::Query::Context] The context for the query where the error occurred
      # @return void
      def parse_error(parse_err, ctx)
        ctx.errors.push(parse_err)
      end

      def lazy_resolve(lazy_class, value_method)
        lazy_methods.set(lazy_class, value_method)
      end

      def instrument(instrument_step, instrumenter, options = {})
        own_instrumenters[instrument_step] << instrumenter
      end

      # Add several directives at once
      # @param new_directives [Class]
      def directives(*new_directives)
        if new_directives.any?
          new_directives.flatten.each { |d| directive(d) }
        end

        find_inherited_value(:directives, default_directives).merge(own_directives)
      end

      # Attach a single directive to this schema
      # @param new_directive [Class]
      # @return void
      def directive(new_directive)
        add_type_and_traverse(new_directive, root: false)
      end

      def default_directives
        @default_directives ||= {
          "include" => GraphQL::Schema::Directive::Include,
          "skip" => GraphQL::Schema::Directive::Skip,
          "deprecated" => GraphQL::Schema::Directive::Deprecated,
          "oneOf" => GraphQL::Schema::Directive::OneOf,
        }.freeze
      end

      def tracer(new_tracer)
        own_tracers << new_tracer
      end

      def tracers
        find_inherited_value(:tracers, EMPTY_ARRAY) + own_tracers
      end

      def query_analyzer(new_analyzer)
        own_query_analyzers << new_analyzer
      end

      def query_analyzers
        find_inherited_value(:query_analyzers, EMPTY_ARRAY) + own_query_analyzers
      end

      def multiplex_analyzer(new_analyzer)
        own_multiplex_analyzers << new_analyzer
      end

      def multiplex_analyzers
        find_inherited_value(:multiplex_analyzers, EMPTY_ARRAY) + own_multiplex_analyzers
      end

      def sanitized_printer(new_sanitized_printer = nil)
        if new_sanitized_printer
          @own_sanitized_printer = new_sanitized_printer
        else
          @own_sanitized_printer || GraphQL::Language::SanitizedPrinter
        end
      end

      # Execute a query on itself.
      # @see {Query#initialize} for arguments.
      # @return [Hash] query result, ready to be serialized as JSON
      def execute(query_str = nil, **kwargs)
        if query_str
          kwargs[:query] = query_str
        end
        # Some of the query context _should_ be passed to the multiplex, too
        multiplex_context = if (ctx = kwargs[:context])
          {
            backtrace: ctx[:backtrace],
            tracers: ctx[:tracers],
            dataloader: ctx[:dataloader],
          }
        else
          {}
        end
        # Since we're running one query, don't run a multiplex-level complexity analyzer
        all_results = multiplex([kwargs], max_complexity: nil, context: multiplex_context)
        all_results[0]
      end

      # Execute several queries on itself, concurrently.
      #
      # @example Run several queries at once
      #   context = { ... }
      #   queries = [
      #     { query: params[:query_1], variables: params[:variables_1], context: context },
      #     { query: params[:query_2], variables: params[:variables_2], context: context },
      #   ]
      #   results = MySchema.multiplex(queries)
      #   render json: {
      #     result_1: results[0],
      #     result_2: results[1],
      #   }
      #
      # @see {Query#initialize} for query keyword arguments
      # @see {Execution::Multiplex#run_all} for multiplex keyword arguments
      # @param queries [Array<Hash>] Keyword arguments for each query
      # @param context [Hash] Multiplex-level context
      # @return [Array<Hash>] One result for each query in the input
      def multiplex(queries, **kwargs)
        GraphQL::Execution::Interpreter.run_all(self, queries, **kwargs)
      end

      def instrumenters
        inherited_instrumenters = find_inherited_value(:instrumenters) || Hash.new { |h,k| h[k] = [] }
        inherited_instrumenters.merge(own_instrumenters) do |_step, inherited, own|
          inherited + own
        end
      end

      # @api private
      def add_subscription_extension_if_necessary
        if !defined?(@subscription_extension_added) && subscription && self.subscriptions
          @subscription_extension_added = true
          subscription.all_field_definitions.each do |field|
            if !field.extensions.any? { |ext| ext.is_a?(Subscriptions::DefaultSubscriptionResolveExtension) }
              field.extension(Subscriptions::DefaultSubscriptionResolveExtension)
            end
          end
        end
      end

      def query_stack_error(query, err)
        query.context.errors.push(GraphQL::ExecutionError.new("This query is too large to execute."))
      end

