# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
#!/usr/bin/env python3

# Copyright 2015 Corentin Julé <corentinjule@gmail.com>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.

import os
import os.path
import zipfile
import logging

import pytest

from PyQt5.QtCore import QUrl

from qutebrowser.browser import adblock

pytestmark = pytest.mark.usefixtures('qapp', 'config_tmpdir')

# TODO See ../utils/test_standarddirutils for OSError and caplog assertion

WHITELISTED_HOSTS = ('qutebrowser.org', 'mediumhost.io')

BLOCKLIST_HOSTS = ('localhost',
                   'mediumhost.io',
                   'malware.badhost.org',
                   '4-verybadhost.com',
                   'ads.worsthostever.net')

CLEAN_HOSTS = ('goodhost.gov', 'verygoodhost.com')

URLS_TO_CHECK = ('http://localhost',
                 'http://mediumhost.io',
                 'ftp://malware.badhost.org',
                 'http://4-verybadhost.com',
                 'http://ads.worsthostever.net',
                 'http://goodhost.gov',
                 'ftp://verygoodhost.com',
                 'http://qutebrowser.org')


class BaseDirStub:

    """Mock for objreg.get('args') called in adblock.HostBlocker.read_hosts."""

    def __init__(self):
        self.basedir = None


@pytest.fixture
def basedir(fake_args):
    """Register a Fake basedir."""
    fake_args.basedir = None


def create_zipfile(directory, files, zipname='test'):
    """Return a path to a newly created zip file.

    Args:
        directory: path object where to create the zip file.
        files: list of filenames (relative to directory) to each file to add.
        zipname: name to give to the zip file.
    """
    zipfile_path = directory / zipname + '.zip'
    with zipfile.ZipFile(str(zipfile_path), 'w') as new_zipfile:
        for file_path in files:
            new_zipfile.write(str(directory / file_path),
                              arcname=os.path.basename(str(file_path)))
            # Removes path from file name
    return str(zipname + '.zip')


def create_blocklist(directory, blocked_hosts=BLOCKLIST_HOSTS,
                     name='hosts', line_format='one_per_line'):
    """Return a path to a blocklist file.

    Args:
        directory: path object where to create the blocklist file
        blocked_hosts: an iterable of string hosts to add to the blocklist
        name: name to give to the blocklist file
        line_format: 'etc_hosts'  -->  /etc/hosts format
                    'one_per_line'  -->  one host per line format
                    'not_correct'  -->  Not a correct hosts file format.
    """
    blocklist_file = directory / name
    with open(str(blocklist_file), 'w', encoding='UTF-8') as blocklist:
        # ensure comments are ignored when processing blocklist
        blocklist.write('# Blocked Hosts List #\n\n')
        if line_format == 'etc_hosts':  # /etc/hosts like format
            for host in blocked_hosts:
                blocklist.write('127.0.0.1  ' + host + '\n')
        elif line_format == 'one_per_line':
            for host in blocked_hosts:
                blocklist.write(host + '\n')
        elif line_format == 'not_correct':
            for host in blocked_hosts:
                blocklist.write(host + ' This is not a correct hosts file\n')
        else:
            raise ValueError('Incorrect line_format argument')
    return name


def assert_urls(host_blocker, blocked=BLOCKLIST_HOSTS[1:],
                whitelisted=WHITELISTED_HOSTS, urls_to_check=URLS_TO_CHECK):
    """Test if Urls to check are blocked or not by HostBlocker.

    Ensure URLs in 'blocked' and not in 'whitelisted' are blocked.
    All other URLs must not be blocked.
    """
    whitelisted = list(whitelisted)
    for str_url in urls_to_check:
        url = QUrl(str_url)
        host = url.host()
        if host in blocked and host not in whitelisted:
            assert host_blocker.is_blocked(url)
        else:
            assert not host_blocker.is_blocked(url)


def blocklist_to_url(filename):
    """Get an example.com-URL with the given filename as path."""
    assert not os.path.isabs(filename), filename
    url = QUrl('http://example.com/')
    url.setPath('/' + filename)
    assert url.isValid(), url.errorString()
    return url


def generic_blocklists(directory):
    """Return a generic list of files to be used in hosts-block-lists option.

