from __future__ import annotations

import io
import os
import os.path
import tempfile
import time
from collections.abc import Generator
from pathlib import Path
from typing import Any

import pytest

from PIL import Image, PdfParser, features

from .helper import hopper, mark_if_feature_version, skip_unless_feature


def helper_save_as_pdf(tmp_path: Path, mode: str, **kwargs: Any) -> str:
    # Arrange
    im = hopper(mode)
    outfile = str(tmp_path / ("temp_" + mode + ".pdf"))

    # Act
    im.save(outfile, **kwargs)

    # Assert
    assert os.path.isfile(outfile)
    assert os.path.getsize(outfile) > 0
    with PdfParser.PdfParser(outfile) as pdf:
        if kwargs.get("append_images", False) or kwargs.get("append", False):
            assert len(pdf.pages) > 1
        else:
            assert len(pdf.pages) > 0
    with open(outfile, "rb") as fp:
        contents = fp.read()
    size = tuple(
        float(d) for d in contents.split(b"/MediaBox [ 0 0 ")[1].split(b"]")[0].split()
    )
    assert im.size == size

    return outfile


@pytest.mark.parametrize("mode", ("L", "P", "RGB", "CMYK"))
def test_save(tmp_path: Path, mode: str) -> None:
    helper_save_as_pdf(tmp_path, mode)


@skip_unless_feature("jpg_2000")
@pytest.mark.parametrize("mode", ("LA", "RGBA"))
def test_save_alpha(tmp_path: Path, mode: str) -> None:
    helper_save_as_pdf(tmp_path, mode)


def test_p_alpha(tmp_path: Path) -> None:
    # Arrange
    outfile = str(tmp_path / "temp.pdf")
    with Image.open("Tests/images/pil123p.png") as im:
        assert im.mode == "P"
        assert isinstance(im.info["transparency"], bytes)

        # Act
        im.save(outfile)

    # Assert
    with open(outfile, "rb") as fp:
        contents = fp.read()
    assert b"\n/SMask " in contents


def test_monochrome(tmp_path: Path) -> None:
    # Arrange
    mode = "1"

    # Act / Assert
    outfile = helper_save_as_pdf(tmp_path, mode)
    assert os.path.getsize(outfile) < (5000 if features.check("libtiff") else 15000)


def test_unsupported_mode(tmp_path: Path) -> None:
    im = hopper("PA")
    outfile = str(tmp_path / "temp_PA.pdf")

    with pytest.raises(ValueError):
        im.save(outfile)


def test_resolution(tmp_path: Path) -> None:
    im = hopper()

    outfile = str(tmp_path / "temp.pdf")
    im.save(outfile, resolution=150)

    with open(outfile, "rb") as fp:
        contents = fp.read()

    size = tuple(
        float(d)
        for d in contents.split(b"stream\nq ")[1].split(b" 0 0 cm")[0].split(b" 0 0 ")
    )
    assert size == (61.44, 61.44)

    size = tuple(
        float(d) for d in contents.split(b"/MediaBox [ 0 0 ")[1].split(b"]")[0].split()
    )
    assert size == (61.44, 61.44)


@pytest.mark.parametrize(
    "params",
    (
        {"dpi": (75, 150)},
        {"dpi": (75, 150), "resolution": 200},
    ),
)
def test_dpi(params: dict[str, int | tuple[int, int]], tmp_path: Path) -> None:
    im = hopper()

    outfile = str(tmp_path / "temp.pdf")
    im.save(outfile, "PDF", **params)

    with open(outfile, "rb") as fp:
        contents = fp.read()

    size = tuple(
        float(d)
        for d in contents.split(b"stream\nq ")[1].split(b" 0 0 cm")[0].split(b" 0 0 ")
    )
    assert size == (122.88, 61.44)

    size = tuple(
        float(d) for d in contents.split(b"/MediaBox [ 0 0 ")[1].split(b"]")[0].split()
    )
    assert size == (122.88, 61.44)


