# Author: Steven J. Bethard <steven.bethard@gmail.com>.

import inspect
import os
import shutil
import stat
import sys
import textwrap
import tempfile
import unittest
import argparse

from io import StringIO

from test import support
from unittest import mock
class StdIOBuffer(StringIO):
    pass

class TestCase(unittest.TestCase):

    def setUp(self):
        # The tests assume that line wrapping occurs at 80 columns, but this
        # behaviour can be overridden by setting the COLUMNS environment
        # variable.  To ensure that this width is used, set COLUMNS to 80.
        env = support.EnvironmentVarGuard()
        env['COLUMNS'] = '80'
        self.addCleanup(env.__exit__)


class TempDirMixin(object):

    def setUp(self):
        self.temp_dir = tempfile.mkdtemp()
        self.old_dir = os.getcwd()
        os.chdir(self.temp_dir)

    def tearDown(self):
        os.chdir(self.old_dir)
        for root, dirs, files in os.walk(self.temp_dir, topdown=False):
            for name in files:
                os.chmod(os.path.join(self.temp_dir, name), stat.S_IWRITE)
        shutil.rmtree(self.temp_dir, True)

    def create_readonly_file(self, filename):
        file_path = os.path.join(self.temp_dir, filename)
        with open(file_path, 'w') as file:
            file.write(filename)
        os.chmod(file_path, stat.S_IREAD)

class Sig(object):

    def __init__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs


class NS(object):

    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)

    def __repr__(self):
        sorted_items = sorted(self.__dict__.items())
        kwarg_str = ', '.join(['%s=%r' % tup for tup in sorted_items])
        return '%s(%s)' % (type(self).__name__, kwarg_str)

    def __eq__(self, other):
        return vars(self) == vars(other)


class ArgumentParserError(Exception):

    def __init__(self, message, stdout=None, stderr=None, error_code=None):
        Exception.__init__(self, message, stdout, stderr)
        self.message = message
        self.stdout = stdout
        self.stderr = stderr
        self.error_code = error_code


def stderr_to_parser_error(parse_args, *args, **kwargs):
    # if this is being called recursively and stderr or stdout is already being
    # redirected, simply call the function and let the enclosing function
    # catch the exception
    if isinstance(sys.stderr, StdIOBuffer) or isinstance(sys.stdout, StdIOBuffer):
        return parse_args(*args, **kwargs)

    # if this is not being called recursively, redirect stderr and
    # use it as the ArgumentParserError message
    old_stdout = sys.stdout
    old_stderr = sys.stderr
    sys.stdout = StdIOBuffer()
    sys.stderr = StdIOBuffer()
    try:
        try:
            result = parse_args(*args, **kwargs)
            for key in list(vars(result)):
                if getattr(result, key) is sys.stdout:
                    setattr(result, key, old_stdout)
                if getattr(result, key) is sys.stderr:
                    setattr(result, key, old_stderr)
            return result
        except SystemExit:
            code = sys.exc_info()[1].code
            stdout = sys.stdout.getvalue()
            stderr = sys.stderr.getvalue()
            raise ArgumentParserError("SystemExit", stdout, stderr, code)
    finally:
        sys.stdout = old_stdout
        sys.stderr = old_stderr


class ErrorRaisingArgumentParser(argparse.ArgumentParser):

    def parse_args(self, *args, **kwargs):
        parse_args = super(ErrorRaisingArgumentParser, self).parse_args
        return stderr_to_parser_error(parse_args, *args, **kwargs)

    def exit(self, *args, **kwargs):
        exit = super(ErrorRaisingArgumentParser, self).exit
        return stderr_to_parser_error(exit, *args, **kwargs)

    def error(self, *args, **kwargs):
        error = super(ErrorRaisingArgumentParser, self).error
        return stderr_to_parser_error(error, *args, **kwargs)


class ParserTesterMetaclass(type):
    """Adds parser tests using the class attributes.

