# -*- coding: UTF-8 -*-

# Copyright (c) 2010, Pascal Volk

# See COPYING for distribution information.

"""

    VirtualMailManager.common

    Some common functions

"""

import os

import re

from VirtualMailManager import ENCODING

from VirtualMailManager.constants.ERROR import \

     NOT_EXECUTABLE, NO_SUCH_BINARY, NO_SUCH_DIRECTORY

from VirtualMailManager.errors import VMMError

_version_re = re.compile(r'^(\d+)\.(\d+)\.(?:(\d+)|(alpha|beta|rc)(\d+))$')

_ = lambda msg: msg

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 get_unicode(string):

    """Converts `string` to `unicode`, if necessary."""

    if isinstance(string, unicode):

        return string

    return unicode(string, ENCODING, 'replace')

def is_dir(path):

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

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

    """

    path = expand_path(path)

    if not os.path.isdir(path):

        raise VMMError(_(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 `VMMError` if the `binary` isn't a file or is not

    executable.

    """

    binary = expand_path(binary)

    if not os.path.isfile(binary):

        raise VMMError(_(u"'%s' is not a file") % get_unicode(binary),

                       NO_SUCH_BINARY)

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

        raise VMMError(_(u"File is not executable: '%s'") %

                       get_unicode(binary), NOT_EXECUTABLE)

    return binary

def version_hex(version_string):

    Raises a `ValueError` if the *version_string* has the wrong™ format.

    """

    version = 0

    version_mo = _version_re.match(version_string)

    if not version_mo:

        raise ValueError('Invalid version string: %r' % version_string)

    major, minor, patch, level, serial = version_mo.groups()

    if patch:

    if serial:

    return version

del _