from __future__ import annotations

import struct
from io import BytesIO
from pathlib import Path

import pytest

from PIL import Image
from PIL.VtfImagePlugin import (
    VTFException,
    VtfImageFile,
    VtfPF,
    _closest_power,
    _get_mipmap_count,
    _get_texture_size,
)

from .helper import assert_image_equal, assert_image_similar


@pytest.mark.parametrize(
    "size, expected_size",
    [
        (8, 8),
        (7, 8),
        (9, 8),
        (192, 256),
        (1, 1),
        (2000, 2048),
    ],
)
def test_closest_power(size: int, expected_size: int) -> None:
    assert _closest_power(size) == expected_size


@pytest.mark.parametrize(
    "size, expected_count",
    [
        ((1, 1), 1),
        ((2, 2), 2),
        ((4, 4), 3),
        ((8, 8), 4),
        ((128, 128), 8),
        ((256, 256), 9),
        ((512, 512), 10),
        ((1024, 1024), 11),
        ((1024, 1), 11),
    ],
)
def test_get_mipmap_count(size: tuple[int, int], expected_count: int) -> None:
    assert _get_mipmap_count(size) == expected_count


@pytest.mark.parametrize(
    "pixel_format, size, expected_size",
    [
        (VtfPF.DXT1, (16, 16), (16 * 16) // 2),
        (VtfPF.DXT1_ONEBITALPHA, (16, 16), (16 * 16) // 2),
        (VtfPF.DXT3, (16, 16), 16 * 16),
        (VtfPF.DXT5, (16, 16), 16 * 16),
        (VtfPF.BGR888, (16, 16), 16 * 16 * 3),
        (VtfPF.RGB888, (16, 16), 16 * 16 * 3),
        (VtfPF.RGBA8888, (16, 16), 16 * 16 * 4),
        (VtfPF.UV88, (16, 16), 16 * 16 * 2),
        (VtfPF.A8, (16, 16), 16 * 16),
        (VtfPF.I8, (16, 16), 16 * 16),
        (VtfPF.IA88, (16, 16), 16 * 16 * 2),
    ],
)
def test_get_texture_size(
    pixel_format: VtfPF, size: tuple[int, int], expected_size: int
) -> None:
    assert _get_texture_size(pixel_format, size) == expected_size


@pytest.mark.parametrize(
    "etalon_path, file_path, expected_mode, epsilon",
    [
        ("Tests/images/vtf_i8.png", "Tests/images/vtf_i8.vtf", "L", 0),
        ("Tests/images/vtf_a8.png", "Tests/images/vtf_a8.vtf", "RGBA", 0),
        ("Tests/images/vtf_ia88.png", "Tests/images/vtf_ia88.vtf", "LA", 0),
        ("Tests/images/vtf_uv88.png", "Tests/images/vtf_uv88.vtf", "RGB", 0),
        ("Tests/images/vtf_rgb888.png", "Tests/images/vtf_rgb888.vtf", "RGB", 0),
        ("Tests/images/vtf_bgr888.png", "Tests/images/vtf_bgr888.vtf", "RGB", 0),
        ("Tests/images/vtf_dxt1.png", "Tests/images/vtf_dxt1.vtf", "RGBA", 3),
        ("Tests/images/vtf_dxt1A.png", "Tests/images/vtf_dxt1A.vtf", "RGBA", 8),
        ("Tests/images/vtf_rgba8888.png", "Tests/images/vtf_rgba8888.vtf", "RGBA", 0),
    ],
)
def test_vtf_read(
    etalon_path: str, file_path: str, expected_mode: str, epsilon: int
) -> None:
    with Image.open(file_path) as f:
        assert f.mode == expected_mode
        with Image.open(etalon_path) as e:
            converted_e = e.convert(expected_mode)
        if epsilon:
            assert_image_similar(converted_e, f, epsilon)
        else:
            assert_image_equal(converted_e, f)


def test_invalid_file() -> None:
    invalid_file = "Tests/images/flower.jpg"

    with pytest.raises(SyntaxError, match="not a VTF file"):
        VtfImageFile(invalid_file)


def test_vtf_read_unsupported_version() -> None:
    b = BytesIO(b"VTF\x00" + struct.pack("<2I", 7, 5))
    with pytest.raises(VTFException, match=r"Unsupported VTF version: \(7, 5\)"):
        with Image.open(b):
            pass


def test_vtf_read_unsupported_pixel_format() -> None:
    b = BytesIO(b"VTF\x00" + struct.pack("<2I40xI7x", 7, 2, 1))
    with pytest.raises(VTFException, match="Unsupported VTF pixel format: 1"):
        with Image.open(b):
            pass


@pytest.mark.parametrize(
    "pixel_format, file_path, expected_mode, epsilon",
    [
        (VtfPF.I8, "Tests/images/vtf_i8.png", "L", 0),
        (VtfPF.A8, "Tests/images/vtf_a8.png", "RGBA", 0),
        (VtfPF.IA88, "Tests/images/vtf_ia88.png", "LA", 0),
        (VtfPF.UV88, "Tests/images/vtf_uv88.png", "RGB", 0),
        (VtfPF.RGB888, "Tests/images/vtf_rgb888.png", "RGB", 0),
        (VtfPF.BGR888, "Tests/images/vtf_bgr888.png", "RGB", 0),
        (VtfPF.DXT1, "Tests/images/vtf_dxt1.png", "RGBA", 3),
        (VtfPF.RGBA8888, "Tests/images/vtf_rgba8888.png", "RGBA", 0),
    ],
)
@pytest.mark.parametrize("version", ((7, 1), (7, 2), (7, 3)))
def test_vtf_save(
    pixel_format: VtfPF,
    file_path: str,
    expected_mode: str,
    epsilon: int,
    version: tuple[int, int],
    tmp_path: Path,
) -> None:
    im: Image.Image
    with Image.open(file_path) as im:
        out = tmp_path / "tmp.vtf"
        im.save(out, pixel_format=pixel_format, version=version)
        if pixel_format == VtfPF.DXT1:
            im = im.convert("RGBA")
        with Image.open(out) as expected:
            assert expected.mode == expected_mode
            if epsilon:
                assert_image_similar(im, expected, epsilon)
            else:
                assert_image_equal(im, expected)


def test_vtf_save_unsupported_mode(tmp_path: Path) -> None:
    out = tmp_path / "temp.vtf"
    im = Image.new("HSV", (1, 1))
    with pytest.raises(OSError, match="cannot write mode HSV as VTF"):
        im.save(out)


def test_vtf_save_unsupported_version(tmp_path: Path) -> None:
    out = tmp_path / "temp.vtf"
    im = Image.new("L", (1, 1))
    with pytest.raises(VTFException, match=r"Unsupported VTF version: \(7, 5\)"):
        im.save(out, version=(7, 5))