import unittest
from pathlib import Path

from w3lib.encoding import html_to_unicode

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


SAMPLEDIR = Path(tests_datadir, 'compressed')


class GunzipTest(unittest.TestCase):

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

        r2 = Response("http://www.example.com", body=gunzip(r1.body))
        self.assertFalse(gzip_magic_number(r2))
        self.assertEqual(len(r2.body), 9950)

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

    def test_gunzip_no_gzip_file_raises(self):
        self.assertRaises(IOError, gunzip, (SAMPLEDIR / 'feed-sample1.xml').read_bytes())

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

        r2 = Response("http://www.example.com", body=gunzip(r1.body))
        assert r2.body.endswith(b'</html>')
        self.assertFalse(gzip_magic_number(r2))

    def test_is_gzipped_empty(self):
        r1 = Response("http://www.example.com")
        self.assertFalse(gzip_magic_number(r1))

    def test_gunzip_illegal_eof(self):
        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")
        self.assertEqual(len(text), len(expected_text))
        self.assertEqual(text, expected_text)