"""
Guards the OpenTelemetry Flask instrumentation contract Dify relies on.

Flask can run teardown handlers more than once for a request. Instrumentation
versions before 0.63b0 left the span activation and context token in
``request.environ`` after the first teardown, so the second one detached an
already-used token and the OTel API logged "Failed to detach context" for every
affected request.
"""

import logging
from collections.abc import Iterator

import flask
import pytest
from opentelemetry.instrumentation.flask import FlaskInstrumentor


@pytest.fixture
def instrumented_app() -> Iterator[flask.Flask]:
    app = flask.Flask(__name__)

    @app.route("/ping")
    def ping() -> str:
        return "pong"

    instrumentor = FlaskInstrumentor()
    instrumentor.instrument_app(app)
    yield app
    instrumentor.uninstrument_app(app)


@pytest.mark.usefixtures("tracer_provider_with_memory_exporter")
def test_duplicate_teardown_does_not_log_detach_failure(
    instrumented_app: flask.Flask, caplog: pytest.LogCaptureFixture
) -> None:
    handlers = instrumented_app.teardown_request_funcs[None]
    # instrument_app registers its teardown handler last.
    index = len(handlers) - 1
    instrumentation_teardown = handlers[index]
    calls = 0

    def teardown_twice(exc: BaseException | None) -> None:
        nonlocal calls
        calls += 1
        instrumentation_teardown(exc)
        instrumentation_teardown(exc)

    handlers[index] = teardown_twice
    try:
        with caplog.at_level(logging.ERROR, logger="opentelemetry.context"):
            assert instrumented_app.test_client().get("/ping").status_code == 200
    finally:
        handlers[index] = instrumentation_teardown

    assert calls == 1, "the instrumentation teardown never ran, so nothing was exercised"
    assert "Failed to detach context" not in caplog.text