# Samba-specific bits for optparse
# Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2007
#
# 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/>.
#

"""Support for parsing Samba-related command-line options."""

__docformat__ = "restructuredText"

import optparse
from copy import copy
import os
from samba.credentials import (
    Credentials,
    AUTO_USE_KERBEROS,
    DONT_USE_KERBEROS,
    MUST_USE_KERBEROS,
)
import sys


class SambaOptions(optparse.OptionGroup):
    """General Samba-related command line options."""

    def __init__(self, parser):
        from samba import fault_setup
        fault_setup()
        from samba.param import LoadParm
        optparse.OptionGroup.__init__(self, parser, "Samba Common Options")
        self.add_option("-s", "--configfile", action="callback",
                        type=str, metavar="FILE", help="Configuration file",
                        callback=self._load_configfile)
        self.add_option("-d", "--debuglevel", action="callback",
                        type=str, metavar="DEBUGLEVEL", help="debug level",
                        callback=self._set_debuglevel)
        self.add_option("--option", action="callback",
                        type=str, metavar="OPTION",
                        help="set smb.conf option from command line",
                        callback=self._set_option)
        self.add_option("--realm", action="callback",
                        type=str, metavar="REALM", help="set the realm name",
                        callback=self._set_realm)
        self._configfile = None
        self._lp = LoadParm()
        self.realm = None

    def get_loadparm_path(self):
        """Return path to the smb.conf file specified on the command line."""
        return self._configfile

    def _load_configfile(self, option, opt_str, arg, parser):
        self._configfile = arg

    def _set_debuglevel(self, option, opt_str, arg, parser):
        self._lp.set('debug level', arg)
        parser.values.debuglevel = arg

    def _set_realm(self, option, opt_str, arg, parser):
        self._lp.set('realm', arg)
        self.realm = arg

    def _set_option(self, option, opt_str, arg, parser):
        if arg.find('=') == -1:
            raise optparse.OptionValueError(
                "--option option takes a 'a=b' argument")
        a = arg.split('=')
        try:
            self._lp.set(a[0], a[1])
        except Exception as e:
            raise optparse.OptionValueError(
                "invalid --option option value %r: %s" % (arg, e))

    def get_loadparm(self):
        """Return loadparm object with data specified on the command line."""
        if self._configfile is not None:
            self._lp.load(self._configfile)
        elif os.getenv("SMB_CONF_PATH") is not None:
            self._lp.load(os.getenv("SMB_CONF_PATH"))
        else:
            self._lp.load_default()
        return self._lp


class VersionOptions(optparse.OptionGroup):
    """Command line option for printing Samba version."""
    def __init__(self, parser):
        optparse.OptionGroup.__init__(self, parser, "Version Options")
        self.add_option("-V", "--version", action="callback",
                        callback=self._display_version,
                        help="Display version number")

    def _display_version(self, option, opt_str, arg, parser):
        import samba
        print(samba.version)
        sys.exit(0)


def parse_kerberos_arg(arg, opt_str):
    if arg.lower() in ["yes", 'true', '1']:
        return MUST_USE_KERBEROS
    elif arg.lower() in ["no", 'false', '0']:
        return DONT_USE_KERBEROS
    elif arg.lower() in ["auto"]:
        return AUTO_USE_KERBEROS
    else:
        raise optparse.OptionValueError("invalid %s option value: %s" %
                                        (opt_str, arg))


class CredentialsOptions(optparse.OptionGroup):
    """Command line options for specifying credentials."""

    def __init__(self, parser, special_name=None):
        self.special_name = special_name
        if special_name is not None:
            self.section = "Credentials Options (%s)" % special_name
        else:
            self.section = "Credentials Options"

