"""Test the pypdf._utils module."""
import functools
import io
import re
import subprocess
import sys
from datetime import datetime, timedelta, timezone
from pathlib import Path
from typing import Any, Callable

import pytest

import pypdf._utils
from pypdf._utils import (
    File,
    Version,
    _get_max_pdf_version_header,
    _human_readable_bytes,
    check_if_whitespace_only,
    classproperty,
    deprecate_with_replacement,
    deprecation_no_replacement,
    format_iso8824_date,
    mark_location,
    matrix_multiply,
    parse_iso8824_date,
    read_block_backwards,
    read_previous_line,
    read_until_regex,
    read_until_whitespace,
    rename_kwargs,
    skip_over_comment,
    skip_over_whitespace,
)
from pypdf.errors import DeprecationError, PdfReadError, PdfStreamError

from . import is_sublist


@pytest.mark.parametrize(
    ("stream", "expected"),
    [
        (io.BytesIO(b"foo"), False),
        (io.BytesIO(b""), False),
        (io.BytesIO(b" "), True),
        (io.BytesIO(b"  "), True),
        (io.BytesIO(b"  \n"), True),
        (io.BytesIO(b"    \n"), True),
        (io.BytesIO(b"\f"), True),
    ],
)
def test_skip_over_whitespace(stream, expected):
    assert skip_over_whitespace(stream) == expected


@pytest.mark.parametrize(
    ("value", "expected"),
    [
        (b"foo", False),
        (b" a", False),
        (b" a\n b", False),
        (b"", True),
        (b" ", True),
        (b"  ", True),
        (b"  \n", True),
        (b"    \n", True),
        (b"\f", True),
    ],
)
def test_check_if_whitespace_only(value, expected):
    assert check_if_whitespace_only(value) is expected


def test_read_until_whitespace():
    assert read_until_whitespace(io.BytesIO(b"foo"), maxchars=1) == b"f"


@pytest.mark.parametrize(
    ("stream", "remainder"),
    [
        (io.BytesIO(b"% foobar\n"), b""),
        (io.BytesIO(b""), b""),
        (io.BytesIO(b" "), b" "),
        (io.BytesIO(b"% foo%\nbar"), b"bar"),
    ],
)
def test_skip_over_comment(stream, remainder):
    skip_over_comment(stream)
    assert stream.read() == remainder


def test_read_until_regex_premature_ending_name():
    stream = io.BytesIO(b"")
    assert read_until_regex(stream, re.compile(b".")) == b""


def test_read_until_regex_match_in_first_chunk():
    """Match within the first 16-byte chunk."""
    stream = io.BytesIO(b"hello world")
    result = read_until_regex(stream, re.compile(b" "))
    assert result == b"hello"
    assert stream.tell() == 5


def test_read_until_regex_match_in_second_chunk():
    """Match lands in the second chunk (past first 16 bytes)."""
    payload = b"0123456789abcdefghij"
    assert len(payload) == 20
    data = payload + b" rest"
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(b" "))
    assert result == payload
    assert stream.tell() == 20


def test_read_until_regex_match_at_chunk_boundary():
    """Delimiter sits exactly at byte 16 (first byte of second chunk)."""
    payload = b"0123456789abcdef"
    assert len(payload) == 16
    data = payload + b" after"
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(b" "))
    assert result == payload
    assert stream.tell() == 16


def test_read_until_regex_multi_byte_spanning_boundary():
    """Multi-byte regex pattern spans across a chunk boundary."""
    # "X" at byte 15 (last byte of first chunk), "Y" at byte 16 (first of second)
    payload = b"0123456789abcde"
    assert len(payload) == 15
    data = payload + b"XYafter"
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(b"XY"))
    assert result == payload
    assert stream.tell() == 15


def test_read_until_regex_no_match_exhausted():
    """No match - stream is fully consumed and all data returned."""
    data = b"0123456789" * 10
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(b"ZZZ"))
    assert result == data


def test_read_until_regex_exponential_chunk_growth():
    """Verify correctness with long input that exercises chunk doubling."""
    payload = (b"0123456789abcdef" * 3125)[:50_000]
    assert len(payload) == 50_000
    data = payload + b"|done"
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(rb"\|"))
    assert result == payload
    assert stream.tell() == 50_000


