class GraphQL::Language::DocumentFromSchemaDefinition

def ast_directives(member)
  ast_directives = member.ast_node ? member.ast_node.directives : []
  # If this schema was built from IDL, it will already have `@deprecated` in `ast_node.directives`
  if member.respond_to?(:deprecation_reason) &&
      (reason = member.deprecation_reason) &&
      ast_directives.none? { |d| d.name == "deprecated" }
    arguments = []
    if reason != GraphQL::Schema::Directive::DEFAULT_DEPRECATION_REASON
      arguments << GraphQL::Language::Nodes::Argument.new(
        name: "reason",
        value: reason
      )
    end
    ast_directives += [
      GraphQL::Language::Nodes::Directive.new(
        name: GraphQL::Directive::DeprecatedDirective.graphql_name,
        arguments: arguments
      )
    ]
  end
  ast_directives
end

def build_argument_node(argument)
  if argument.default_value?
    default_value = build_default_value(argument.default_value, argument.type)
  else
    default_value = nil
  end
  argument_node = GraphQL::Language::Nodes::InputValueDefinition.new(
    name: argument.graphql_name,
    description: argument.description,
    type: build_type_name_node(argument.type),
    default_value: default_value,
    directives: ast_directives(argument),
  )
  argument_node
end

def build_argument_nodes(arguments)
  arguments
    .map { |arg| build_argument_node(arg) }
    .sort_by(&:name)
end

def build_default_value(default_value, type)
  if default_value.nil?
    return GraphQL::Language::Nodes::NullValue.new(name: "null")
  end
  case type.kind.name
  when "SCALAR"
    type.coerce_isolated_result(default_value)
  when "ENUM"
    GraphQL::Language::Nodes::Enum.new(name: type.coerce_isolated_result(default_value))
  when "INPUT_OBJECT"
    GraphQL::Language::Nodes::InputObject.new(
      arguments: default_value.to_h.map do |arg_name, arg_value|
        arg_type = type.arguments.fetch(arg_name.to_s).type
        GraphQL::Language::Nodes::Argument.new(
          name: arg_name.to_s,
          value: build_default_value(arg_value, arg_type)
        )
      end
    )
  when "NON_NULL"
    build_default_value(default_value, type.of_type)
  when "LIST"
    default_value.to_a.map { |v| build_default_value(v, type.of_type) }
  else
    raise GraphQL::RequiredImplementationMissingError, "Unexpected default value type #{type.inspect}"
  end
end

def build_definition_nodes
  definitions = []
  definitions << build_schema_node if include_schema_node?
  definitions += build_directive_nodes(warden.directives)
  definitions += build_type_definition_nodes(warden.reachable_types)
  definitions
end

def build_directive_location_node(location)
  GraphQL::Language::Nodes::DirectiveLocation.new(
    name: location.to_s
  )
end

def build_directive_location_nodes(locations)
  locations.map { |location| build_directive_location_node(location) }
end

def build_directive_node(directive)
  GraphQL::Language::Nodes::DirectiveDefinition.new(
    name: directive.graphql_name,
    arguments: build_argument_nodes(warden.arguments(directive)),
    locations: build_directive_location_nodes(directive.locations),
    description: directive.description,
  )
end

def build_directive_nodes(directives)
  if !include_built_in_directives
    directives = directives.reject { |directive| directive.default_directive? }
  end
  directives
    .map { |directive| build_directive_node(directive) }
    .sort_by(&:name)
end

def build_enum_type_node(enum_type)
  GraphQL::Language::Nodes::EnumTypeDefinition.new(
    name: enum_type.graphql_name,
    values: warden.enum_values(enum_type).sort_by(&:graphql_name).map do |enum_value|
      build_enum_value_node(enum_value)
    end,
    description: enum_type.description,
    directives: ast_directives(enum_type),
  )
end

def build_enum_value_node(enum_value)
  GraphQL::Language::Nodes::EnumValueDefinition.new(
    name: enum_value.graphql_name,
    description: enum_value.description,
    directives: ast_directives(enum_value),
  )
end

def build_field_node(field)
  GraphQL::Language::Nodes::FieldDefinition.new(
    name: field.graphql_name,
    arguments: build_argument_nodes(warden.arguments(field)),
    type: build_type_name_node(field.type),
    description: field.description,
    directives: ast_directives(field),
  )
end

def build_field_nodes(fields)
  fields
    .map { |field| build_field_node(field) }
    .sort_by(&:name)
end

