import pytest
import gc
import uuid
import os

import sentry_sdk
from sentry_sdk import Hub, start_span, start_transaction
from sentry_sdk.tracing import Span, Transaction
from sentry_sdk.tracing_utils import has_tracestate_enabled

try:
    from unittest import mock  # python 3.3 and above
except ImportError:
    import mock  # python < 3.3


def test_span_trimming(sentry_init, capture_events):
    sentry_init(traces_sample_rate=1.0, _experiments={"max_spans": 3})
    events = capture_events()

    with start_transaction(name="hi"):
        for i in range(10):
            with start_span(op="foo{}".format(i)):
                pass

    (event,) = events

    assert len(event["spans"]) == 3

    span1, span2, span3 = event["spans"]
    assert span1["op"] == "foo0"
    assert span2["op"] == "foo1"
    assert span3["op"] == "foo2"


def test_transaction_naming(sentry_init, capture_events):
    sentry_init(traces_sample_rate=1.0)
    events = capture_events()

    # only transactions have names - spans don't
    with pytest.raises(TypeError):
        start_span(name="foo")
    assert len(events) == 0

    # default name in event if no name is passed
    with start_transaction() as transaction:
        pass
    assert len(events) == 1
    assert events[0]["transaction"] == "<unlabeled transaction>"

    # the name can be set once the transaction's already started
    with start_transaction() as transaction:
        transaction.name = "name-known-after-transaction-started"
    assert len(events) == 2
    assert events[1]["transaction"] == "name-known-after-transaction-started"

    # passing in a name works, too
    with start_transaction(name="a"):
        pass
    assert len(events) == 3
    assert events[2]["transaction"] == "a"


def test_start_transaction(sentry_init):
    sentry_init(traces_sample_rate=1.0)

    # you can have it start a transaction for you
    result1 = start_transaction(
        name="/interactions/other-dogs/new-dog", op="greeting.sniff"
    )
    assert isinstance(result1, Transaction)
    assert result1.name == "/interactions/other-dogs/new-dog"
    assert result1.op == "greeting.sniff"

    # or you can pass it an already-created transaction
    preexisting_transaction = Transaction(
        name="/interactions/other-dogs/new-dog", op="greeting.sniff"
    )
    result2 = start_transaction(preexisting_transaction)
    assert result2 is preexisting_transaction


def test_finds_transaction_on_scope(sentry_init):
    sentry_init(traces_sample_rate=1.0)

    transaction = start_transaction(name="dogpark")

    scope = Hub.current.scope

    # See note in Scope class re: getters and setters of the `transaction`
    # property. For the moment, assigning to scope.transaction merely sets the
    # transaction name, rather than putting the transaction on the scope, so we
    # have to assign to _span directly.
    scope._span = transaction

    # Reading scope.property, however, does what you'd expect, and returns the
    # transaction on the scope.
    assert scope.transaction is not None
    assert isinstance(scope.transaction, Transaction)
    assert scope.transaction.name == "dogpark"

    # If the transaction is also set as the span on the scope, it can be found
    # by accessing _span, too.
    assert scope._span is not None
    assert isinstance(scope._span, Transaction)
    assert scope._span.name == "dogpark"


def test_finds_transaction_when_descendent_span_is_on_scope(
    sentry_init,
):
    sentry_init(traces_sample_rate=1.0)

    transaction = start_transaction(name="dogpark")
    child_span = transaction.start_child(op="sniffing")

    scope = Hub.current.scope
    scope._span = child_span

    # this is the same whether it's the transaction itself or one of its
    # decedents directly attached to the scope
    assert scope.transaction is not None
    assert isinstance(scope.transaction, Transaction)
    assert scope.transaction.name == "dogpark"

