# -*- coding: UTF-8 -*-
# Copyright (c) 2007 - 2010, Pascal Volk
# See COPYING for distribution information.
# package initialization code
#

import os
import re
import locale

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',
]


# Try to set all of the locales according to the current
# environment variables and get the character encoding.
try:
    locale.setlocale(locale.LC_ALL, '')
except locale.Error:
    locale.setlocale(locale.LC_ALL, 'C')
ENCODING = locale.nl_langinfo(locale.CODESET)

RE_ASCII_CHARS = """^[\x20-\x7E]*$"""
RE_DOMAIN = """^(?:[a-z0-9-]{1,63}\.){1,}[a-z]{2,6}$"""


def get_unicode(string):
    """Converts `string` to `unicode`, if necessary."""
    if isinstance(string, unicode):
        return string
    return unicode(string, ENCODING, 'replace')

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