#!/usr/bin/env python3
# encoding: utf-8

# This file is part of steamos-devkit
# SPDX-License-Identifier: LGPL-2.1+
#
# Copyright 2017-2018 Collabora Ltd
#
# This package is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This package 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this package.  If not, see
# <http://www.gnu.org/licenses/>.

# Sample script run to identify the machine we are running on. This
# is used by the devkit daemon to choose an identity for the machine,
# and can also be run directly.
#
# A script or binary (written in any language) named devkit-1-identify
# can be placed in the same directory as this sample, and it will be
# used preferentially.
#
# Execution environment:
# - Runs as root, or as an ordinary user who can run games
# - Part of a non-interactive secure shell session
# Input:
# - None
# Output:
# - Exit 0 on success or nonzero on error
# - On success, must print JSON to stdout containing one object with
#   the following keys and string values, all of which are optional:
#   - "machine_id": The hexadecimal systemd/D-Bus machine-id(5)
#     (in the case of a conflict between systemd's /etc/machine-id and
#     D-Bus' traditional /var/lib/dbus/machine-id, the systemd version
#     should be preferred)
#   - "hostname": The machine-readable hostname as set by sethostname(2)
#   - "pretty_hostname": A human-friendly version of the hostname as
#     found in systemd's machine-info(5)
#   - "product_family", "product_name", "product_serial", "product_uuid",
#     "sys_vendor": as for /sys/devices/virtual/dmi/id
#   - "product": The best human-friendly description of the machine
#     hardware we can devise, for example "Alienware ASM100"
#   - "serial": The best hardware serial number we can devise
#   - "machine_name": The best unique name for the machine that we can
#     devise
# - Any diagnostic messages must be printed to stderr only

import json
import os
import re
import socket
import subprocess
import sys

_MACHINE_ID_RE = re.compile(r'^[0-9A-Fa-f]{32,32}$')
_USELESS_HOSTNAMES = frozenset((
    'debian',
    'host',
    'localhost',
    'steamos',
    'ubuntu',
))
# The case combination sometimes varies, so this is lowercased and we
# use lower() to compare.
_USELESS_DMI_NAMES = frozenset((
    'to be filled by o.e.m.',
))

if __name__ == '__main__':

    info = {}
    steam_serialnumber = None

    for k in ('product_family', 'product_name', 'product_serial',
              'product_uuid', 'sys_vendor'):
        try:
            with open('/sys/devices/virtual/dmi/id/{}'.format(k)) as reader:
                v = reader.read().strip()

                if v and v.lower() not in _USELESS_DMI_NAMES:
                    info[k] = v
        except (IOError, OSError, UnicodeError):
            pass

    try:
        for f in ('/etc/machine-id', '/var/lib/dbus/machine-id'):
            with open(f) as reader:
                v = reader.read().strip()

                if _MACHINE_ID_RE.match(v):
                    info['machine_id'] = v
    except (IOError, OSError, UnicodeError):
        pass

    if 'product_family' in info and 'sys_vendor' in info:
        info['product'] = '{sys_vendor} {product_family}'.format(**info)
    elif 'product_name' in info and 'sys_vendor' in info:
        info['product'] = '{sys_vendor} {product_name}'.format(**info)
    elif 'product_family' in info:
        info['product'] = info['product_family']
    elif 'product_name' in info:
        info['product'] = info['product_name']

    if os.access('/usr/bin/hostnamectl', os.X_OK):
        try:
            v = subprocess.check_output([
                'hostnamectl', '--pretty',
            ]).decode('utf-8').strip()
        except (subprocess.CalledProcessError, UnicodeError):
            pass
        else:
            if v:
                info['pretty_hostname'] = v

            v = subprocess.check_output([
                'hostnamectl', '--static',
            ]).decode('utf-8').strip()

            if v:
                info['hostname'] = v

    if 'hostname' not in info:
        try:
            info['hostname'] = socket.gethostname()
        except (IOError, OSError, UnicodeError):
            pass

    if steam_serialnumber:
        info['serial'] = steam_serialnumber
    elif 'product_serial' in info:
        info['serial'] = info['product_serial']

    if 'product' in info:
        info['machine_name'] = info['product']

    if 'hostname' in info and info['hostname'] not in _USELESS_HOSTNAMES:
        info['machine_name'] = info['hostname']

    if 'pretty_hostname' in info:
        info['machine_name'] = info['pretty_hostname']

    json.dump(info, sys.stdout, indent=4, sort_keys=True)
    print()