import unittest
import dbus
import subprocess
import os
import time
import re
import shutil
import sys
import multiprocessing
from datetime import datetime
from enum import Enum
from systemd import journal
from time import monotonic

import gi
gi.require_version('GUdev', '1.0')
from gi.repository import GUdev

test_devs = None
FLIGHT_RECORD_FILE = "flight_record.log"

multiprocessing.set_start_method("fork")


def run_command(command):
    res = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE)

    out, err = res.communicate()
    if res.returncode != 0:
        output = out.decode().strip() + "\n\n" + err.decode().strip()
    else:
        output = out.decode().strip()
    return (res.returncode, output)


def get_call_long(call):
    def call_long(*args, **kwargs):
        """Do an async call with a very long timeout (unless specified otherwise)"""
        if 'timeout' not in kwargs:
            kwargs['timeout'] = 100  # seconds
        return call(*args, **kwargs)

    return call_long


def get_version_from_lsb():
    ret, out = run_command("lsb_release -rs")
    if ret != 0:
        raise RuntimeError("Cannot get distro version from lsb_release output: '%s'" % out)

    return out.split(".")[0]


def get_version_from_pretty_name(pretty_name):
    """ Try to get distro and version from 'OperatingSystemPrettyName'
        hostname property.

        It should look like this:
         - "Debian GNU/Linux 9 (stretch)"
         - "Fedora 27 (Workstation Edition)"
         - "CentOS Linux 7 (Core)"

        So just return first word as distro and first number as version.
    """
    distro = pretty_name.split()[0].lower()
    match = re.search(r"\d+", pretty_name)
    if match is not None:
        version = match.group(0)
    else:
        version = get_version_from_lsb()

    return (distro, version)


def get_version():
    """ Try to get distro and version
    """

    bus = dbus.SystemBus()

    # get information about the distribution from systemd (hostname1)
    sys_info = bus.get_object("org.freedesktop.hostname1", "/org/freedesktop/hostname1")
    cpe = str(sys_info.Get("org.freedesktop.hostname1", "OperatingSystemCPEName", dbus_interface=dbus.PROPERTIES_IFACE))

    if cpe:
        # 2nd to 4th fields from e.g. "cpe:/o:fedoraproject:fedora:25" or "cpe:/o:redhat:enterprise_linux:7.3:GA:server"
        _project, distro, version = tuple(cpe.split(":")[2:5])
        # we want just the major version, so remove all decimal places (if any)
        version = str(int(float(version)))
    else:
        pretty_name = str(sys_info.Get("org.freedesktop.hostname1", "OperatingSystemPrettyName", dbus_interface=dbus.PROPERTIES_IFACE))
        distro, version = get_version_from_pretty_name(pretty_name)

    return (distro, version)


class DBusProperty(object):

    TIMEOUT = 5

    def __init__(self, obj, iface, prop):
        self.obj = obj
        self.iface = iface
        self.prop = prop

        self._value = None

    @property
    def value(self):
        if self._value is None:
            self._update_value()
        return self._value

    def _update_value(self):
        self._value = self.obj.Get(self.iface, self.prop, dbus_interface=dbus.PROPERTIES_IFACE)

    def _check(self, timeout, check_fn, poll_vg=None):
        for _ in range(int(timeout / 0.5)):
            try:
                self._update_value()
                if check_fn(self.value):
                    return True
            except Exception:
                # ignore all exceptions -- they might be result of property
                # not having the expected type (e.g. 'None' when checking for len)
                pass
            if poll_vg:
                poll_vg.Poll(dbus_interface='org.freedesktop.UDisks2.VolumeGroup')
            time.sleep(0.5)

        return False

    def assertEqual(self, value, timeout=TIMEOUT, getter=None, poll_vg=None, msg=None):
        if getter is not None:
            check_fn = lambda x: getter(x) == value
        else:
            check_fn = lambda x: x == value
        ret = self._check(timeout, check_fn, poll_vg)

