from encodings.idna import ToASCII, ToUnicode

from VirtualMailManager.constants.ERROR import \

     DOMAIN_INVALID, DOMAIN_TOO_LONG, NOT_EXECUTABLE, NO_SUCH_BINARY, \

     NO_SUCH_DIRECTORY

from VirtualMailManager.constants.VERSION import *

from VirtualMailManager.Exceptions import VMMException

__all__ = [

    # imported modules

    'os', 're', 'locale',

    # version information from VERSION

    '__author__', '__date__', '__version__',

    # error codes

    'ENCODING', 'ace2idna', 'chk_domainname', 'exec_ok', 'expand_path',

    'get_unicode', 'idn2ascii', 'is_dir',

]

RE_ASCII_CHARS = """^[\x20-\x7E]*$"""

RE_DOMAIN = """^(?:[a-z0-9-]{1,63}\.){1,}[a-z]{2,6}$"""

def expand_path(path):

    """Expands paths, starting with ``.`` or ``~``, to an absolute path."""

    if path.startswith('.'):

        return os.path.abspath(path)

    if path.startswith('~'):

        return os.path.expanduser(path)

    return path

def is_dir(path):

    """Checks if ``path`` is a directory.

    Throws a `VMMException` if ``path`` is not a directory.

    """

    path = expand_path(path)

    if not os.path.isdir(path):

        raise VMMException(_(u'“%s” is not a directory') % get_unicode(path),

                           NO_SUCH_DIRECTORY)

    return path

def exec_ok(binary):

    """Checks if the ``binary`` exists and if it is executable.

    Throws a `VMMException` if the ``binary`` isn't a file or is not

    executable.

    """

    binary = expand_path(binary)

    if not os.path.isfile(binary):

        raise VMMException(_(u'“%s” is not a file') % get_unicode(binary),

                           NO_SUCH_BINARY)

    if not os.access(binary, os.X_OK):

        raise VMMException(_(u'File is not executable: “%s”') % \

                           get_unicode(binary), NOT_EXECUTABLE)

    return binary

def idn2ascii(domainname):

    """Converts the idn domain name `domainname` into punycode."""

    return '.'.join([ToASCII(lbl) for lbl in domainname.split('.') if lbl])

def ace2idna(domainname):

    """Converts the domain name `domainname` from ACE according to IDNA."""

    return u'.'.join([ToUnicode(lbl) for lbl in domainname.split('.') if lbl])

def chk_domainname(domainname):

    """Returns the validated domain name `domainname`.

    It also converts the name of the domain from IDN to ASCII, if necessary.

    Throws an VMMException, if the domain name is too long or doesn't look

    like a valid domain name (label.label.label).

    """

    if not re.match(RE_ASCII_CHARS, domainname):

        domainname = idn2ascii(domainname)

    if len(domainname) > 255:

        raise VMMException(_(u'The domain name is too long.'), DOMAIN_TOO_LONG)

    if not re.match(RE_DOMAIN, domainname):

        raise VMMException(_(u'The domain name “%s” is invalid.') % domainname,

                           DOMAIN_INVALID)

    return domainname