import io

from PIL import Image

from app import imaging


def _jpeg_with_exif(tags: dict) -> bytes:
    image = Image.new("RGB", (64, 40), "white")
    exif = Image.Exif()
    for tag, value in tags.items():
        exif[tag] = value
    buffer = io.BytesIO()
    image.save(buffer, format="JPEG", exif=exif.tobytes())
    return buffer.getvalue()


def test_aufnahmezeit_wird_gelesen():
    raw = _jpeg_with_exif({0x9003: "2026:09:01 14:23:05"})

    meta = imaging.read_metadata(raw)

    assert meta["captured_at"].startswith("2026-09-01T14:23:05")


def test_gps_wird_in_dezimalgrad_umgerechnet():
    raw = _jpeg_with_exif(
        {0x8825: {1: "N", 2: (52.0, 19.0, 18.0), 3: "E", 4: (9.0, 48.0, 28.0)}}
    )

    meta = imaging.read_metadata(raw)

    assert meta["lat"] == 52.321667
    assert meta["lon"] == 9.807778


def test_suedliche_und_westliche_koordinaten_werden_negativ():
    raw = _jpeg_with_exif(
        {0x8825: {1: "S", 2: (33.0, 55.0, 0.0), 3: "W", 4: (18.0, 25.0, 0.0)}}
    )

    meta = imaging.read_metadata(raw)

    assert meta["lat"] < 0
    assert meta["lon"] < 0


def test_foto_ohne_exif_liefert_leere_metadaten():
    buffer = io.BytesIO()
    Image.new("RGB", (32, 32), "white").save(buffer, format="JPEG")

    meta = imaging.read_metadata(buffer.getvalue())

    assert meta == {"captured_at": None, "lat": None, "lon": None}


def test_kaputte_datei_wirft_nicht():
    assert imaging.read_metadata(b"kein bild") == {
        "captured_at": None,
        "lat": None,
        "lon": None,
    }


def test_dekodieren_liefert_bgr_array():
    buffer = io.BytesIO()
    Image.new("RGB", (20, 10), (255, 0, 0)).save(buffer, format="PNG")

    array = imaging.decode(buffer.getvalue())

    assert array.shape == (10, 20, 3)
    assert tuple(array[0, 0]) == (0, 0, 255)  # Rot liegt in BGR hinten