from copy import copy
from collections import deque
from functools import wraps
from itertools import chain

from sentry_sdk.utils import logger, capture_internal_exceptions
from sentry_sdk._types import MYPY

if MYPY:
    from typing import Any
    from typing import Dict
    from typing import Optional
    from typing import Deque
    from typing import List
    from typing import Callable
    from typing import TypeVar

    from sentry_sdk._types import (
        Breadcrumb,
        Event,
        EventProcessor,
        ErrorProcessor,
        ExcInfo,
        Hint,
        Type,
    )

    from sentry_sdk.tracing import Span

    F = TypeVar("F", bound=Callable[..., Any])
    T = TypeVar("T")


global_event_processors = []  # type: List[EventProcessor]


def add_global_event_processor(processor):
    # type: (EventProcessor) -> None
    global_event_processors.append(processor)


def _attr_setter(fn):
    # type: (Any) -> Any
    return property(fset=fn, doc=fn.__doc__)


def _disable_capture(fn):
    # type: (F) -> F
    @wraps(fn)
    def wrapper(self, *args, **kwargs):
        # type: (Any, *Dict[str, Any], **Any) -> Any
        if not self._should_capture:
            return
        try:
            self._should_capture = False
            return fn(self, *args, **kwargs)
        finally:
            self._should_capture = True

    return wrapper  # type: ignore


class Scope(object):
    """The scope holds extra information that should be sent with all
    events that belong to it.
    """

    # NOTE: Even though it should not happen, the scope needs to not crash when
    # accessed by multiple threads. It's fine if it's full of races, but those
    # races should never make the user application crash.
    #
    # The same needs to hold for any accesses of the scope the SDK makes.

    __slots__ = (
        "_level",
        "_name",
        "_fingerprint",
        "_transaction",
        "_user",
        "_tags",
        "_contexts",
        "_extras",
        "_breadcrumbs",
        "_event_processors",
        "_error_processors",
        "_should_capture",
        "_span",
    )

    def __init__(self):
        # type: () -> None
        self._event_processors = []  # type: List[EventProcessor]
        self._error_processors = []  # type: List[ErrorProcessor]

        self._name = None  # type: Optional[str]
        self.clear()

    def clear(self):
        # type: () -> None
        """Clears the entire scope."""
        self._level = None  # type: Optional[str]
        self._fingerprint = None  # type: Optional[List[str]]
        self._transaction = None  # type: Optional[str]
        self._user = None  # type: Optional[Dict[str, Any]]

        self._tags = {}  # type: Dict[str, Any]
        self._contexts = {}  # type: Dict[str, Dict[str, Any]]
        self._extras = {}  # type: Dict[str, Any]

        self.clear_breadcrumbs()
        self._should_capture = True

        self._span = None  # type: Optional[Span]

    @_attr_setter
    def level(self, value):
        # type: (Optional[str]) -> None
        """When set this overrides the level. Deprecated in favor of set_level."""
        self._level = value

    def set_level(self, value):
        # type: (Optional[str]) -> None
        """Sets the level for the scope."""
        self._level = value

    @_attr_setter
    def fingerprint(self, value):
        # type: (Optional[List[str]]) -> None
        """When set this overrides the default fingerprint."""
        self._fingerprint = value

    @_attr_setter
    def transaction(self, value):
        # type: (Optional[str]) -> None
        """When set this forces a specific transaction name to be set."""
        self._transaction = value
        span = self._span
        if span:
            span.transaction = value

    @_attr_setter
    def user(self, value):
        # type: (Dict[str, Any]) -> None
        """When set a specific user is bound to the scope. Deprecated in favor of set_user."""
        self._user = value

    def set_user(self, value):
        # type: (Dict[str, Any]) -> None
        """Sets a user for the scope."""
        self._user = value

    @property
    def span(self):
        # type: () -> Optional[Span]
        """Get/set current tracing span."""
        return self._span

