# common functions for samba-tool python commands
#
# Copyright Andrew Tridgell 2010
# Copyright Giampaolo Lauria 2011 <lauria2@yahoo.com>
#
# 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 re
from samba.dcerpc import nbt
from samba.net import Net
from samba.netcmd import CommandError
import ldb


# In MS AD, setting a timeout to '(never)' corresponds to this value
NEVER_TIMESTAMP = int(-0x8000000000000000)


def _get_user_realm_domain(user, sam=None):
    r""" get the realm or the domain and the base user
        from user like:
        * username
        * DOMAIN\username
        * username@REALM

         A SamDB object can also be passed in to check
        our domain or realm against the obtained ones.
    """
    baseuser = user
    m = re.match(r"(\w+)\\(\w+$)", user)
    if m:
        domain = m.group(1)
        baseuser = m.group(2)

        if sam is not None:
            our_domain = sam.domain_netbios_name()
            if domain.lower() != our_domain.lower():
                raise CommandError(f"Given domain '{domain}' does not match "
                                   f"our domain '{our_domain}'!")

        return (baseuser.lower(), "", domain.upper())

    realm = ""
    m = re.match(r"(\w+)@(\w+)", user)
    if m:
        baseuser = m.group(1)
        realm = m.group(2)

        if sam is not None:
            our_realm = sam.domain_dns_name()
            our_realm_initial = our_realm.split('.', 1)[0]
            if realm.lower() != our_realm_initial.lower():
                raise CommandError(f"Given realm '{realm}' does not match our "
                                   f"realm '{our_realm}'!")

    return (baseuser.lower(), realm.upper(), "")


def netcmd_dnsname(lp):
    '''return the full DNS name of our own host. Used as a default
       for hostname when running status queries'''
    return lp.get('netbios name').lower() + "." + lp.get('realm').lower()


def netcmd_finddc(lp, creds, realm=None):
    '''Return domain-name of a writable/ldap-capable DC for the default
       domain (parameter "realm" in smb.conf) unless another realm has been
       specified as argument'''
    net = Net(creds=creds, lp=lp)
    if realm is None:
        realm = lp.get('realm')
    cldap_ret = net.finddc(domain=realm,
                           flags=nbt.NBT_SERVER_LDAP | nbt.NBT_SERVER_DS | nbt.NBT_SERVER_WRITABLE)
    return cldap_ret.pdc_dns_name


def netcmd_get_domain_infos_via_cldap(lp, creds, address=None):
    '''Return domain information (CLDAP record) of the ldap-capable
       DC with the specified address'''
    net = Net(creds=creds, lp=lp)
    cldap_ret = net.finddc(address=address,
                           flags=nbt.NBT_SERVER_LDAP | nbt.NBT_SERVER_DS)
    return cldap_ret

def is_printable_attr_val(val):
    import unicodedata

    # The value must be convertible to a string value.
    try:
        str_val = str(val)
    except:
        return False

    # Characters of the Unicode Character Category "C" ("Other") are
    # supposed to be not printable. The category "C" includes control
    # characters, format specifier and others.
    for c in str_val:
        if unicodedata.category(c)[0] == 'C':
            return False

    return True

def get_ldif_for_editor(samdb, msg):

    # Copy the given message, because we do not
    # want to modify the original message.
    m = ldb.Message()
    m.dn = msg.dn

    for k in msg.keys():
        if k == "dn":
            continue
        vals = msg[k]
        m[k] = vals
        need_base64 = False
        for v in vals:
            if is_printable_attr_val(v):
                continue
            need_base64 = True
            break
        if not need_base64:
            m[k].set_flags(ldb.FLAG_FORCE_NO_BASE64_LDIF)

    result_ldif = samdb.write_ldif(m, ldb.CHANGETYPE_NONE)

    return result_ldif


def timestamp_to_mins(timestamp_str):
    """Converts a timestamp in -100 nanosecond units to minutes"""
    # treat a timestamp of 'never' the same as zero (this should work OK for
    # most settings, and it displays better than trying to convert
    # -0x8000000000000000 to minutes)
    if int(timestamp_str) == NEVER_TIMESTAMP:
        return 0
    else:
        return abs(int(timestamp_str)) / (1e7 * 60)


def timestamp_to_days(timestamp_str):
    """Converts a timestamp in -100 nanosecond units to days"""
    return timestamp_to_mins(timestamp_str) / (60 * 24)


def attr_default(msg, attrname, default):
    '''get an attribute from a ldap msg with a default'''
    if attrname in msg:
        return msg[attrname][0]
    return default