# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
This module prvoides the tools used to internally run the astropy test suite
from the installed astropy.  It makes use of the `pytest` testing framework.
"""

import errno
import shlex
import sys
import base64
import zlib
import functools
import os
import subprocess
import shutil
import tempfile

try:
    # Import pkg_resources to prevent it from issuing warnings upon being
    # imported from within py.test.  See
    # https://github.com/astropy/astropy/pull/537 for a detailed explanation.
    import pkg_resources
except ImportError:
    pass

from distutils.core import Command

from .. import test

if os.environ.get('ASTROPY_USE_SYSTEM_PYTEST') or '_pytest' in sys.modules:
    import pytest

else:
    from ..extern import pytest as extern_pytest

    if sys.version_info >= (3, 0):
        exec("def do_exec_def(co, loc): exec(co, loc)\n")
        extern_pytest.do_exec = do_exec_def

        import pickle
        unpacked_sources = extern_pytest.sources.encode("ascii")
        unpacked_sources = pickle.loads(
            zlib.decompress(base64.decodebytes(unpacked_sources)))
    else:
        exec("def do_exec_def(co, loc): exec co in loc\n")
        extern_pytest.do_exec = do_exec_def

        import pickle as pickle
        unpacked_sources = pickle.loads(
            zlib.decompress(base64.decodestring(extern_pytest.sources)))

    importer = extern_pytest.DictImporter(unpacked_sources)
    sys.meta_path.append(importer)

    pytest = importer.load_module('pytest')


# Monkey-patch py.test to work around issue #811
# https://github.com/astropy/astropy/issues/811
from _pytest.assertion import rewrite as _rewrite
_orig_write_pyc = _rewrite._write_pyc
def _write_pyc_wrapper(co, source_path, pyc):
    """Wraps the internal _write_pyc method in py.test to recognize
    PermissionErrors and just stop trying to cache its generated pyc files if
    it can't write them to the __pycache__ directory.

    When py.test scans for test modules, it actually rewrites the bytecode
    of each test module it discovers--this is how it manages to add extra
    instrumentation to the assert builtin.  Normally it caches these
    rewritten bytecode files--``_write_pyc()`` is just a function that handles
    writing the rewritten pyc file to the cache.  If it returns ``False`` for
    any reason py.test will stop trying to cache the files altogether.  The
    original function catches some cases, but it has a long-standing bug of
    not catching permission errors on the ``__pycache__`` directory in Python
    3.  Hence this patch.
    """

    try:
        return _orig_write_pyc(co, source_path, pyc)
    except IOError as e:
        if e.errno == errno.EACCES:
            return False
_rewrite._write_pyc = _write_pyc_wrapper


# pytest marker to mark tests which get data from the web
remote_data = pytest.mark.remote_data


class TestRunner(object):
    def __init__(self, base_path):
        self.base_path = base_path

    def run_tests(self, package=None, test_path=None, args=None, plugins=None,
                  verbose=False, pastebin=None, remote_data=False, pep8=False,
                  pdb=False, coverage=False, open_files=False):
        """
        The docstring for this method lives in astropy/__init__.py:test
        """
        if package is None:
            package_path = self.base_path
        else:
            package_path = os.path.join(self.base_path,
                                        package.replace('.', os.path.sep))

            if not os.path.isdir(package_path):
                raise ValueError('Package not found: {0}'.format(package))

        if test_path:
            package_path = os.path.join(package_path,
                                        os.path.abspath(test_path))

        all_args = package_path

        # add any additional args entered by the user
        if args is not None:
            all_args += ' {0}'.format(args)

        # add verbosity flag
        if verbose:
            all_args += ' -v'

        # turn on pastebin output
        if pastebin is not None:
            if pastebin in ['failed', 'all']:
                all_args += ' --pastebin={0}'.format(pastebin)
            else:
                raise ValueError("pastebin should be 'failed' or 'all'")

        # run @remote_data tests
        if remote_data:
            all_args += ' --remote-data'

        if pep8:
            try:
                import pytest_pep8
            except ImportError:
                raise ImportError('PEP8 checking requires pytest-pep8 plugin: '
                                  'http://pypi.python.org/pypi/pytest-pep8')
            else:
                all_args += ' --pep8 -k pep8'

        # activate post-mortem PDB for failing tests
        if pdb:
            all_args += ' --pdb'

        if coverage:
            try:
                import pytest_cov
            except ImportError:
                raise ImportError(
                    'Coverage reporting requires pytest-cov plugin: '
                    'http://pypi.python.org/pypi/pytest-cov')
            else:
                # Don't use get_pkg_data_filename here, because it
                # requires importing astropy.config and thus screwing
                # up coverage results for those packages.
                coveragerc = os.path.join(
                    os.path.dirname(__file__), 'coveragerc')

                # We create a coveragerc that is specific to the version
                # of Python we're running, so that we can mark branches
                # as being specifically for Python 2 or Python 3
                with open(coveragerc, 'r') as fd:
                    coveragerc_content = fd.read()
                if sys.version_info[0] >= 3:
                    ignore_python_version = '2'
                else:
                    ignore_python_version = '3'
                coveragerc_content = coveragerc_content.replace(
                    "{ignore_python_version}", ignore_python_version)
                with tempfile.NamedTemporaryFile(delete=False) as tmp:
                    tmp.write(coveragerc_content)

                all_args += (
                    ' --cov-report html --cov astropy'
                    ' --cov-config {0}'.format(tmp.name))

