from __future__ import annotations

import sys
from io import BytesIO
from pathlib import Path

import pytest

from PIL import Image, PpmImagePlugin

from .helper import (
    assert_image_equal,
    assert_image_equal_tofile,
    assert_image_similar,
    hopper,
)

# sample ppm stream
TEST_FILE = "Tests/images/hopper.ppm"


def test_sanity() -> None:
    with Image.open(TEST_FILE) as im:
        assert im.mode == "RGB"
        assert im.size == (128, 128)
        assert im.format == "PPM"
        assert im.get_format_mimetype() == "image/x-portable-pixmap"


@pytest.mark.parametrize(
    "data, mode, pixels",
    (
        (b"P2 3 1 4 0 2 4", "L", (0, 128, 255)),
        (b"P2 3 1 257 0 128 257", "I", (0, 32640, 65535)),
        # P3 with maxval < 255
        (
            b"P3 3 1 17 0 1 2 8 9 10 15 16 17",
            "RGB",
            ((0, 15, 30), (120, 135, 150), (225, 240, 255)),
        ),
        # P3 with maxval > 255
        # Scale down to 255, since there is no RGB mode with more than 8-bit
        (
            b"P3 3 1 257 0 1 2 128 129 130 256 257 257",
            "RGB",
            ((0, 1, 2), (127, 128, 129), (254, 255, 255)),
        ),
        (b"P5 3 1 4 \x00\x02\x04", "L", (0, 128, 255)),
        (b"P5 3 1 257 \x00\x00\x00\x80\x01\x01", "I", (0, 32640, 65535)),
        # P6 with maxval < 255
        (
            b"P6 3 1 17 \x00\x01\x02\x08\x09\x0A\x0F\x10\x11",
            "RGB",
            (
                (0, 15, 30),
                (120, 135, 150),
                (225, 240, 255),
            ),
        ),
        # P6 with maxval > 255
        (
            b"P6 3 1 257 \x00\x00\x00\x01\x00\x02"
            b"\x00\x80\x00\x81\x00\x82\x01\x00\x01\x01\xFF\xFF",
            "RGB",
            (
                (0, 1, 2),
                (127, 128, 129),
                (254, 255, 255),
            ),
        ),
    ),
)
def test_arbitrary_maxval(
    data: bytes, mode: str, pixels: tuple[int | tuple[int, int, int], ...]
) -> None:
    fp = BytesIO(data)
    with Image.open(fp) as im:
        assert im.size == (3, 1)
        assert im.mode == mode

        px = im.load()
        assert tuple(px[x, 0] for x in range(3)) == pixels


def test_16bit_pgm() -> None:
    with Image.open("Tests/images/16_bit_binary.pgm") as im:
        assert im.mode == "I"
        assert im.size == (20, 100)
        assert im.get_format_mimetype() == "image/x-portable-graymap"

        assert_image_equal_tofile(im, "Tests/images/16_bit_binary_pgm.tiff")


def test_16bit_pgm_write(tmp_path: Path) -> None:
    with Image.open("Tests/images/16_bit_binary.pgm") as im:
        filename = str(tmp_path / "temp.pgm")
        im.save(filename, "PPM")

        assert_image_equal_tofile(im, filename)


def test_pnm(tmp_path: Path) -> None:
    with Image.open("Tests/images/hopper.pnm") as im:
        assert_image_similar(im, hopper(), 0.0001)

        filename = str(tmp_path / "temp.pnm")
        im.save(filename)

        assert_image_equal_tofile(im, filename)


def test_pfm(tmp_path: Path) -> None:
    with Image.open("Tests/images/hopper.pfm") as im:
        assert im.info["scale"] == 1.0
        assert_image_equal(im, hopper("F"))

        filename = str(tmp_path / "tmp.pfm")
        im.save(filename)

        assert_image_equal_tofile(im, filename)


def test_pfm_big_endian(tmp_path: Path) -> None:
    with Image.open("Tests/images/hopper_be.pfm") as im:
        assert im.info["scale"] == 2.5
        assert_image_equal(im, hopper("F"))

        filename = str(tmp_path / "tmp.pfm")
        im.save(filename)

        assert_image_equal_tofile(im, filename)


@pytest.mark.parametrize(
    "data",
    [
        b"Pf 1 1 NaN \0\0\0\0",
        b"Pf 1 1 inf \0\0\0\0",
        b"Pf 1 1 -inf \0\0\0\0",
        b"Pf 1 1 0.0 \0\0\0\0",
        b"Pf 1 1 -0.0 \0\0\0\0",
    ],
)
def test_pfm_invalid(data: bytes) -> None:
    with pytest.raises(ValueError):
        with Image.open(BytesIO(data)):
            pass


@pytest.mark.parametrize(
    "plain_path, raw_path",
    (
        (
            "Tests/images/hopper_1bit_plain.pbm",  # P1
            "Tests/images/hopper_1bit.pbm",  # P4
        ),
        (
            "Tests/images/hopper_8bit_plain.pgm",  # P2
            "Tests/images/hopper_8bit.pgm",  # P5
        ),
        (
            "Tests/images/hopper_8bit_plain.ppm",  # P3
            "Tests/images/hopper_8bit.ppm",  # P6
        ),
    ),
)
def test_plain(plain_path: str, raw_path: str) -> None:
    with Image.open(plain_path) as im:
        assert_image_equal_tofile(im, raw_path)


def test_16bit_plain_pgm() -> None:
    # P2 with maxval 2 ** 16 - 1
    with Image.open("Tests/images/hopper_16bit_plain.pgm") as im:
        assert im.mode == "I"
        assert im.size == (128, 128)
        assert im.get_format_mimetype() == "image/x-portable-graymap"

