#!/usr/bin/python2
# Authors:
#   Petr Viktorin <pviktori@redhat.com>
#   John Dennis <jdennis@redhat.com>
#   Martin Kosek <mkosek@redhat.com>
#
# Copyright (C) 2011  Red Hat
# see file 'COPYING' for use and warranty information
#
# 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/>.

# Test the managed permission ACIs against a known-good ACI list
# to ensure that changes aren't made lightly.
# Can either regenerate ACI.txt, or validate against it.

import sys
import difflib
from argparse import ArgumentParser

from ipalib import api
from ipapython.dn import DN
from ipapython.ipaldap import LDAPEntry, LDAPClient


def parse_options():
    parser = ArgumentParser()
    parser.add_argument('--validate', dest='validate', action='store_true',
        default=False, help='Validate the API vs the stored API')
    parser.add_argument('filename', nargs='?', default='ACI.txt',
        help='File to create or validate, default: ACI.txt')

    options = parser.parse_args()
    return options


def generate_aci_lines(api):
    """Yields ACI lines as they appear in ACI.txt, with trailing newline"""
    update_plugin = api.Updater['update_managed_permissions']
    perm_plugin = api.Object['permission']
    fake_ldap = LDAPClient('', force_schema_updates=False, no_schema=True)
    for name, template, obj in update_plugin.get_templates():
        dn = perm_plugin.get_dn(name)
        entry = fake_ldap.make_entry(dn)
        update_plugin.update_entry(
            obj=obj,
            entry=entry,
            template=template,
            anonymous_read_aci=None,
            is_new=True,
        )
        aci = perm_plugin.make_aci(entry)
        yield 'dn: %s\n' % entry.single_value['ipapermlocation']
        yield 'aci: %s\n' % aci

        check_member_attrs(name, template)


def check_member_attrs(name, template):
    """Check that member* attrs are always present together for read

    ldap2._process_memberofindirect reads all these attributes together;
    if the user doesn't have rights to one of them, the entire entry is
    left out and memberofindirect processing returns wrong a result.
    So we need all of them be readable.
    """
    checked_attrs = ['member', 'memberuser', 'memberhost']
    perm_attrs = template.get('ipapermdefaultattr', ())
    flags = [(a in perm_attrs) for a in checked_attrs]
    if 'read' in template['ipapermright'] and any(flags) and not all(flags):
        raise AssertionError("'%s' includes some  but not all of %s" %
                             (name, checked_attrs))


def main(options):
    api.bootstrap(
        context='cli',
        in_server=False,
        debug=False,
        verbose=0,
        validate_api=True,
        enable_ra=True,
        mode='developer',
        plugins_on_demand=False,
        basedn=DN('dc=ipa,dc=example'),
        realm='IPA.EXAMPLE',
    )
    api.import_plugins('ipaserver.plugins.ldap2')
    api.import_plugins('ipaserver.install.plugins.update_managed_permissions')
    api.finalize()

    output_lines = list(generate_aci_lines(api))

    if options.validate:
        with open(options.filename) as file:
            file_lines = file.readlines()
        if file_lines != output_lines:
            diff = list(difflib.unified_diff(
                file_lines,
                output_lines,
                fromfile='existing %s' % options.filename,
                tofile='new result',
            ))
            for line in diff:
                print line,
            print>>sys.stderr
            print>>sys.stderr, 'Managed permission ACI validation failed.'
            print>>sys.stderr, 'Re-check permission changes and run `makeaci`.'
            exit('%s validation failed' % options.filename)
    else:
        with open(options.filename, 'w') as file:
            file.writelines(output_lines)


if __name__ == '__main__':
    options = parse_options()
    main(options)