    This list contains :
    - a remote zip file with 1 hosts file and 2 useless files
    - a remote zip file with only useless files
        (Should raise a FileNotFoundError)
    - a remote zip file with only one valid hosts file
    - a local text file with valid hosts
    - a remote text file without valid hosts format.
    """
    # remote zip file with 1 hosts file and 2 useless files
    file1 = create_blocklist(directory, blocked_hosts=CLEAN_HOSTS,
                             name='README', line_format='not_correct')
    file2 = create_blocklist(directory, blocked_hosts=BLOCKLIST_HOSTS[:3],
                             name='hosts', line_format='etc_hosts')
    file3 = create_blocklist(directory, blocked_hosts=CLEAN_HOSTS,
                             name='false_positive', line_format='one_per_line')
    files_to_zip = [file1, file2, file3]
    blocklist1 = blocklist_to_url(
        create_zipfile(directory, files_to_zip, 'block1'))

    # remote zip file without file named hosts
    # (Should raise a FileNotFoundError)
    file1 = create_blocklist(directory, blocked_hosts=CLEAN_HOSTS,
                             name='md5sum', line_format='etc_hosts')
    file2 = create_blocklist(directory, blocked_hosts=CLEAN_HOSTS,
                             name='README', line_format='not_correct')
    file3 = create_blocklist(directory, blocked_hosts=CLEAN_HOSTS,
                             name='false_positive', line_format='one_per_line')
    files_to_zip = [file1, file2, file3]
    blocklist2 = blocklist_to_url(
        create_zipfile(directory, files_to_zip, 'block2'))

    # remote zip file with only one valid hosts file inside
    file1 = create_blocklist(directory, blocked_hosts=[BLOCKLIST_HOSTS[3]],
                             name='malwarelist', line_format='etc_hosts')
    blocklist3 = blocklist_to_url(create_zipfile(directory, [file1], 'block3'))

    # local text file with valid hosts
    blocklist4 = QUrl.fromLocalFile(str(directory / create_blocklist(
        directory, blocked_hosts=[BLOCKLIST_HOSTS[4]],
        name='mycustomblocklist', line_format='one_per_line')))
    assert blocklist4.isValid(), blocklist4.errorString()

    # remote text file without valid hosts format
    blocklist5 = blocklist_to_url(create_blocklist(
        directory, blocked_hosts=CLEAN_HOSTS, name='notcorrectlist',
        line_format='not_correct'))

    return [blocklist1.toString(), blocklist2.toString(),
            blocklist3.toString(), blocklist4.toString(),
            blocklist5.toString()]


def test_disabled_blocking_update(basedir, config_stub, download_stub,
                                  data_tmpdir, tmpdir, win_registry, caplog):
    """Ensure no URL is blocked when host blocking is disabled."""
    config_stub.val.content.host_blocking.lists = generic_blocklists(tmpdir)
    config_stub.val.content.host_blocking.enabled = False

    host_blocker = adblock.HostBlocker()
    host_blocker.adblock_update()
    while host_blocker._in_progress:
        current_download = host_blocker._in_progress[0]
        with caplog.at_level(logging.ERROR):
            current_download.successful = True
            current_download.finished.emit()
    host_blocker.read_hosts()
    for str_url in URLS_TO_CHECK:
        assert not host_blocker.is_blocked(QUrl(str_url))


def test_no_blocklist_update(config_stub, download_stub,
                             data_tmpdir, basedir, tmpdir, win_registry):
    """Ensure no URL is blocked when no block list exists."""
    config_stub.val.content.host_blocking.lists = None
    config_stub.val.content.host_blocking.enabled = True