def test_read_until_regex_match_spanning_later_boundary():
    """Multi-byte match spanning a boundary after chunk size has grown."""
    # Chunk 1: 16 bytes, chunk 2: 32 bytes → total 48 after two reads.
    # Place "END" at offset 47 so it spans bytes 47-49.
    payload = (b"0123456789abcdef" * 3)[:47]
    assert len(payload) == 47
    data = payload + b"ENDrest"
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(b"END"))
    assert result == payload
    assert stream.tell() == 47


def test_read_until_regex_tail_overlap_is_fixed():
    """Tail overlap is 16 bytes regardless of chunk size growth.

    Chunk reads: 16, 32, 64 -> total 112. Place a 16-byte pattern starting
    one byte before the 64-byte chunk boundary (at offset 47) so it spans
    into the third chunk. This only works if the tail kept from chunk 2
    covers at least 16 bytes.
    """
    pattern = b"ABCDEFGHIJKLMNOP"  # 16 bytes
    assert len(pattern) == 16
    # Chunk 1: 16 bytes, chunk 2: 32 bytes -> boundary at offset 48.
    # Pattern starts at 47, spanning bytes 47-62.
    payload = b"x" * 47
    data = payload + pattern + b"rest"
    stream = io.BytesIO(data)
    result = read_until_regex(stream, re.compile(re.escape(pattern)))
    assert result == payload
    assert stream.tell() == 47


@pytest.mark.parametrize(
    ("a", "b", "expected"),
    [
        (((3,),), ((7,),), ((21,),)),
        (((3, 7),), ((5,), (13,)), ((3 * 5.0 + 7 * 13,),)),
        (((3,), (7,)), ((5, 13),), ((3 * 5, 3 * 13), (7 * 5, 7 * 13))),
    ],
)
def test_matrix_multiply(a, b, expected):
    assert matrix_multiply(a, b) == expected


def test_mark_location():
    stream = io.BytesIO(b"abde" * 6000)
    mark_location(stream)
    Path("pypdf_pdfLocation.txt").unlink()  # cleanup


def test_deprecate_no_replacement():
    with pytest.warns(
            expected_warning=DeprecationWarning,
            match="foo is deprecated and will be removed in pypdf 3.0.0."
    ):
        pypdf._utils.deprecate_no_replacement("foo", removed_in="3.0.0")


@pytest.mark.parametrize(
    ("dat", "pos", "to_read", "expected", "expected_pos"),
    [
        (b"abc", 1, 0, b"", 1),
        (b"abc", 1, 1, b"a", 0),
        (b"abc", 2, 1, b"b", 1),
        (b"abc", 2, 2, b"ab", 0),
        (b"abc", 3, 1, b"c", 2),
        (b"abc", 3, 2, b"bc", 1),
        (b"abc", 3, 3, b"abc", 0),
        (b"", 0, 1, None, 0),
        (b"a", 0, 1, None, 0),
        (b"abc", 0, 10, None, 0),
    ],
)
def test_read_block_backwards(dat, pos, to_read, expected, expected_pos):
    s = io.BytesIO(dat)
    s.seek(pos)
    if expected is not None:
        assert read_block_backwards(s, to_read) == expected
    else:
        with pytest.raises(PdfStreamError):
            read_block_backwards(s, to_read)
    assert s.tell() == expected_pos


def test_read_block_backwards_at_start():
    s = io.BytesIO(b"abc")
    with pytest.raises(PdfStreamError) as _:
        read_previous_line(s)


@pytest.mark.parametrize(
    ("dat", "pos", "expected", "expected_pos"),
    [
        (b"abc", 1, b"a", 0),
        (b"abc", 2, b"ab", 0),
        (b"abc", 3, b"abc", 0),
        (b"abc\n", 3, b"abc", 0),
        (b"abc\n", 4, b"", 3),
        (b"abc\n\r", 4, b"", 3),
        (b"abc\nd", 5, b"d", 3),
        # Skip over multiple CR/LF bytes
        (b"abc\n\r\ndef", 9, b"def", 3),
    ],
    ids=list(range(8)),
)
def test_read_previous_line(dat, pos, expected, expected_pos):
    s = io.BytesIO(dat)
    s.seek(pos)
    assert read_previous_line(s) == expected
    assert s.tell() == expected_pos


