#!/usr/bin/python
#
# Sets password settings.
# (Password complexity, history length, minimum password length, the minimum
# and maximum password age) on a Samba4 server
#
# Copyright Matthias Dieter Wallnoefer 2009
# Copyright Andrew Kroeger 2009
# Copyright Jelmer Vernooij 2009
#
# 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 3 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/>.
#

import samba.getopt as options
import ldb

from samba.auth import system_session
from samba.samdb import SamDB
from samba.dcerpc.samr import DOMAIN_PASSWORD_COMPLEX
from samba.netcmd import Command, CommandError, Option

class cmd_pwsettings(Command):
    """Sets password settings.

    Password complexity, history length, minimum password length, the minimum 
    and maximum password age) on a Samba4 server.
    """

    synopsis = "(show | set <options>)"

    takes_optiongroups = {
        "sambaopts": options.SambaOptions,
        "versionopts": options.VersionOptions,
        "credopts": options.CredentialsOptions,
        }

    takes_options = [
        Option("-H", help="LDB URL for database or target server", type=str),
        Option("--quiet", help="Be quiet", action="store_true"),
        Option("--complexity", type="choice", choices=["on","off","default"],
          help="The password complexity (on | off | default). Default is 'on'"),
        Option("--history-length",
          help="The password history length (<integer> | default).  Default is 24.", type=str),
        Option("--min-pwd-length",
          help="The minimum password length (<integer> | default).  Default is 7.", type=str),
        Option("--min-pwd-age",
          help="The minimum password age (<integer in days> | default).  Default is 0.", type=str),
        Option("--max-pwd-age",
          help="The maximum password age (<integer in days> | default).  Default is 43.", type=str),
          ]

    takes_args = ["subcommand"]

    def run(self, subcommand, H=None, min_pwd_age=None, max_pwd_age=None,
            quiet=False, complexity=None, history_length=None,
            min_pwd_length=None, credopts=None, sambaopts=None,
            versionopts=None):
        lp = sambaopts.get_loadparm()
        creds = credopts.get_credentials(lp)

        if H is not None:
            url = H
        else:
            url = lp.get("sam database")

        samdb = SamDB(url=url, session_info=system_session(),
            credentials=creds, lp=lp)

        domain_dn = SamDB.domain_dn(samdb)
        res = samdb.search(domain_dn, scope=ldb.SCOPE_BASE,
          attrs=["pwdProperties", "pwdHistoryLength", "minPwdLength",
                 "minPwdAge", "maxPwdAge"])
        assert(len(res) == 1)
        try:
            pwd_props = int(res[0]["pwdProperties"][0])
            pwd_hist_len = int(res[0]["pwdHistoryLength"][0])
            cur_min_pwd_len = int(res[0]["minPwdLength"][0])
            # ticks -> days
            cur_min_pwd_age = int(abs(int(res[0]["minPwdAge"][0])) / (1e7 * 60 * 60 * 24))
            cur_max_pwd_age = int(abs(int(res[0]["maxPwdAge"][0])) / (1e7 * 60 * 60 * 24))
        except KeyError:
            raise CommandError("Could not retrieve password properties!")

        if subcommand == "show":
            self.message("Password informations for domain '%s'" % domain_dn)
            self.message("")
            if pwd_props & DOMAIN_PASSWORD_COMPLEX != 0:
                self.message("Password complexity: on")
            else:
                self.message("Password complexity: off")
            self.message("Password history length: %d" % pwd_hist_len)
            self.message("Minimum password length: %d" % cur_min_pwd_len)
            self.message("Minimum password age (days): %d" % cur_min_pwd_age)
            self.message("Maximum password age (days): %d" % cur_max_pwd_age)
        elif subcommand == "set":
            msgs = []
            m = ldb.Message()
            m.dn = ldb.Dn(samdb, domain_dn)

            if complexity is not None:
                if complexity == "on" or complexity == "default":
                    pwd_props = pwd_props | DOMAIN_PASSWORD_COMPLEX
                    msgs.append("Password complexity activated!")
                elif complexity == "off":
                    pwd_props = pwd_props & (~DOMAIN_PASSWORD_COMPLEX)
                    msgs.append("Password complexity deactivated!")

                m["pwdProperties"] = ldb.MessageElement(str(pwd_props),
                  ldb.FLAG_MOD_REPLACE, "pwdProperties")

            if history_length is not None:
                if history_length == "default":
                    pwd_hist_len = 24
                else:
                    pwd_hist_len = int(history_length)

                if pwd_hist_len < 0 or pwd_hist_len > 24:
                    raise CommandError("Password history length must be in the range of 0 to 24!")

                m["pwdHistoryLength"] = ldb.MessageElement(str(pwd_hist_len),
                  ldb.FLAG_MOD_REPLACE, "pwdHistoryLength")
                msgs.append("Password history length changed!")

            if min_pwd_length is not None:
                if min_pwd_length == "default":
                    min_pwd_len = 7
                else:
                    min_pwd_len = int(min_pwd_length)

                if min_pwd_len < 0 or min_pwd_len > 14:
                    raise CommandError("Minimum password length must be in the range of 0 to 14!")

                m["minPwdLength"] = ldb.MessageElement(str(min_pwd_len),
                  ldb.FLAG_MOD_REPLACE, "minPwdLength")
                msgs.append("Minimum password length changed!")

            if min_pwd_age is not None:
                if min_pwd_age == "default":
                    min_pwd_age = 0
                else:
                    min_pwd_age = int(min_pwd_age)

                if min_pwd_age < 0 or min_pwd_age > 998:
                    raise CommandError("Minimum password age must be in the range of 0 to 998!")

                # days -> ticks
                min_pwd_age_ticks = -int(min_pwd_age * (24 * 60 * 60 * 1e7))

                m["minPwdAge"] = ldb.MessageElement(str(min_pwd_age_ticks),
                  ldb.FLAG_MOD_REPLACE, "minPwdAge")
                msgs.append("Minimum password age changed!")

            if max_pwd_age is not None:
                if max_pwd_age == "default":
                    max_pwd_age = 43
                else:
                    max_pwd_age = int(max_pwd_age)

                if max_pwd_age < 0 or max_pwd_age > 999:
                    raise CommandError("Maximum password age must be in the range of 0 to 999!")

                # days -> ticks
                max_pwd_age_ticks = -int(max_pwd_age * (24 * 60 * 60 * 1e7))

                m["maxPwdAge"] = ldb.MessageElement(str(max_pwd_age_ticks),
                  ldb.FLAG_MOD_REPLACE, "maxPwdAge")
                msgs.append("Maximum password age changed!")

            if max_pwd_age > 0 and min_pwd_age >= max_pwd_age:
                raise CommandError("Maximum password age (%d) must be greater than minimum password age (%d)!" % (max_pwd_age, min_pwd_age))

            samdb.modify(m)
            msgs.append("All changes applied successfully!")
            self.message("\n".join(msgs))
        else:
            raise CommandError("Wrong argument '%s'!" % subcommand)