import re
import os
import sys
import socket
import time
import struct
import dpkt
import dpkt.dns
from threading import Thread, Event


# this is a test case write with tiny-test-fw.
# to run test cases outside tiny-test-fw,
# we need to set environment variable `TEST_FW_PATH`,
# then get and insert `TEST_FW_PATH` to sys path before import FW module

try:
    import IDF
    from IDF.IDFDUT import ESP32DUT
except ImportError:
    test_fw_path = os.getenv("TEST_FW_PATH")
    if test_fw_path and test_fw_path not in sys.path:
        sys.path.insert(0, test_fw_path)
    import IDF

import DUT

# g_run_server = True
# g_done = False
stop_mdns_server = Event()
esp_answered = Event()


def get_dns_query_for_esp(esp_host):
    dns = dpkt.dns.DNS(b'\x00\x00\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x01')
    dns.qd[0].name = esp_host + u'.local'
    print("Created query for esp host: {} ".format(dns.__repr__()))
    return dns.pack()


def get_dns_answer_to_mdns(tester_host):
    dns = dpkt.dns.DNS(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
    dns.op = dpkt.dns.DNS_QR | dpkt.dns.DNS_AA
    dns.rcode = dpkt.dns.DNS_RCODE_NOERR
    arr = dpkt.dns.DNS.RR()
    arr.cls = dpkt.dns.DNS_IN
    arr.type = dpkt.dns.DNS_A
    arr.name = tester_host
    arr.ip = socket.inet_aton('127.0.0.1')
    dns. an.append(arr)
    print("Created answer to mdns query: {} ".format(dns.__repr__()))
    return dns.pack()


def get_dns_answer_to_mdns_lwip(tester_host, id):
    dns = dpkt.dns.DNS(b"\x5e\x39\x84\x00\x00\x01\x00\x01\x00\x00\x00\x00\x0a\x64\x61\x76\x69\x64"
                       b"\x2d\x63\x6f\x6d\x70\x05\x6c\x6f\x63\x61\x6c\x00\x00\x01\x00\x01\xc0\x0c"
                       b"\x00\x01\x00\x01\x00\x00\x00\x0a\x00\x04\xc0\xa8\x0a\x6c")
    dns.qd[0].name = tester_host
    dns.an[0].name = tester_host
    dns.an[0].ip = socket.inet_aton('127.0.0.1')
    dns.an[0].rdata = socket.inet_aton('127.0.0.1')
    dns.id = id
    print("Created answer to mdns (lwip) query: {} ".format(dns.__repr__()))
    return dns.pack()


def mdns_server(esp_host):
    global esp_answered
    UDP_IP = "0.0.0.0"
    UDP_PORT = 5353
    MCAST_GRP = '224.0.0.251'
    TESTER_NAME = u'tinytester.local'
    TESTER_NAME_LWIP = u'tinytester-lwip.local'
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
    sock.bind((UDP_IP,UDP_PORT))
    mreq = struct.pack("4sl", socket.inet_aton(MCAST_GRP), socket.INADDR_ANY)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
    sock.settimeout(30)
    while not stop_mdns_server.is_set():
        try:
            if not esp_answered.is_set():
                sock.sendto(get_dns_query_for_esp(esp_host), (MCAST_GRP,UDP_PORT))
                time.sleep(0.2)
            data, addr = sock.recvfrom(1024)
            dns = dpkt.dns.DNS(data)
            if len(dns.qd) > 0 and dns.qd[0].type == dpkt.dns.DNS_A:
                if dns.qd[0].name == TESTER_NAME:
                    print("Received query: {} ".format(dns.__repr__()))
                    sock.sendto(get_dns_answer_to_mdns(TESTER_NAME), (MCAST_GRP,UDP_PORT))
                elif dns.qd[0].name == TESTER_NAME_LWIP:
                    print("Received query: {} ".format(dns.__repr__()))
                    sock.sendto(get_dns_answer_to_mdns_lwip(TESTER_NAME_LWIP, dns.id), addr)
            if len(dns.an) > 0 and dns.an[0].type == dpkt.dns.DNS_A:
                if dns.an[0].name == esp_host + u'.local':
                    print("Received answer to esp32-mdns query: {}".format(dns.__repr__()))
                    esp_answered.set()
        except socket.timeout:
            break
        except dpkt.UnpackError:
            continue


@IDF.idf_example_test(env_tag="Example_WIFI")
def test_examples_protocol_mdns(env, extra_data):
    global stop_mdns_server
    """
    steps: |
      1. join AP + init mdns example
      2. get the dut host name (and IP address)
      3. check the mdns name is accessible
      4. check DUT output if mdns advertized host is resolved
    """
    dut1 = env.get_dut("mdns-test", "examples/protocols/mdns", dut_class=ESP32DUT)
    # check and log bin size
    binary_file = os.path.join(dut1.app.binary_path, "mdns-test.bin")
    bin_size = os.path.getsize(binary_file)
    IDF.log_performance("mdns-test_bin_size", "{}KB".format(bin_size // 1024))
    IDF.check_performance("mdns-test_bin_size", bin_size // 1024)
    # 1. start mdns application
    dut1.start_app()
    # 2. get the dut host name (and IP address)
    specific_host = dut1.expect(re.compile(r"mdns hostname set to: \[([^\]]+)\]"), timeout=30)
    specific_host = str(specific_host[0])
    thread1 = Thread(target=mdns_server, args=(specific_host,))
    thread1.start()
    try:
        dut1.expect(re.compile(r" sta ip: ([^,]+),"), timeout=30)
    except DUT.ExpectTimeout:
        stop_mdns_server.set()
        thread1.join()
        raise ValueError('ENV_TEST_FAILURE: Cannot connect to AP')
    # 3. check the mdns name is accessible
    if not esp_answered.wait(timeout=30):
        raise ValueError('Test has failed: did not receive mdns answer within timeout')
    # 4. check DUT output if mdns advertized host is resolved
    try:
        dut1.expect(re.compile(r"mdns-test: Query A: tinytester.local resolved to: 127.0.0.1"), timeout=30)
        dut1.expect(re.compile(r"mdns-test: gethostbyname: tinytester-lwip.local resolved to: 127.0.0.1"), timeout=30)
        dut1.expect(re.compile(r"mdns-test: getaddrinfo: tinytester-lwip.local resolved to: 127.0.0.1"), timeout=30)
    finally:
        stop_mdns_server.set()
        thread1.join()


if __name__ == '__main__':
    test_examples_protocol_mdns()