        if not ret:
            if getter is not None:
                raise AssertionError('%s != %s%s' % (getter(self._value), value, ' (%s)' % msg if msg else ''))
            else:
                raise AssertionError('%s != %s%s' % (self._value, value, ' (%s)' % msg if msg else ''))

    def assertNotEqual(self, value, timeout=TIMEOUT, getter=None, msg=None):
        if getter is not None:
            check_fn = lambda x: getter(x) != value
        else:
            check_fn = lambda x: x != value
        ret = self._check(timeout, check_fn)

        if not ret:
            if getter is not None:
                raise AssertionError('%s != %s%s' % (getter(self._value), value, ' (%s)' % msg if msg else ''))
            else:
                raise AssertionError('%s != %s%s' % (self._value, value, ' (%s)' % msg if msg else ''))

    def assertAlmostEqual(self, value, delta, timeout=TIMEOUT, getter=None):
        if getter is not None:
            check_fn = lambda x: abs(getter(x) - value) <= delta
        else:
            check_fn = lambda x: abs(x - value) <= delta
        ret = self._check(timeout, check_fn)

        if not ret:
            if getter is not None:
                raise AssertionError('%s is not almost equal to %s (delta = %s)' % (getter(self._value),
                                                                                    value, delta))
            else:
                raise AssertionError('%s is not almost equal to %s (delta = %s)' % (self._value,
                                                                                    value, delta))

    def assertGreater(self, value, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: x > value
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s is not greater than %s%s' % (self._value, value, ' (%s)' % msg if msg else ''))

    def assertLess(self, value, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: x < value
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s is not less than %s%s' % (self._value, value, ' (%s)' % msg if msg else ''))

    def assertIn(self, lst, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: x in lst
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s not found in %s' % (self._value, lst))

    def assertNotIn(self, lst, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: x not in lst
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s unexpectedly found in %s%s' % (self._value, lst, ' (%s)' % msg if msg else ''))

    def assertTrue(self, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: bool(x)
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s is not true%s' % (self._value, ' (%s)' % msg if msg else ''))

    def assertFalse(self, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: not bool(x)
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s is not false%s' % (self._value, ' (%s)' % msg if msg else ''))

    def assertIsNone(self, timeout=TIMEOUT):
        check_fn = lambda x: x is None
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s is not None' % self._value)

    def assertIsNotNone(self, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: x is not None
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('unexpectedly None%s' % ' (%s)' % msg if msg else '')

    def assertLen(self, length, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: len(x) == length
        ret = self._check(timeout, check_fn)

        if not ret:
            if not hasattr(self._value, '__len__'):
                raise AssertionError('%s has no length' % type(self._value))
            else:
                raise AssertionError('Expected length %d, but %s has length %d%s' % (length,
                                                                                     self._value,
                                                                                     len(self._value,
                                                                                     ' (%s)' % msg if msg else '')))
    def assertContains(self, member, timeout=TIMEOUT, msg=None):
        check_fn = lambda x: member in x
        ret = self._check(timeout, check_fn)

        if not ret:
            raise AssertionError('%s does not contain %s%s' % (self._value, member, ' (%s)' % msg if msg else ''))


class UdisksTestCase(unittest.TestCase):
    iface_prefix = None
    path_prefix = None
    bus = None
    vdevs = None
    distro = (None, None, None)       # (project, distro_name, version)
    no_options = dbus.Dictionary(signature="sv")

    @classmethod
    def setUpClass(self):
        self.iface_prefix = 'org.freedesktop.UDisks2'
        self.path_prefix = '/org/freedesktop/UDisks2'
        self.bus = dbus.SystemBus()

        self.distro = get_version()

        self._orig_call_async = self.bus.call_async
        self._orig_call_blocking = self.bus.call_blocking
        self.bus.call_async = get_call_long(self._orig_call_async)
        self.bus.call_blocking = get_call_long(self._orig_call_blocking)
        self.vdevs = test_devs
        assert len(self.vdevs) > 3

