import os
import subprocess
import time

# NoMachine services / processes that lock files in C:\Program Files\NoMachine\bin
NX_SERVICE = 'nxservice'
NX_PROCESSES = [
    'nxplayer.exe', 'nxclient.exe', 'nxrunner.exe', 'nxdisplay.exe',
    'nxnode.exe', 'nxserver.exe', 'nxexec.exe', 'nxfs.exe',
    'nxfsserver.exe', 'nxkb.exe', 'nxlpd.exe', 'nxpost.exe',
    'nxsh.exe', 'nxupdatecli.exe', 'nxd.exe', 'nxdx32.exe',
    'nxdx64.exe', 'nxservice64.exe', 'nxservice.exe'
]


def _run_quiet(cmd):
    # run a command, hide output, never raise
    try:
        devnull = open(os.devnull, 'w')
        rc = subprocess.call(cmd, stdout=devnull, stderr=devnull)
        devnull.close()
        return rc
    except Exception:
        return 1


# Stop NoMachine service and kill all its processes so DLLs are not locked
def stop_nomachine():
    _run_quiet(['net', 'stop', NX_SERVICE])
    time.sleep(5)
    for proc in NX_PROCESSES:
        _run_quiet(['taskkill', '/F', '/IM', proc])
    time.sleep(3)


# Start NoMachine service after install / update
def start_nomachine():
    _run_quiet(['net', 'start', NX_SERVICE])


# dir: string -> directory where installer exist
# args: string -> which includes all parameters with space delimiter
def spm_install(dir, args):
    os.chdir(dir)
    argslist = args.split()
    try:
        stop_nomachine()
        subprocess.check_call(argslist)
        time.sleep(15)
        start_nomachine()
        print 'retcode' + str(0) + 'retcode'
    except subprocess.CalledProcessError as e:
        print 'retcode' + str(e.returncode) + 'retcode'
    except OSError:
        print 'retcode' + str(1) + 'retcode'


# dir: string -> directory where installer exist
# args: string -> which includes all parameters with space delimiter
def spm_uninstall(dir, args):
    os.chdir(dir)
    argslist = args.split()
    try:
        stop_nomachine()
        subprocess.check_call(argslist)
        time.sleep(10)
        print 'retcode' + str(0) + 'retcode'
    except subprocess.CalledProcessError as e:
        print 'retcode' + str(e.returncode) + 'retcode'
    except OSError:
        print 'retcode' + str(1) + 'retcode'


# dir: string -> directory where installer exist
# args: string -> which includes all parameters with space delimiter
def spm_update(dir, args):
    os.chdir(dir)
    argslist = args.split()
    try:
        stop_nomachine()
        try:
            subprocess.check_call(argslist)
        except subprocess.CalledProcessError:
            # first attempt failed (file lock etc.) - stop everything again and retry once
            stop_nomachine()
            time.sleep(5)
            subprocess.check_call(argslist)
        time.sleep(15)
        start_nomachine()
        print 'retcode' + str(0) + 'retcode'
    except subprocess.CalledProcessError as e:
        print 'retcode' + str(e.returncode) + 'retcode'
    except OSError:
        print 'retcode' + str(1) + 'retcode'