"""
Networking client to connect to a server and find server hosts
"""
import ipaddress
import random

import psutil
import socket

SERVER_PORT = 29987
SERVER_BUFFER = 1024
SCAN_TIMEOUT = 3


class InterfaceInfo:
    """
    Class used for storing interface information to make it easier to use
    """

    def __init__(self, interface_name, network):
        self.interface_name = interface_name
        self.network = network

    def __str__(self):
        return 'Interface:{0}, Network:{1}'.format(self.interface_name, self.network)

    def __repr__(self):
        return '(Interface:{0}, Network:{1})'.format(self.interface_name, self.network)


def request_server_info(server_ip, server_port):
    """
    Request server info from a PyPong server given an IP and a port

    :param server_ip: Server IP to request info from
    :param server_port: Port to connect to server on
    :return: response given by server (or lack thereof)
    """
    request = 'PYPONGREQ;SVRINFO'

    udp_client_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    # Timeout is set to SCAN_TIMEOUT plus a random number between 0 and SCAN_TIMEOUT so that threads can
    # start asynchronously to avoid a lot of requests being sent to machines at once
    # Average time is SCAN_TIMEOUT*1.5
    udp_client_socket.settimeout(SCAN_TIMEOUT + (SCAN_TIMEOUT * random.random()))
    try:
        udp_client_socket.sendto(str.encode(request, 'UTF-8'), (server_ip, server_port))
    except OSError:
        pass
    try:
        server_response = udp_client_socket.recvfrom(SERVER_BUFFER)[0].decode('UTF-8')
    except TimeoutError:
        server_response = '{0};TIMEOUT'.format(server_ip)
    except UnicodeDecodeError:
        server_response = '{0};MANGLED_RESPONSE'.format(server_ip)

    udp_client_socket.close()
    return server_response


def get_interface_info():
    """
    Gets information using psutil about the current machine's interfaces and their networks. This only works for IPv4
    networks and will not return any data in regard to IPv6 links.

    :return: List of InterfaceInfo objects containing information about all interfaces on the current machine excluding
    the loopback interface (lo or 127.0.0.1)
    """
    raw_interface_data = psutil.net_if_addrs()
    interface_data = []

    for interface in raw_interface_data:
        # Extract needed information from psutil and put it into a InterfaceInfo object
        address = (raw_interface_data.get(interface)[0]).address
        cidr_suffix = ipaddress.IPv4Network('{0}/{1}'.format(address, raw_interface_data.get(interface)[0].netmask),
                                            strict=False).prefixlen

        # Do not add the loopback interface or IPv6 interfaces
        if ':' not in address and address != '127.0.0.1':
            interface_data.append(InterfaceInfo(interface, '{0}/{1}'.format(address, cidr_suffix)))
    return interface_data


def get_ips_from_network(network):
    """
    Generate a list of IP addresses given an address in CIDR notation. This works from smallest to largest, meaning that
    it builds a list starting at <ADDRESS>/32 (aka just the current machine) decrementing the CIDR by 1 until the
    correct subnet is reached.

    :param network:
    :return:
    """
    network_split = network.split('/')
    address = network_split[0]
    cidr = int(network_split[1])
    all_addresses = []

    test_cidr = 32  # Start with the machine itself
    while test_cidr >= cidr:
        # Generate all addresses inside the current subnet given by 'address/test_cidr'
        current_addresses = [str(ip) for ip in ipaddress.IPv4Network('{0}/{1}'.format(address, test_cidr),
                                                                     strict=False)]

        # Do not add the address again if it is already in the list of all addresses
        for test_address in current_addresses:
            if test_address not in all_addresses:
                all_addresses.append(test_address)
        test_cidr -= 1

    return all_addresses


def check_ip(ip_address):
    """
    Check a single IP address for a running game server

    :param ip_address: IP address to check
    :return: response of the server (or timeout if none)
    """
    response = request_server_info(ip_address, SERVER_PORT)
    return response