def build_input_object_node(input_object)
  GraphQL::Language::Nodes::InputObjectTypeDefinition.new(
    name: input_object.graphql_name,
    fields: build_argument_nodes(warden.arguments(input_object)),
    description: input_object.description,
    directives: ast_directives(input_object),
  )
end

def build_interface_type_node(interface_type)
  GraphQL::Language::Nodes::InterfaceTypeDefinition.new(
    name: interface_type.graphql_name,
    description: interface_type.description,
    fields: build_field_nodes(warden.fields(interface_type)),
    directives: ast_directives(interface_type),
  )
end

def build_object_type_node(object_type)
  GraphQL::Language::Nodes::ObjectTypeDefinition.new(
    name: object_type.graphql_name,
    interfaces: warden.interfaces(object_type).sort_by(&:graphql_name).map { |iface| build_type_name_node(iface) },
    fields: build_field_nodes(warden.fields(object_type)),
    description: object_type.description,
    directives: ast_directives(object_type),
  )
end

def build_scalar_type_node(scalar_type)
  GraphQL::Language::Nodes::ScalarTypeDefinition.new(
    name: scalar_type.graphql_name,
    description: scalar_type.description,
    directives: ast_directives(scalar_type),
  )
end

def build_schema_node
  GraphQL::Language::Nodes::SchemaDefinition.new(
    query: (q = warden.root_type_for_operation("query")) && q.graphql_name,
    mutation: (m = warden.root_type_for_operation("mutation")) && m.graphql_name,
    subscription: (s = warden.root_type_for_operation("subscription")) && s.graphql_name,
    # This only supports directives from parsing,
    # use a custom printer to add to this list.
    directives: ast_directives(@schema),
  )
end

def build_type_definition_node(type)
  case type.kind.name
  when "OBJECT"
    build_object_type_node(type)
  when "UNION"
    build_union_type_node(type)
  when "INTERFACE"
    build_interface_type_node(type)
  when "SCALAR"
    build_scalar_type_node(type)
  when "ENUM"
    build_enum_type_node(type)
  when "INPUT_OBJECT"
    build_input_object_node(type)
  else
    raise TypeError
  end
end

def build_type_definition_nodes(types)
  if !include_introspection_types
    types = types.reject { |type| type.introspection? }
  end
  if !include_built_in_scalars
    types = types.reject { |type| type.kind.scalar? && type.default_scalar? }
  end
  types
    .map { |type| build_type_definition_node(type) }
    .sort_by(&:name)
end

def build_type_name_node(type)
  case type.kind.name
  when "LIST"
    GraphQL::Language::Nodes::ListType.new(
      of_type: build_type_name_node(type.of_type)
    )
  when "NON_NULL"
    GraphQL::Language::Nodes::NonNullType.new(
      of_type: build_type_name_node(type.of_type)
    )
  else
    GraphQL::Language::Nodes::TypeName.new(name: type.graphql_name)
  end
end

def build_union_type_node(union_type)
  GraphQL::Language::Nodes::UnionTypeDefinition.new(
    name: union_type.graphql_name,
    description: union_type.description,
    types: warden.possible_types(union_type).sort_by(&:graphql_name).map { |type| build_type_name_node(type) },
    directives: ast_directives(union_type),
  )
end

def document
  GraphQL::Language::Nodes::Document.new(
    definitions: build_definition_nodes
  )
end

def include_schema_node?
  always_include_schema || !schema_respects_root_name_conventions?(schema)
end

def initialize(
  schema, context: nil, only: nil, except: nil, include_introspection_types: false,
  include_built_in_directives: false, include_built_in_scalars: false, always_include_schema: false
)
  @schema = schema
  @always_include_schema = always_include_schema
  @include_introspection_types = include_introspection_types
  @include_built_in_scalars = include_built_in_scalars
  @include_built_in_directives = include_built_in_directives
  filter = GraphQL::Filter.new(only: only, except: except)
  if @schema.respond_to?(:visible?)
    filter = filter.merge(only: @schema.method(:visible?))
  end
  schema_context = schema.context_class.new(query: nil, object: nil, schema: schema, values: context)
  @warden = GraphQL::Schema::Warden.new(
    filter,
    schema: @schema,
    context: schema_context,
  )
end

def schema_respects_root_name_conventions?(schema)
  (schema.query.nil? || schema.query.graphql_name == 'Query') &&
  (schema.mutation.nil? || schema.mutation.graphql_name == 'Mutation') &&
  (schema.subscription.nil? || schema.subscription.graphql_name == 'Subscription')
end