# -*- coding: utf-8 -*-
#
# userGroupIds.py - allocate new user and group ids according to prefs
# Copyright © 2006, 2007, 2009 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.
#
# Authors:
# Nils Philippsen <nils@redhat.com>

import string
import libuser

high_uid_ignore = ['nfsnobody']
high_gid_ignore = ['nfsnobody']

class DuplicateUidNumberError (Exception):
    def __init__ (self, uidNumber):
        self.uidNumber = uidNumber

class DuplicateGidNumberError (Exception):
    def __init__ (self, gidNumber):
        self.gidNumber = gidNumber

def find_uid_gid (lu_admin, preferences, uidNumber = None, gidNumber = None):
    """
    Try to find a free uid/gid number pair based on preferences, eventually with a given uid number.
    """
    # get all users
    users = lu_admin.enumerateUsersFull ()
    # hide some
    usersNotHidden = filter (lambda x: x[libuser.USERNAME][0] not in high_uid_ignore, users)
    # get their UIDs
    uidNumbers = []
    for u in usersNotHidden:
        try:
            uidNumbers.append (u[libuser.UIDNUMBER][0])
        except KeyError:
            # e.g. entry only in /etc/shadow
            pass

    if uidNumber == None:
        uidNumber = 500
        if preferences['ASSIGN_HIGHEST_UID']:
            for uidNum in uidNumbers:
                if uidNum > uidNumber:
                    uidNumber = uidNum + 1
        while uidNumber in uidNumbers:
            uidNumber += 1
        while gidNumber == None or uidNumber in uidNumbers:
            if uidNumber not in uidNumbers:
                try:
                    gidNumber = find_gid (lu_admin, preferences, preferences['PREFER_SAME_UID_GID'] and uidNumber or None)
                except DuplicateGidNumberError:
                    uidNumber += 1
            else:
                uidNumber += 1
    else:
        if uidNumber in uidNumbers:
            raise DuplicateUidNumberError (uidNumber)
        gidNumber = find_gid (lu_admin, preferences, gidNumber != None and gidNumber or (preferences['PREFER_SAME_UID_GID'] and uidNumber or None))

    return (uidNumber, gidNumber)

def find_gid (lu_admin, preferences, gidNumber = None):
    """
    Try to find a free gid number based on preferences, eventually with a given gid number.
    """
    # get all groups
    groups = lu_admin.enumerateGroupsFull ()
    # hide some
    groupsNotHidden = filter (lambda x: x[libuser.GROUPNAME][0] not in high_gid_ignore, groups)
    # get their GIDs
    gidNumbers = []
    for g in groupsNotHidden:
        try:
            gidNumbers.append (g[libuser.GIDNUMBER][0])
        except KeyError:
            # e.g. entry only in /etc/gshadow
            pass

    if gidNumber == None:
        gidNumber = 500
        if preferences['ASSIGN_HIGHEST_GID']:
            for gidNum in gidNumbers:
                if gidNum > gidNumber:
                    gidNumber = gidNum + 1
        while gidNumber in gidNumbers:
            gidNumber += 1
    else:
        if gidNumber in gidNumbers:
            raise DuplicateGidNumberError (gidNumber)

    return gidNumber