@mark_if_feature_version(
    pytest.mark.valgrind_known_error, "libjpeg_turbo", "2.0", reason="Known Failing"
)
def test_save_all(tmp_path: Path) -> None:
    # Single frame image
    helper_save_as_pdf(tmp_path, "RGB", save_all=True)

    # Multiframe image
    with Image.open("Tests/images/dispose_bgnd.gif") as im:
        outfile = str(tmp_path / "temp.pdf")
        im.save(outfile, save_all=True)

        assert os.path.isfile(outfile)
        assert os.path.getsize(outfile) > 0

        # Append images
        ims = [hopper()]
        im.copy().save(outfile, save_all=True, append_images=ims)

        assert os.path.isfile(outfile)
        assert os.path.getsize(outfile) > 0

        # Test appending using a generator
        def im_generator(ims: list[Image.Image]) -> Generator[Image.Image, None, None]:
            yield from ims

        im.save(outfile, save_all=True, append_images=im_generator(ims))

    assert os.path.isfile(outfile)
    assert os.path.getsize(outfile) > 0

    # Append JPEG images
    with Image.open("Tests/images/flower.jpg") as jpeg:
        jpeg.save(outfile, save_all=True, append_images=[jpeg.copy()])

    assert os.path.isfile(outfile)
    assert os.path.getsize(outfile) > 0


def test_multiframe_normal_save(tmp_path: Path) -> None:
    # Test saving a multiframe image without save_all
    with Image.open("Tests/images/dispose_bgnd.gif") as im:
        outfile = str(tmp_path / "temp.pdf")
        im.save(outfile)

    assert os.path.isfile(outfile)
    assert os.path.getsize(outfile) > 0


def test_pdf_open(tmp_path: Path) -> None:
    # fail on a buffer full of null bytes
    with pytest.raises(PdfParser.PdfFormatError):
        PdfParser.PdfParser(buf=bytearray(65536))

    # make an empty PDF object
    with PdfParser.PdfParser() as empty_pdf:
        assert len(empty_pdf.pages) == 0
        assert len(empty_pdf.info) == 0
        assert not empty_pdf.should_close_buf
        assert not empty_pdf.should_close_file

    # make a PDF file
    pdf_filename = helper_save_as_pdf(tmp_path, "RGB")

    # open the PDF file
    with PdfParser.PdfParser(filename=pdf_filename) as hopper_pdf:
        assert len(hopper_pdf.pages) == 1
        assert hopper_pdf.should_close_buf
        assert hopper_pdf.should_close_file

    # read a PDF file from a buffer with a non-zero offset
    with open(pdf_filename, "rb") as f:
        content = b"xyzzy" + f.read()
    with PdfParser.PdfParser(buf=content, start_offset=5) as hopper_pdf:
        assert len(hopper_pdf.pages) == 1
        assert not hopper_pdf.should_close_buf
        assert not hopper_pdf.should_close_file

    # read a PDF file from an already open file
    with open(pdf_filename, "rb") as f:
        with PdfParser.PdfParser(f=f) as hopper_pdf:
            assert len(hopper_pdf.pages) == 1
            assert hopper_pdf.should_close_buf
            assert not hopper_pdf.should_close_file


def test_pdf_append_fails_on_nonexistent_file() -> None:
    im = hopper("RGB")
    with tempfile.TemporaryDirectory() as temp_dir:
        with pytest.raises(OSError):
            im.save(os.path.join(temp_dir, "nonexistent.pdf"), append=True)


def check_pdf_pages_consistency(pdf: PdfParser.PdfParser) -> None:
    assert pdf.pages_ref is not None
    pages_info = pdf.read_indirect(pdf.pages_ref)
    assert b"Parent" not in pages_info
    assert b"Kids" in pages_info
    kids_not_used = pages_info[b"Kids"]
    for page_ref in pdf.pages:
        while True:
            if page_ref in kids_not_used:
                kids_not_used.remove(page_ref)
            page_info = pdf.read_indirect(page_ref)
            assert b"Parent" in page_info
            page_ref = page_info[b"Parent"]
            if page_ref == pdf.pages_ref:
                break
        assert pdf.pages_ref == page_info[b"Parent"]
    assert kids_not_used == []


def test_pdf_append(tmp_path: Path) -> None:
    # make a PDF file
    pdf_filename = helper_save_as_pdf(tmp_path, "RGB", producer="PdfParser")

