#!/usr/bin/env python3
import os
import sys
import re
import subprocess
import datetime
import signal
import time
from threading import Thread

__log_prefix__ = '/home/minecraft/log/'
__folderprefix__ = '/dev/shm/'
__folder__ = __folderprefix__
__players__ = 'players'
__status__ = 'status'
__pipe__ = 'input_pipe'
__log__ = 'none.log'

__STATUSSTRINGS__ = { 0: "Not running",
		1: "Starting",
		2: "Running",
		3: "Stopping"
		}

def __setfiles__(identifier):
	global __folder__
	global __players__
	global __status__
	global __pipe__
	global __log__
	__folder__ = __folderprefix__ + 'mcwrapper_' + identifier + '/'
	__players__ = __folder__ + 'players'
	__status__ = __folder__ + 'status'
	__pipe__ = __folder__ + 'input_pipe'
	__log__ = __log_prefix__ + identifier + '/' + \
		datetime.datetime.now().strftime('%y-%m-%d-%H-%M-%S')

def __user_join__(username):
	print("User '" + username + "' joined server.")
	with open(__players__, 'a') as f:
		f.write(username + '\n')

def __user_leave__(username):
	print("User '" + username + "' left server.")
	players = set()
	with open(__players__) as f:
		for line in f:
			pl = line.rstrip()
			if pl != username:
				players.add(line.rstrip())
	with open(__players__, 'w') as f:
		f.writelines(players)
		if players:
			f.write('\n')


def __server_init__(identifier):
	__setfiles__(identifier)
	__server_clean__() # Clean before execute
	print("Wrapper initializing with identifier: " + identifier)
	try:
		os.mkdir(__folder__)
	except Exception:
		pass
	if os.path.isfile(__status__):
		sys.exit("Server status file already exists. Is another wrapper running?")
	with open(__status__, 'w') as f:
		f.write(__STATUSSTRINGS__[1])
	os.mkfifo(__pipe__, 0o640)

def __server_start__():
	print("Server start.")
	with open(__status__, 'w') as f:
		f.write(__STATUSSTRINGS__[2])
	pass

def __server_stop__():
	print("Server stop.")
	with open(__status__, 'w') as f:
		f.write(__STATUSSTRINGS__[3])
	pass

def __server_clean__():
	print("Wrapper clean.")
	try:
		os.remove(__players__)
	except Exception:
		pass
	try:
		os.remove(__status__)
	except Exception:
		pass
	try:
		os.remove(__pipe__)
	except Exception:
		pass

def __parse_line__(line):
	if ': Done' in line:
		__server_start__()
	elif ': Stopping the server' in line:
		__server_stop__()
	elif 'logged in with entity id' in line:
		name = line[len('[00:00:00] [Server thread/INFO]: '):]
		name = name[:name.index('[')]
		__user_join__(name)
	elif 'left the game' in line:
		name = line[len('[00:00:00] [Server thread/INFO]: '):]
		name = name[:name.index(' ')]
		__user_leave__(name)

#################################################################################

class __InputThread__(Thread):
	def __init__(self, pipein, pipeprocess):
		Thread.__init__(self, name='InputThread')
		self.pipein = pipein
		self.pipeprocess = pipeprocess
		self.stopread = False
	def stopexec(self):
		self.stopread = True
	def wake(self):
		with open(__pipe__, 'w') as f:
			f.write("\n")
			f.flush()
	def run(self):
		with open(self.pipein, 'r') as p:
			while not self.stopread:
				ln = p.readline()
				if ln:
					print("Input: " + ln, end="")
					self.pipeprocess.write(bytes(ln, sys.getdefaultencoding()))
					self.pipeprocess.flush()
				else:
					time.sleep(1)
			try:
				os.remove(__pipe__)
			except Exception:
				pass

def __server_send_stop__():
	global prc
	prc.stdin.write(bytes("/stop\n", sys.getdefaultencoding()))
	prc.stdin.flush()

def mcexec(identifier, cmd):
	"""Executes cmd and parses output for server status changes.

	  cmd     - List of program and arguments to be executed.
	  logfile - Path in string. To entered file will be printed out full process output.
	  """
	global prc
	__server_init__(identifier)
	try:
		os.makedirs(__log_prefix__ + identifier)
	except Exception:
		pass
	prc = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
			stderr=subprocess.STDOUT)
	inputThread = __InputThread__(__pipe__, prc.stdin)
	inputThread.start()
	inputThread.wake() # Input thread is stack in waiting for first line
	for linen in prc.stdout:
		line = linen.decode(sys.getdefaultencoding())
		with open(__log__, 'a') as flg:
			flg.write(line)
		__parse_line__(line.rstrip())
	inputThread.stopexec()
	__server_clean__()

#################################################################################

def __get_status__(identifier):
	if not os.path.isfile(__status__):
		return 0
	else:
		with open(__status__) as f:
			status = f.readline().rstrip()
			for key, val in __STATUSSTRINGS__.items():
				if val == status:
					return key

def server_stop(identifier):
	__setfiles__(identifier)
	status = __get_status__(identifier)
	if status == 0:
		sys.exit("Such server is not running")
	elif status == 1:
		print("Server is starting. Waiting...")
		while __get_status__(identifier) != 2:
			time.sleep(1)
	elif status == 3:
		sys.exit("Server already stops")
	with open(__pipe__, 'w') as f:
		f.write("/stop\n")
		f.flush()
	while os.path.isfile(__status__):
		pass

def server_say(identifier, message):
	__setfiles__(identifier)
	if __get_status__(identifier) != 2:
		sys.exit("Server is not running")
	with open(__pipe__, 'w') as f:
		f.write("/say " + ' '.join(map(str, message)))
		f.flush()

#################################################################################

def __signal_term__(_signo, _stack_frame):
	__server_send_stop__()

if __name__ == '__main__':
	todo = sys.argv[1]
	identifier = sys.argv[2]
	if todo == 'start':
		signal.signal(signal.SIGTERM, __signal_term__)
		cmd = sys.argv[3:]
		mcexec(identifier, cmd)
		__server_clean__()
	elif todo == 'stop':
		server_stop(identifier)
	elif todo == 'say':
		message = sys.argv[3:]
		server_say(identifier, message)
	else:
		print("unknown action: " + todo)