#!/usr/bin/python

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

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

if os.getuid() != 0:
    fail('Please run this program as root/with sudo')

cur_dir = os.path.abspath(os.path.dirname(__file__))

server_path = os.path.join(cur_dir, 'automation', 'trex_control_plane', 'server')
if server_path not in sys.path:
    sys.path.append(server_path)

ext_libs_path = os.path.join(cur_dir, 'external_libs')
if ext_libs_path not in sys.path:
    sys.path.append(ext_libs_path)

if 'start-live' not in sys.argv:
    import CCustomLogger
    CCustomLogger.setup_daemon_logger('TRexServer', '/var/log/trex/trex_daemon_server.log')

import trex_server
import netstat

try:
    from termstyle import termstyle
except ImportError:
    import termstyle


def get_daemon_pid():
    pid = None
    for conn in netstat.netstat():
        if conn[2] == '0.0.0.0' and int(conn[3]) == args.daemon_port and conn[6] == 'LISTEN':
            pid = conn[7]
            if pid is None:
                raise Exception('Found the connection, but could not determine pid: %s' % conn)
            break
    return pid


# faster variant of get_daemon_pid
def is_running():
    for conn in netstat.netstat(with_pid = False):
        if conn[2] == '0.0.0.0' and int(conn[3]) == args.daemon_port and conn[6] == 'LISTEN':
            return True
    return False


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


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


def restart_daemon():
    if is_running():
        kill_daemon()
        sleep(0.5)
    start_daemon()


def kill_daemon():
    pid = get_daemon_pid()
    if not pid:
        print(termstyle.red('TRex server daemon is NOT running'))
        return True
    pid = int(pid)
    for sig in (signal.SIGTERM, signal.SIGKILL):
        os.kill(pid, sig)
        for i in range(50):
            if not is_running():
                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.\n' \
         'Return code: %s\nStdout: %s\nStderr: %s' % return_code, stdout, stderr) # 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()

daemon_dir = os.path.dirname(os.path.realpath(__file__))
mkpath('/var/log/trex')
mkpath('/var/run/trex')

action_funcs[args.action]()