"""Thumbnail backfill: _thumb_is_valid helper + backfill_thumbnails planner."""

import pytest

from backend.app.tasks.thumbnail import _thumb_is_valid

pytestmark = pytest.mark.integration


def test_thumb_is_valid_jpeg(tmp_path):
    p = tmp_path / "good.jpg"
    p.write_bytes(b"\xff\xd8\xff\xe0" + b"\x00" * 100)
    assert _thumb_is_valid(p) is True


def test_thumb_is_valid_png(tmp_path):
    p = tmp_path / "good.png"
    p.write_bytes(b"\x89PNG\r\n\x1a\n" + b"\x00" * 100)
    assert _thumb_is_valid(p) is True


def test_thumb_is_valid_too_short(tmp_path):
    p = tmp_path / "tiny"
    p.write_bytes(b"\xff\xd8")
    assert _thumb_is_valid(p) is False


def test_thumb_is_valid_wrong_magic(tmp_path):
    p = tmp_path / "garbage"
    p.write_bytes(b"\x00" * 12)
    assert _thumb_is_valid(p) is False


def test_thumb_is_valid_missing_file(tmp_path):
    assert _thumb_is_valid(tmp_path / "nope") is False