from __future__ import annotations

from gzip import BadGzipFile
from pathlib import Path

import pytest
from w3lib.encoding import html_to_unicode

from scrapy.http import Response
from scrapy.utils.gz import gunzip, gzip_magic_number
from tests import tests_datadir

SAMPLEDIR = Path(tests_datadir, "compressed")


def test_gunzip_basic():
    r1 = Response(
        "http://www.example.com",
        body=(SAMPLEDIR / "feed-sample1.xml.gz").read_bytes(),
    )
    assert gzip_magic_number(r1)

    r2 = Response("http://www.example.com", body=gunzip(r1.body))
    assert not gzip_magic_number(r2)
    assert len(r2.body) == 9950


def test_gunzip_truncated():
    text = gunzip((SAMPLEDIR / "truncated-crc-error.gz").read_bytes())
    assert text.endswith(b"</html")


def test_gunzip_no_gzip_file_raises():
    with pytest.raises(BadGzipFile):
        gunzip((SAMPLEDIR / "feed-sample1.xml").read_bytes())


def test_gunzip_truncated_short():
    r1 = Response(
        "http://www.example.com",
        body=(SAMPLEDIR / "truncated-crc-error-short.gz").read_bytes(),
    )
    assert gzip_magic_number(r1)

    r2 = Response("http://www.example.com", body=gunzip(r1.body))
    assert r2.body.endswith(b"</html>")
    assert not gzip_magic_number(r2)


def test_is_gzipped_empty():
    r1 = Response("http://www.example.com")
    assert not gzip_magic_number(r1)


def test_gunzip_illegal_eof():
    text = html_to_unicode(
        "charset=cp1252", gunzip((SAMPLEDIR / "unexpected-eof.gz").read_bytes())
    )[1]
    expected_text = (SAMPLEDIR / "unexpected-eof-output.txt").read_text(
        encoding="utf-8"
    )
    assert len(text) == len(expected_text)
    assert text == expected_text