        # check for opened files after each test
        if open_files:
            try:
                subproc = subprocess.Popen(
                    ['lsof -F0 -n -p {0}'.format(os.getpid())],
                    shell=True, stdout=subprocess.PIPE)
                output = subproc.communicate()[0].strip()
            except subprocess.CalledProcessError:
                raise SystemError(
                    "open file detection requested, but could not "
                    "successfully run the 'lsof' command")

            all_args += ' --open-files'

            print("Checking for unclosed files")

        try:
            all_args = shlex.split(
                all_args, posix=not sys.platform.startswith('win'))

            result = pytest.main(args=all_args, plugins=plugins)
        finally:
            if coverage:
                if not tmp.closed:
                    tmp.close()
                os.remove(tmp.name)

        return result

    run_tests.__doc__ = test.__doc__


class astropy_test(Command, object):
    user_options = [
        ('package=', 'P',
         "The name of a specific package to test, e.g. 'io.fits' or 'utils'.  "
         "If nothing is specified all default Astropy tests are run."),
        ('test-path=', 't', 'Specify a test location by path. Must be '
         'specified absolutely or relative to the current directory. '
         'May be a single file or directory.'),
        ('verbose-results', 'V',
         'Turn on verbose output from pytest. Same as specifying `-v` in '
         '`args`.'),
        ('plugins=', 'p',
         'Plugins to enable when running pytest.  Same as specifying `-p` in '
         '`args`.'),
        ('pastebin=', 'b',
         "Enable pytest pastebin output. Either 'all' or 'failed'."),
        ('args=', 'a', 'Additional arguments to be passed to pytest'),
        ('remote-data', 'R', 'Run tests that download remote data'),
        ('pep8', '8', 'Enable PEP8 checking and disable regular tests. '
         'Same as specifying `--pep8 -k pep8` in `args`. Requires the '
         'pytest-pep8 plugin.'),
        ('pdb', 'd', 'Turn on PDB post-mortem analysis for failing tests. '
         'Same as specifying `--pdb` in `args`.'),
        ('coverage', 'c', 'Create a coverage report. Requires the pytest-cov '
         'plugin is installed'),
        ('open-files', 'o', 'Fail if any tests leave files open')
    ]

    package_name = None

    def initialize_options(self):
        self.package = None
        self.test_path = None
        self.verbose_results = False
        self.plugins = None
        self.pastebin = None
        self.args = None
        self.remote_data = False
        self.pep8 = False
        self.pdb = False
        self.coverage = False
        self.open_files = False

    def finalize_options(self):
        # Normally we would validate the options here, but that's handled in
        # run_tests
        pass

    def run(self):
        self.reinitialize_command('build', inplace=False)
        self.run_command('build')
        build_cmd = self.get_finalized_command('build')
        new_path = os.path.abspath(build_cmd.build_lib)

        # Copy the build to a temporary directory for the purposes of testing
        # - this avoids creating pyc and __pycache__ directories inside the
        # build directory
        tmp_dir = tempfile.mkdtemp(prefix='astropy-test-')
        testing_path = os.path.join(tmp_dir, os.path.basename(new_path))
        shutil.copytree(new_path, testing_path)

        try:

            # Run the tests in a subprocess--this is necessary since new extension
            # modules may have appeared, and this is the easiest way to set up a
            # new environment

            # We need to set a flag in the child's environment so that
            # unnecessary code is not imported before py.test can start
            # up, otherwise the coverage results will be artifically low.
            if sys.version_info[0] >= 3:
                set_flag = "import builtins; builtins._ASTROPY_TEST_ = True"
            else:
                set_flag = "import __builtin__; __builtin__._ASTROPY_TEST_ = True"

            cmd = ('{0}; import {1.package_name}, sys; sys.exit('
                   '{1.package_name}.test('
                   'package={1.package!r}, '
                   'test_path={1.test_path!r}, '
                   'args={1.args!r}, '
                   'plugins={1.plugins!r}, '
                   'verbose={1.verbose_results!r}, '
                   'pastebin={1.pastebin!r}, '
                   'remote_data={1.remote_data!r}, '
                   'pep8={1.pep8!r}, '
                   'pdb={1.pdb!r}, '
                   'coverage={1.coverage!r}, '
                   'open_files={1.open_files!r}))')
            cmd = cmd.format(set_flag, self)

            #override the config locations to not make a new directory nor use
            #existing cache or config
            os.environ['XDG_CONFIG_HOME'] = tempfile.mkdtemp('astropy_config')
            os.environ['XDG_CACHE_HOME'] = tempfile.mkdtemp('astropy_cache')
            os.mkdir(os.path.join(os.environ['XDG_CONFIG_HOME'], 'astropy'))
            os.mkdir(os.path.join(os.environ['XDG_CACHE_HOME'], 'astropy'))

            try:
                retcode = subprocess.call([sys.executable, '-c', cmd],
                                          cwd=testing_path, close_fds=False)
            finally:
                # kill the temporary dirs
                shutil.rmtree(os.environ['XDG_CONFIG_HOME'])
                shutil.rmtree(os.environ['XDG_CACHE_HOME'])

            if self.coverage and retcode == 0:
                # Copy the htmlcov from build/lib.../htmlcov to a more
                # obvious place
                if os.path.exists('htmlcov'):
                    shutil.rmtree('htmlcov')
                shutil.copytree(os.path.join(testing_path, 'htmlcov'), 'htmlcov')

        finally:

            # Remove temporary directory
            shutil.rmtree(tmp_dir)

        raise SystemExit(retcode)


class raises(object):
    """
    A decorator to mark that a test should raise a given exception.
    Use as follows::

        @raises(ZeroDivisionError)
        def test_foo():
            x = 1/0
    """
    # pep-8 naming exception -- this is a decorator class
    def __init__(self, exc):
        self._exc = exc

    def __call__(self, func):
        @functools.wraps(func)
        def run_raises_test(*args, **kwargs):
            pytest.raises(self._exc, func, *args, **kwargs)
        return run_raises_test