    # here we see that it is in fact the span on the scope, rather than the
    # transaction itself
    assert scope._span is not None
    assert isinstance(scope._span, Span)
    assert scope._span.op == "sniffing"


def test_finds_orphan_span_on_scope(sentry_init):
    # this is deprecated behavior which may be removed at some point (along with
    # the start_span function)
    sentry_init(traces_sample_rate=1.0)

    span = start_span(op="sniffing")

    scope = Hub.current.scope
    scope._span = span

    assert scope._span is not None
    assert isinstance(scope._span, Span)
    assert scope._span.op == "sniffing"


def test_finds_non_orphan_span_on_scope(sentry_init):
    sentry_init(traces_sample_rate=1.0)

    transaction = start_transaction(name="dogpark")
    child_span = transaction.start_child(op="sniffing")

    scope = Hub.current.scope
    scope._span = child_span

    assert scope._span is not None
    assert isinstance(scope._span, Span)
    assert scope._span.op == "sniffing"


def test_circular_references(monkeypatch, sentry_init, request):
    # TODO: We discovered while writing this test about transaction/span
    # reference cycles that there's actually also a circular reference in
    # `serializer.py`, between the functions `_serialize_node` and
    # `_serialize_node_impl`, both of which are defined inside of the main
    # `serialize` function, and each of which calls the other one. For now, in
    # order to avoid having those ref cycles give us a false positive here, we
    # can mock out `serialize`. In the long run, though, we should probably fix
    # that. (Whenever we do work on fixing it, it may be useful to add
    #
    #     gc.set_debug(gc.DEBUG_LEAK)
    #     request.addfinalizer(lambda: gc.set_debug(~gc.DEBUG_LEAK))
    #
    # immediately after the initial collection below, so we can see what new
    # objects the garbage collecter has to clean up once `transaction.finish` is
    # called and the serializer runs.)
    monkeypatch.setattr(
        sentry_sdk.client,
        "serialize",
        mock.Mock(
            return_value=None,
        ),
    )

    # In certain versions of python, in some environments (specifically, python
    # 3.4 when run in GH Actions), we run into a `ctypes` bug which creates
    # circular references when `uuid4()` is called, as happens when we're
    # generating event ids. Mocking it with an implementation which doesn't use
    # the `ctypes` function lets us avoid having false positives when garbage
    # collecting. See https://bugs.python.org/issue20519.
    monkeypatch.setattr(
        uuid,
        "uuid4",
        mock.Mock(
            return_value=uuid.UUID(bytes=os.urandom(16)),
        ),
    )

    gc.disable()
    request.addfinalizer(gc.enable)

    sentry_init(traces_sample_rate=1.0)

    # Make sure that we're starting with a clean slate before we start creating
    # transaction/span reference cycles
    gc.collect()

    dogpark_transaction = start_transaction(name="dogpark")
    sniffing_span = dogpark_transaction.start_child(op="sniffing")
    wagging_span = dogpark_transaction.start_child(op="wagging")

    # At some point, you have to stop sniffing - there are balls to chase! - so finish
    # this span while the dogpark transaction is still open
    sniffing_span.finish()

    # The wagging, however, continues long past the dogpark, so that span will
    # NOT finish before the transaction ends. (Doing it in this order proves
    # that both finished and unfinished spans get their cycles broken.)
    dogpark_transaction.finish()

    # Eventually you gotta sleep...
    wagging_span.finish()

    # assuming there are no cycles by this point, these should all be able to go
    # out of scope and get their memory deallocated without the garbage
    # collector having anything to do
    del sniffing_span
    del wagging_span
    del dogpark_transaction

    assert gc.collect() == 0


# TODO (kmclb) remove this test once tracestate is a real feature
@pytest.mark.parametrize("tracestate_enabled", [True, False, None])
def test_has_tracestate_enabled(sentry_init, tracestate_enabled):
    experiments = (
        {"propagate_tracestate": tracestate_enabled}
        if tracestate_enabled is not None
        else {}
    )
    sentry_init(_experiments=experiments)

    if tracestate_enabled is True:
        assert has_tracestate_enabled() is True
    else:
        assert has_tracestate_enabled() is False