from functools import wraps
from typing import TYPE_CHECKING, Any, Optional, Sequence

from sentry_sdk.integrations import DidNotEnable, Integration
from sentry_sdk.utils import parse_version

from .client import ClientInterceptor
from .server import ServerInterceptor

try:
    import grpc
    from grpc import Channel, Server, intercept_channel
    from grpc.aio import Channel as AsyncChannel
    from grpc.aio import Server as AsyncServer

    from .aio.client import (
        SentryUnaryStreamClientInterceptor as AsyncUnaryStreamClientIntercetor,
    )
    from .aio.client import (
        SentryUnaryUnaryClientInterceptor as AsyncUnaryUnaryClientInterceptor,
    )
    from .aio.server import ServerInterceptor as AsyncServerInterceptor
except ImportError:
    raise DidNotEnable("grpcio is not installed.")

# Hack to get new Python features working in older versions
# without introducing a hard dependency on `typing_extensions`
# from: https://stackoverflow.com/a/71944042/300572
if TYPE_CHECKING:
    from typing import Callable, ParamSpec
else:
    # Fake ParamSpec
    class ParamSpec:
        def __init__(self, _):
            self.args = None
            self.kwargs = None

    # Callable[anything] will return None
    class _Callable:
        def __getitem__(self, _):
            return None

    # Make instances
    Callable = _Callable()

P = ParamSpec("P")

GRPC_VERSION = parse_version(grpc.__version__)


def _is_channel_intercepted(channel: "Channel") -> bool:
    interceptor = getattr(channel, "_interceptor", None)
    while interceptor is not None:
        if isinstance(interceptor, ClientInterceptor):
            return True

        inner_channel = getattr(channel, "_channel", None)
        if inner_channel is None:
            return False

        channel = inner_channel
        interceptor = getattr(channel, "_interceptor", None)

    return False


def _wrap_channel_sync(func: "Callable[P, Channel]") -> "Callable[P, Channel]":
    "Wrapper for synchronous secure and insecure channel."

    @wraps(func)
    def patched_channel(*args: "Any", **kwargs: "Any") -> "Channel":
        channel = func(*args, **kwargs)
        if not _is_channel_intercepted(channel):
            return intercept_channel(channel, ClientInterceptor())
        else:
            return channel

    return patched_channel


def _wrap_intercept_channel(func: "Callable[P, Channel]") -> "Callable[P, Channel]":
    @wraps(func)
    def patched_intercept_channel(
        channel: "Channel", *interceptors: "grpc.ServerInterceptor"
    ) -> "Channel":
        if _is_channel_intercepted(channel):
            interceptors = tuple(
                [
                    interceptor
                    for interceptor in interceptors
                    if not isinstance(interceptor, ClientInterceptor)
                ]
            )
        else:
            interceptors = interceptors
        return intercept_channel(channel, *interceptors)

    return patched_intercept_channel  # type: ignore


def _wrap_channel_async(
    func: "Callable[P, AsyncChannel]",
) -> "Callable[P, AsyncChannel]":
    "Wrapper for asynchronous secure and insecure channel."

    @wraps(func)
    def patched_channel(  # type: ignore
        *args: "P.args",
        interceptors: "Optional[Sequence[grpc.aio.ClientInterceptor]]" = None,
        **kwargs: "P.kwargs",
    ) -> "Channel":
        sentry_interceptors = [
            AsyncUnaryUnaryClientInterceptor(),
            AsyncUnaryStreamClientIntercetor(),
        ]
        interceptors = [*sentry_interceptors, *(interceptors or [])]
        return func(*args, interceptors=interceptors, **kwargs)  # type: ignore

    return patched_channel  # type: ignore


def _wrap_sync_server(func: "Callable[P, Server]") -> "Callable[P, Server]":
    """Wrapper for synchronous server."""

    @wraps(func)
    def patched_server(  # type: ignore
        *args: "P.args",
        interceptors: "Optional[Sequence[grpc.ServerInterceptor]]" = None,
        **kwargs: "P.kwargs",
    ) -> "Server":
        interceptors = [
            interceptor
            for interceptor in interceptors or []
            if not isinstance(interceptor, ServerInterceptor)
        ]
        server_interceptor = ServerInterceptor()
        interceptors = [server_interceptor, *(interceptors or [])]
        return func(*args, interceptors=interceptors, **kwargs)  # type: ignore

    return patched_server  # type: ignore


def _wrap_async_server(func: "Callable[P, AsyncServer]") -> "Callable[P, AsyncServer]":
    """Wrapper for asynchronous server."""

    @wraps(func)
    def patched_aio_server(  # type: ignore
        *args: "P.args",
        interceptors: "Optional[Sequence[grpc.ServerInterceptor]]" = None,
        **kwargs: "P.kwargs",
    ) -> "Server":
        server_interceptor = AsyncServerInterceptor()
        interceptors = [
            server_interceptor,
            *(interceptors or []),
        ]

        try:
            # We prefer interceptors as a list because of compatibility with
            # opentelemetry https://github.com/getsentry/sentry-python/issues/4389
            # However, prior to grpc 1.42.0, only tuples were accepted, so we
            # have no choice there.
            if GRPC_VERSION is not None and GRPC_VERSION < (1, 42, 0):
                interceptors = tuple(interceptors)
        except Exception:
            pass

        return func(*args, interceptors=interceptors, **kwargs)  # type: ignore

    return patched_aio_server  # type: ignore


class GRPCIntegration(Integration):
    identifier = "grpc"

    @staticmethod
    def setup_once() -> None:
        import grpc

        grpc.insecure_channel = _wrap_channel_sync(grpc.insecure_channel)
        grpc.secure_channel = _wrap_channel_sync(grpc.secure_channel)
        grpc.intercept_channel = _wrap_intercept_channel(grpc.intercept_channel)

        grpc.aio.insecure_channel = _wrap_channel_async(grpc.aio.insecure_channel)
        grpc.aio.secure_channel = _wrap_channel_async(grpc.aio.secure_channel)

        grpc.server = _wrap_sync_server(grpc.server)
        grpc.aio.server = _wrap_async_server(grpc.aio.server)
