# coding: utf-8

import re
import json
import pickle
import textwrap
import unittest
import importlib.metadata

try:
    import pyfakefs.fake_filesystem_unittest as ffs
except ImportError:
    from .stubs import fake_filesystem_unittest as ffs

from . import fixtures
from importlib.metadata import (
    Distribution, EntryPoint,
    PackageNotFoundError, distributions,
    entry_points, metadata, version,
    )


class BasicTests(fixtures.DistInfoPkg, unittest.TestCase):
    version_pattern = r'\d+\.\d+(\.\d)?'

    def test_retrieves_version_of_self(self):
        dist = Distribution.from_name('distinfo-pkg')
        assert isinstance(dist.version, str)
        assert re.match(self.version_pattern, dist.version)

    def test_for_name_does_not_exist(self):
        with self.assertRaises(PackageNotFoundError):
            Distribution.from_name('does-not-exist')

    def test_package_not_found_mentions_metadata(self):
        """
        When a package is not found, that could indicate that the
        packgae is not installed or that it is installed without
        metadata. Ensure the exception mentions metadata to help
        guide users toward the cause. See #124.
        """
        with self.assertRaises(PackageNotFoundError) as ctx:
            Distribution.from_name('does-not-exist')

        assert "metadata" in str(ctx.exception)

    def test_new_style_classes(self):
        self.assertIsInstance(Distribution, type)


class ImportTests(fixtures.DistInfoPkg, unittest.TestCase):
    def test_import_nonexistent_module(self):
        # Ensure that the MetadataPathFinder does not crash an import of a
        # non-existent module.
        with self.assertRaises(ImportError):
            importlib.import_module('does_not_exist')

    def test_resolve(self):
        entries = dict(entry_points()['entries'])
        ep = entries['main']
        self.assertEqual(ep.load().__name__, "main")

    def test_entrypoint_with_colon_in_name(self):
        entries = dict(entry_points()['entries'])
        ep = entries['ns:sub']
        self.assertEqual(ep.value, 'mod:main')

    def test_resolve_without_attr(self):
        ep = EntryPoint(
            name='ep',
            value='importlib.metadata',
            group='grp',
            )
        assert ep.load() is importlib.metadata


class NameNormalizationTests(
        fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
    @staticmethod
    def pkg_with_dashes(site_dir):
        """
        Create minimal metadata for a package with dashes
        in the name (and thus underscores in the filename).
        """
        metadata_dir = site_dir / 'my_pkg.dist-info'
        metadata_dir.mkdir()
        metadata = metadata_dir / 'METADATA'
        with metadata.open('w') as strm:
            strm.write('Version: 1.0\n')
        return 'my-pkg'

    def test_dashes_in_dist_name_found_as_underscores(self):
        """
        For a package with a dash in the name, the dist-info metadata
        uses underscores in the name. Ensure the metadata loads.
        """
        pkg_name = self.pkg_with_dashes(self.site_dir)
        assert version(pkg_name) == '1.0'

    @staticmethod
    def pkg_with_mixed_case(site_dir):
        """
        Create minimal metadata for a package with mixed case
        in the name.
        """
        metadata_dir = site_dir / 'CherryPy.dist-info'
        metadata_dir.mkdir()
        metadata = metadata_dir / 'METADATA'
        with metadata.open('w') as strm:
            strm.write('Version: 1.0\n')
        return 'CherryPy'

    def test_dist_name_found_as_any_case(self):
        """
        Ensure the metadata loads when queried with any case.
        """
        pkg_name = self.pkg_with_mixed_case(self.site_dir)
        assert version(pkg_name) == '1.0'
        assert version(pkg_name.lower()) == '1.0'
        assert version(pkg_name.upper()) == '1.0'


class NonASCIITests(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
    @staticmethod
    def pkg_with_non_ascii_description(site_dir):
        """
        Create minimal metadata for a package with non-ASCII in
        the description.
        """
        metadata_dir = site_dir / 'portend.dist-info'
        metadata_dir.mkdir()
        metadata = metadata_dir / 'METADATA'
        with metadata.open('w', encoding='utf-8') as fp:
            fp.write('Description: pôrˈtend\n')
        return 'portend'

