#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#  
#  
#  asrc-server.py
#  
#  Copyright 2012 - 2013 Fanir-Thuban <projects@mail.fanir.de>
#  
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#  
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#  
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#  
#  
#  aSRC (Aliased Server Remote Control)
#  - SERVER -
#  
#  program version: 0.0.0.20130426
#  protocol version: 0.2.20130423
#  
#



import sys, os, socket, socketserver, threading, time


class ThreadedRequestHandler(socketserver.StreamRequestHandler):
    
    def handle(self):
        """
        Handles incoming connections
        """
        
        # Set time for timeout in seconds
        self.timeout = TIMEOUT
        
        # Print a line with the adress of the connected client
        if VERBOSITY >=3:
            print("Client connected: " + str(self.client_address))
        
        # send motd
        self.request.sendall(comm.motd(MOTD) + "\n", ENCODING))
        
        # Receive data
        self.data = str(self.rfile.readline().strip(), ENCODING)
        
        # content handler
        self.request.sendall(bytes(
            comm.handler(str(self.client_address), self.data), ENCODING))


class ThreadedTCPServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
    pass


def main():
    # import global settings
    global VERBOSITY, HOST, PORT, TIMEOUT, ENCODING
    
    from include import argparser, comm
    
    comm.init(ServerVersion, ProtocolVersion, VERBOSITY, aliases)
    
    # parse arguments
    parser = argparser
    args = parser.parse(ServerVersion, ProtocolVersion)
    
    # look for pid file
    if os.path.exists("pid"):
        # remove, ...
        if args.delete_pid_file: os.remove("pid")
        # ... ignore ...
        elif args.allow_multiple_instances: pass
        # ... or exit
        else:
            print(
                "\npid file already exists\n"\
                "If the server didn't shut down correctly, "\
                "just delete this file or pass -n\n"\
                "If you want to start multiple instances, pass -m\n")
            return 1
    
    # set settings if command line options are given
    if args.host: HOST = args.host
    if args.port: PORT = args.port
    if args.timeout: TIMEOUT = args.timeout
    if args.encoding: ENCODING = args.encoding
    if args.verbosity: VERBOSITY = args.verbosity
    
    # write pid file
    pidf = open("pid", 'w')
    pidf.write(str(os.getpid()))
    pidf.close()
    
    print("aSRC Server\n"\
        "Server version: " + ServerVersion + "\n"\
        "Protocol version: " + ProtocolVersion + "\n\n"\
        "To stop the server, press Ctrl-C\n")
    
    try:
        if VERBOSITY >= 1: print("Initializing server...")
        # Create server
        server = ThreadedTCPServer((HOST, PORT), ThreadedRequestHandler)
        
        if VERBOSITY >= 1: print("Starting server on",
            server.server_address[0], "port", server.server_address[1], "...")
        # Start a thread with the server -- that thread will then start one
        # more thread for each request
        ServerThread = threading.Thread(target = server.serve_forever)
        
        # Exit the server thread when the main thread terminates
        ServerThread.daemon = True
        ServerThread.start()
        
        
        while True:
            time.sleep(10)
    
    # exit if Ctrl-C is pressed
    except KeyboardInterrupt:
        print("\nGot Ctrl-C, shutting down server...")
        
        try:
            server.shutdown()
            os.remove("pid")
        except: print("Failed to shutdown server correctly, "\
                "socket may be still in use or wasn't even started:",
                sys.exc_info())
    #except:
    #   print("\nAn error occured:\n", sys.exc_info(), "\n")
    
    if VERBOSITY >= 3: input("Press Enter to continue\n")
    return 0


if __name__ == '__main__':
    
    ServerVersion = "0.0.0"
    ProtocolVersion = "0.2"
    
    
    ##############
    #  SETTINGS  #
    ##############
    
    # IP or hostname (use 0.0.0.0 for all interfaces) and port, on which
    # the server should listen
    HOST = '127.0.0.1'
    PORT = 24642
    
    # Timeout of a connection in seconds - still doesn't work obviously...
    TIMEOUT = 15
    
    # Encoding to be used when communicating with a client
    ENCODING = 'utf-8'
    
    # Dictionary of aliases. Use python syntax. You can use
    # the variable send for text to send to the client.
    #
    # Shell commands can be executed with:
    #     import subprocess
    #     send = subprocess.check_output(["command", "arg", "somemorearg"])
    #
    # You don't have to include sys, os, socket, socketserver,
    # threading and time, through they are included already.
    aliases = dict(
        who = '''
import subprocess
send = subprocess.check_output(["whoami"])
''',
        where = '''
import subprocess
send = subprocess.check_output(["pwd"])
''',
        uname = '''
import os
send = os.uname()
''',
        date = '''
import subprocess
send = subprocess.check_output(["date"])
''',
        ping_fanir = '''
import subprocess
send = subprocess.check_output(["ping", "-c 2", "fanir.de"])
''')
    
    # This is sent to the client after the connection is established
    MOTD = "Welcome! This is only a test server, for developing purposes.\n"\
    "Here (may) be more text..."
    
    # Verbosity of logging.
    # Can be from 0 (only default output) to 3 (debug messages)
    VERBOSITY = 3
    ##############
    
    
    main()