# ruff: noqa: UP006, UP007
from __future__ import annotations

import re
from functools import partial
from pathlib import Path, PurePath
from typing import (
    TYPE_CHECKING,
    Any,
    Callable,
    ClassVar,
    Dict,
    Literal,
    Optional,
    Sequence,
    Set,
    Type,
    TypedDict,
    Union,
    cast,
)
from uuid import UUID

from msgspec import NODEFAULT, Meta, Struct, ValidationError, convert, defstruct
from msgspec.structs import asdict
from typing_extensions import Annotated

from litestar._signature.types import ExtendedMsgSpecValidationError
from litestar._signature.utils import (
    _get_decoder_for_type,
    _normalize_annotation,
    _validate_signature_dependencies,
)
from litestar.datastructures.state import ImmutableState
from litestar.datastructures.url import URL
from litestar.dto import AbstractDTO, DTOData
from litestar.enums import ParamType, ScopeType
from litestar.exceptions import InternalServerException, ValidationException
from litestar.params import KwargDefinition, ParameterKwarg
from litestar.typing import FieldDefinition  # noqa
from litestar.utils import is_class_and_subclass
from litestar.utils.dataclass import simple_asdict

if TYPE_CHECKING:
    from typing_extensions import NotRequired

    from litestar.connection import ASGIConnection
    from litestar.types import AnyCallable, TypeDecodersSequence
    from litestar.utils.signature import ParsedSignature

__all__ = (
    "ErrorMessage",
    "SignatureModel",
)


class ErrorMessage(TypedDict):
    # key may not be set in some cases, like when a query param is set but
    # doesn't match the required length during `attrs` validation
    # in this case, we don't show a key at all as it will be empty
    key: NotRequired[str]
    message: str
    source: NotRequired[Literal["body"] | ParamType]


MSGSPEC_CONSTRAINT_FIELDS = (
    "gt",
    "ge",
    "lt",
    "le",
    "multiple_of",
    "pattern",
    "min_length",
    "max_length",
)

ERR_RE = re.compile(r"`\$\.(.+)`$")

DEFAULT_TYPE_DECODERS = [
    (lambda x: is_class_and_subclass(x, (Path, PurePath, ImmutableState, UUID)), lambda t, v: t(v)),
]


def _deserializer(target_type: Any, value: Any, default_deserializer: Callable[[Any, Any], Any]) -> Any:
    if isinstance(value, DTOData):
        return value

    if isinstance(value, target_type):
        return value

    if decoder := getattr(target_type, "_decoder", None):
        return decoder(target_type, value)

    return default_deserializer(target_type, value)


class SignatureModel(Struct):
    """Model that represents a function signature that uses a msgspec specific type or types."""

    _data_dto: ClassVar[Optional[Type[AbstractDTO]]]
    _dependency_name_set: ClassVar[Set[str]]
    _fields: ClassVar[Dict[str, FieldDefinition]]
    _return_annotation: ClassVar[Any]

    @classmethod
    def _create_exception(cls, connection: ASGIConnection, messages: list[ErrorMessage]) -> Exception:
        """Create an exception class - either a ValidationException or an InternalServerException, depending on whether
            the failure is in client provided values or injected dependencies.

        Args:
            connection: An ASGI connection instance.
            messages: A list of error messages.

        Returns:
            An Exception
        """
        method = connection.method if hasattr(connection, "method") else ScopeType.WEBSOCKET  # pyright: ignore
        if client_errors := [
            err_message
            for err_message in messages
            if ("key" in err_message and err_message["key"] not in cls._dependency_name_set) or "key" not in err_message
        ]:
            path = URL.from_components(
                path=connection.url.path,
                query=connection.url.query,
            )
            return ValidationException(detail=f"Validation failed for {method} {path}", extra=client_errors)
        return InternalServerException()

    @classmethod
    def _build_error_message(cls, keys: Sequence[str], exc_msg: str, connection: ASGIConnection) -> ErrorMessage:
        """Build an error message.

        Args:
            keys: A list of keys.
            exc_msg: A message.
            connection: An ASGI connection instance.

        Returns:
            An ErrorMessage
        """

        message: ErrorMessage = {"message": exc_msg.split(" - ")[0]}

        if keys:
            message["key"] = key = ".".join(keys)
            if keys[0].startswith("data"):
                message["key"] = message["key"].replace("data.", "")
                message["source"] = "body"
            elif key in connection.query_params:
                message["source"] = ParamType.QUERY

            elif key in cls._fields and isinstance(cls._fields[key].kwarg_definition, ParameterKwarg):
                if cast(ParameterKwarg, cls._fields[key].kwarg_definition).cookie:
                    message["source"] = ParamType.COOKIE
                elif cast(ParameterKwarg, cls._fields[key].kwarg_definition).header:
                    message["source"] = ParamType.HEADER
                else:
                    message["source"] = ParamType.QUERY

        return message

    @classmethod
    def _collect_errors(cls, deserializer: Callable[[Any, Any], Any], **kwargs: Any) -> list[tuple[str, Exception]]:
        exceptions: list[tuple[str, Exception]] = []
        for field_name in cls._fields:
            try:
                raw_value = kwargs[field_name]
                annotation = cls.__annotations__[field_name]
                convert(raw_value, type=annotation, strict=False, dec_hook=deserializer, str_keys=True)
            except Exception as e:  # noqa: BLE001
                exceptions.append((field_name, e))

        return exceptions

    @classmethod
    def parse_values_from_connection_kwargs(cls, connection: ASGIConnection, **kwargs: Any) -> dict[str, Any]:
        """Extract values from the connection instance and return a dict of parsed values.

