import io
import os
import os.path
import tempfile
import time

import pytest

from PIL import Image, PdfParser

from .helper import hopper


def helper_save_as_pdf(tmp_path, mode, **kwargs):
    # 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(
        int(d) for d in contents.split(b"/MediaBox [ 0 0 ")[1].split(b"]")[0].split()
    )
    assert im.size == size

    return outfile


def test_monochrome(tmp_path):
    # Arrange
    mode = "1"

    # Act / Assert
    helper_save_as_pdf(tmp_path, mode)


def test_greyscale(tmp_path):
    # Arrange
    mode = "L"

    # Act / Assert
    helper_save_as_pdf(tmp_path, mode)


def test_rgb(tmp_path):
    # Arrange
    mode = "RGB"

    # Act / Assert
    helper_save_as_pdf(tmp_path, mode)


def test_p_mode(tmp_path):
    # Arrange
    mode = "P"

    # Act / Assert
    helper_save_as_pdf(tmp_path, mode)


def test_cmyk_mode(tmp_path):
    # Arrange
    mode = "CMYK"

    # Act / Assert
    helper_save_as_pdf(tmp_path, mode)


def test_unsupported_mode(tmp_path):
    im = hopper("LA")
    outfile = str(tmp_path / "temp_LA.pdf")

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


def test_save_all(tmp_path):
    # 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 imGenerator(ims):
            yield from ims

        im.save(outfile, save_all=True, append_images=imGenerator(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):
    # 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):
    # 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():
    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):
    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):
    # 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):
    # 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():
    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
