#!/usr/bin/python

import os, sys, getpass
import tempfile
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)
    # pipes might stuck, even with timeout
    with tempfile.TemporaryFile() as stdout_file, tempfile.TemporaryFile() as stderr_file:
        proc = subprocess.Popen(shlex.split(command), stdout = stdout_file, stderr = stderr_file, cwd = daemon_dir)
        proc.wait()
        stdout_file.seek(0)
        stderr_file.seek(0)
        return (proc.returncode, stdout_file.read().decode(errors = 'replace'), stderr_file.read().decode(errors = 'replace'))


def get_daemon_pid():
    err = None
    for i in range(5):
        try:
            return_code, stdout, stderr = run_command('netstat -tlnp')
            if return_code:
                raise Exception('Failed to run netstat.\nStdout: %s\nStderr: %s' % (stdout, 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]:
                        raise Exception('Expecting pid/program name in netstat line of using port %s, got: %s' % (args.daemon_port, line))
                    pid, program = line_arr[-1].split('/')
                    if 'python' not in program and 'trex_server' not in program and 'trex_daemon_server' not in program:
                        raise Exception('Some other program holds port %s, not our daemon: %s. Please verify.' % (args.daemon_port, program))
                    return int(pid)
            return None
        except Exception as e:
            err = e
            sleep(0.1)
    fail('Could not determine daemon pid, err: %s' % err)


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.\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]()