# -*- coding: utf-8 -*-
# Copyright (C) 2015 Anne Mulhern <amulhern@redhat.com>

# This library is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation; either version 2.1 of the License, or (at your
# option) any later version.

# This library 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 Lesser General Public License
# for more details.

# You should have received a copy of the GNU Lesser General Public License
# along with this library; if not, write to the Free Software Foundation,
# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

"""
    tests.test_discover
    ===================

    Tests discovering what device is meant by somewhat unspecific information.

    .. moduleauthor:: mulhern <amulhern@redhat.com>
"""


from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import os

import pyudev

from pyudev import DeviceFileHypothesis
from pyudev import DeviceNameHypothesis
from pyudev import DeviceNumberHypothesis
from pyudev import DevicePathHypothesis
from pyudev import Discovery

import pytest

from hypothesis import assume
from hypothesis import given
from hypothesis import settings
from hypothesis import strategies


_CONTEXT = pyudev.Context()
_DEVICES = _CONTEXT.list_devices()

NUM_TESTS = 5

class TestUtilities(object):
    """
    Some utilities used by the actual tests.
    """

    @staticmethod
    def get_device_numbers(a_device, a_string):
        """
        Get the device number from the device in a few formats.

        :param :class:`Device` a_device: the device
        :param  str a_string: a likely string between the major and minor
        :returns: a tuple of device numbers
        :rtype: tuple of str
        """
        device_number = a_device.device_number
        major_number = os.major(device_number)
        minor_number = os.minor(device_number)
        pair_number = "%s%s%s" % (major_number, a_string, minor_number)
        return (str(device_number), pair_number)

    @staticmethod
    def get_paths(a_device):
        """
        Get some variants on a device path.

        :param :class:`Device` a_device: the device
        :returns: a tuple of paths in sysfs
        :rtype: tuple of str
        """
        sys_path = a_device.sys_path
        (_, _, truncated_path) = sys_path[1:].partition('/')
        return (sys_path, truncated_path, a_device.device_path)

    @staticmethod
    def get_files(a_device):
        """
        Get a bunch of files, including device nodes and links.

        :param :class:`Device` a_device: the device
        :returns: a list of files
        :rtype: list of str
        """
        links = list(a_device.device_links)
        names = [os.path.basename(l) for l in links]
        links.extend(names)

        device_node = a_device.device_node
        if device_node:
            links.append(device_node)
        return links

class TestDiscovery(object):
    """
    Test discovery of an object from limited bits of its description.
    """

    _CONTEXT = pyudev.Context()
    _DISCOVER = Discovery()
    _DISCOVER.setup(_CONTEXT)

    @given(
       strategies.sampled_from(_DEVICES).filter(lambda x: x.device_number),
       strategies.text(":, -/+=").filter(lambda x: x)
    )
    @settings(max_examples=NUM_TESTS)
    def test_device_number(self, a_device, a_string):
        """
        Test lookup by a device number.

        Note that device number is per class, so there may be two
        devices with the same device number.
        """
        for number in TestUtilities.get_device_numbers(a_device, a_string):
            res = DeviceNumberHypothesis.get_devices(self._CONTEXT, number)
            assert a_device in res

    @given(strategies.sampled_from(_DEVICES))
    @settings(max_examples=NUM_TESTS)
    def test_path(self, a_device):
        """
        Test lookup by path.
        """
        for path in TestUtilities.get_paths(a_device):
            res = DevicePathHypothesis.get_devices(self._CONTEXT, path)
            assert res == set((a_device,))

    @given(strategies.sampled_from(_DEVICES))
    @settings(max_examples=NUM_TESTS)
    def test_name(self, a_device):
        """
        Test lookup by device name.

        Note that there may be multiple devices corresponding to the name
        in different subsystems.
        """
        name = a_device.sys_name
        res = DeviceNameHypothesis.get_devices(self._CONTEXT, name)
        assert a_device in res

    _devices = [d for d in _DEVICES if list(d.device_links)]
    @pytest.mark.skipif(
        len(_devices) == 0,
        reason="no device with device links"
    )
    @given(strategies.sampled_from(_devices))
    @settings(max_examples=NUM_TESTS, min_satisfying_examples=1)
    def test_device_file(self, a_device):
        """
        Test lookup by device file.

        Skip any devices that are multipath device paths because links
        may point to other paths in multipath group (rhbz#1263441).
        """
        assume(not 'DM_MULTIPATH_TIMESTAMP' in a_device.properties)
        links = TestUtilities.get_files(a_device)
        devs = frozenset(
           d for l in links for d in DeviceFileHypothesis.get_devices(
              self._CONTEXT,
              l
           )
        )
        assert devs == set((a_device,))

    @given(
       strategies.sampled_from(_DEVICES),
       strategies.text(":, -/+=").filter(lambda x: x)
    )
    @settings(max_examples=NUM_TESTS)
    def test_anything(self, a_device, a_string):
        """
        Grab any of the likely candidates for looking up a device.
        """
        assume(not 'DM_MULTIPATH_TIMESTAMP' in a_device.properties)

        values = list(TestUtilities.get_device_numbers(a_device, a_string))
        values.extend(TestUtilities.get_paths(a_device))
        values.append(a_device.sys_name)
        values.extend(TestUtilities.get_files(a_device))

        results = frozenset(
           d for v in values for d in self._DISCOVER.get_devices(
              self._CONTEXT,
              v
           )
        )

        assert a_device in results