    @classmethod
    def tearDownClass(self):
        self.bus.call_async = self._orig_call_async
        self.bus.call_blocking = self._orig_call_blocking

    def run(self, *args):
        record = []
        now = datetime.now()
        now_mono = monotonic()
        with open(FLIGHT_RECORD_FILE, "a") as record_f:
            record_f.write("================%s[%0.8f] %s.%s.%s================\n" % (now.strftime('%Y-%m-%d %H:%M:%S'),
                                                                                     now_mono,
                                                                                     self.__class__.__module__,
                                                                                     self.__class__.__name__,
                                                                                     self._testMethodName))
            with JournalRecorder("journal", record):
                with CmdFlightRecorder("udisksctl monitor", ["udisksctl", "monitor"], record):
                    with CmdFlightRecorder("udevadm monitor", ["udevadm", "monitor"], record):
                        super(UdisksTestCase, self).run(*args)
            record_f.write("".join(record))
        self.udev_settle()

    @classmethod
    def get_object(self, path_suffix):
        # if given full path, just use it, otherwise prepend the prefix
        if path_suffix.startswith(self.path_prefix):
            path = path_suffix
        else:
            path = self.path_prefix + path_suffix
        try:
            # self.iface_prefix is the same as the DBus name we acquire
            obj = self.bus.get_object(self.iface_prefix, path)
        except:
            obj = None
        return obj

    @classmethod
    def get_interface(self, obj, iface_suffix):
        """Get interface for the given object either specified by an object path suffix
        (appended to the common UDisks2 prefix) or given as the object
        itself.

        :param obj: object to get the interface for
        :type obj: str or dbus.proxies.ProxyObject
        :param iface_suffix: suffix appended to the common UDisks2 interface prefix
        :type iface_suffix: str

        """
        if isinstance(obj, str):
            obj = self.get_object(obj)
        return dbus.Interface(obj, self.iface_prefix + iface_suffix)

    @classmethod
    def get_property(self, obj, iface_suffix, prop):
        return DBusProperty(obj, self.iface_prefix + iface_suffix, prop)

    @classmethod
    def get_property_raw(self, obj, iface_suffix, prop):
        res = obj.Get(self.iface_prefix + iface_suffix, prop, dbus_interface=dbus.PROPERTIES_IFACE)
        return res

    @classmethod
    def get_device(self, dev_name):
        """Get block device object for a given device (e.g. "sda")"""
        dev = self.get_object('/block_devices/' + os.path.basename(dev_name))
        return dev

    @classmethod
    def get_drive_name(self, device):
        """Get drive name for the given block device object"""
        drive_name = self.get_property_raw(device, '.Block', 'Drive').split('/')[-1]
        return drive_name

    @classmethod
    def udev_settle(self):
        self.run_command('udevadm settle')

    @classmethod
    def wipe_fs(self, device):
        for _ in range(10):
            ret, _out = self.run_command('wipefs -a %s' % device)
            if ret == 0:
                return True
            time.sleep(1)

        return False

    def try_unmount(self, path):
        """Handle unmount and retry if busy"""
        for _ in range(10):
            ret, out = self.run_command('umount %s' % path)
            # the mount may either be unmounted already or not exist anymore
            if ret == 0 or "not mounted" in out or "no mount point specified" in out or "mountpoint not found" in out:
                return
            if "target is busy" not in out:
                break
            time.sleep(0.5)
        self.fail('Failed to unmount %s: %s' % (path, out))

    def _conf_backup(self, conf_file):
        """ Backup and restore @conf_file during cleanup. If @conf_file doesn't exist, it
            will be removed during cleanup
        """
        if os.path.exists(conf_file):
            # conf file exists -> backup and restore
            contents = self.read_file(conf_file)
            self.addCleanup(self.write_file, conf_file, contents)
        else:
            # conf file doesn't exist -> remove during cleanup
            self.addCleanup(shutil.rmtree, conf_file, True)

