# .-=[ fdfc.py ]============================================================-. #
# | Furcadia Data Flow Corrector 1.0 (c) by IceDragon of QuickFox.org        | #
# |==========================================================================| #
# | This script aims to try and improve connectivity between Furcadia client | #
# | and the Furcadia file server along with providing debugging ground for   | #
# | unusual fileserver behavior. This script was made for Farren Dustfur as  | #
# | an attempt to deal with his download stalls on dialup... Hope it works.  | #
# '-========================================================================-' #


###--# Imports #--###
from socket import *
from select import select
from time   import time


###--# Configuration #--###
# Target address/port.
target_addr = ( 'hades.furcadia.com', 21 )

# Local port.
local_port  = 1337


###--# Global Variables #--###
fdServer  = None
fdClients = []

###--# Functions #--###
def fdfc_listen ():
    global local_port, fdServer
    
    bind_addr = ( '127.0.0.1', local_port )
    
    fd = socket( AF_INET, SOCK_STREAM, 0 )
    
    fd.bind        ( bind_addr )
    fd.listen      ( 3 )
    fd.setblocking ( 0 )
    
    fdServer = fd
    
    print "+++ Listening on %s:%d for incoming connections..." % bind_addr
    
    return True
# fdfc_listen()


def fdfc_handle_incoming ():
    global fdServer, fdClients, target_addr
    
    ( fdc, addr_info ) = fdServer.accept()
    
    print "+++ Incoming from %s:%d!" % addr_info

    fds = socket( AF_INET, SOCK_STREAM, 0 )
    
    fds.connect     ( target_addr )
    fds.setblocking ( 0 )
    fdc.setblocking ( 0 )
    
    # Forming client data instance.
    client_data = {
	"client":     fdc,
	"server":     fds,
	"buffer":     '',
	"bytesIn":    0,
	"bytesOut":   0,
	"connTime":   time(),
	"packetSize": 1024,
	"phase":      'COMMAND'
    }
    
    fdClients.append( client_data )
    return True
# fdfc_handle_incoming()


def fdfc_handle_S2C ( client_data ):
    global fdClients
    
    data = client_data['server'].recv( client_data['packetSize'] )
    size = len( data )
    
    client_data['bytesIn'] += size
    
    if( size <= 0 ):
	print "--- Received EOF from server - terminating corresponding connections..."
	client_data['server'].close()
	client_data['client'].close()
	print "iii Transfer rate: %ld bytes in, %ld bytes out." % ( client_data['bytesIn'], client_data['bytesOut'] )
	fdClients.remove( client_data )
	return
    
    if( client_data['phase'] == "RAW" ):
	sent_size = 0

	while sent_size < size:
	    ss = client_data['client'].send( data )
	    sent_size += ss
	    data = data[ ss: ]
	# while
	return
    
    if( client_data['phase'] == "COMMAND" ):
	( cmd, args ) = data.strip().split( ' ', 1 )
	
	if( cmd == "44" ):
	    ( fSize, nPackets, packetSize, startPacket ) = args.split( ' ' )
	    if( int( packetSize ) != client_data['packetSize'] ):
		print " !! WARNING: Server reset packetsize from %d to %d!" % ( client_data['packetSize'], int( packetSize ) )

	    print " >> (44) File exists (%s bytes), %s-packet burst from packet %s (Packet Size: %s) - entering transfer mode." % (fSize, nPackets, startPacket, packetSize)
	    client_data['packetSize'] = int( packetSize )
	    client_data['phase']      = 'TRANSFER'
	elif( cmd == "41" ):
	    print " >> (41) Warning: Target file not found on the server!"
	elif( cmd == "46" ):
	    print " >> (46) Transfer abort command received!"
	elif( cmd == "47" ):
	    print " >> (47) Transfer resume command received."
	elif( cmd == "59" ):
	    print " >> (59) Transfer complete - switching to RAW mode (disabling functionality)..."
	    client_data['phase'] = 'RAW'
	
	client_data['client'].send( data )
	
	return

    if( client_data['phase'] == "TRANSFER" ):
	client_data['buffer'] += data
	size = len( client_data['buffer'] )
	
	if( data.split( ' ', 1 )[0] == '59' ):
	    print " ii Transfer complete - switching to RAW mode (disabling functionality)..."
	    client_data['phase'] = 'RAW'
	    client_data['client'].send( client_data['buffer'] )
	    client_data['client'].send( data )
	    return

