import re
import warnings
from typing import (
 TYPE_CHECKING,
 Any,
 Literal,
)

import fastapi
from fastapi._compat import (
 ModelField,
 PydanticSchemaGenerationError,
 Undefined,
 annotation_is_pydantic_v1,
)
from fastapi.datastructures import DefaultPlaceholder, DefaultType
from fastapi.exceptions import FastAPIDeprecationWarning, PydanticV1NotSupportedError
from pydantic.fields import FieldInfo

from ._compat import v2

if TYPE_CHECKING: # pragma: nocover
 from .routing import APIRoute


def is_body_allowed_for_status_code(status_code: int | str | None) -> bool:
 if status_code is None:
 return True
 # Ref: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#patterned-fields-1
 if status_code in {
 "default",
 "1XX",
 "2XX",
 "3XX",
 "4XX",
 "5XX",
 }:
 return True
 current_status_code = int(status_code)
 return not (current_status_code < 200 or current_status_code in {204, 205, 304})


def get_path_param_names(path: str) -> set[str]:
 return set(re.findall("{(.*?)}", path))


_invalid_args_message = (
 "Invalid args for response field! Hint: "
 "check that {type_} is a valid Pydantic field type. "
 "If you are using a return type annotation that is not a valid Pydantic "
 "field (e.g. Union[Response, dict, None]) you can disable generating the "
 "response model from the type annotation with the path operation decorator "
 "parameter response_model=None. Read more: "
 "https://fastapi.tiangolo.com/tutorial/response-model/"
)


def create_model_field(
 name: str,
 type_: Any,
 default: Any | None = Undefined,
 field_info: FieldInfo | None = None,
 alias: str | None = None,
 mode: Literal["validation", "serialization"] = "validation",
) -> ModelField:
 if annotation_is_pydantic_v1(type_):
 raise PydanticV1NotSupportedError(
 "pydantic.v1 models are no longer supported by FastAPI."
 f" Please update the response model {type_!r}."
 )
 field_info = field_info or FieldInfo(annotation=type_, default=default, alias=alias)
 try:
 return v2.ModelField(mode=mode, name=name, field_info=field_info)
 except PydanticSchemaGenerationError:
 raise fastapi.exceptions.FastAPIError(
 _invalid_args_message.format(type_=type_)
 ) from None


def generate_operation_id_for_path(
 *, name: str, path: str, method: str
) -> str: # pragma: nocover
 warnings.warn(
 message="fastapi.utils.generate_operation_id_for_path() was deprecated, "
 "it is not used internally, and will be removed soon",
 category=FastAPIDeprecationWarning,
 stacklevel=2,
 )
 operation_id = f"{name}{path}"
 operation_id = re.sub(r"\W", "_", operation_id)
 operation_id = f"{operation_id}_{method.lower()}"
 return operation_id


def generate_unique_id(route: "APIRoute") -> str:
 operation_id = f"{route.name}{route.path_format}"
 operation_id = re.sub(r"\W", "_", operation_id)
 assert route.methods
 operation_id = f"{operation_id}_{list(route.methods)[0].lower()}"
 return operation_id


def deep_dict_update(main_dict: dict[Any, Any], update_dict: dict[Any, Any]) -> None:
 for key, value in update_dict.items():
 if (
 key in main_dict
 and isinstance(main_dict[key], dict)
 and isinstance(value, dict)
 ):
 deep_dict_update(main_dict[key], value)
 elif (
 key in main_dict
 and isinstance(main_dict[key], list)
 and isinstance(update_dict[key], list)
 ):
 main_dict[key] = main_dict[key] + update_dict[key]
 else:
 main_dict[key] = value


def get_value_or_default(
 first_item: DefaultPlaceholder | DefaultType,
 *extra_items: DefaultPlaceholder | DefaultType,
) -> DefaultPlaceholder | DefaultType:
 """
 Pass items or `DefaultPlaceholder`s by descending priority.

 The first one to _not_ be a `DefaultPlaceholder` will be returned.

 Otherwise, the first item (a `DefaultPlaceholder`) will be returned.
 """
 items = (first_item,) + extra_items
 for item in items:
 if not isinstance(item, DefaultPlaceholder):
 return item
 return first_item