    Classes of this type should specify the following attributes:

    argument_signatures -- a list of Sig objects which specify
        the signatures of Argument objects to be created
    failures -- a list of args lists that should cause the parser
        to fail
    successes -- a list of (initial_args, options, remaining_args) tuples
        where initial_args specifies the string args to be parsed,
        options is a dict that should match the vars() of the options
        parsed out of initial_args, and remaining_args should be any
        remaining unparsed arguments
    """

    def __init__(cls, name, bases, bodydict):
        if name == 'ParserTestCase':
            return

        # default parser signature is empty
        if not hasattr(cls, 'parser_signature'):
            cls.parser_signature = Sig()
        if not hasattr(cls, 'parser_class'):
            cls.parser_class = ErrorRaisingArgumentParser

        # ---------------------------------------
        # functions for adding optional arguments
        # ---------------------------------------
        def no_groups(parser, argument_signatures):
            """Add all arguments directly to the parser"""
            for sig in argument_signatures:
                parser.add_argument(*sig.args, **sig.kwargs)

        def one_group(parser, argument_signatures):
            """Add all arguments under a single group in the parser"""
            group = parser.add_argument_group('foo')
            for sig in argument_signatures:
                group.add_argument(*sig.args, **sig.kwargs)

        def many_groups(parser, argument_signatures):
            """Add each argument in its own group to the parser"""
            for i, sig in enumerate(argument_signatures):
                group = parser.add_argument_group('foo:%i' % i)
                group.add_argument(*sig.args, **sig.kwargs)

        # --------------------------
        # functions for parsing args
        # --------------------------
        def listargs(parser, args):
            """Parse the args by passing in a list"""
            return parser.parse_args(args)

        def sysargs(parser, args):
            """Parse the args by defaulting to sys.argv"""
            old_sys_argv = sys.argv
            sys.argv = [old_sys_argv[0]] + args
            try:
                return parser.parse_args()
            finally:
                sys.argv = old_sys_argv

        # class that holds the combination of one optional argument
        # addition method and one arg parsing method
        class AddTests(object):

            def __init__(self, tester_cls, add_arguments, parse_args):
                self._add_arguments = add_arguments
                self._parse_args = parse_args

                add_arguments_name = self._add_arguments.__name__
                parse_args_name = self._parse_args.__name__
                for test_func in [self.test_failures, self.test_successes]:
                    func_name = test_func.__name__
                    names = func_name, add_arguments_name, parse_args_name
                    test_name = '_'.join(names)

                    def wrapper(self, test_func=test_func):
                        test_func(self)
                    try:
                        wrapper.__name__ = test_name
                    except TypeError:
                        pass
                    setattr(tester_cls, test_name, wrapper)

            def _get_parser(self, tester):
                args = tester.parser_signature.args
                kwargs = tester.parser_signature.kwargs
                parser = tester.parser_class(*args, **kwargs)
                self._add_arguments(parser, tester.argument_signatures)
                return parser

            def test_failures(self, tester):
                parser = self._get_parser(tester)
                for args_str in tester.failures:
                    args = args_str.split()
                    with tester.assertRaises(ArgumentParserError, msg=args):
                        parser.parse_args(args)

            def test_successes(self, tester):
                parser = self._get_parser(tester)
                for args, expected_ns in tester.successes:
                    if isinstance(args, str):
                        args = args.split()
                    result_ns = self._parse_args(parser, args)
                    tester.assertEqual(expected_ns, result_ns)

        # add tests for each combination of an optionals adding method
        # and an arg parsing method
        for add_arguments in [no_groups, one_group, many_groups]:
            for parse_args in [listargs, sysargs]:
                AddTests(cls, add_arguments, parse_args)

bases = TestCase,
ParserTestCase = ParserTesterMetaclass('ParserTestCase', bases, {})