    @classmethod
    def read_file(self, filename):
        with open(filename, 'r') as f:
            content = f.read()
        return content

    @classmethod
    def write_file(self, filename, content, ignore_nonexistent=False, binary=False):
        try:
            with open(filename, 'wb' if binary else 'w') as f:
                f.write(content)
        except OSError as e:
            if not ignore_nonexistent:
                raise e

    @classmethod
    def remove_file(self, filename, ignore_nonexistent=False):
        try:
            os.remove(filename)
        except OSError as e:
            if not ignore_nonexistent:
                raise e

    @classmethod
    def run_command(self, command):
        return run_command(command)

    @classmethod
    def module_available(cls, module):
        ret, _out = cls.run_command('modprobe %s' % module)
        return ret == 0

    @classmethod
    def check_module_loaded(self, module):
        """Tries to load specified module. No checks for extra Manager interface are done.
           Returns False when module is not available, True when the module initialized
           successfully, raises an exception otherwise.
        """
        manager_obj = self.get_object('/Manager')
        manager = self.get_interface(manager_obj, '.Manager')
        try:
            manager.EnableModule(module, dbus.Boolean(True))
            return True
        except dbus.exceptions.DBusException as e:
            msg = r"Error initializing module '%s': .*\.so: cannot open shared object file: No such file or directory" % module
            if re.search(msg, e.get_dbus_message()):
                return False
            else:
                raise

    @classmethod
    def ay_to_str(self, ay):
        """Convert a bytearray (terminated with '\0') to a string"""

        return ''.join(chr(x) for x in ay[:-1])

    @classmethod
    def str_to_ay(self, string, terminate=True):
        """Convert a string to a bytearray (terminated with '\0')"""

        if terminate:
            string += '\0'

        return dbus.Array([dbus.Byte(ord(c)) for c in string],
                          signature=dbus.Signature('y'), variant_level=1)

    @classmethod
    def bytes_to_ay(self, bytes):
        """Convert Python bytes to a DBus bytearray"""

        return dbus.Array([dbus.Byte(b) for b in bytes],
                          signature=dbus.Signature('y'), variant_level=1)

    @classmethod
    def set_udev_properties(self, device, props):
        """Sets one or more udev properties for the 'device' identified by its serial number.
           Note that this overwrites previously set properties. Pass props=None to remove
           the rules.

        :type props: dict
        """
        UDISKS_UDEV_RULES = "/run/udev/rules.d/99-udisks_test.rules"

        udev = GUdev.Client()
        dev = udev.query_by_device_file(device)
        serial = dev.get_property("ID_SERIAL")

        try:
            os.makedirs("/run/udev/rules.d/")
        except OSError:
            # already exists
            pass

        if props:
            rules = ""
            for i in props:
                rules += ', ENV{%s}="%s"' % (i, props[i])
            self.write_file(UDISKS_UDEV_RULES,
                            'ENV{ID_SERIAL}=="%s"%s\n' % (serial, rules))
        else:
            self.remove_file(UDISKS_UDEV_RULES, ignore_nonexistent=True)
        self.run_command("udevadm control --reload")
        uevent_path = os.path.join(dev.get_sysfs_path(), "uevent")
        self.write_file(uevent_path, "change\n")
        self.udev_settle()
        # FIXME: need to give udisksd some time to process the uevent
        time.sleep(1)

    @classmethod
    def assertHasIface(self, obj, iface):
        for _ in range(20):
            obj_intro = dbus.Interface(obj, "org.freedesktop.DBus.Introspectable")
            intro_data = obj_intro.Introspect()
            if 'interface name="%s"' % iface in intro_data:
                return
            time.sleep(0.5)

        raise AssertionError("Object '%s' has no interface '%s'" % (obj.object_path, iface))

    def assertStartswith(self, val, prefix):
        if not val.startswith(prefix):
            raise AssertionError("'%s' does not start with '%s'" % (val, prefix))


class FlightRecorder(object):
    """Context manager for recording data/logs

    This is the abstract implementation that does nothing. Subclasses are
    expected to override the methods below to actually do something useful.

