#!/usr/bin/env python

# Copyright 2014 Red Hat Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import argparse
import json
import os
import sys


def eprint(msg):
    sys.stderr.write(msg)
    sys.stderr.write("\n")


def os_family(distro):
    family = None
    if distro in ['fedora', 'rhel', 'rhel7', 'centos7']:
        family = 'redhat'
    elif distro in ['debian', 'ubuntu']:
        family = 'debian'
    elif distro == 'opensuse':
        family = 'suse'

    return family


def main():
    parser = argparse.ArgumentParser(
        description="Translate package name to distro specific name."
                    " Exits with 1 if error is encountered, 2 if no pkg-map"
                    " file is found. Otherwise exits with 0.")
    parser.add_argument('--element', default='',
                        help='The element (namespace) to use for translation.')
    parser.add_argument('--distro', default=os.environ.get('DISTRO_NAME'),
                        help='The distro name to use for translation.'
                        ' Defaults to DISTRO_NAME')
    parser.add_argument('--missing-ok', action="store_true",
                        help='Do not consider missing mappings an error.'
                             ' Causes packages where no mapping is set to be'
                             ' printed.')
    args, extra = parser.parse_known_args()

    if not args.element:
        eprint('Please specify an --element argument.')
        sys.exit(1)

    if not args.distro:
        eprint('Please specify a --distro argument or set DISTRO_NAME.')
        sys.exit(1)

    map_file = '/usr/share/pkg-map/%s' % args.element
    if not os.path.exists(map_file):
        eprint('Map file for %s element does not exist.' % args.element)
        if args.missing_ok:
            for name in extra:
                print(name)
            sys.exit(0)
        sys.exit(2)

    with open(map_file) as fd:
        package_names = json.loads(fd.read())

    # Parse mapping data in this form using distro/family/default
    # Most specific takes priority (distro is most specific).
    # An empty package list can be provided.
    # Example for Nova and Glance (using fictitious name for Fedora and SUSE
    # and package mapping for SUSE family)
    # {
    #   "distro": {
    #     "fedora": {
    #       "nova_package": "openstack-compute",
    #       "glance_package": "openstack-image"
    #     }
    #   },
    #   "family": {
    #     "redhat": {
    #       "nova_package": "openstack-nova",
    #       "glance_package": "openstack-glance"
    #     },
    #     "suse": {
    #       "nova_package": ""
    #    }
    #   },
    #   "default": {
    #     "nova_package": "nova",
    #     "glance_package": "glance"
    #   }
    # }
    name_map = package_names.get('default', {})
    if 'family' in package_names:
        family_map = package_names['family'].get(os_family(args.distro))
        if family_map:
            name_map.update(family_map)
    if 'distro' in package_names:
        distro_map = package_names['distro'].get(args.distro)
        if distro_map:
            name_map.update(distro_map)

    for name in extra:
        pkg_name = name_map.get(name)
        if pkg_name:
            print(pkg_name)
        elif name in name_map:
            continue
        else:
            err_msg = 'Missing package name for distro/element: %s/%s'
            eprint(err_msg % (args.distro, args.element))
            if args.missing_ok:
                print(name)
            else:
                sys.exit(1)

    sys.exit(0)

if __name__ == '__main__':
    main()