import email.parser
import email.policy
from io import StringIO
from pathlib import Path
import pytest
from unittest import TestCase

from flit_core import config
from flit_core.common import (
    Module, get_info_from_module, InvalidVersion, NoVersionError, check_version,
    normalize_file_permissions, Metadata, make_metadata,
)

samples_dir = Path(__file__).parent / 'samples'

class ModuleTests(TestCase):
    def test_ns_package_importable(self):
        i = Module('ns1.pkg', samples_dir / 'ns1-pkg')
        assert i.path == Path(samples_dir, 'ns1-pkg', 'ns1', 'pkg')
        assert i.file == Path(samples_dir, 'ns1-pkg', 'ns1', 'pkg', '__init__.py')
        assert i.is_package

        assert i.in_namespace_package
        assert i.namespace_package_name == 'ns1'

    def test_package_importable(self):
        i = Module('package1', samples_dir)
        assert i.path == samples_dir / 'package1'
        assert i.file == samples_dir / 'package1' / '__init__.py'
        assert i.is_package

    def test_module_importable(self):
        i = Module('module1', samples_dir)
        assert i.path == samples_dir / 'module1.py'
        assert not i.is_package

    def test_missing_name(self):
        with self.assertRaises(ValueError):
            i = Module('doesnt_exist', samples_dir)

    def test_conflicting_modules(self):
        with pytest.raises(ValueError, match="Multiple"):
            Module('module1', samples_dir / 'conflicting_modules')

    def test_get_info_from_module(self):
        info = get_info_from_module(Module('module1', samples_dir))
        self.assertEqual(info, {'summary': 'Example module',
                                'version': '0.1'}
                         )

        info = get_info_from_module(Module('module2', samples_dir))
        self.assertEqual(info, {'summary': 'Docstring formatted like this.',
                                'version': '7.0'}
                         )

        pkg1 = Module('package1', samples_dir)
        info = get_info_from_module(pkg1)
        self.assertEqual(info, {'summary': 'A sample package',
                                'version': '0.1'}
                         )
        info = get_info_from_module(pkg1, for_fields=['version'])
        self.assertEqual(info, {'version': '0.1'})
        info = get_info_from_module(pkg1, for_fields=['description'])
        self.assertEqual(info, {'summary': 'A sample package'})
        info = get_info_from_module(pkg1, for_fields=[])
        self.assertEqual(info, {})

        info = get_info_from_module(Module('moduleunimportable', samples_dir))
        self.assertEqual(info, {'summary': 'A sample unimportable module',
                                'version': '0.1'}
                         )

        info = get_info_from_module(Module('moduleunimportabledouble', samples_dir))
        self.assertEqual(info, {'summary': 'A sample unimportable module with double assignment',
                                'version': '0.1'}
                         )

        info = get_info_from_module(Module('module1', samples_dir / 'constructed_version'))
        self.assertEqual(info, {'summary': 'This module has a __version__ that requires runtime interpretation',
                                'version': '1.2.3'}
                         )

        info = get_info_from_module(Module('package1', samples_dir / 'imported_version'))
        self.assertEqual(info, {'summary': 'This module has a __version__ that requires a relative import',
                                'version': '0.5.8'}
                         )

        with self.assertRaises(InvalidVersion):
            get_info_from_module(Module('invalid_version1', samples_dir))

    def test_version_raise(self):
        with pytest.raises(InvalidVersion):
            check_version('a.1.0.beta0')

        with pytest.raises(InvalidVersion):
            check_version('3!')

        with pytest.raises(InvalidVersion):
            check_version((1, 2))

        with pytest.raises(NoVersionError):
            check_version(None)

        assert check_version('4.1.0beta1') == '4.1.0b1'
        assert check_version('v1.2') == '1.2'

def test_normalize_file_permissions():
    assert normalize_file_permissions(0o100664) == 0o100644 # regular file
    assert normalize_file_permissions(0o40775) == 0o40755   # directory

@pytest.mark.parametrize(
    ("requires_python", "expected_result"),
    [
        ("", True),
        (">2.7", True),
        ("3", False),
        (">= 3.7", False),
        ("<4, > 3.2", False),
        (">3.4", False),
        (">=2.7, !=3.0.*, !=3.1.*, !=3.2.*", True),
        ("== 3.9", False),
        ("~=2.7", True),
        ("~=3.9", False),
    ],
)
def test_supports_py2(requires_python, expected_result):
    metadata = object.__new__(Metadata)
    metadata.requires_python = requires_python
    result = metadata.supports_py2
    assert result == expected_result

def test_make_metadata():
    project_dir = samples_dir / 'pep621_nodynamic'
    ini_info = config.read_flit_config(project_dir / 'pyproject.toml')
    module = Module(ini_info.module, project_dir)
    print(module.file)
    md = make_metadata(module, ini_info)
    assert md.version == '0.3'
    assert md.summary == "Statically specified description"

def test_metadata_multiline(tmp_path):
    d = {
        'name': 'foo',
        'version': '1.0',
        # Example from: https://packaging.python.org/specifications/core-metadata/#author
        'author': ('C. Schultz, Universal Features Syndicate\n'
                   'Los Angeles, CA <cschultz@peanuts.example.com>'),
    }
    md = Metadata(d)
    sio = StringIO()
    md.write_metadata_file(sio)
    sio.seek(0)

    msg = email.parser.Parser(policy=email.policy.compat32).parse(sio)
    assert msg['Name'] == d['name']
    assert msg['Version'] == d['version']
    assert [l.lstrip() for l in msg['Author'].splitlines()] == d['author'].splitlines()
    assert not msg.defects