"""Filtro local_dt: il backend parla UTC, la presentazione e' in Europe/Rome (#42)."""
from datetime import datetime, timezone

import pytest


@pytest.fixture
def local_dt(flask_app):
    return flask_app.jinja_env.filters["local_dt"]


def test_summer_time(local_dt):
    assert local_dt("2026-10-06T08:00:00+00:00") == "06/10/2026 10:00"


def test_winter_time(local_dt):
    assert local_dt("2026-01-15T08:00:00+00:00") == "15/01/2026 09:00"


def test_naive_is_utc(local_dt):
    assert local_dt("2026-10-06T08:00:00") == "06/10/2026 10:00"


def test_datetime_object_and_format(local_dt):
    dt = datetime(2026, 10, 6, 8, 0, tzinfo=timezone.utc)
    assert local_dt(dt, "%H:%M") == "10:00"


@pytest.mark.parametrize("empty", [None, ""])
def test_empty(local_dt, empty):
    assert local_dt(empty) == "-"