# for unknown reason if the parameters are passed through pytest, errors are reported
def test_read_previous_line2():
    # Include a block full of newlines...
    test_read_previous_line(
        b"abc" + b"\n" * (2 * io.DEFAULT_BUFFER_SIZE) + b"d",
        2 * io.DEFAULT_BUFFER_SIZE + 4,
        b"d",
        3,
    )
    # Include a block full of non-newline characters
    test_read_previous_line(
        b"abc\n" + b"d" * (2 * io.DEFAULT_BUFFER_SIZE),
        2 * io.DEFAULT_BUFFER_SIZE + 4,
        b"d" * (2 * io.DEFAULT_BUFFER_SIZE),
        3,
    )
    # Both
    test_read_previous_line(
        b"abcxyz"
        + b"\n" * (2 * io.DEFAULT_BUFFER_SIZE)
        + b"d" * (2 * io.DEFAULT_BUFFER_SIZE),
        4 * io.DEFAULT_BUFFER_SIZE + 6,
        b"d" * (2 * io.DEFAULT_BUFFER_SIZE),
        6,
    )


def test_get_max_pdf_version_header():
    with pytest.raises(ValueError) as exc:
        _get_max_pdf_version_header(b"", b"PDF-1.2")
    assert exc.value.args[0] == "Neither b'' nor b'PDF-1.2' are proper headers"


def test_read_block_backwards_exception():
    stream = io.BytesIO(b"foobar")
    stream.seek(6)
    with pytest.raises(PdfReadError) as exc:
        read_block_backwards(stream, 7)
    assert exc.value.args[0] == "Could not read malformed PDF file"


def test_deprecate_with_replacement():
    def foo() -> None:
        deprecate_with_replacement("foo", "bar", removed_in="4.3.2")

    with pytest.warns(
        DeprecationWarning,
        match="foo is deprecated and will be removed in pypdf 4.3.2. Use bar instead.",
    ):
        foo()


def test_deprecation_no_replacement():
    def foo() -> None:
        deprecation_no_replacement("foo", removed_in="4.3.2")

    with pytest.raises(
        DeprecationError,
        match=r"foo is deprecated and was removed in pypdf 4\.3\.2\.",
    ):
        foo()


def test_rename_kwargs():
    def deprecation_bookmark_nofail(**aliases: str) -> Callable:
        """
        Decorator for deprecated term "bookmark".

        To be used for methods and function arguments
            outline_item = a bookmark
            outline = a collection of outline items.
        """

        def decoration(func: Callable) -> Any:  # type: ignore
            @functools.wraps(func)
            def wrapper(*args: Any, **kwargs: Any) -> Any:  # type: ignore
                rename_kwargs(func.__name__, kwargs, aliases, fail=False)
                return func(*args, **kwargs)

            return wrapper

        return decoration

    @deprecation_bookmark_nofail(old_param="new_param")
    def foo(old_param: int = 1, baz: int = 2, new_param: int = 1) -> None:
        pass

    expected_msg = (
        "foo received both old_param and new_param as an argument. "
        "old_param is deprecated. Use new_param instead."
    )
    with pytest.raises(TypeError, match=expected_msg):
        foo(old_param=12, new_param=13)

    with pytest.warns(
        DeprecationWarning,
        match="old_param is deprecated as an argument. Use new_param instead",
    ):
        foo(old_param=12)


def test_rename_kwargs__stacklevel(tmp_path: Path) -> None:
    script = tmp_path / "script.py"
    script.write_text("""
import functools
import warnings

from pypdf._utils import rename_kwargs

def deprecation(**aliases: str):
    def decoration(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            rename_kwargs(func.__name__, kwargs, aliases, fail=False)
            return func(*args, **kwargs)

        return wrapper

    return decoration

@deprecation(old_param="new_param")
def foo(old_param: int = 1, baz: int = 2, new_param: int = 1) -> None:
    pass

warnings.simplefilter("always")
foo(old_param=12)
    """)

    result = subprocess.run([sys.executable, script], capture_output=True, text=True)  # noqa: S603
    assert result.returncode == 0
    assert result.stderr == (
        f"{script}:23: DeprecationWarning: old_param is deprecated as an argument. "
        f"Use new_param instead\n  foo(old_param=12)\n"
    )


