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"""Utilities for unit testing"""

import os
import sys
import stat
import tempfile
import unittest
import logging

from ganeti import utils


def GetSourceDir():
  return os.environ.get("TOP_SRCDIR", ".")


def TestDataFilename(name):
  """Returns the filename of a given test data file.

  @type name: str
  @param name: the 'base' of the file name, as present in
      the test/data directory
  @rtype: str
  @return: the full path to the filename, such that it can
      be used in 'make distcheck' rules

  """
  return "%s/test/data/%s" % (GetSourceDir(), name)


def ReadTestData(name):
  """Returns the content of a test data file.

  This is just a very simple wrapper over utils.ReadFile with the
  proper test file name.

  """
  return utils.ReadFile(TestDataFilename(name))


def _SetupLogging(verbose):
  """Setupup logging infrastructure.

  """
  fmt = logging.Formatter("%(asctime)s: %(threadName)s"
                          " %(levelname)s %(message)s")

  if verbose:
    handler = logging.StreamHandler()
  else:
    handler = logging.FileHandler(os.devnull, "a")

  handler.setLevel(logging.NOTSET)
  handler.setFormatter(fmt)

  root_logger = logging.getLogger("")
  root_logger.setLevel(logging.NOTSET)
  root_logger.addHandler(handler)


class GanetiTestProgram(unittest.TestProgram):
  def runTests(self):
    """Runs all tests.

    """
    _SetupLogging("LOGTOSTDERR" in os.environ)

    sys.stderr.write("Running %s\n" % self.progName)
    sys.stderr.flush()

    # Ensure assertions will be evaluated
    if not __debug__:
      raise Exception("Not running in debug mode, assertions would not be"
                      " evaluated")

    # Check again, this time with a real assertion
    try:
      assert False
    except AssertionError:
      pass
    else:
      raise Exception("Assertion not evaluated")

    return unittest.TestProgram.runTests(self)


# pylint: disable=R0904
class GanetiTestCase(unittest.TestCase):
  """Helper class for unittesting.

  This class defines a few utility functions that help in building
  unittests. Child classes must call the parent setup and cleanup.

  """
  def setUp(self):
    self._temp_files = []
    self.patches = {}
    self.mocks = {}

  def MockOut(self, name, patch=None):
    if patch is None:
      patch = name
    self.patches[name] = patch
    self.mocks[name] = patch.start()

  def tearDown(self):
    while self._temp_files:
      try:
        utils.RemoveFile(self._temp_files.pop())
      except EnvironmentError:
        pass

    for patch in self.patches.values():
      patch.stop()

    self.patches = {}
    self.mocks = {}

  def assertFileContent(self, file_name, expected_content):
    """Checks that the content of a file is what we expect.

    @type file_name: str
    @param file_name: the file whose contents we should check
    @type expected_content: str
    @param expected_content: the content we expect

    """
    actual_content = utils.ReadFile(file_name)
    self.assertEqual(actual_content, expected_content)

  def assertFileContentNotEqual(self, file_name, reference_content):
    """Checks that the content of a file is different to the reference.

    @type file_name: str
    @param file_name: the file whose contents we should check
    @type reference_content: str
    @param reference_content: the content we use as reference

    """
    actual_content = utils.ReadFile(file_name)
    self.assertNotEqual(actual_content, reference_content)

  def assertFileMode(self, file_name, expected_mode):
    """Checks that the mode of a file is what we expect.

    @type file_name: str
    @param file_name: the file whose contents we should check
    @type expected_mode: int
    @param expected_mode: the mode we expect

    """
    st = os.stat(file_name)
    actual_mode = stat.S_IMODE(st.st_mode)
    self.assertEqual(actual_mode, expected_mode)

  def assertFileUid(self, file_name, expected_uid):
    """Checks that the user id of a file is what we expect.

    @type file_name: str
    @param file_name: the file whose contents we should check
    @type expected_uid: int
    @param expected_uid: the user id we expect

    """
    st = os.stat(file_name)
    actual_uid = st.st_uid
    self.assertEqual(actual_uid, expected_uid)

  def assertFileGid(self, file_name, expected_gid):
    """Checks that the group id of a file is what we expect.

    @type file_name: str
    @param file_name: the file whose contents we should check
    @type expected_gid: int
    @param expected_gid: the group id we expect

    """
    st = os.stat(file_name)
    actual_gid = st.st_gid
    self.assertEqual(actual_gid, expected_gid)

  def assertEqualValues(self, first, second, msg=None):
    """Compares two values whether they're equal.

    Tuples are automatically converted to lists before comparing.

    """
    return self.assertEqual(UnifyValueType(first),
                            UnifyValueType(second),
                            msg=msg)

  def _CreateTempFile(self):
    """Creates a temporary file and adds it to the internal cleanup list.

    This method simplifies the creation and cleanup of temporary files
    during tests.

    """
    fh, fname = tempfile.mkstemp(prefix="ganeti-test", suffix=".tmp")
    os.close(fh)
    self._temp_files.append(fname)
    return fname

# pylint: enable=R0904


def patch_object(*args, **kwargs):
  """Unified patch_object for various versions of Python Mock.

  Different Python Mock versions provide incompatible versions of patching an
  object. More recent versions use _patch_object, older ones used patch_object.
  This function unifies the different variations.

  """
  import mock
  try:
    # pylint: disable=W0212
    return mock._patch_object(*args, **kwargs)
  except AttributeError:
    # pylint: disable=E1101
    return mock.patch_object(*args, **kwargs)


def UnifyValueType(data):
  """Converts all tuples into lists.

  This is useful for unittests where an external library doesn't keep types.

  """
  if isinstance(data, (tuple, list)):
    return [UnifyValueType(i) for i in data]

  elif isinstance(data, dict):
    return dict([(UnifyValueType(key), UnifyValueType(value))
                 for (key, value) in data.iteritems()])

  return data


class CallCounter(object):
  """Utility class to count number of calls to a function/method.

  """
  def __init__(self, fn):
    """Initializes this class.

    @type fn: Callable

    """
    self._fn = fn
    self._count = 0

  def __call__(self, *args, **kwargs):
    """Calls wrapped function with given parameters.

    """
    self._count += 1
    return self._fn(*args, **kwargs)

  def Count(self):
    """Returns number of calls.

    @rtype: number

    """
    return self._count