        self.ask_for_password = True
        self.ipaddress = None
        self.machine_pass = False
        optparse.OptionGroup.__init__(self, parser, self.section)
        self._add_option("--simple-bind-dn", metavar="DN", action="callback",
                         callback=self._set_simple_bind_dn, type=str,
                         help="DN to use for a simple bind")
        self._add_option("--password", metavar="PASSWORD", action="callback",
                         help="Password", type=str, callback=self._set_password)
        self._add_option("-U", "--username", metavar="USERNAME",
                         action="callback", type=str,
                         help="Username", callback=self._parse_username)
        self._add_option("-W", "--workgroup", metavar="WORKGROUP",
                         action="callback", type=str,
                         help="Workgroup", callback=self._parse_workgroup)
        self._add_option("-N", "--no-pass", action="callback",
                         help="Don't ask for a password",
                         callback=self._set_no_password)
        self._add_option("-k", "--kerberos", metavar="KERBEROS",
                         action="callback", type=str,
                         help="Use Kerberos", callback=self._set_kerberos)
        self._add_option("", "--ipaddress", metavar="IPADDRESS",
                         action="callback", type=str,
                         help="IP address of server",
                         callback=self._set_ipaddress)
        self._add_option("-P", "--machine-pass",
                         action="callback",
                         help="Use stored machine account password",
                         callback=self._set_machine_pass)
        self._add_option("--krb5-ccache", metavar="KRB5CCNAME",
                         action="callback", type=str,
                         help="Kerberos Credentials cache",
                         callback=self._set_krb5_ccache)
        self.creds = Credentials()

    def _ensure_secure_proctitle(self, opt_str, secret_data, data_type="password"):
        """ Make sure no sensitive data (e.g. password) resides in proctitle. """
        import re
        try:
            import setproctitle
        except ModuleNotFoundError:
            msg = ("WARNING: Using %s on command line is insecure. "
                    "Please install the setproctitle python module.\n"
                    % data_type)
            sys.stderr.write(msg)
            sys.stderr.flush()
            return False
        # Regex to search and replace secret data + option with.
        #   .*[ ]+  -> Before the option must be one or more spaces.
        #   [= ]    -> The option and the secret data might be separated by space
        #              or equal sign.
        #   [ ]*.*  -> After the secret data might be one, many or no space.
        pass_opt_re_str = "(.*[ ]+)(%s[= ]%s)([ ]*.*)" % (opt_str, secret_data)
        pass_opt_re = re.compile(pass_opt_re_str)
        # Get current proctitle.
        cur_proctitle = setproctitle.getproctitle()
        # Make sure we build the correct regex.
        if not pass_opt_re.match(cur_proctitle):
            msg = ("Unable to hide %s in proctitle. This is most likely "
                    "a bug!\n" % data_type)
            sys.stderr.write(msg)
            sys.stderr.flush()
            return False
        # String to replace secret data with.
        secret_data_replacer = "xxx"
        # Build string to replace secret data and option with. And as we dont
        # want to change anything else than the secret data within the proctitle
        # we have to check if the option was passed with space or equal sign as
        # separator.
        opt_pass_with_eq = "%s=%s" % (opt_str, secret_data)
        opt_pass_part = re.sub(pass_opt_re_str, r'\2', cur_proctitle)
        if opt_pass_part == opt_pass_with_eq:
            replace_str = "%s=%s" % (opt_str, secret_data_replacer)
        else:
            replace_str = "%s %s" % (opt_str, secret_data_replacer)
        # Build new proctitle:
        new_proctitle = re.sub(pass_opt_re_str,
                            r'\1' + replace_str + r'\3',
                            cur_proctitle)
        # Set new proctitle.
        setproctitle.setproctitle(new_proctitle)

    def _add_option(self, *args1, **kwargs):
        if self.special_name is None:
            return self.add_option(*args1, **kwargs)

        args2 = ()
        for a in args1:
            if not a.startswith("--"):
                continue
            args2 += (a.replace("--", "--%s-" % self.special_name),)
        self.add_option(*args2, **kwargs)

    def _parse_username(self, option, opt_str, arg, parser):
        self.creds.parse_string(arg)
        self.machine_pass = False

    def _parse_workgroup(self, option, opt_str, arg, parser):
        self.creds.set_domain(arg)

    def _set_password(self, option, opt_str, arg, parser):
        self._ensure_secure_proctitle(opt_str, arg, "password")
        self.creds.set_password(arg)
        self.ask_for_password = False
        self.machine_pass = False

    def _set_no_password(self, option, opt_str, arg, parser):
        self.ask_for_password = False

    def _set_machine_pass(self, option, opt_str, arg, parser):
        self.machine_pass = True

    def _set_ipaddress(self, option, opt_str, arg, parser):
        self.ipaddress = arg

    def _set_kerberos(self, option, opt_str, arg, parser):
        self.creds.set_kerberos_state(parse_kerberos_arg(arg, opt_str))

    def _set_simple_bind_dn(self, option, opt_str, arg, parser):
        self.creds.set_bind_dn(arg)

    def _set_krb5_ccache(self, option, opt_str, arg, parser):
        self.creds.set_named_ccache(arg)

    def get_credentials(self, lp, fallback_machine=False):
        """Obtain the credentials set on the command-line.