    @staticmethod
    def pkg_with_non_ascii_description_egg_info(site_dir):
        """
        Create minimal metadata for an egg-info package with
        non-ASCII in the description.
        """
        metadata_dir = site_dir / 'portend.dist-info'
        metadata_dir.mkdir()
        metadata = metadata_dir / 'METADATA'
        with metadata.open('w', encoding='utf-8') as fp:
            fp.write(textwrap.dedent("""
                Name: portend

                pôrˈtend
                """).lstrip())
        return 'portend'

    def test_metadata_loads(self):
        pkg_name = self.pkg_with_non_ascii_description(self.site_dir)
        meta = metadata(pkg_name)
        assert meta['Description'] == 'pôrˈtend'

    def test_metadata_loads_egg_info(self):
        pkg_name = self.pkg_with_non_ascii_description_egg_info(self.site_dir)
        meta = metadata(pkg_name)
        assert meta.get_payload() == 'pôrˈtend\n'


class DiscoveryTests(fixtures.EggInfoPkg,
                     fixtures.DistInfoPkg,
                     unittest.TestCase):

    def test_package_discovery(self):
        dists = list(distributions())
        assert all(
            isinstance(dist, Distribution)
            for dist in dists
            )
        assert any(
            dist.metadata['Name'] == 'egginfo-pkg'
            for dist in dists
            )
        assert any(
            dist.metadata['Name'] == 'distinfo-pkg'
            for dist in dists
            )

    def test_invalid_usage(self):
        with self.assertRaises(ValueError):
            list(distributions(context='something', name='else'))


class DirectoryTest(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
    def test_egg_info(self):
        # make an `EGG-INFO` directory that's unrelated
        self.site_dir.joinpath('EGG-INFO').mkdir()
        # used to crash with `IsADirectoryError`
        with self.assertRaises(PackageNotFoundError):
            version('unknown-package')

    def test_egg(self):
        egg = self.site_dir.joinpath('foo-3.6.egg')
        egg.mkdir()
        with self.add_sys_path(egg):
            with self.assertRaises(PackageNotFoundError):
                version('foo')


class MissingSysPath(fixtures.OnSysPath, unittest.TestCase):
    site_dir = '/does-not-exist'

    def test_discovery(self):
        """
        Discovering distributions should succeed even if
        there is an invalid path on sys.path.
        """
        importlib.metadata.distributions()


class InaccessibleSysPath(fixtures.OnSysPath, ffs.TestCase):
    site_dir = '/access-denied'

    def setUp(self):
        super(InaccessibleSysPath, self).setUp()
        self.setUpPyfakefs()
        self.fs.create_dir(self.site_dir, perm_bits=000)

    def test_discovery(self):
        """
        Discovering distributions should succeed even if
        there is an invalid path on sys.path.
        """
        list(importlib.metadata.distributions())


class TestEntryPoints(unittest.TestCase):
    def __init__(self, *args):
        super(TestEntryPoints, self).__init__(*args)
        self.ep = importlib.metadata.EntryPoint('name', 'value', 'group')

    def test_entry_point_pickleable(self):
        revived = pickle.loads(pickle.dumps(self.ep))
        assert revived == self.ep

    def test_immutable(self):
        """EntryPoints should be immutable"""
        with self.assertRaises(AttributeError):
            self.ep.name = 'badactor'

    def test_repr(self):
        assert 'EntryPoint' in repr(self.ep)
        assert 'name=' in repr(self.ep)
        assert "'name'" in repr(self.ep)

    def test_hashable(self):
        """EntryPoints should be hashable"""
        hash(self.ep)

    def test_json_dump(self):
        """
        json should not expect to be able to dump an EntryPoint
        """
        with self.assertRaises(Exception):
            json.dumps(self.ep)

    def test_module(self):
        assert self.ep.module == 'value'

    def test_attr(self):
        assert self.ep.attr is None


class FileSystem(
        fixtures.OnSysPath, fixtures.SiteDir, fixtures.FileBuilder,
        unittest.TestCase):
    def test_unicode_dir_on_sys_path(self):
        """
        Ensure a Unicode subdirectory of a directory on sys.path
        does not crash.
        """
        fixtures.build_files(
            {self.unicode_filename(): {}},
            prefix=self.site_dir,
            )
        list(distributions())
