"""
Implements the wrapper for the Astropy test runner in the form of the
``./setup.py test`` distutils command.
"""


import os
import shutil
import subprocess
import sys
import tempfile

from setuptools import Command

from ..extern import six


def _fix_user_options(options):
    """
    This is for Python 2.x and 3.x compatibility.  distutils expects Command
    options to all be byte strings on Python 2 and Unicode strings on Python 3.
    """

    def to_str_or_none(x):
        if x is None:
            return None
        return str(x)

    return [tuple(to_str_or_none(x) for x in y) for y in options]


class AstropyTest(Command, object):
    description = 'Run the tests for this package'

    user_options = [
        ('package=', 'P',
         "The name of a specific package to test, e.g. 'io.fits' or 'utils'.  "
         "If nothing is specified, all default tests are run."),
        ('test-path=', 't',
         'Specify a test location by path.  If a relative path to a  .py file, '
         'it is relative to the built package, so e.g., a  leading "astropy/" '
         'is necessary.  If a relative  path to a .rst file, it is relative to '
         'the directory *below* the --docs-path directory, so a leading '
         '"docs/" is usually necessary.  May also be an absolute path.'),
        ('verbose-results', 'V',
         'Turn on verbose output from pytest.'),
        ('plugins=', 'p',
         'Plugins to enable when running pytest.'),
        ('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. '
         'Requires the pytest-pep8 plugin.'),
        ('pdb', 'd',
         'Start the interactive Python debugger on errors.'),
        ('coverage', 'c',
         'Create a coverage report. Requires the coverage package.'),
        ('open-files', 'o', 'Fail if any tests leave files open.  Requires the '
         'psutil package.'),
        ('parallel=', 'j',
         'Run the tests in parallel on the specified number of '
         'CPUs.  If negative, all the cores on the machine will be '
         'used.  Requires the pytest-xdist plugin.'),
        ('docs-path=', None,
         'The path to the documentation .rst files.  If not provided, and '
         'the current directory contains a directory called "docs", that '
         'will be used.'),
        ('skip-docs', None,
         "Don't test the documentation .rst files."),
        ('repeat=', None,
         'How many times to repeat each test (can be used to check for '
         'sporadic failures).'),
        ('temp-root=', None,
         'The root directory in which to create the temporary testing files. '
         'If unspecified the system default is used (e.g. /tmp) as explained '
         'in the documentation for tempfile.mkstemp.')
    ]

    user_options = _fix_user_options(user_options)

    package_name = ''

    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
        self.parallel = 0
        self.docs_path = None
        self.skip_docs = False
        self.repeat = None
        self.temp_root = None

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

    def generate_testing_command(self):
        """
        Build a Python script to run the tests.
        """

        cmd_pre = ''  # Commands to run before the test function
        cmd_post = ''  # Commands to run after the test function

        if self.coverage:
            pre, post = self._generate_coverage_commands()
            cmd_pre += pre
            cmd_post += post

        if six.PY3:
            set_flag = "import builtins; builtins._ASTROPY_TEST_ = True"
        else:
            set_flag = "import __builtin__; __builtin__._ASTROPY_TEST_ = True"

        cmd = ('{cmd_pre}{0}; import {1.package_name}, sys; result = ('
               '{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}, '
               'open_files={1.open_files!r}, '
               'parallel={1.parallel!r}, '
               'docs_path={1.docs_path!r}, '
               'skip_docs={1.skip_docs!r}, '
               'repeat={1.repeat!r})); '
               '{cmd_post}'
               'sys.exit(result)')
        return cmd.format(set_flag, self, cmd_pre=cmd_pre, cmd_post=cmd_post)

    def run(self):
        """
        Run the tests!
        """

        # Ensure there is a doc path
        if self.docs_path is None:
            cfg_docs_dir = self.distribution.get_option_dict('build_sphinx').get('source_dir', None)

            # Some affiliated packages use this.
            # See astropy/package-template#157
            if cfg_docs_dir is not None and os.path.exists(cfg_docs_dir[1]):
                self.docs_path = os.path.abspath(cfg_docs_dir[1])