    @span.setter
    def span(self, span):
        # type: (Optional[Span]) -> None
        self._span = span
        if span is not None:
            span_transaction = span.transaction
            if span_transaction:
                self._transaction = span_transaction

    def set_tag(
        self,
        key,  # type: str
        value,  # type: Any
    ):
        # type: (...) -> None
        """Sets a tag for a key to a specific value."""
        self._tags[key] = value

    def remove_tag(
        self, key  # type: str
    ):
        # type: (...) -> None
        """Removes a specific tag."""
        self._tags.pop(key, None)

    def set_context(
        self,
        key,  # type: str
        value,  # type: Any
    ):
        # type: (...) -> None
        """Binds a context at a certain key to a specific value."""
        self._contexts[key] = value

    def remove_context(
        self, key  # type: str
    ):
        # type: (...) -> None
        """Removes a context."""
        self._contexts.pop(key, None)

    def set_extra(
        self,
        key,  # type: str
        value,  # type: Any
    ):
        # type: (...) -> None
        """Sets an extra key to a specific value."""
        self._extras[key] = value

    def remove_extra(
        self, key  # type: str
    ):
        # type: (...) -> None
        """Removes a specific extra key."""
        self._extras.pop(key, None)

    def clear_breadcrumbs(self):
        # type: () -> None
        """Clears breadcrumb buffer."""
        self._breadcrumbs = deque()  # type: Deque[Breadcrumb]

    def add_event_processor(
        self, func  # type: EventProcessor
    ):
        # type: (...) -> None
        """Register a scope local event processor on the scope.

        :param func: This function behaves like `before_send.`
        """
        if len(self._event_processors) > 20:
            logger.warning(
                "Too many event processors on scope! Clearing list to free up some memory: %r",
                self._event_processors,
            )
            del self._event_processors[:]

        self._event_processors.append(func)

    def add_error_processor(
        self,
        func,  # type: ErrorProcessor
        cls=None,  # type: Optional[Type[BaseException]]
    ):
        # type: (...) -> None
        """Register a scope local error processor on the scope.

        :param func: A callback that works similar to an event processor but is invoked with the original exception info triple as second argument.

        :param cls: Optionally, only process exceptions of this type.
        """
        if cls is not None:
            cls_ = cls  # For mypy.
            real_func = func

            def func(event, exc_info):
                # type: (Event, ExcInfo) -> Optional[Event]
                try:
                    is_inst = isinstance(exc_info[1], cls_)
                except Exception:
                    is_inst = False
                if is_inst:
                    return real_func(event, exc_info)
                return event

        self._error_processors.append(func)

    @_disable_capture
    def apply_to_event(
        self,
        event,  # type: Event
        hint,  # type: Hint
    ):
        # type: (...) -> Optional[Event]
        """Applies the information contained on the scope to the given event."""

        def _drop(event, cause, ty):
            # type: (Dict[str, Any], Any, str) -> Optional[Any]
            logger.info("%s (%s) dropped event (%s)", ty, cause, event)
            return None

        if self._level is not None:
            event["level"] = self._level

        if event.get("type") != "transaction":
            event.setdefault("breadcrumbs", []).extend(self._breadcrumbs)

        if event.get("user") is None and self._user is not None:
            event["user"] = self._user

        if event.get("transaction") is None and self._transaction is not None:
            event["transaction"] = self._transaction

        if event.get("fingerprint") is None and self._fingerprint is not None:
            event["fingerprint"] = self._fingerprint

        if self._extras:
            event.setdefault("extra", {}).update(self._extras)

        if self._tags:
            event.setdefault("tags", {}).update(self._tags)

        if self._contexts:
            event.setdefault("contexts", {}).update(self._contexts)

        if self._span is not None:
            contexts = event.setdefault("contexts", {})
            if not contexts.get("trace"):
                contexts["trace"] = self._span.get_trace_context()

        exc_info = hint.get("exc_info")
        if exc_info is not None:
            for error_processor in self._error_processors:
                new_event = error_processor(event, exc_info)
                if new_event is None:
                    return _drop(event, error_processor, "error processor")
                event = new_event

        for event_processor in chain(global_event_processors, self._event_processors):
            new_event = event
            with capture_internal_exceptions():
                new_event = event_processor(event, hint)
            if new_event is None:
                return _drop(event, event_processor, "event processor")
            event = new_event

        return event

    def __copy__(self):
        # type: () -> Scope
        rv = object.__new__(self.__class__)  # type: Scope

        rv._level = self._level
        rv._name = self._name
        rv._fingerprint = self._fingerprint
        rv._transaction = self._transaction
        rv._user = self._user

        rv._tags = dict(self._tags)
        rv._contexts = dict(self._contexts)
        rv._extras = dict(self._extras)

        rv._breadcrumbs = copy(self._breadcrumbs)
        rv._event_processors = list(self._event_processors)
        rv._error_processors = list(self._error_processors)

        rv._should_capture = self._should_capture
        rv._span = self._span

        return rv

    def __repr__(self):
        # type: () -> str
        return "<%s id=%s name=%s>" % (
            self.__class__.__name__,
            hex(id(self)),
            self._name,
        )
