"""Cache-key golden rules: keyed by pixel hash + size + version, so identity
changes invalidate and EXIF-only changes reuse."""

from photo_pipeline.models import Asset
from photo_pipeline.services.thumbnails import THUMB_VERSION, ThumbnailService


def _asset(pixel=None, sha="deadbeef"):
    return Asset(
        id="a1",
        original_path="a.jpg",
        current_path="a.jpg",
        current_sha256=sha,
        pixel_sha256=pixel,
        hash_version=1,
    )


def test_key_is_pixel_size_and_version():
    key = ThumbnailService._cache_key(_asset(pixel="PIX"), 512)
    assert key == f"PIX-512-v{THUMB_VERSION}"


def test_different_size_changes_key():
    asset = _asset(pixel="PIX")
    assert ThumbnailService._cache_key(asset, 256) != ThumbnailService._cache_key(asset, 512)


def test_different_pixels_change_key():
    assert ThumbnailService._cache_key(_asset(pixel="P1"), 512) != ThumbnailService._cache_key(
        _asset(pixel="P2"), 512
    )


def test_undecodable_asset_keys_by_source_bytes():
    key = ThumbnailService._cache_key(_asset(pixel=None, sha="abc123"), 256)
    assert key == f"src:abc123-256-v{THUMB_VERSION}"