"""iso(): the single date/datetime→JSON serializer the routes share (R6 S1a)."""

from datetime import date, datetime, timezone

from app.utils import iso, normalize_description


def test_none_maps_to_none():
    assert iso(None) is None


def test_plain_date_serializes_as_iso_date():
    # MediaAsset.upload_date is a `date`, not a datetime — the contract must accept it.
    assert iso(date(2026, 7, 26)) == "2026-07-26"


def test_aware_datetime_keeps_offset():
    dt = datetime(2026, 7, 26, 12, 30, 0, tzinfo=timezone.utc)
    assert iso(dt) == "2026-07-26T12:30:00+00:00"


def test_naive_datetime_serializes_without_offset():
    dt = datetime(2026, 7, 26, 12, 30, 0)
    assert iso(dt) == "2026-07-26T12:30:00"


def test_matches_datetime_isoformat_contract():
    # iso is exactly `dt.isoformat()` for a present value — guards the routes that used to
    # hand-roll `x.isoformat() if x else None`.
    dt = datetime(2020, 1, 2, 3, 4, 5, 678901, tzinfo=timezone.utc)
    assert iso(dt) == dt.isoformat()


def test_normalize_description_none_stays_none():
    assert normalize_description(None) is None


def test_normalize_description_drops_blank_lines():
    # A YouTube contact block padded with runs of blank lines — the waste we strip before storing.
    raw = "Contact us\n\n\nEmail: a@b.com\n \nInstagram: @x\n\n\n"
    assert normalize_description(raw) == "Contact us\nEmail: a@b.com\nInstagram: @x"


def test_normalize_description_right_strips_and_trims():
    assert normalize_description("  hi there  \n\n  bye  ") == "  hi there\n  bye"


def test_normalize_description_all_blank_collapses_to_empty():
    assert normalize_description("\n \n\t\n") == ""


def test_normalize_description_single_line_unchanged():
    assert normalize_description("just one line") == "just one line"


def test_normalize_description_folds_crlf_line_endings():
    # splitlines() folds CR/CRLF to \n — a documented, benign line-ending normalization.
    assert normalize_description("a\r\nb\r\n\r\nc") == "a\nb\nc"