#!/usr/bin/python

import os, sys, getpass
from time import time, sleep
import subprocess, shlex, multiprocessing
from argparse import ArgumentParser
from distutils.dir_util import mkpath

def fail(msg):
    print(msg)
    sys.exit(-1)

if getpass.getuser() != 'root':
    fail('Please run this program as root/with sudo')

sys.path.append(os.path.join('automation', 'trex_control_plane', 'server'))
if 'start-live' not in sys.argv:
    import CCustomLogger
    CCustomLogger.setup_daemon_logger('TRexServer', '/var/log/trex/trex_daemon_server.log')
import trex_server

try:
    from termstyle import termstyle
except ImportError:
    import termstyle


def run_command(command, timeout = 10):
    commmand = 'timeout %s %s' % (timeout, command)
    proc = subprocess.Popen(shlex.split(command), stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd = os.getcwd())
    stdout, stderr = proc.communicate()
    return (proc.returncode, stdout.decode(errors = 'replace'), stderr.decode(errors = 'replace'))


def get_daemon_pid():
    return_code, stdout, stderr = run_command('netstat -tlnp')
    if return_code:
        fail('Failed to determine which program holds port %s, netstat error: %s' % (args.daemon_port, stderr))
    for line in stdout.splitlines():
        if '0.0.0.0:%s' % args.daemon_port in line:
            line_arr = line.split()
            if '/' not in line_arr[-1]:
                fail('Expecting pid/program name in netstat line of using port %s, got: %s' % (args.daemon_port, line_arr[-1]))
            pid, program = line_arr[-1].split('/')
            if 'python' not in program and 'trex_server' not in program and 'trex_daemon_server' not in program:
                fail('Some other program holds port %s, not our daemon: %s. Please verify.' % (args.daemon_port, program))
            return int(pid)
    return None


def show_daemon_status():
    if get_daemon_pid():
        print(termstyle.red('TRex server daemon is running'))
    else:
        print(termstyle.red('TRex server daemon is NOT running'))


def start_daemon():
    if get_daemon_pid():
        print(termstyle.red('TRex server daemon is already running'))
        return
    # Usual daemon will die with current process, detach it with double fork
    # https://www.safaribooksonline.com/library/view/python-cookbook/0596001673/ch06s08.html
    pid = os.fork()
    if pid > 0:
        for i in range(50):
            if get_daemon_pid():
                print(termstyle.green('TRex server daemon is started'))
                os._exit(0)
            sleep(0.1)
        fail(termstyle.red('TRex server daemon failed to run'))
    os.setsid()
    pid = os.fork()
    if pid > 0:
        os._exit(0)
    trex_server.do_main_program()


def start_live():
    if get_daemon_pid():
        fail(termstyle.red('TRex server daemon is already running'))
    trex_server.do_main_program()

def restart_daemon():
    if get_daemon_pid():
        kill_daemon()
    start_daemon()

def kill_daemon():
    pid = get_daemon_pid()
    if not pid:
        print(termstyle.red('TRex server daemon is NOT running'))
        return True
    return_code, stdout, stderr = run_command('kill %s' % pid) # usual kill
    if return_code:
        fail('Failed to kill trex_daemon, error: %s' % stderr)
    for i in range(50):
        if not get_daemon_pid():
            print(termstyle.green('TRex server daemon is killed'))
            return True
        sleep(0.1)
    return_code, stdout, stderr = run_command('kill -9 %s' % pid) # unconditional kill
    if return_code:
        fail('Failed to kill trex_daemon, error: %s' % stderr)
    for i in range(50):
        if not get_daemon_pid():
            print(termstyle.green('TRex server daemon is killed'))
            return True
        sleep(0.1)
    fail('Failed to kill trex_daemon, even with -9. Please review manually.') # should not happen

### Main ###

actions_help = '''Specify action command to be applied on server.
    (*) start      : start the application in as a daemon process.
    (*) show       : prompt an updated status of daemon process (running/ not running).
    (*) stop       : exit the daemon process.
    (*) restart    : stop, then start again the application as daemon process
    (*) start-live : start the application in live mode (no daemon process).
    '''
action_funcs = {'start': start_daemon,
                'show': show_daemon_status,
                'stop': kill_daemon,
                'restart': restart_daemon,
                'start-live': start_live,
                }
trex_server.trex_parser.add_argument('action', choices=action_funcs.keys(),
                        action='store', help=actions_help)
trex_server.trex_parser.usage = None
args = trex_server.trex_parser.parse_args()

mkpath('/var/log/trex')
mkpath('/var/run/trex')

action_funcs[args.action]()