#!/usr/bin/env python3

# Copyright (C) 2013, Linnea Skogtvedt <linnea@linuxavdelingen.no>
# Copyright (C) 2015-2017, Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
#
# 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 2 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

# /etc/xdg/autostart/standardskriver.desktop eksempel:
# [Desktop Entry]
# Type=Application
# Exec=standardskriver
# Name=standardskriver
# StartupNotify=false

SITE_ID_FILE = '/etc/standardskriver.site'
CFG_FILE = '/etc/standardskriver.cfg'
CFG_FILE_EXAMPLE = '''[settings]
enable = yes
order = machine groups
delete lpoptions = yes

# MAC address or IP = printer
# hostname = printer
# hostname.domain = printer
# LTSP client IP = printer
# 10.1.0.0/16 = printer
# (globbing works)

[machine]
00:01:02:03:04:05 = printer01
172.16.34.64 = printer02
hostname = printer01
hostname.domain = printer02

# group name = printer
# (globbing works)

[groups]
group1 = printer01
group2 = printer02
'''
from glob import glob
from fnmatch import fnmatchcase

import sys
import os
import subprocess
import re
from socket import gethostname, getfqdn
import netaddr
from optparse import OptionParser
import configparser

# if configured, check on what site location we are currently running...
site_id = None
if os.access(SITE_ID_FILE, os.R_OK):
    with open(SITE_ID_FILE, 'r') as c_id_f:
        # only read first line
        site_id = c_id_f.readline()
        # sanitize input...
        site_id = re.sub(r'([A-Z0-9]+)(.*\n)', r'\1', site_id)

macaddrs = [open(a).read().replace(':', '').strip().lower() for a in glob('/sys/class/net/*/address')]
macaddrs = [a for a in macaddrs if a]

parser = OptionParser()
parser.add_option('-n', '--dryrun', action='store_true', help='only show what would be done')
options, args = parser.parse_args()

if not os.path.exists(CFG_FILE):
    print('Configuration file %s is missing.' % CFG_FILE, file=sys.stderr)
    print('To create it, redirect the following example to %s and edit the file.' % CFG_FILE, file=sys.stderr)
    print(CFG_FILE_EXAMPLE)
    sys.exit(1)

cfg = configparser.RawConfigParser()
# hack: mac addrs contain :, which clashes with cfg syntax
cfg.OPTCRE = re.compile(
        r'(?P<option>[^=\s][^=]*)'          # very permissive!
        r'\s*(?P<vi>[=])\s*'                 # any number of space/tab,
                                              # followed by separator
                                              # (=), followed
                                              # by any # space/tab
        r'(?P<value>.*)$'                     # everything up to eol
        )
cfg.read_file(open(CFG_FILE, 'r'))

if cfg.get('settings', 'enable') != "yes":
    sys.exit(0)

for x in cfg.get('settings', 'order').split():
    if not x in ('machine', 'groups'):
        print('invalid value {val} in settings/order'.format(val=x))
        sys.exit(1)

hostnames = []
hostnames.append(gethostname())
hostnames.append(getfqdn())

re_ipaddr = re.compile(r'inet (\S+)/')
ipaddrs = []
try:
    ipaddrs.append(os.environ['SSH_CLIENT'].split()[0])
except KeyError:
    pass

p = subprocess.Popen(['/usr/bin/ip', 'a'], env={'LANG': 'C'}, stdout=subprocess.PIPE)
for line in p.stdout:
    m = re_ipaddr.search(line.decode())
    if m:
        ipaddrs.append(m.group(1))
p.wait()

p = subprocess.Popen(['id', '-Gn'], stdout=subprocess.PIPE)
groups = [ g.decode() for g in p.stdout.read().split() ]
p.wait()
#print (groups)

def get_group_match():
    group_sections = []
    if site_id:
        group_sections.append('groups.{site}'.format(site=site_id))
    group_sections.append('groups')
    for section in group_sections:
        try:
            for group, printer in cfg.items(section):
                if group.strip('@') in groups: return printer
        except configparser.NoSectionError:
            pass
    return None

def get_machine_match():
    machine_sections = []
    if site_id:
        machine_sections.append('machine.{site}'.format(site=site_id))
    machine_sections.append('machine')
    for section in machine_sections:
        try:
            for machine, printer in cfg.items(section):
                if any(fnmatchcase(macaddr, machine.replace('-', '').replace(':', '')) for macaddr in macaddrs):
                    return printer
                elif any(fnmatchcase(hostname, machine) for hostname in hostnames):
                    return printer
                else:
                    machines = netaddr.IPSet(machine.split(','))
                    myaddrs = netaddr.IPSet(ipaddrs)
                    if machines & myaddrs:
                        return printer
        except configparser.NoSectionError:
            pass
    return None

matches = []
for item in cfg.get('settings', 'order').split():
    if item == 'machine': matches.append(get_machine_match())
    elif item == 'groups': matches.append(get_group_match())
    else: raise ValueError('%s is not machine or groups' % item)

try:
    printer = [x for x in matches if x][0]
except IndexError: # no match
    if cfg.getboolean('settings', 'delete lpoptions'):
        lpoptions_filename = os.path.expanduser('~/.cups/lpoptions')
        if options.dryrun:
            print('would delete %s' % lpoptions_filename)
        else:
            try:
                os.unlink(lpoptions_filename)
            except OSError:
                pass
    sys.exit(0)

args = ['lpoptions', '-d', printer]
if options.dryrun:
    print('would call %s' % (' '.join(args)))
else:
    subprocess.call(args)