import cStringIO
import tempfile
import os
import shutil
from contextlib import contextmanager
from libpathod import utils

from netlib import tcp


def treader(bytes):
    """
        Construct a tcp.Read object from bytes.
    """
    fp = cStringIO.StringIO(bytes)
    return tcp.Reader(fp)


@contextmanager
def tmpdir(*args, **kwargs):
    orig_workdir = os.getcwd()
    temp_workdir = tempfile.mkdtemp(*args, **kwargs)
    os.chdir(temp_workdir)

    yield temp_workdir

    os.chdir(orig_workdir)
    shutil.rmtree(temp_workdir)


def raises(exc, obj, *args, **kwargs):
    """
        Assert that a callable raises a specified exception.

        :exc An exception class or a string. If a class, assert that an
        exception of this type is raised. If a string, assert that the string
        occurs in the string representation of the exception, based on a
        case-insenstivie match.

        :obj A callable object.

        :args Arguments to be passsed to the callable.

        :kwargs Arguments to be passed to the callable.
    """
    try:
        ret = apply(obj, args, kwargs)
    except Exception, v:
        if isinstance(exc, basestring):
            if exc.lower() in str(v).lower():
                return
            else:
                raise AssertionError(
                    "Expected %s, but caught %s"%(
                        repr(str(exc)), v
                    )
                )
        else:
            if isinstance(v, exc):
                return
            else:
                raise AssertionError(
                    "Expected %s, but caught %s %s"%(
                        exc.__name__, v.__class__.__name__, str(v)
                    )
                )
    raise AssertionError("No exception raised. Return value: {}".format(ret))

test_data = utils.Data(__name__)