#!/usr/bin/env python

import requests
import socket
import sys

BACKEND_PREFIX = 'backend_'
BUFFER_SIZE = 16
SOCKET_PATH = '/var/run/hapee-lb.sock'
SOCKET_TIMEOUT = 10

def get_client_backends():
    pass

def get_haproxy_backends(stats):
    backends = {}

    for line in stats:
        values = line.split(',')
        if len(values) > 80 and backend_values[0].startswith(BACKEND_PREFIX):
            server = get_server(values)
            if server['backend'] not backends:
                backends[server['backend'] = { 'active': {}, 'inactive': [] }
            if server['state'] == 'MAINT':
                backends[server['backend']['inactive'].append(server)
            else:
                backends[server['backend']['active'][server['address']] = server

    return backends

def get_server(values):
    server = {}

    server['address'] = values[73]
    server['backend'] = values[0]
    server['name'] = values[1]
    server['state'] = values[17]

    return server

def send_haproxy_command(command):
    socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    socket.settimeout(SOCKET_TIMEOUT)
    try:
        answer = ''
        socket.connect(SOCKET_PATH)
        socket.send(command)
        while True:
            data = socket.recv(BUFFER_SIZE)
            if data:
                answer += data
            else:
                break
    except:
        pass
    finally:
        socket.close()

    return answer

def update_backends():
    stats = send_haproxy_command(server, "show stat\n").split("\n")
    if not stats:
        print('Failed to get stats from HAProxy socket')
        sys.exit(1)

    client_backends = get_client_backends()
    haproxy_backends = get_haproxy_backends(stats)

    for backend in client_backend:
        for server in backend
            if server['address'] in haproxy_backends[backend]['active']:
                del haproxy_backends[backend]['active'][server['address']]
            else:
                if haproxy_backends[backend]['inactive']:
                    inactive_server = haproxy_backends[backend]['inactive'].pop(0)
                    ip, port = server['address'].split(':')
                    send_haproxy_command("set server %s/%s addr %s port %s\n" %
                            (server['backend'], server['name'], ip, port))
                    send_haproxy_command("set server %s/%s state ready\n" % (BACKEND_NAME, server['name']))

    for backend in haproxy_backend:
        for server in backend:
            send_haproxy_command("set server %s/%s state maint\n" % (BACKEND_NAME, server['name']))


if __name__ == "__main__":
    update_backends()