        Args:
            connection: The ASGI connection instance.
            **kwargs: A dictionary of kwargs.

        Raises:
            ValidationException: If validation failed.
            InternalServerException: If another exception has been raised.

        Returns:
            A dictionary of parsed values
        """
        messages: list[ErrorMessage] = []
        deserializer = partial(_deserializer, default_deserializer=connection.route_handler.default_deserializer)
        try:
            return convert(kwargs, cls, strict=False, dec_hook=deserializer, str_keys=True).to_dict()
        except ExtendedMsgSpecValidationError as e:
            for exc in e.errors:
                keys = [str(loc) for loc in exc["loc"]]
                message = cls._build_error_message(keys=keys, exc_msg=exc["msg"], connection=connection)
                messages.append(message)
            raise cls._create_exception(messages=messages, connection=connection) from e
        except ValidationError as e:
            for field_name, exc in cls._collect_errors(deserializer=deserializer, **kwargs):  # type: ignore[assignment]
                match = ERR_RE.search(str(exc))
                keys = [field_name, str(match.group(1))] if match else [field_name]
                message = cls._build_error_message(keys=keys, exc_msg=str(exc), connection=connection)
                messages.append(message)
            raise cls._create_exception(messages=messages, connection=connection) from e

    def to_dict(self) -> dict[str, Any]:
        """Normalize access to the signature model's dictionary method, because different backends use different methods
        for this.

        Returns: A dictionary of string keyed values.
        """
        return asdict(self)

    @classmethod
    def create(
        cls,
        dependency_name_set: set[str],
        fn: AnyCallable,
        parsed_signature: ParsedSignature,
        type_decoders: TypeDecodersSequence,
        data_dto: type[AbstractDTO] | None = None,
    ) -> type[SignatureModel]:
        fn_name = (
            fn_name if (fn_name := getattr(fn, "__name__", "anonymous")) and fn_name != "<lambda>" else "anonymous"
        )

        dependency_names = _validate_signature_dependencies(
            dependency_name_set=dependency_name_set, fn_name=fn_name, parsed_signature=parsed_signature
        )

        struct_fields: list[tuple[str, Any, Any]] = []

        for field_definition in parsed_signature.parameters.values():
            meta_data: Meta | None = None

            if isinstance(field_definition.kwarg_definition, KwargDefinition):
                meta_kwargs: dict[str, Any] = {"extra": {}}

                kwarg_definition = simple_asdict(field_definition.kwarg_definition, exclude_empty=True)
                if min_items := kwarg_definition.pop("min_items", None):
                    meta_kwargs["min_length"] = min_items
                if max_items := kwarg_definition.pop("max_items", None):
                    meta_kwargs["max_length"] = max_items

                for k, v in kwarg_definition.items():
                    if hasattr(Meta, k) and v is not None:
                        meta_kwargs[k] = v
                    else:
                        meta_kwargs["extra"][k] = v

                meta_data = Meta(**meta_kwargs)

            annotation = cls._create_annotation(
                field_definition=field_definition,
                type_decoders=[*(type_decoders or []), *DEFAULT_TYPE_DECODERS],
                meta_data=meta_data,
                data_dto=data_dto,
            )

            default = field_definition.default if field_definition.has_default else NODEFAULT
            struct_fields.append((field_definition.name, annotation, default))

        return defstruct(  # type:ignore[return-value]
            f"{fn_name}_signature_model",
            struct_fields,
            bases=(cls,),
            module=getattr(fn, "__module__", None),
            namespace={
                "_return_annotation": parsed_signature.return_type.annotation,
                "_dependency_name_set": dependency_names,
                "_fields": parsed_signature.parameters,
                "_data_dto": data_dto,
            },
            kw_only=True,
        )

    @classmethod
    def _create_annotation(
        cls,
        field_definition: FieldDefinition,
        type_decoders: TypeDecodersSequence,
        meta_data: Meta | None = None,
        data_dto: type[AbstractDTO] | None = None,
    ) -> Any:
        # DTOs have already validated their data, so we can just use Any here
        if field_definition.name == "data" and data_dto:
            return Any

        annotation = _normalize_annotation(field_definition=field_definition)

        if annotation is Any:
            return annotation

        if field_definition.is_union:
            types = [
                cls._create_annotation(
                    field_definition=inner_type,
                    type_decoders=type_decoders,
                    meta_data=meta_data,
                )
                for inner_type in field_definition.inner_types
                if not inner_type.is_none_type
            ]
            return Optional[Union[tuple(types)]] if field_definition.is_optional else Union[tuple(types)]  # pyright: ignore

        if decoder := _get_decoder_for_type(annotation, type_decoders=type_decoders):
            # FIXME: temporary (hopefully) hack, see: https://github.com/jcrist/msgspec/issues/497
            setattr(annotation, "_decoder", decoder)

        if meta_data:
            annotation = Annotated[annotation, meta_data]  # pyright: ignore

        return annotation