import importlib.util
from datetime import date, datetime, timedelta, timezone
from pathlib import Path

import pytest


def _load_time_api_module():
    module_path = (
        Path(__file__).resolve().parents[2] / "app" / "services" / "time_api.py"
    )
    spec = importlib.util.spec_from_file_location("tests_time_api_under_test", module_path)
    module = importlib.util.module_from_spec(spec)
    assert spec and spec.loader
    spec.loader.exec_module(module)
    return module


def test_parse_utc_time_rejects_naive_datetimes():
    module = _load_time_api_module()

    with pytest.raises(ValueError, match="timezone information"):
        module.parse_utc_time("2025-01-01T08:00:00")


def test_parse_utc_time_normalizes_offset_datetime_to_utc():
    module = _load_time_api_module()
    result = module.parse_utc_time("2025-01-01T08:00:00+08:00")

    assert result == datetime(2025, 1, 1, 0, 0, tzinfo=timezone.utc)


def test_extract_date_keeps_original_offset_calendar_day():
    module = _load_time_api_module()
    result = module.extract_date("2025-01-01T00:30:00+08:00")

    assert result == date(2025, 1, 1)


def test_utc_now_returns_timezone_aware_utc_datetime():
    module = _load_time_api_module()
    result = module.utc_now()

    assert result.tzinfo == timezone.utc
    assert result.utcoffset() == timedelta(0)