            # fall back on a default path of "docs"
            elif os.path.exists('docs'):  # pragma: no cover
                self.docs_path = os.path.abspath('docs')

        # Build a testing install of the package
        self._build_temp_install()

        # Run everything in a try: finally: so that the tmp dir gets deleted.
        try:
            # Construct this modules testing command
            cmd = self.generate_testing_command()

            # 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

            # On Python 3.x prior to 3.3, the creation of .pyc files
            # is not atomic.  py.test jumps through some hoops to make
            # this work by parsing import statements and carefully
            # importing files atomically.  However, it can't detect
            # when __import__ is used, so its carefulness still fails.
            # The solution here (admittedly a bit of a hack), is to
            # turn off the generation of .pyc files altogether by
            # passing the `-B` switch to `python`.  This does mean
            # that each core will have to compile .py file to bytecode
            # itself, rather than getting lucky and borrowing the work
            # already done by another core.  Compilation is an
            # insignificant fraction of total testing time, though, so
            # it's probably not worth worrying about.
            retcode = subprocess.call([sys.executable, '-B', '-c', cmd],
                                      cwd=self.testing_path, close_fds=False)

        finally:
            # Remove temporary directory
            shutil.rmtree(self.tmp_dir)

        raise SystemExit(retcode)

    def _build_temp_install(self):
        """
        Build the package and copy the build to a temporary directory for
        the purposes of testing this avoids creating pyc and __pycache__
        directories inside the build directory
        """
        self.reinitialize_command('build', inplace=True)
        self.run_command('build')
        build_cmd = self.get_finalized_command('build')
        new_path = os.path.abspath(build_cmd.build_lib)

        # On OSX the default path for temp files is under /var, but in most
        # cases on OSX /var is actually a symlink to /private/var; ensure we
        # dereference that link, because py.test is very sensitive to relative
        # paths...
        tmp_dir = tempfile.mkdtemp(prefix=self.package_name + '-test-',
                                   dir=self.temp_root)
        self.tmp_dir = os.path.realpath(tmp_dir)
        self.testing_path = os.path.join(self.tmp_dir, os.path.basename(new_path))
        shutil.copytree(new_path, self.testing_path)

        # Ideally, docs_path is set properly in run(), but if it is still
        # not set here, do not pretend it is, otherwise bad things happen.
        # See astropy/package-template#157
        if self.docs_path is not None:
            new_docs_path = os.path.join(self.tmp_dir,
                                         os.path.basename(self.docs_path))
            shutil.copytree(self.docs_path, new_docs_path)
            self.docs_path = new_docs_path

        shutil.copy('setup.cfg', self.tmp_dir)

    def _generate_coverage_commands(self):
        """
        This method creates the post and pre commands if coverage is to be
        generated
        """
        if self.parallel != 0:
            raise ValueError(
                "--coverage can not be used with --parallel")

        try:
            import coverage  # pylint: disable=W0611
        except ImportError:
            raise ImportError(
                "--coverage requires that the coverage package is "
                "installed.")

        # 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(
            self.testing_path, self.package_name, 'tests', '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 six.PY3:
            ignore_python_version = '2'
        else:
            ignore_python_version = '3'
        coveragerc_content = coveragerc_content.replace(
            "{ignore_python_version}", ignore_python_version).replace(
                "{packagename}", self.package_name)
        tmp_coveragerc = os.path.join(self.tmp_dir, 'coveragerc')
        with open(tmp_coveragerc, 'wb') as tmp:
            tmp.write(coveragerc_content.encode('utf-8'))

        cmd_pre = (
            'import coverage; '
            'cov = coverage.coverage(data_file="{0}", config_file="{1}"); '
            'cov.start();'.format(
                os.path.abspath(".coverage"), tmp_coveragerc))
        cmd_post = (
            'cov.stop(); '
            'from astropy.tests.helper import _save_coverage; '
            '_save_coverage(cov, result, "{0}", "{1}");'.format(
                os.path.abspath('.'), self.testing_path))

        return cmd_pre, cmd_post