	if( size < client_data['packetSize'] ):
	    print " !! WARNING: Received data less than packet size (%d/%d) - awaiting completion..." % ( size, client_data['packetSize'] )
	    return
	elif( size > client_data['packetSize'] ):
	    print " ii Buffer contains more than expected (%d/%d) - sending only the expected size..." % ( size, client_data['packetSize'] )

	sent_size = 0

	while sent_size < client_data['packetSize']:
	    ss = client_data['client'].send( client_data['buffer'][ :(client_data['packetSize'] - sent_size) ] )
	    sent_size += ss
	    client_data['buffer'] = client_data['buffer'][ ss: ]
	    if( sent_size < client_data['packetSize'] ):
	        print " !! WARNING: Sent less data than needed (%d/%d) - sending the rest..." % ( sent_size, client_data['packetSize'] )
	        continue
	    elif( sent_size > client_data['packetSize'] ):
	        print "!!! WARNING: Sent more data than needed (%d/%d) - programming error?.." % ( sent_size, client_data['packetSize'] )
	# while
	
	    
	return

    return
# fdfc_handle_S2C()


def fdfc_handle_C2S ( client_data ):
    global fdClients

    data = client_data['client'].recv( 1024 )
    size = len( data )
    
    client_data['bytesOut'] += size
    
    if( size <= 0 ):
	print "--- Received EOF from client - terminating corresponding connections..."
	client_data['server'].close()
	client_data['client'].close()
	print "iii Transfer rate: %ld bytes in, %ld bytes out." % ( client_data['bytesIn'], client_data['bytesOut'] )
	fdClients.remove( client_data )
	return
    
    if( client_data['phase'] == "RAW" ):
	sent_size = 0

	while sent_size < size:
	    ss = client_data['server'].send( data )
	    sent_size += ss
	    data = data[ ss: ]
	# while
	return

    if( ' ' in data ):
        (cmd, args) = data.strip().split( ' ', 1 )
    else:
        cmd = data.strip()
    
    if( client_data['phase'] == "COMMAND" ):
	if( cmd == "RC" ):
	    client_data['packetSize'] = int( args.split( ' ' )[5] )
	
	elif( cmd == "USER" ):
	    print " ii File upload attempt detected - switching to RAW mode - corrector disabled."
	    client_data['phase'] = 'RAW'
	
	elif( cmd == "SNCRC" ):
	    print " >> Resynchronization from packet %s - entering TRANSFER mode..." % ( args )
	    client_data['phase'] = 'TRANSFER'
	
	client_data['server'].send( data )
	return

    if( client_data['phase'] == "TRANSFER" ):
	if( cmd == "+MIS" ):
	    print " !! WARNING: Client terminated the transfer (%s) - returning to COMMAND mode..." % ( data.strip() )
	    client_data['phase'] = 'COMMAND'
	
	client_data['server'].send( data )
	return

    return
# fdfc_handle_C2S()


def fdfc_dispatch ():
    global fdClients, fdServer
    
    rlist = []
    
    rlist.append( fdServer )
    
    for client_data in fdClients:
	rlist.append( client_data['server'] )
	rlist.append( client_data['client'] )
    # for
    
    results = select( rlist, [], [], 0.2 )[0]
    
    if fdServer in results:
	fdfc_handle_incoming()
    
    for client_data in fdClients:
	if client_data['server'] in results:
	    try:
		fdfc_handle_S2C( client_data )
	    except Exception, (errno,errstr):
		print "!!! WARNING: Unable to handle Server->Client data: [%d] %s" % ( errno, errstr )
		print "--- Terminating connection..."
		client_data['server'].close()
		client_data['client'].close()
		fdClients.remove( client_data )
	elif client_data['client'] in results:
	    try:
		fdfc_handle_C2S( client_data )
	    except Exception, (errno,errstr):
		print "!!! WARNING: Unable to handle Client->Server data: [%d] %s" % ( errno, errstr )
		print "--- Terminating connection..."
		client_data['server'].close()
		client_data['client'].close()
		fdClients.remove( client_data )
    return
# fdfc_dispatch()


###--# Initialization #--###

print "--+ Furcadia Data Flow Corrector [FDFC] v1.0 by IceDragon <icedragon@quickfox.org> +--\n"

fdfc_listen()

while True:
    fdfc_dispatch()

print "!!! Program reached its end."