"""
This file provides a single interface to unittest objects for our
tests while supporting python < 2.7 via unittest2.

If you need something from the unittest namespace it should be
imported here from the relevant module and then imported into your
test from here
"""

# Import python libs
import os
import sys
import logging
from functools import wraps

# support python < 2.7 via unittest2
if sys.version_info[0:2] < (2, 7):
    try:
        from unittest2 import (
            TestLoader,
            TextTestRunner,
            TestCase,
            expectedFailure,
            TestSuite,
            skipIf,
        )
    except ImportError:
        raise SystemExit("You need to install unittest2 to run the salt tests")
else:
    from unittest import (
        TestLoader,
        TextTestRunner,
        TestCase,
        expectedFailure,
        TestSuite,
        skipIf,
    )


# Set up paths
TEST_DIR = os.path.dirname(os.path.normpath(os.path.abspath(__file__)))
SALT_LIBS = os.path.dirname(TEST_DIR)

for dir_ in [TEST_DIR, SALT_LIBS]:
    if not dir_ in sys.path:
        sys.path.insert(0, dir_)


def destructiveTest(func):
    @wraps(func)
    def wrap(cls):
        if os.environ.get('DESTRUCTIVE_TESTS', 'False').lower() == 'false':
            cls.skipTest('Destructive tests are disabled')
        return func(cls)
    return wrap


class RedirectStdStreams(object):
    """
    Temporarily redirect system output to file like objects.
    Default is to redirect to `os.devnull`, which just mutes output, `stdout`
    and `stderr`.
    """

    def __init__(self, stdout=None, stderr=None):
        if stdout is None:
            stdout = open(os.devnull, 'w')
        if stderr is None:
            stderr = open(os.devnull, 'w')

        self.__stdout = stdout
        self.__stderr = stderr
        self.__redirected = False

    def __enter__(self):
        self.redirect()

    def __exit__(self, exc_type, exc_value, traceback):
        self.unredirect()

    def redirect(self):
        self.old_stdout = sys.stdout
        self.old_stdout.flush()
        self.old_stderr = sys.stderr
        self.old_stderr.flush()
        sys.stdout = self.__stdout
        sys.stderr = self.__stderr
        self.__redirected = True

    def unredirect(self):
        if not self.__redirected:
            return

        self.__stdout.flush()
        self.__stdout.close()
        self.__stderr.flush()
        self.__stderr.close()
        sys.stdout = self.old_stdout
        sys.stderr = self.old_stderr


class TestsLoggingHandler(object):
    '''
    Simple logging handler which can be used to test if certain logging
    messages get emitted or not::

    ..code-block: python

        with TestsLoggingHandler() as handler:
            # (...)               Do what ever you wish here
            handler.messages    # here are the emitted log messages

    '''
    def __init__(self, level=0, format='%(levelname)s:%(message)s'):
        self.level = level
        self.format = format
        self.activated = False
        self.prev_logging_level = None

    def activate(self):
        class Handler(logging.Handler):
            def __init__(self, level):
                logging.Handler.__init__(self, level)
                self.messages = []

            def emit(self, record):
                self.messages.append(self.format(record))

        self.handler = Handler(self.level)
        formatter = logging.Formatter(self.format)
        self.handler.setFormatter(formatter)
        logging.root.addHandler(self.handler)
        self.activated = True
        # Make sure we're running with the lowest logging level with our
        # tests logging handler
        current_logging_level = logging.root.getEffectiveLevel()
        if current_logging_level > logging.DEBUG:
            self.prev_logging_level = current_logging_level
            logging.root.setLevel(0)

    def deactivate(self):
        if not self.activated:
            return
        logging.root.removeHandler(self.handler)
        # Restore previous logging level if changed
        if self.prev_logging_level is not None:
            logging.root.setLevel(self.prev_logging_level)

    @property
    def messages(self):
        if not self.activated:
            return []
        return self.handler.messages

    def clear(self):
        self.handler.messages = []

    def __enter__(self):
        self.activate()
        return self

    def __exit__(self, type, value, traceback):
        self.deactivate()
        self.activated = False