        :param lp: Loadparm object to use.
        :return: Credentials object
        """
        self.creds.guess(lp)
        if self.machine_pass:
            self.creds.set_machine_account(lp)
        elif self.ask_for_password:
            self.creds.set_cmdline_callbacks()

        # possibly fallback to using the machine account, if we have
        # access to the secrets db
        if fallback_machine and not self.creds.authentication_requested():
            try:
                self.creds.set_machine_account(lp)
            except Exception:
                pass

        return self.creds


class CredentialsOptionsDouble(CredentialsOptions):
    """Command line options for specifying credentials of two servers."""

    def __init__(self, parser):
        CredentialsOptions.__init__(self, parser)
        self.no_pass2 = True
        self.add_option("--simple-bind-dn2", metavar="DN2", action="callback",
                        callback=self._set_simple_bind_dn2, type=str,
                        help="DN to use for a simple bind")
        self.add_option("--password2", metavar="PASSWORD2", action="callback",
                        help="Password", type=str,
                        callback=self._set_password2)
        self.add_option("--username2", metavar="USERNAME2",
                        action="callback", type=str,
                        help="Username for second server",
                        callback=self._parse_username2)
        self.add_option("--workgroup2", metavar="WORKGROUP2",
                        action="callback", type=str,
                        help="Workgroup for second server",
                        callback=self._parse_workgroup2)
        self.add_option("--no-pass2", action="store_true",
                        help="Don't ask for a password for the second server")
        self.add_option("--kerberos2", metavar="KERBEROS2",
                        action="callback", type=str,
                        help="Use Kerberos", callback=self._set_kerberos2)
        self.creds2 = Credentials()

    def _parse_username2(self, option, opt_str, arg, parser):
        self.creds2.parse_string(arg)

    def _parse_workgroup2(self, option, opt_str, arg, parser):
        self.creds2.set_domain(arg)

    def _set_password2(self, option, opt_str, arg, parser):
        self.creds2.set_password(arg)
        self.no_pass2 = False

    def _set_kerberos2(self, option, opt_str, arg, parser):
        self.creds2.set_kerberos_state(parse_kerberos_arg(arg, opt_str))

    def _set_simple_bind_dn2(self, option, opt_str, arg, parser):
        self.creds2.set_bind_dn(arg)

    def get_credentials2(self, lp, guess=True):
        """Obtain the credentials set on the command-line.

        :param lp: Loadparm object to use.
        :param guess: Try guess Credentials from environment
        :return: Credentials object
        """
        if guess:
            self.creds2.guess(lp)
        elif not self.creds2.get_username():
            self.creds2.set_anonymous()

        if self.no_pass2:
            self.creds2.set_cmdline_callbacks()
        return self.creds2

# Custom option type to allow the input of sizes using byte, kb, mb ...
# units, e.g. 2Gb, 4KiB ...
#    e.g. Option("--size", type="bytes", metavar="SIZE")
#
def check_bytes(option, opt, value):

    multipliers = {
            "B"  : 1,
            "KB" : 1024,
            "MB" : 1024 * 1024,
            "GB" : 1024 * 1024 * 1024}

    # strip out any spaces
    v = value.replace(" ", "")

    # extract the numeric prefix
    digits = ""
    while v and v[0:1].isdigit() or v[0:1] == '.':
        digits += v[0]
        v = v[1:]

    try:
        m = float(digits)
    except ValueError:
        msg = ("{0} option requires a numeric value, "
               "with an optional unit suffix").format(opt)
        raise optparse.OptionValueError(msg)


    # strip out the 'i' and convert to upper case so
    # kib Kib kb KB are all equivalent
    suffix = v.upper().replace("I", "")
    try:
        return m * multipliers[suffix]
    except KeyError as k:
        msg = ("{0} invalid suffix '{1}', "
               "should be B, Kb, Mb or Gb").format(opt, v)
        raise optparse.OptionValueError(msg)

class SambaOption(optparse.Option):
    TYPES = optparse.Option.TYPES + ("bytes",)
    TYPE_CHECKER = copy(optparse.Option.TYPE_CHECKER)
    TYPE_CHECKER["bytes"] = check_bytes