    host_blocker = adblock.HostBlocker()
    host_blocker.adblock_update()
    host_blocker.read_hosts()
    for dl in download_stub.downloads:
        dl.successful = True
    for str_url in URLS_TO_CHECK:
        assert not host_blocker.is_blocked(QUrl(str_url))


def test_successful_update(config_stub, basedir, download_stub,
                           data_tmpdir, tmpdir, win_registry, caplog):
    """Ensure hosts from host_blocking.lists are blocked after an update."""
    config_stub.val.content.host_blocking.lists = generic_blocklists(tmpdir)
    config_stub.val.content.host_blocking.enabled = True
    config_stub.val.content.host_blocking.whitelist = None

    host_blocker = adblock.HostBlocker()
    host_blocker.adblock_update()
    # Simulate download is finished
    while host_blocker._in_progress:
        current_download = host_blocker._in_progress[0]
        with caplog.at_level(logging.ERROR):
            current_download.successful = True
            current_download.finished.emit()
    host_blocker.read_hosts()
    assert_urls(host_blocker, whitelisted=[])


def test_parsing_multiple_hosts_on_line(config_stub, basedir, download_stub,
                                        data_tmpdir, tmpdir, win_registry,
                                        caplog):
    """Ensure multiple hosts on a line get parsed correctly"""
    host_blocker = adblock.HostBlocker()
    bytes_host_line = ' '.join(BLOCKLIST_HOSTS).encode('utf-8')
    host_blocker._parse_line(bytes_host_line)
    assert_urls(host_blocker, whitelisted=[])


def test_failed_dl_update(config_stub, basedir, download_stub,
                          data_tmpdir, tmpdir, win_registry, caplog):
    """One blocklist fails to download.

    Ensure hosts from this list are not blocked.
    """
    dl_fail_blocklist = blocklist_to_url(create_blocklist(
        tmpdir, blocked_hosts=CLEAN_HOSTS, name='download_will_fail',
        line_format='one_per_line'))
    hosts_to_block = (generic_blocklists(tmpdir) +
                      [dl_fail_blocklist.toString()])
    config_stub.val.content.host_blocking.lists = hosts_to_block
    config_stub.val.content.host_blocking.enabled = True
    config_stub.val.content.host_blocking.whitelist = None

    host_blocker = adblock.HostBlocker()
    host_blocker.adblock_update()
    while host_blocker._in_progress:
        current_download = host_blocker._in_progress[0]
        # if current download is the file we want to fail, make it fail
        if current_download.name == dl_fail_blocklist.path():
            current_download.successful = False
        else:
            current_download.successful = True
        with caplog.at_level(logging.ERROR):
            current_download.finished.emit()
    host_blocker.read_hosts()
    assert_urls(host_blocker, whitelisted=[])


@pytest.mark.parametrize('location', ['content', 'comment'])
def test_invalid_utf8(config_stub, download_stub, tmpdir, data_tmpdir,
                      caplog, location):
    """Make sure invalid UTF-8 is handled correctly.

    See https://github.com/qutebrowser/qutebrowser/issues/2301
    """
    blocklist = tmpdir / 'blocklist'
    if location == 'comment':
        blocklist.write_binary(b'# nbsp: \xa0\n')
    else:
        assert location == 'content'
        blocklist.write_binary(b'https://www.example.org/\xa0')
    for url in BLOCKLIST_HOSTS:
        blocklist.write(url + '\n', mode='a')

    url = blocklist_to_url('blocklist')
    config_stub.val.content.host_blocking.lists = [url.toString()]
    config_stub.val.content.host_blocking.enabled = True
    config_stub.val.content.host_blocking.whitelist = None

    host_blocker = adblock.HostBlocker()
    host_blocker.adblock_update()
    current_download = host_blocker._in_progress[0]

    if location == 'content':
        with caplog.at_level(logging.ERROR):
            current_download.successful = True
            current_download.finished.emit()
        expected = (r"Failed to decode: "
                    r"b'https://www.example.org/\xa0localhost")
        assert caplog.records[-2].message.startswith(expected)
    else:
        current_download.successful = True
        current_download.finished.emit()

    host_blocker.read_hosts()
    assert_urls(host_blocker, whitelisted=[])


def test_invalid_utf8_compiled(config_stub, config_tmpdir, data_tmpdir,
                               monkeypatch, caplog):
    """Make sure invalid UTF-8 in the compiled file is handled."""
    config_stub.val.content.host_blocking.lists = []

