#!/usr/bin/env python
#
# dispatcher.py - Subprocess running as root to call larch scripts
#
# (c) Copyright 2010 Michael Towers (larch42 at googlemail dot com)
#
# This file is part of the larch project.
#
#    larch 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.
#
#    larch 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 larch; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
#----------------------------------------------------------------------------
#2010.07.19

import os, sys, threading, signal
from subprocess import Popen, PIPE, STDOUT
try:
    import json as serialize
except:
    import simplejson as serialize

module_dir = os.path.dirname(os.path.realpath(__file__))
base_dir = os.path.dirname(module_dir)


def out(key, line):
    sys.stdout.write(str(key) + ':' + line + '\n')
    sys.stdout.flush()

# Signal dispatcher started
out(0, '==')

def input_reader():
    global process
    id = process.pid
    while True:
        line = process.stdout.readline()
        if not line:
            break

        out(id, line.rstrip())

    process.wait()
    out(id, '/%d' % process.returncode)
    process = None

def kill():
    """Kill subprocesses (well, interrupt actually).
    """
    if process:
        os.killpg(process.pid, signal.SIGINT)


process = None
while True:
    line = sys.stdin.readline()
    if line:
        line = line.rstrip()
    else:
        # Controlling process died
        break
    cmdx = line.split(None, 1)
    cmd = cmdx[0]
    response = ''
    if cmd in ('archin', 'larchify', 'live_iso', 'live_part', 'boot_iso',
            'test'):
        # Start a larch script, together with a thread to read from it.
        # The arguments are passed as a serialized list
        if process:
            response = ("!*** Bug (Dispatcher ERROR):"
                    " process already running (%d)" % process.pid)
        else:
            cmdx2 = cmdx[1].split(':', 1)
            cmds = ([base_dir + '/cli/%s.py' % cmd, '-s']
                    + serialize.loads(cmdx2[1]))
            process = Popen(cmds,
                    preexec_fn=os.setpgrp,  # to facilitate interruption
                    cwd=cmdx2[0],           # set to project directory
                    stdin=PIPE,
                    stdout=PIPE,
                    stderr=STDOUT)
            t = threading.Thread(target=input_reader, args=())
            t.start()

    elif cmd.startswith('??'):
        process.stdin.write(cmd + '\n')
        process.stdin.flush()
    elif cmd == 'kill':
        kill()
    elif cmd != 'quit':
        response = "!*** Bug (Dispatcher command): " + line
    sys.stderr.write(response + '\n!+\n')
    sys.stderr.flush()
    if cmd == 'quit':
        break

kill()