#!/usr/bin/env python3
#
# This script returns 0 when run on a platform supported by the current
# branch of LinuxCNC, and 1 when run on an unsupported platform.  It is
# intended to guide build automation on whether or not to try to build.
#
# Copyright: 2014, 2016
# Author:    Sebastian Kuzminsky <seb@highlab.com>
#
# 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.

import os
import sys
import subprocess
import re

if sys.version_info.minor < 7:
    raise SystemExit("System Python is too old")

supported_oses = [ 'linux' ]
supported_cpus = [ 'amd64', 'i386', 'arm' ]
supported_kernel_flavors = [ 'rtai', 'rtpreempt', 'vanilla' ]


def detect_os():
    return os.uname()[0].lower()


def detect_kernel_flavor(uname):
    try:
        f = open("/boot/config-%s" % uname)
    except IOError:
        print("no kernel configuration found for %s, assuming vanilla" % uname)
        return 'vanilla'
    l = f.read(-1)
    f.close()

    config_ipipe = re.search('^CONFIG_IPIPE', l, re.MULTILINE)
    config_xeno = re.search('^CONFIG_XENO_', l, re.MULTILINE)
    config_rtpreempt = re.search('^CONFIG_PREEMPT_RT', l, re.MULTILINE)

    if config_ipipe and not config_xeno and not config_rtpreempt:
        return 'rtai'
    elif config_ipipe and config_xeno and not config_rtpreempt:
        return 'xenomai'
    elif not config_ipipe and not config_xeno and config_rtpreempt:
        return 'rtpreempt'
    else:
        return 'vanilla'


os = detect_os()

if os == 'linux':
    cpu = subprocess.check_output(['dpkg-architecture', '-qDEB_HOST_ARCH_CPU']).strip().decode()
    distributor = subprocess.check_output(['lsb_release', '--id', '--short']).strip().decode()
    release = subprocess.check_output(['lsb_release', '--release', '--short']).strip().decode()
    try:
        major, minor = re.split('\.', release)
    except ValueError as e:
        major = release
        minor = "0"
    try:
        release_major = int(major)
        release_minor = int(minor)
    except ValueError as e:
	# Debian Unstable and Testing do not have a release number, the value is 'n/a'
        release_major = 666
        release_minor = 0

    uname = subprocess.check_output(['uname', '-r']).strip().decode()
    kernel_flavor = detect_kernel_flavor(uname)

else:
    print("unknown OS:", os)
    sys.exit(1)


print("os =", os)
print("cpu =", cpu)
print("distributor =", distributor)
print("release =", release)
print("    major =", release_major)
print("    minor =", release_minor)
print("uname = %s (%s)" % (uname, kernel_flavor))

if os not in supported_oses:
    print("unsupported OS!")
    sys.exit(1)

if cpu not in supported_cpus:
    print("unsupported CPU!")
    sys.exit(1)

if distributor == 'Ubuntu':
    if release_major < 20:
        print("release is too old!")
        sys.exit(1)

if distributor == 'Debian':
    if release_major < 10:
        print("release is too old!")
        sys.exit(1)

if kernel_flavor not in supported_kernel_flavors:
    print("unsupported kernel flavor")
    sys.exit(1)

print("this platform is supported!")
sys.exit(0)