# SPDX-License-Identifier: AGPL-3.0-or-later

# kpov_util should be imported by add_assignment.py

instructions = {
    'si':"""
<pre>Postavi tri računalnike - SimpleArbiter z diska simpleArbiter, TestClient z diska testClient in NATServer. NATServer naj ima dva omrežna vmesnika - z enim naj bo
povezan na omrežje, od koder bo imel dostop do Interneta, z drugim pa na SimpleArbiter. TestClient naj bo povezan na isto omrežje z dostopom do Interneta kot NATServer.
Poskrbi, da bo NATServer služil kot DHCP strežnik ter privzeti prehod za SimpleArbiter.
Na SimpleArbiter preberi vrednosti NET, PORT_OUTER in PORT_INNER ter vpiši IP_TEST_CLIENT. Poskrbi, da
bo omrežje med SimpleArbiter in NATServer na področju NET. Nato poskrbi, da se
bo TCP promet z omrežja z dostopom do Interneta na vrata PORT_OUTER prepošiljal na SimpleArbiter na vrata PORT_INNER.</pre>"""
}

computers = {
    'TestClient': {
        'disks': [
            {   'name': 'maliNetworkManager',
            },
        ],
        'network_interfaces': [{'network': 'test-net'}],
        'flavor': 'm1.tiny',
        'config_drive': False

    },
    'NATServer': {
        'disks': [
            {   'name': 'student-NATServer',
            },
        ],
        'network_interfaces': [{'network': 'net1'}, {'network': 'test-net'}],
        'flavor': 'm1.tiny',
        'config_drive': False

    },
    'SimpleArbiter': {
        'disks': [
            {   'name': 'simpleArbiter',
            },
        ],
        'network_interfaces': [{'network': 'net1'}],
        'flavor': 'm1.tiny',
        'config_drive': False
    }
}

networks = { 'net1': {'public': False}, 'test-net': {'public': True} }

params_meta = {
    'IP_TEST_CLIENT': {'descriptions': {'si': 'Naslov TestClient'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
    'IP_NAT': {'descriptions': {'si': 'Naslov NATServer, dostopen s TestClient'}, 'w': True, 'public':True, 'type': 'IP', 'generated': False},
    'PORT_OUTER': {'descriptions': {'si': 'Zunanja vrata'}, 'w': False, 'public':True, 'type': 'port', 'generated': True},
    'PORT_INNER': {'descriptions': {'si': 'Notranja vrata'}, 'w': False, 'public': True, 'type': 'port', 'generated': True},
    'NET': {'descriptions': {'si': 'Področje naslovov med SimpleArbiter in TestClient'}, 'w': False, 'public': True, 'type': 'NET', 'generated': True},
}

def task(IP_TEST_CLIENT, IP_NAT, PORT_OUTER, PORT_INNER, NET):
    import random
    import time
    import pexpect
    from pexpect import pxssh

    results = dict()
    tcpdump = pexpect.spawn('sudo /usr/sbin/tcpdump src host {} and dst port {}'.format(IP_TEST_CLIENT, PORT_INNER), encoding='utf-8')
    sshconn = pxssh.pxssh(encoding='utf-8')
    sshconn.login(IP_TEST_CLIENT, 'student', 'vaje')
    r = random.Random()
    k = r.randint(10, 15)
    results['pre_nc'] = str(k)
    results['nc_pre'] = ""
    for i in range(k):
        sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
        sshconn.sendline()
        sshconn.sendintr()
        sshconn.prompt()
        results['nc_pre'] += sshconn.before
    nc = pexpect.spawn('nc -l -p {}'.format(PORT_INNER), encoding='utf-8')
    sshconn.sendline()
    sshconn.prompt()
    sshconn.sendline("nc {} {}".format(IP_NAT, PORT_OUTER))
    results['post_nc'] = "".join([r.choice("abcd\n") for i in range(100)])
    sshconn.sendline(results['post_nc'])
    time.sleep(1)
    sshconn.sendintr()
    nc.expect(pexpect.EOF)
    results['nc_ret'] = nc.before
    results['route'] = pexpect.run('ip route list 0/0', encoding='utf-8')
    results['traceroute'] = pexpect.run('traceroute {}'.format(IP_TEST_CLIENT), encoding='utf-8')
    # wait for traceroute
    time.sleep(10)
    tcpdump.sendintr()
    tcpdump.expect(pexpect.EOF)
    results['tcpdump'] = tcpdump.before
    sshconn.prompt()
    results['nc_post'] = sshconn.before
    sshconn.close()
    # nc.expect(pexpect.EOF)
    return results
    
def gen_params(user_id, params_meta):
    params = dict()
    r = random.Random(user_id)
    params['PORT_INNER'] = str(r.randint(6000, 10000))
    params['PORT_OUTER'] = str(r.randint(10001, 15000))
    params['NET'] = kpov_util.IPv4_subnet_gen(r, "10.36.0.0/14", 24)
    return params

def task_check(results, params):
    import re
    import pickle
    score = 0
    hints = []
    local_net = params['NET'][:params['NET'].rfind('.')]
    s = "default via ({}\\.[0-9]+)".format(re.escape(local_net))
    res = re.search(s, results['route'])
    if res:
        ip_nat_internal = res.groups(1)[0]
        score += 1
    else:
        ip_nat_internal = 'abrakadabra'
    #    print (s, results['route'],)
    s = "traceroute to {ip_test} \\({ip_test}\\), 30 hops max, 60 byte packets\
\r\n 1  {ip_nat} \\({ip_nat}\\)  [0-9.]+ ms  [0-9.]+ ms  [0-9.]+ ms\
.*{ip_test} \\({ip_test}\\)".format(
        ip_nat = re.escape(ip_nat_internal), 
        ip_test = re.escape(params['IP_TEST_CLIENT'])
    )
    if re.search(s, results['traceroute'], re.DOTALL):
        score += 1
    else:
        hints += [s + str(results['traceroute'])]
    if len(results['post_nc']) == 100:
        score += 1
    else:
        hints += [str(results['post_nc']) + str(len(results['post_nc']))]
    if results['nc_ret'] == (results['post_nc'] + '\n').replace('\n', '\r\n'):
        score += 1
    else:
        hints += ['wrong nc']
    s = "Connection refused"
    res = re.findall(s, results['nc_pre'])
    if len(res) >= 2:
        score += 3
    else:
        hints += [s + str(results['nc_pre'])]
    s = "\r\n"
    if re.search(s, results['nc_post']):
        score += 1
    else:
        hints += [s + str(results['nc_post'])]
    rejected_count = int(results['pre_nc'])
    accepted_count = results['nc_ret'].count('\r\n')
    s = ".*verbose output suppressed.*listening on.*dropped by kernel.*"
    if re.match(s, results['tcpdump'], re.DOTALL):
        score += 1
    else:
        hints += [s + str(results['tcpdump'])]
    res = re.findall("length .*\r\n", results['tcpdump'])
    total_len = 0
    n_empty = 0
    for i in res:
        k = int(i[len("length "):].strip())
        total_len += k
        if k == 0:
            n_empty += 1
    # print total_len, rejected_count, n_empty
    if total_len == 101 and rejected_count <= n_empty:
        score += 1
    else:
        hints += [s + str(results['tcpdump'])]
    return score, hints

def prepare_disks(templates, task_params, global_params):
    write_default_config(templates['simpleArbiter'], global_params)