from cStringIO import StringIO
from twisted.trial import unittest
from twisted.internet import threads # CLI tests use deferToThread
from ...util.assertutil import precondition
from ...util.encodingutil import (unicode_platform,
                                  get_filesystem_encoding,
                                  unicode_to_argv)
from ...scripts import runner
from ..common_util import ReallyEqualMixin

def parse_options(basedir, command, args):
    o = runner.Options()
    o.parseOptions(["--node-directory", basedir, command] + args)
    while hasattr(o, "subOptions"):
        o = o.subOptions
    return o

class CLITestMixin(ReallyEqualMixin):
    def do_cli(self, verb, *args, **kwargs):
        precondition(not [True for arg in args if not isinstance(arg, str)],
                     "arguments to do_cli must be strs -- convert using unicode_to_argv", args=args)

        # client_num is used to execute client CLI commands on a specific client.
        client_num = kwargs.get("client_num", 0)

        nodeargs = [
            "--node-directory", unicode_to_argv(self.get_clientdir(i=client_num)),
            ]
        argv = nodeargs + [verb] + list(args)
        stdin = kwargs.get("stdin", "")
        stdout, stderr = StringIO(), StringIO()
        d = threads.deferToThread(runner.runner, argv, run_by_human=False,
                                  stdin=StringIO(stdin),
                                  stdout=stdout, stderr=stderr)
        def _done(rc):
            return rc, stdout.getvalue(), stderr.getvalue()
        d.addCallback(_done)
        return d

    def skip_if_cannot_represent_filename(self, u):
        precondition(isinstance(u, unicode))

        enc = get_filesystem_encoding()
        if not unicode_platform():
            try:
                u.encode(enc)
            except UnicodeEncodeError:
                raise unittest.SkipTest("A non-ASCII filename could not be encoded on this platform.")