    # open it, check pages and info
    with PdfParser.PdfParser(pdf_filename, mode="r+b") as pdf:
        assert len(pdf.pages) == 1
        assert len(pdf.info) == 4
        assert pdf.info.Title == os.path.splitext(os.path.basename(pdf_filename))[0]
        assert pdf.info.Producer == "PdfParser"
        assert b"CreationDate" in pdf.info
        assert b"ModDate" in pdf.info
        check_pdf_pages_consistency(pdf)

        # append some info
        pdf.info.Title = "abc"
        pdf.info.Author = "def"
        pdf.info.Subject = "ghi\uABCD"
        pdf.info.Keywords = "qw)e\\r(ty"
        pdf.info.Creator = "hopper()"
        pdf.start_writing()
        pdf.write_xref_and_trailer()

    # open it again, check pages and info again
    with PdfParser.PdfParser(pdf_filename) as pdf:
        assert len(pdf.pages) == 1
        assert len(pdf.info) == 8
        assert pdf.info.Title == "abc"
        assert b"CreationDate" in pdf.info
        assert b"ModDate" in pdf.info
        check_pdf_pages_consistency(pdf)

    # append two images
    mode_cmyk = hopper("CMYK")
    mode_p = hopper("P")
    mode_cmyk.save(pdf_filename, append=True, save_all=True, append_images=[mode_p])

    # open the PDF again, check pages and info again
    with PdfParser.PdfParser(pdf_filename) as pdf:
        assert len(pdf.pages) == 3
        assert len(pdf.info) == 8
        assert PdfParser.decode_text(pdf.info[b"Title"]) == "abc"
        assert pdf.info.Title == "abc"
        assert pdf.info.Producer == "PdfParser"
        assert pdf.info.Keywords == "qw)e\\r(ty"
        assert pdf.info.Subject == "ghi\uABCD"
        assert b"CreationDate" in pdf.info
        assert b"ModDate" in pdf.info
        check_pdf_pages_consistency(pdf)


def test_pdf_info(tmp_path: Path) -> None:
    # make a PDF file
    pdf_filename = helper_save_as_pdf(
        tmp_path,
        "RGB",
        title="title",
        author="author",
        subject="subject",
        keywords="keywords",
        creator="creator",
        producer="producer",
        creationDate=time.strptime("2000", "%Y"),
        modDate=time.strptime("2001", "%Y"),
    )

    # open it, check pages and info
    with PdfParser.PdfParser(pdf_filename) as pdf:
        assert len(pdf.info) == 8
        assert pdf.info.Title == "title"
        assert pdf.info.Author == "author"
        assert pdf.info.Subject == "subject"
        assert pdf.info.Keywords == "keywords"
        assert pdf.info.Creator == "creator"
        assert pdf.info.Producer == "producer"
        assert pdf.info.CreationDate == time.strptime("2000", "%Y")
        assert pdf.info.ModDate == time.strptime("2001", "%Y")
        check_pdf_pages_consistency(pdf)


def test_pdf_append_to_bytesio() -> None:
    im = hopper("RGB")
    f = io.BytesIO()
    im.save(f, format="PDF")
    initial_size = len(f.getvalue())
    assert initial_size > 0
    im = hopper("P")
    f = io.BytesIO(f.getvalue())
    im.save(f, format="PDF", append=True)
    assert len(f.getvalue()) > initial_size


@pytest.mark.timeout(1)
@pytest.mark.skipif("PILLOW_VALGRIND_TEST" in os.environ, reason="Valgrind is slower")
@pytest.mark.parametrize("newline", (b"\r", b"\n"))
def test_redos(newline: bytes) -> None:
    malicious = b" trailer<<>>" + newline * 3456

    # This particular exception isn't relevant here.
    # The important thing is it doesn't timeout, cause a ReDoS (CVE-2021-25292).
    with pytest.raises(PdfParser.PdfFormatError):
        PdfParser.PdfParser(buf=malicious)