    # Make sure the HostBlocker doesn't delete blocked-hosts in __init__
    monkeypatch.setattr(adblock.HostBlocker, '_update_files',
                        lambda _self: None)

    (config_tmpdir / 'blocked-hosts').write_binary(
        b'https://www.example.org/\xa0')
    (data_tmpdir / 'blocked-hosts').ensure()

    host_blocker = adblock.HostBlocker()
    with caplog.at_level(logging.ERROR):
        host_blocker.read_hosts()
    assert caplog.records[-1].message == "Failed to read host blocklist!"


def test_blocking_with_whitelist(config_stub, basedir, download_stub,
                                 data_tmpdir, tmpdir):
    """Ensure hosts in content.host_blocking.whitelist are never blocked."""
    # Simulate adblock_update has already been run
    # by creating a file named blocked-hosts,
    # Exclude localhost from it as localhost is never blocked via list
    filtered_blocked_hosts = BLOCKLIST_HOSTS[1:]
    blocklist = create_blocklist(data_tmpdir,
                                 blocked_hosts=filtered_blocked_hosts,
                                 name='blocked-hosts',
                                 line_format='one_per_line')
    config_stub.val.content.host_blocking.lists = [blocklist]
    config_stub.val.content.host_blocking.enabled = True
    config_stub.val.content.host_blocking.whitelist = list(WHITELISTED_HOSTS)

    host_blocker = adblock.HostBlocker()
    host_blocker.read_hosts()
    assert_urls(host_blocker)


def test_config_change_initial(config_stub, basedir, download_stub,
                               data_tmpdir, tmpdir):
    """Test emptying host_blocking.lists with existing blocked_hosts.

    - A blocklist is present in host_blocking.lists and blocked_hosts is
      populated
    - User quits qutebrowser, empties host_blocking.lists from his config
    - User restarts qutebrowser, does adblock-update
    """
    create_blocklist(tmpdir, blocked_hosts=BLOCKLIST_HOSTS,
                     name='blocked-hosts', line_format='one_per_line')
    config_stub.val.content.host_blocking.lists = None
    config_stub.val.content.host_blocking.enabled = True
    config_stub.val.content.host_blocking.whitelist = None

    host_blocker = adblock.HostBlocker()
    host_blocker.read_hosts()
    for str_url in URLS_TO_CHECK:
        assert not host_blocker.is_blocked(QUrl(str_url))


def test_config_change(config_stub, basedir, download_stub,
                       data_tmpdir, tmpdir):
    """Ensure blocked-hosts resets if host-block-list is changed to None."""
    filtered_blocked_hosts = BLOCKLIST_HOSTS[1:]  # Exclude localhost
    blocklist = blocklist_to_url(create_blocklist(
        tmpdir, blocked_hosts=filtered_blocked_hosts, name='blocked-hosts',
        line_format='one_per_line'))
    config_stub.val.content.host_blocking.lists = [blocklist.toString()]
    config_stub.val.content.host_blocking.enabled = True
    config_stub.val.content.host_blocking.whitelist = None

    host_blocker = adblock.HostBlocker()
    host_blocker.read_hosts()
    config_stub.set_obj('content.host_blocking.lists', None)
    host_blocker.read_hosts()
    for str_url in URLS_TO_CHECK:
        assert not host_blocker.is_blocked(QUrl(str_url))