from typing import Any, Union

from graphql import GraphQLSchema
from graphql.execution import ExecutionResult, execute
from graphql.language.ast import Document
from promise import Promise

from gql.transport import Transport


class LocalSchemaTransport(Transport):
    """A transport for executing GraphQL queries against a local schema."""

    def __init__(
        self,  # type: LocalSchemaTransport
        schema,  # type: GraphQLSchema
    ):
        """Initialize the transport with the given local schema.

        :param schema: Local schema as GraphQLSchema object
        """
        self.schema = schema

    def execute(self, document, *args, **kwargs):
        # type: (Document, *Any, **Any) -> Union[ExecutionResult, Promise[ExecutionResult]]
        """Execute the given document against the configured local schema.

        :param document: GraphQL query as AST Node object.
        :param args: Positional options for execute method from graphql-core library.
        :param kwargs: Keyword options passed to execute method from graphql-core library.
        :return: Either ExecutionResult or a Promise that resolves to ExecutionResult object.
        """
        return execute(self.schema, document, *args, **kwargs)