#!/usr/bin/env python3
from socket import *
from _thread import start_new_thread
from subprocess import getoutput
from struct import *

# Protocol:
#   Opcode 1:  usercount
#   Opcode 2:  uptime
#   Opcode 255:  disconnect
#   Either way, the server sends a 2-byte response

# Create a socket, open it, and get ready for connections
our_socket = socket(AF_INET, SOCK_STREAM)
our_socket.bind(("0.0.0.0", 5105))
our_socket.listen(5)

# This function will be running once per client
def handle_client(cskt):
    while True:
        try:
            opcode = unpack(">B", cskt.recv(1))[0]
        except:
            break
        print("received opcode", opcode)
        if opcode == 1:
            usercount = int(getoutput('who | sed "s/ .*//g" | sort -u | wc -l'))
            usercount_encoded = pack(">H", usercount)
            cskt.send(usercount_encoded) # This is 2 bytes
        elif opcode == 2:
            uptime = int(getoutput('uptime | grep -o " [0-9]* days" | sed s/days//g'))
            uptime_encoded = pack(">H", uptime)
            cskt.send(uptime_encoded) # This is also 2 bytes
        else: # Another option:  if opcode not in [1, 2]:
            break
    print("Done with client on socket ", cskt)
    cskt.close()

# This loop runs one iteration per new connection
while True:
    client_socket, client_address = our_socket.accept()
    start_new_thread(handle_client, (client_socket, ))
    print("We got a new connection from:  ", client_address[0], client_address[1])

our_socket.close()