    """

    def __init__(self, desc):
        """
        :param str desc: description of the recorder

        """
        self._desc = desc

    def _start(self):
        """Start recording"""

    def _stop(self):
        """Stop recording"""
        pass

    def _save(self):
        """Save the record"""
        pass

    def __enter__(self):
        self._start()

    def __exit__(self, exc_type, exc_val, exc_tb):
        self._stop()
        self._save()

        # Returning False means that the exception we have potentially been
        # given as arguments was not handled
        return False


class CmdFlightRecorder(FlightRecorder):
    """Flight recorder running a command and gathering its standard and error output"""

    def __init__(self, desc, argv, store):
        """
        :param str desc: description of the recorder
        :param argv: command and arguments to run
        :type argv: list of str
        :param store: a list-like object to append the data/logs to

        """
        super(CmdFlightRecorder, self).__init__(desc)
        self._argv = argv
        self._store = store
        self._proc = None

    def _start(self):
        self._proc = subprocess.Popen(self._argv, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

    def _stop(self):
        self._proc.terminate()

    def _save(self):
        # err is in out (see above)
        out, _err = self._proc.communicate()
        rec = '<<<<< ' + self._desc + ' >>>>>' + '\n' + out.decode() + '\n\n'
        self._store.append(rec)


class JournalRecorder(FlightRecorder):
    """Flight recorder for gathering logs (journal)"""

    def __init__(self, desc, store):
        """
        :param str desc: description of the recorder
        :param store: a list-like object to append the data/logs to

        """
        super(JournalRecorder, self).__init__(desc)
        self._store = store
        self._started = None
        self._stopped = None

    def _start(self):
        self._started = time.time()

    def _stop(self):
        self._stopped = time.time()

    def _save(self):
        j = journal.Reader(converters={"MESSAGE": lambda x: x.decode(errors="replace")})
        j.this_boot()
        j.seek_realtime(self._started)
        journal_data = ""

        entry = j.get_next()
        while entry and int(entry["__REALTIME_TIMESTAMP"].timestamp()) <= int(self._stopped):
            if "_COMM" in entry and "_PID" in entry:
                source = "%s[%d]" % (entry["_COMM"], entry["_PID"])
            else:
                source = "kernel"
            journal_data += "%s[%0.8f] %s: %s\n" % (entry["__REALTIME_TIMESTAMP"].strftime("%H:%M:%S"),
                                                    entry["__MONOTONIC_TIMESTAMP"][0].total_seconds(),
                                                    source, entry["MESSAGE"])
            entry = j.get_next()
        rec = '<<<<< ' + self._desc + ' >>>>>' + '\n' + journal_data + '\n\n\n'
        self._store.append(rec)


class TestTags(Enum):
    ALL = "all"               # "default" tag for running all tests
    SLOW = "slow"             # slow tests
    UNSTABLE = "unstable"     # randomly failing tests
    UNSAFE = "unsafe"         # tests that change system configuration
    NOSTORAGE = "nostorage"   # tests that don't work with storage
    EXTRADEPS = "extradeps"   # tests that require special configuration and/or device to run

    @classmethod
    def get_tags(cls):
        return [t.value for t in cls.__members__.values()]

    @classmethod
    def get_tag_by_value(cls, value):
        tag = next((t for t in cls.__members__.values() if t.value == value), None)

        if not tag:
            raise ValueError('Unknown value "%s"' % value)

        return tag


def tag_test(*tags):
    def decorator(func):
        func.slow = TestTags.SLOW in tags
        func.unstable = TestTags.UNSTABLE in tags
        func.unsafe = TestTags.UNSAFE in tags
        func.nostorage = TestTags.NOSTORAGE in tags
        func.extradeps = TestTags.EXTRADEPS in tags

        return func

    return decorator