@pytest.mark.parametrize(
    ("input_int", "expected_output"),
    [
        (123, "123 Byte"),
        (1234, "1.2 kB"),
        (123_456, "123.5 kB"),
        (1_234_567, "1.2 MB"),
        (1_234_567_890, "1.2 GB"),
        (1_234_567_890_000, "1234.6 GB"),
    ],
)
def test_human_readable_bytes(input_int, expected_output):
    """_human_readable_bytes correctly transforms the integer to a string."""
    assert _human_readable_bytes(input_int) == expected_output


def test_file_class():
    """File class can be instantiated and string representation is ok."""
    f = File(name="image.png", data=b"")
    assert str(f) == "File(name=image.png, data: 0 Byte)"
    # hash(b"") varies between CPython and PyPy
    assert repr(f) == f"File(name=image.png, data: 0 Byte, hash: {hash(b'')})"


@pytest.mark.parametrize(
    ("text", "expected"),
    [
        ("D:20210318000756", "2021-03-18T00:07:56"),
        ("20210318000756", "2021-03-18T00:07:56"),
        ("D:2021", "2021-01-01T00:00:00"),
        ("D:202103", "2021-03-01T00:00:00"),
        ("D:20210304", "2021-03-04T00:00:00"),
        ("D:2021030402", "2021-03-04T02:00:00"),
        ("D:20210408054711", "2021-04-08T05:47:11"),
        ("D:20210408054711Z", "2021-04-08T05:47:11+00:00"),
        ("D:20210408054711Z00", "2021-04-08T05:47:11+00:00"),
        ("D:20210408054711Z0000", "2021-04-08T05:47:11+00:00"),
        ("D:20210408075331+02'00'", "2021-04-08T07:53:31+02:00"),
        ("D:20210408075331-03'00'", "2021-04-08T07:53:31-03:00"),
    ],
)
def test_parse_datetime(text, expected):
    date = parse_iso8824_date(text)
    date_str = (date.isoformat() + date.strftime("%z"))[: len(expected)]
    assert date_str == expected


@pytest.mark.parametrize(
    ("text", "expected"),
    [
        ("", None),
        (None, None),
    ],
)
def test_parse_datetime_edge_cases(text, expected):
    date = parse_iso8824_date(text)
    assert date == expected


def test_parse_datetime_err():
    with pytest.raises(ValueError) as ex:
        parse_iso8824_date("D:20210408T054711Z")
    assert ex.value.args[0] == "Can not convert date: D:20210408T054711Z"
    assert parse_iso8824_date("D:20210408054711").tzinfo is None


def test_format_iso8824_date():
    """Test format_iso8824_date function with timezone handling."""
    dt_naive = datetime(2021, 3, 18, 12, 7, 56)
    result = format_iso8824_date(dt_naive)
    assert result == "D:20210318120756"

    dt_utc = datetime(2021, 3, 18, 12, 7, 56, tzinfo=timezone.utc)
    result = format_iso8824_date(dt_utc)
    assert result == "D:20210318120756+00'00'"

    dt_positive = datetime(2021, 3, 18, 12, 7, 56, tzinfo=timezone(timedelta(hours=2, minutes=30)))
    result = format_iso8824_date(dt_positive)
    assert result == "D:20210318120756+02'30'"

    dt_negative = datetime(2021, 3, 18, 12, 7, 56, tzinfo=timezone(timedelta(hours=-5, minutes=-30)))
    result = format_iso8824_date(dt_negative)
    assert result == "D:20210318120756-05'30'"


