"""Tests für Cover-Funktionen."""

from pathlib import Path

from PIL import Image

from musiksammlung.cover import copy_covers, find_cover, prepare_cover


def _make_image(path: Path, size: tuple[int, int] = (100, 100), mode: str = "RGB") -> Path:
    img = Image.new(mode, size, color=(200, 100, 50))
    fmt = "PNG" if path.suffix.lower() == ".png" else "JPEG"
    if mode == "RGBA" and fmt == "JPEG":
        img = img.convert("RGB")
    img.save(str(path), fmt)
    return path


class TestFindCover:
    """Tests für find_cover."""

    def test_finds_frontcover_jpg(self, tmp_path: Path) -> None:
        (tmp_path / "frontcover.jpg").touch()
        assert find_cover(tmp_path, "front") == tmp_path / "frontcover.jpg"

    def test_finds_frontcover_png(self, tmp_path: Path) -> None:
        (tmp_path / "frontcover.png").touch()
        assert find_cover(tmp_path, "front") == tmp_path / "frontcover.png"

    def test_jpg_preferred_over_png(self, tmp_path: Path) -> None:
        (tmp_path / "frontcover.jpg").touch()
        (tmp_path / "frontcover.png").touch()
        # .jpg wird zuerst geprüft
        assert find_cover(tmp_path, "front") == tmp_path / "frontcover.jpg"

    def test_finds_backcover(self, tmp_path: Path) -> None:
        (tmp_path / "backcover.jpg").touch()
        assert find_cover(tmp_path, "back") == tmp_path / "backcover.jpg"

    def test_returns_none_if_missing(self, tmp_path: Path) -> None:
        assert find_cover(tmp_path, "front") is None
        assert find_cover(tmp_path, "back") is None

    def test_follows_symlink(self, tmp_path: Path) -> None:
        real = tmp_path / "original.jpg"
        real.touch()
        link = tmp_path / "frontcover.jpg"
        link.symlink_to(real)
        assert find_cover(tmp_path, "front") == link

    def test_ignores_wrong_names(self, tmp_path: Path) -> None:
        (tmp_path / "cover.jpg").touch()
        (tmp_path / "back.jpg").touch()
        assert find_cover(tmp_path, "front") is None


class TestPrepareCover:
    def test_creates_jpeg_output(self, tmp_path: Path) -> None:
        src = _make_image(tmp_path / "src.jpg")
        dst = tmp_path / "out.jpg"
        prepare_cover(src, dst)
        assert dst.exists()
        assert Image.open(dst).format == "JPEG"

    def test_scales_down_large_image(self, tmp_path: Path) -> None:
        src = _make_image(tmp_path / "src.jpg", size=(2000, 2000))
        dst = tmp_path / "out.jpg"
        prepare_cover(src, dst, max_size=1200)
        assert max(Image.open(dst).size) <= 1200

    def test_does_not_upscale_small_image(self, tmp_path: Path) -> None:
        src = _make_image(tmp_path / "src.jpg", size=(300, 300))
        dst = tmp_path / "out.jpg"
        prepare_cover(src, dst, max_size=1200)
        assert max(Image.open(dst).size) <= 300

    def test_converts_rgba_to_rgb(self, tmp_path: Path) -> None:
        src = tmp_path / "src.png"
        Image.new("RGBA", (100, 100), (255, 0, 0, 128)).save(str(src), "PNG")
        dst = tmp_path / "out.jpg"
        prepare_cover(src, dst)
        assert Image.open(dst).mode == "RGB"

    def test_creates_parent_directory(self, tmp_path: Path) -> None:
        src = _make_image(tmp_path / "src.jpg")
        dst = tmp_path / "subdir" / "nested" / "out.jpg"
        prepare_cover(src, dst)
        assert dst.exists()


class TestCopyCovers:
    def test_copies_front_cover(self, tmp_path: Path) -> None:
        src = _make_image(tmp_path / "src.jpg")
        copy_covers(src, None, tmp_path)
        assert (tmp_path / "frontcover.jpg").exists()

    def test_copies_back_cover(self, tmp_path: Path) -> None:
        src = _make_image(tmp_path / "src.jpg")
        copy_covers(None, src, tmp_path)
        assert (tmp_path / "backcover.jpg").exists()

    def test_copies_both_covers(self, tmp_path: Path) -> None:
        front = _make_image(tmp_path / "front.jpg")
        back = _make_image(tmp_path / "back.jpg")
        copy_covers(front, back, tmp_path)
        assert (tmp_path / "frontcover.jpg").exists()
        assert (tmp_path / "backcover.jpg").exists()

    def test_skips_nonexistent_front(self, tmp_path: Path) -> None:
        copy_covers(tmp_path / "nope.jpg", None, tmp_path)
        assert not (tmp_path / "frontcover.jpg").exists()

    def test_skips_nonexistent_back(self, tmp_path: Path) -> None:
        copy_covers(None, tmp_path / "nope.jpg", tmp_path)
        assert not (tmp_path / "backcover.jpg").exists()

    def test_existing_frontcover_not_overwritten_when_no_source(self, tmp_path: Path) -> None:
        existing = _make_image(tmp_path / "frontcover.jpg")
        original_mtime = existing.stat().st_mtime
        copy_covers(None, None, tmp_path)
        assert (tmp_path / "frontcover.jpg").stat().st_mtime == original_mtime