        # P5 with maxval 2 ** 16 - 1
        assert_image_equal_tofile(im, "Tests/images/hopper_16bit.pgm")


@pytest.mark.parametrize(
    "header, data, comment_count",
    (
        (b"P1\n2 2", b"1010", 10**6),
        (b"P2\n3 1\n4", b"0 2 4", 1),
        (b"P3\n2 2\n255", b"0 0 0 001 1 1 2 2 2 255 255 255", 10**6),
    ),
)
def test_plain_data_with_comment(
    tmp_path: Path, header: bytes, data: bytes, comment_count: int
) -> None:
    path1 = str(tmp_path / "temp1.ppm")
    path2 = str(tmp_path / "temp2.ppm")
    comment = b"# comment" * comment_count
    with open(path1, "wb") as f1, open(path2, "wb") as f2:
        f1.write(header + b"\n\n" + data)
        f2.write(header + b"\n" + comment + b"\n" + data + comment)

    with Image.open(path1) as im:
        assert_image_equal_tofile(im, path2)


@pytest.mark.parametrize("data", (b"P1\n128 128\n", b"P3\n128 128\n255\n"))
def test_plain_truncated_data(tmp_path: Path, data: bytes) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(data)

    with Image.open(path) as im:
        with pytest.raises(ValueError):
            im.load()


@pytest.mark.parametrize("data", (b"P1\n128 128\n1009", b"P3\n128 128\n255\n100A"))
def test_plain_invalid_data(tmp_path: Path, data: bytes) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(data)

    with Image.open(path) as im:
        with pytest.raises(ValueError):
            im.load()


@pytest.mark.parametrize(
    "data",
    (
        b"P3\n128 128\n255\n012345678910",  # half token too long
        b"P3\n128 128\n255\n012345678910 0",  # token too long
    ),
)
def test_plain_ppm_token_too_long(tmp_path: Path, data: bytes) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(data)

    with Image.open(path) as im:
        with pytest.raises(ValueError):
            im.load()


def test_plain_ppm_value_negative(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P3\n128 128\n255\n-1")

    with Image.open(path) as im:
        with pytest.raises(ValueError, match="Channel value is negative"):
            im.load()


def test_plain_ppm_value_too_large(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P3\n128 128\n255\n256")

    with Image.open(path) as im:
        with pytest.raises(ValueError, match="Channel value too large"):
            im.load()


def test_magic() -> None:
    with pytest.raises(SyntaxError):
        PpmImagePlugin.PpmImageFile(fp=BytesIO(b"PyInvalid"))


def test_header_with_comments(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P6 #comment\n#comment\r12#comment\r8\n128 #comment\n255\n")

    with Image.open(path) as im:
        assert im.size == (128, 128)


def test_non_integer_token(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P6\nTEST")

    with pytest.raises(ValueError):
        with Image.open(path):
            pass


def test_header_token_too_long(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P6\n 01234567890")

    with pytest.raises(ValueError) as e:
        with Image.open(path):
            pass

    assert str(e.value) == "Token too long in file header: 01234567890"


def test_truncated_file(tmp_path: Path) -> None:
    # Test EOF in header
    path = str(tmp_path / "temp.pgm")
    with open(path, "wb") as f:
        f.write(b"P6")

    with pytest.raises(ValueError) as e:
        with Image.open(path):
            pass

    assert str(e.value) == "Reached EOF while reading header"

    # Test EOF for PyDecoder
    fp = BytesIO(b"P5 3 1 4")
    with Image.open(fp) as im:
        with pytest.raises(ValueError):
            im.load()


def test_not_enough_image_data(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P2 1 2 255 255")

    with Image.open(path) as im:
        with pytest.raises(ValueError):
            im.load()


@pytest.mark.parametrize("maxval", (b"0", b"65536"))
def test_invalid_maxval(maxval: bytes, tmp_path: Path) -> None:
    path = str(tmp_path / "temp.ppm")
    with open(path, "wb") as f:
        f.write(b"P6\n3 1 " + maxval)

    with pytest.raises(ValueError) as e:
        with Image.open(path):
            pass

    assert str(e.value) == "maxval must be greater than 0 and less than 65536"


def test_neg_ppm() -> None:
    # Storage.c accepted negative values for xsize, ysize.  the
    # internal open_ppm function didn't check for sanity but it
    # has been removed. The default opener doesn't accept negative
    # sizes.

    with pytest.raises(OSError):
        with Image.open("Tests/images/negative_size.ppm"):
            pass


def test_mimetypes(tmp_path: Path) -> None:
    path = str(tmp_path / "temp.pgm")

    with open(path, "wb") as f:
        f.write(b"P4\n128 128\n255")
    with Image.open(path) as im:
        assert im.get_format_mimetype() == "image/x-portable-bitmap"

    with open(path, "wb") as f:
        f.write(b"PyCMYK\n128 128\n255")
    with Image.open(path) as im:
        assert im.get_format_mimetype() == "image/x-portable-anymap"


@pytest.mark.parametrize("buffer", (True, False))
def test_save_stdout(buffer: bool) -> None:
    old_stdout = sys.stdout

    class MyStdOut:
        buffer = BytesIO()

    mystdout: MyStdOut | BytesIO = MyStdOut() if buffer else BytesIO()

    sys.stdout = mystdout  # type: ignore[assignment]

    with Image.open(TEST_FILE) as im:
        im.save(sys.stdout, "PPM")

    # Reset stdout
    sys.stdout = old_stdout

    if isinstance(mystdout, MyStdOut):
        mystdout = mystdout.buffer
    with Image.open(mystdout) as reloaded:
        assert_image_equal_tofile(reloaded, TEST_FILE)