# ===============
# Optionals tests
# ===============

class TestOptionalsSingleDash(ParserTestCase):
    """Test an Optional with a single-dash option string"""

    argument_signatures = [Sig('-x')]
    failures = ['-x', 'a', '--foo', '-x --foo', '-x -y']
    successes = [
        ('', NS(x=None)),
        ('-x a', NS(x='a')),
        ('-xa', NS(x='a')),
        ('-x -1', NS(x='-1')),
        ('-x-1', NS(x='-1')),
    ]


class TestOptionalsSingleDashCombined(ParserTestCase):
    """Test an Optional with a single-dash option string"""

    argument_signatures = [
        Sig('-x', action='store_true'),
        Sig('-yyy', action='store_const', const=42),
        Sig('-z'),
    ]
    failures = ['a', '--foo', '-xa', '-x --foo', '-x -z', '-z -x',
                '-yx', '-yz a', '-yyyx', '-yyyza', '-xyza']
    successes = [
        ('', NS(x=False, yyy=None, z=None)),
        ('-x', NS(x=True, yyy=None, z=None)),
        ('-za', NS(x=False, yyy=None, z='a')),
        ('-z a', NS(x=False, yyy=None, z='a')),
        ('-xza', NS(x=True, yyy=None, z='a')),
        ('-xz a', NS(x=True, yyy=None, z='a')),
        ('-x -za', NS(x=True, yyy=None, z='a')),
        ('-x -z a', NS(x=True, yyy=None, z='a')),
        ('-y', NS(x=False, yyy=42, z=None)),
        ('-yyy', NS(x=False, yyy=42, z=None)),
        ('-x -yyy -za', NS(x=True, yyy=42, z='a')),
        ('-x -yyy -z a', NS(x=True, yyy=42, z='a')),
    ]


class TestOptionalsSingleDashLong(ParserTestCase):
    """Test an Optional with a multi-character single-dash option string"""

    argument_signatures = [Sig('-foo')]
    failures = ['-foo', 'a', '--foo', '-foo --foo', '-foo -y', '-fooa']
    successes = [
        ('', NS(foo=None)),
        ('-foo a', NS(foo='a')),
        ('-foo -1', NS(foo='-1')),
        ('-fo a', NS(foo='a')),
        ('-f a', NS(foo='a')),
    ]


class TestOptionalsSingleDashSubsetAmbiguous(ParserTestCase):
    """Test Optionals where option strings are subsets of each other"""

    argument_signatures = [Sig('-f'), Sig('-foobar'), Sig('-foorab')]
    failures = ['-f', '-foo', '-fo', '-foo b', '-foob', '-fooba', '-foora']
    successes = [
        ('', NS(f=None, foobar=None, foorab=None)),
        ('-f a', NS(f='a', foobar=None, foorab=None)),
        ('-fa', NS(f='a', foobar=None, foorab=None)),
        ('-foa', NS(f='oa', foobar=None, foorab=None)),
        ('-fooa', NS(f='ooa', foobar=None, foorab=None)),
        ('-foobar a', NS(f=None, foobar='a', foorab=None)),
        ('-foorab a', NS(f=None, foobar=None, foorab='a')),
    ]


class TestOptionalsSingleDashAmbiguous(ParserTestCase):
    """Test Optionals that partially match but are not subsets"""

    argument_signatures = [Sig('-foobar'), Sig('-foorab')]
    failures = ['-f', '-f a', '-fa', '-foa', '-foo', '-fo', '-foo b']
    successes = [
        ('', NS(foobar=None, foorab=None)),
        ('-foob a', NS(foobar='a', foorab=None)),
        ('-foor a', NS(foobar=None, foorab='a')),
        ('-fooba a', NS(foobar='a', foorab=None)),
        ('-foora a', NS(foobar=None, foorab='a')),
        ('-foobar a', NS(foobar='a', foorab=None)),
        ('-foorab a', NS(foobar=None, foorab='a')),
    ]


class TestOptionalsNumeric(ParserTestCase):
    """Test an Optional with a short opt string"""

    argument_signatures = [Sig('-1', dest='one')]
    failures = ['-1', 'a', '-1 --foo', '-1 -y', '-1 -1', '-1 -2']
    successes = [
        ('', NS(one=None)),
        ('-1 a', NS(one='a')),
        ('-1a', NS(one='a')),
        ('-1-2', NS(one='-2')),
    ]