from typing import Any, Collection, List, Union, cast

from ...error import GraphQLError
from ...language import (
    is_type_definition_node,
    is_type_system_definition_node,
    is_type_system_extension_node,
    Node,
    NamedTypeNode,
    TypeDefinitionNode,
)
from ...type import introspection_types, specified_scalar_types
from ...pyutils import did_you_mean, suggestion_list
from . import ASTValidationRule, ValidationContext, SDLValidationContext

__all__ = ["KnownTypeNamesRule"]


class KnownTypeNamesRule(ASTValidationRule):
    """Known type names

    A GraphQL document is only valid if referenced types (specifically variable
    definitions and fragment conditions) are defined by the type schema.

    See https://spec.graphql.org/draft/#sec-Fragment-Spread-Type-Existence
    """

    def __init__(self, context: Union[ValidationContext, SDLValidationContext]):
        super().__init__(context)
        schema = context.schema
        self.existing_types_map = schema.type_map if schema else {}

        defined_types = []
        for def_ in context.document.definitions:
            if is_type_definition_node(def_):
                def_ = cast(TypeDefinitionNode, def_)
                defined_types.append(def_.name.value)
        self.defined_types = set(defined_types)

        self.type_names = list(self.existing_types_map) + defined_types

    def enter_named_type(
        self,
        node: NamedTypeNode,
        _key: Any,
        parent: Node,
        _path: Any,
        ancestors: List[Node],
    ) -> None:
        type_name = node.name.value
        if (
            type_name not in self.existing_types_map
            and type_name not in self.defined_types
        ):
            try:
                definition_node = ancestors[2]
            except IndexError:
                definition_node = parent
            is_sdl = is_sdl_node(definition_node)
            if is_sdl and type_name in standard_type_names:
                return

            suggested_types = suggestion_list(
                type_name,
                list(standard_type_names) + self.type_names
                if is_sdl
                else self.type_names,
            )
            self.report_error(
                GraphQLError(
                    f"Unknown type '{type_name}'." + did_you_mean(suggested_types),
                    node,
                )
            )


standard_type_names = set(specified_scalar_types).union(introspection_types)


def is_sdl_node(value: Union[Node, Collection[Node], None]) -> bool:
    return (
        value is not None
        and not isinstance(value, list)
        and (
            is_type_system_definition_node(cast(Node, value))
            or is_type_system_extension_node(cast(Node, value))
        )
    )