import sys
from copy import deepcopy
from functools import wraps
from typing import TYPE_CHECKING

import sentry_sdk
from sentry_sdk.consts import SPANDATA
from sentry_sdk.integrations import DidNotEnable
from sentry_sdk.scope import should_send_default_pii
from sentry_sdk.traces import StreamedSpan, get_current_span
from sentry_sdk.tracing import SOURCE_FOR_STYLE, TransactionSource
from sentry_sdk.tracing_utils import has_span_streaming_enabled
from sentry_sdk.utils import transaction_from_function

if TYPE_CHECKING:
    from typing import Any, Awaitable, Callable, Dict

    from sentry_sdk._types import Event

try:
    from sentry_sdk.integrations.starlette import (
        StarletteIntegration,
        StarletteRequestExtractor,
        _get_cached_request_body_attribute,
    )
except DidNotEnable:
    raise DidNotEnable("Starlette is not installed")

try:
    import fastapi  # type: ignore
except ImportError:
    raise DidNotEnable("FastAPI is not installed")


_DEFAULT_TRANSACTION_NAME = "generic FastAPI request"


# Vendored: https://github.com/Kludex/starlette/blob/0a29b5ccdcbd1285c75c4fdb5d62ae1d244a21b0/starlette/_utils.py#L11-L17
if sys.version_info >= (3, 13):  # pragma: no cover
    from inspect import iscoroutinefunction
else:
    from asyncio import iscoroutinefunction


class FastApiIntegration(StarletteIntegration):
    identifier = "fastapi"

    @staticmethod
    def setup_once() -> None:
        patch_get_request_handler()


def _set_transaction_name_and_source(
    scope: "sentry_sdk.Scope", transaction_style: str, request: "Any"
) -> None:
    name = ""

    if transaction_style == "endpoint":
        endpoint = request.scope.get("endpoint")
        if endpoint:
            name = transaction_from_function(endpoint) or ""

    elif transaction_style == "url":
        route = request.scope.get("route")

        if route:
            # FastAPI >= 0.137 stores the prefix-resolved path on an
            # effective_route_context in scope["fastapi"], while
            # scope["route"].path holds the unprefixed original.
            # Prefer the effective context path when available.
            effective_route_context = request.scope.get("fastapi", {}).get(
                "effective_route_context"
            )
            context_path = getattr(effective_route_context, "path", None)

            if context_path:
                name = context_path
            else:
                path = getattr(route, "path", None)
                if path is not None:
                    name = path

    if not name:
        name = _DEFAULT_TRANSACTION_NAME
        source = TransactionSource.ROUTE
    else:
        source = SOURCE_FOR_STYLE[transaction_style]

    scope.set_transaction_name(name, source=source)


async def _wrap_async_handler(
    handler: "Callable[..., Awaitable[Any]]", *args: "Any", **kwargs: "Any"
) -> "Any":
    """
    Wraps an asynchronous handler function to attach request info to errors and the server segment span.
    The request body cached on the Starlette Request object is attached to streamed spans, but consuming the request body in the event
    processor can still cause application hangs.
    """
    client = sentry_sdk.get_client()
    integration = client.get_integration(FastApiIntegration)
    if integration is None:
        return await handler(*args, **kwargs)

    request = args[0]

    _set_transaction_name_and_source(
        sentry_sdk.get_current_scope(), integration.transaction_style, request
    )
    sentry_scope = sentry_sdk.get_isolation_scope()
    extractor = StarletteRequestExtractor(request)
    info = await extractor.extract_request_info()

    def _make_request_event_processor(
        req: "Any", integration: "Any"
    ) -> "Callable[[Event, Dict[str, Any]], Event]":
        def event_processor(event: "Event", hint: "Dict[str, Any]") -> "Event":
            # Extract information from request
            request_info = event.get("request", {})
            if info:
                if "cookies" in info and should_send_default_pii():
                    request_info["cookies"] = info["cookies"]
                if "data" in info:
                    request_info["data"] = info["data"]
            event["request"] = deepcopy(request_info)

            return event

        return event_processor

    sentry_scope._name = FastApiIntegration.identifier
    sentry_scope.add_event_processor(
        _make_request_event_processor(request, integration)
    )

    try:
        return await handler(*args, **kwargs)
    finally:
        current_span = get_current_span()

        if type(current_span) is StreamedSpan:
            request_body = _get_cached_request_body_attribute(
                client=client, request=request
            )
            if request_body:
                current_span._segment.set_attribute(
                    SPANDATA.HTTP_REQUEST_BODY_DATA,
                    request_body,
                )


def patch_get_request_handler() -> None:
    old_get_request_handler = fastapi.routing.get_request_handler

    def _sentry_get_request_handler(*args: "Any", **kwargs: "Any") -> "Any":
        dependant = kwargs.get("dependant")
        if (
            dependant
            and dependant.call is not None
            and not iscoroutinefunction(dependant.call)
            # FastAPI >= 0.137 calls get_request_handler() on every request
            # (router-tree traversal) rather than once at registration. Guard
            # against accumulating _sentry_call wrappers on the shared
            # dependant object, which would cause a RecursionError after ~987
            # requests as the call chain grows past Python's recursion limit.
            and not getattr(dependant.call, "_sentry_is_patched", False)
        ):
            old_call = dependant.call

            @wraps(old_call)
            def _sentry_call(*args: "Any", **kwargs: "Any") -> "Any":
                current_scope = sentry_sdk.get_current_scope()

                client = sentry_sdk.get_client()
                if has_span_streaming_enabled(client.options):
                    current_span = current_scope.streamed_span

                    if type(current_span) is StreamedSpan:
                        segment = current_span._segment
                        segment._update_active_thread()

                elif current_scope.transaction is not None:
                    current_scope.transaction.update_active_thread()

                sentry_scope = sentry_sdk.get_isolation_scope()
                if sentry_scope.profile is not None:
                    sentry_scope.profile.update_active_thread_id()

                return old_call(*args, **kwargs)

            _sentry_call._sentry_is_patched = True  # type: ignore[attr-defined]
            dependant.call = _sentry_call

        old_app = old_get_request_handler(*args, **kwargs)

        async def _sentry_app(*args: "Any", **kwargs: "Any") -> "Any":
            return await _wrap_async_handler(old_app, *args, **kwargs)

        return _sentry_app

    fastapi.routing.get_request_handler = _sentry_get_request_handler