      # Call the given block at the right time, either:
      # - Right away, if `value` is not registered with `lazy_resolve`
      # - After resolving `value`, if it's registered with `lazy_resolve` (eg, `Promise`)
      # @api private
      def after_lazy(value, &block)
        if lazy?(value)
          GraphQL::Execution::Lazy.new do
            result = sync_lazy(value)
            # The returned result might also be lazy, so check it, too
            after_lazy(result, &block)
          end
        else
          yield(value) if block_given?
        end
      end

      # Override this method to handle lazy objects in a custom way.
      # @param value [Object] an instance of a class registered with {.lazy_resolve}
      # @return [Object] A GraphQL-ready (non-lazy) object
      # @api private
      def sync_lazy(value)
        lazy_method = lazy_method_name(value)
        if lazy_method
          synced_value = value.public_send(lazy_method)
          sync_lazy(synced_value)
        else
          value
        end
      end

      # @return [Symbol, nil] The method name to lazily resolve `obj`, or nil if `obj`'s class wasn't registered with {#lazy_resolve}.
      def lazy_method_name(obj)
        lazy_methods.get(obj)
      end

      # @return [Boolean] True if this object should be lazily resolved
      def lazy?(obj)
        !!lazy_method_name(obj)
      end

      # Return a lazy if any of `maybe_lazies` are lazy,
      # otherwise, call the block eagerly and return the result.
      # @param maybe_lazies [Array]
      # @api private
      def after_any_lazies(maybe_lazies)
        if maybe_lazies.any? { |l| lazy?(l) }
          GraphQL::Execution::Lazy.all(maybe_lazies).then do |result|
            yield result
          end
        else
          yield maybe_lazies
        end
      end

      private

      # @param t [Module, Array<Module>]
      # @return [void]
      def add_type_and_traverse(t, root:)
        if root
          @root_types ||= []
          @root_types << t
        end
        new_types = Array(t)
        addition = Schema::Addition.new(schema: self, own_types: own_types, new_types: new_types)
        addition.types.each do |name, types_entry| # rubocop:disable Development/ContextIsPassedCop -- build-time, not query-time
          if (prev_entry = own_types[name])
            prev_entries = case prev_entry
            when Array
              prev_entry
            when Module
              own_types[name] = [prev_entry]
            else
              raise "Invariant: unexpected prev_entry at #{name.inspect} when adding #{t.inspect}"
            end

            case types_entry
            when Array
              prev_entries.concat(types_entry)
              prev_entries.uniq! # in case any are being re-visited
            when Module
              if !prev_entries.include?(types_entry)
                prev_entries << types_entry
              end
            else
              raise "Invariant: unexpected types_entry at #{name} when adding #{t.inspect}"
            end
          else
            if types_entry.is_a?(Array)
              types_entry.uniq!
            end
            own_types[name] = types_entry
          end
        end

        own_possible_types.merge!(addition.possible_types) { |key, old_val, new_val| old_val + new_val }
        own_union_memberships.merge!(addition.union_memberships)

        addition.references.each { |thing, pointers|
          pointers.each { |pointer| references_to(thing, from: pointer) }
        }

        addition.directives.each { |dir_class| own_directives[dir_class.graphql_name] = dir_class }

        addition.arguments_with_default_values.each do |arg|
          arg.validate_default_value
        end
      end

      def lazy_methods
        if !defined?(@lazy_methods)
          if inherited_map = find_inherited_value(:lazy_methods)
            # this isn't _completely_ inherited :S (Things added after `dup` won't work)
            @lazy_methods = inherited_map.dup
          else
            @lazy_methods = GraphQL::Execution::Lazy::LazyMethodMap.new
            @lazy_methods.set(GraphQL::Execution::Lazy, :value)
            @lazy_methods.set(GraphQL::Dataloader::Request, :load)
          end
        end
        @lazy_methods
      end

      def own_types
        @own_types ||= {}
      end

      def non_introspection_types
        find_inherited_value(:non_introspection_types, EMPTY_HASH).merge(own_types)
      end

      def own_plugins
        @own_plugins ||= []
      end

      def own_orphan_types
        @own_orphan_types ||= []
      end

      def own_possible_types
        @own_possible_types ||= {}
      end

      def own_union_memberships
        @own_union_memberships ||= {}
      end

      def own_directives
        @own_directives ||= {}
      end

      def own_instrumenters
        @own_instrumenters ||= Hash.new { |h,k| h[k] = [] }
      end

      def own_tracers
        @own_tracers ||= []
      end

      def own_query_analyzers
        @defined_query_analyzers ||= []
      end

      def own_multiplex_analyzers
        @own_multiplex_analyzers ||= []
      end
    end

    # Install these here so that subclasses will also install it.
    self.connections = GraphQL::Pagination::Connections.new(schema: self)
  end
end