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

import gettext
import os
import re
import locale

from encodings.idna import ToASCII, ToUnicode

from VirtualMailManager.constants.ERROR import \
     DOMAIN_INVALID, DOMAIN_TOO_LONG, LOCALPART_INVALID, LOCALPART_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', 'check_domainname', 'check_localpart', '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 = r"^[\x20-\x7E]*$"
RE_DOMAIN = r"^(?:[a-z0-9-]{1,63}\.){1,}[a-z]{2,6}$"
RE_LOCALPART = r"[^\w!#$%&'\*\+-\.\/=?^_`{\|}~]"


# there may be many domain and e-mail address checks
re_obj_domain = re.compile(RE_DOMAIN)
re_obj_localpart = re.compile(RE_LOCALPART)


gettext.install('vmm', '/usr/local/share/locale', unicode=1)


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 check_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_obj_domain.match(domainname):
        domainname = idn2ascii(domainname)
    if len(domainname) > 255:
        raise VMMException(_(u'The domain name is too long'), DOMAIN_TOO_LONG)
    if not re_obj_domain.match(domainname):
        raise VMMException(_(u'The domain name %r is invalid') % domainname,
                           DOMAIN_INVALID)
    return domainname


def check_localpart(localpart):
    """Returns the validated local-part *localpart*.

    Throws a `VMMException` if the local-part is too long or contains
    invalid characters.
    """
    if len(localpart) > 64:
        raise VMMException(_(u'The local-part %r is too long') % localpart,
                           LOCALPART_TOO_LONG)
    invalid_chars = set(re_obj_localpart.findall(localpart))
    if invalid_chars:
        i_chars = u''.join((u'"%s" ' % c for c in invalid_chars))
        raise VMMException(_(u"The local-part %(l_part)r contains invalid \
characters: %(i_chars)s") %
                           {'l_part': localpart, 'i_chars': i_chars},
                           LOCALPART_INVALID)
    return localpart