def test_format_iso8824_date_roundtrip():
    dt_naive = datetime(2021, 3, 18, 12, 7, 56)
    formatted = format_iso8824_date(dt_naive)
    parsed = parse_iso8824_date(formatted)
    assert parsed == dt_naive

    dt_utc = datetime(2021, 3, 18, 12, 7, 56, tzinfo=timezone.utc)
    formatted = format_iso8824_date(dt_utc)
    parsed = parse_iso8824_date(formatted)
    assert parsed == dt_utc

    dt_positive = datetime(2021, 3, 18, 12, 7, 56, tzinfo=timezone(timedelta(hours=2, minutes=30)))
    formatted = format_iso8824_date(dt_positive)
    parsed = parse_iso8824_date(formatted)
    assert parsed == dt_positive

    dt_negative = datetime(2021, 3, 18, 12, 7, 56, tzinfo=timezone(timedelta(hours=-5, minutes=-30)))
    formatted = format_iso8824_date(dt_negative)
    parsed = parse_iso8824_date(formatted)
    assert parsed == dt_negative


def test_is_sublist():
    # Basic checks:
    assert is_sublist([0, 1], [0, 1, 2]) is True
    assert is_sublist([0, 2], [0, 1, 2]) is True
    assert is_sublist([1, 2], [0, 1, 2]) is True
    assert is_sublist([0, 3], [0, 1, 2]) is False
    # Ensure order is checked:
    assert is_sublist([1, 0], [0, 1, 2]) is False
    # Ensure duplicates are handled:
    assert is_sublist([0, 1, 1], [0, 1, 1, 2]) is True
    assert is_sublist([0, 1, 1], [0, 1, 2]) is False
    # Edge cases with empty lists:
    assert is_sublist([], [0, 1, 2]) is True
    assert is_sublist([0, 1], []) is False
    # Self-sublist edge case:
    assert is_sublist([0, 1, 2], [0, 1, 2]) is True


@pytest.mark.parametrize(
    ("left", "right", "is_less_than"),
    [
        ("1", "2", True),
        ("2", "1", False),
        ("1", "1", False),
        ("1.0", "1.1", True),
        ("1", "1.1", True),
        # Suffix left
        ("1a", "2", True),
        ("2a", "1", False),
        ("1a", "1", False),
        ("1.0a", "1.1", True),
        # I'm not sure about that, but seems special enough that it
        # probably doesn't matter:
        ("1a", "1.1", False),
        # Suffix right
        ("1", "2a", True),
        ("2", "1a", False),
        ("1", "1a", True),
        ("1.0", "1.1a", True),
        ("1", "1.1a", True),
        ("", "0.0.0", True),
        # Just suffix matters ... hm, I think this is actually wrong:
        ("1.0a", "1.0", False),
        ("1.0", "1.0a", True),
    ],
)
def test_version_compare(left, right, is_less_than):
    assert (Version(left) < Version(right)) is is_less_than


def test_version_compare_equal_str():
    a = Version("1.0")
    assert a != "1.0"


def test_version_compare_lt_str():
    a = Version("1.0")
    with pytest.raises(ValueError) as exc:
        a < "1.0"  # noqa: B015
    assert exc.value.args[0] == "Version cannot be compared against <class 'str'>"


def test_bad_version():
    assert Version("a").components == [(0, "a")]


def test_version_eq_hash():
    version1 = Version("1.0")
    version2 = Version("1.0")
    version3 = Version("1.1")
    assert version1 == version2
    assert version1 != version3
    assert hash(version1) == hash(version2)
    assert hash(version1) != hash(version3)


def test_classproperty():
    class Container:
        @classproperty
        def value1(cls) -> int:  # noqa: N805
            return 42

        @classproperty
        def value2(cls) -> int:  # noqa: N805
            return 1337

        @classproperty
        def value3(cls) -> int:  # noqa: N805
            return 1

        @value3.getter
        def value3(cls) -> int:  # noqa: N805
            return 2

    assert Container.value1 == 42
    assert Container.value2 == 1337
    assert Container.value3 == 2
    assert Container().value1 == 42
    assert Container().value2 == 1337
    assert Container().value3 == 2