"""
============
DNS Browsing
============

Explore the space around known hosts & ips for extra catches.
"""

import asyncio
import re
import sys
from collections.abc import Callable
from ipaddress import IPv4Network

from aiodns import DNSResolver

from theHarvester.lib import hostchecker
from theHarvester.lib.core import DATA_DIR

#####################################################################
# DNS FORCE
#####################################################################

DNS_NAMES = DATA_DIR / 'wordlists' / 'dns-names.txt'


class DnsForce:
    def __init__(self, domain, dnsserver, verbose: bool = False) -> None:
        self.domain = domain
        self.subdo = False
        self.verbose = verbose
        # self.dnsserver = [dnsserver] if isinstance(dnsserver, str) else dnsserver
        # self.dnsserver = list(map(str, dnsserver.split(','))) if isinstance(dnsserver, str) else dnsserver
        self.dnsserver = dnsserver
        with DNS_NAMES.open('r') as file:
            self.list = file.readlines()
        self.domain = domain.replace('www.', '')
        self.list = [f'{word.strip()}.{self.domain}' for word in self.list]

    async def run(self):
        print(f'Starting DNS brute forcing with {len(self.list)} words')
        checker = hostchecker.Checker(self.list, nameservers=self.dnsserver)
        resolved_pair, hosts, ips = await checker.check()
        return resolved_pair, hosts, ips


#####################################################################
# DNS REVERSE
#####################################################################


IP_REGEX = r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}'
PORT_REGEX = r'\d{1,5}'
NETMASK_REGEX: str = r'\d{1,2}|' + IP_REGEX
NETWORK_REGEX: str = rf'\b({IP_REGEX})(?:\:({PORT_REGEX}))?(?:\/({NETMASK_REGEX}))?\b'


def serialize_ip_range(ip: str, netmask: str = '24') -> str:
    """
    Serialize a network range in a constant format, 'x.x.x.x/y'.

    Parameters
    ----------
    ip: str.
        A serialized ip in the format 'x.x.x.x'.
        Extra information like port (':z') or subnet ('/n')
        will be ignored.
    netmask: str.
        The subnet subdivision, represented by a 2 digit netmask.

    Returns
    -------
    out: str.
        The network OSI address, like '192.168.0.0/24'.
    """
    __ip_matches = re.search(NETWORK_REGEX, ip, re.IGNORECASE)
    if __ip_matches and __ip_matches.groups():
        __ip = __ip_matches.group(1)
        __netmask = netmask if netmask else __ip_matches.group(3)
        if __ip and __netmask:
            return str(IPv4Network(f'{__ip}/{__netmask}', strict=False))
        elif __ip:
            return str(IPv4Network('{}/{}'.format(__ip, '24'), strict=False))

    # invalid input ip
    return ''


def list_ips_in_network_range(iprange: str) -> list[str]:
    """
    List all the IPs in the range.

    Parameters
    ----------
    iprange: str.
        A serialized ip range, like '1.2.3.0/24'.
        The last digit can be set to anything, it will be ignored.

    Returns
    -------
    out: list.
        The list of IPs in the range.
    """
    try:
        __network = IPv4Network(iprange, strict=False)
        return [__address.exploded for __address in __network.hosts()]
    except Exception:
        return []


async def reverse_single_ip(ip: str, resolver: DNSResolver) -> str:
    """
    Reverse a single IP and output the linked CNAME, if it exists.
        Parameters
        ----------
        :param ip:  IP address to reverse
        :param resolver: DNS server to use

        Returns
        -------
        :return str: with the corresponding CNAME or None
    """
    try:
        __host = await resolver.gethostbyaddr(ip)
        return __host.name if __host else ''
    except Exception:
        return ''


async def reverse_all_ips_in_range(iprange: str, callback: Callable, nameservers: list[str] | None = None) -> None:
    """
    Reverse all the IPs stored in a network range.
    All the queries are made concurrently.

    Parameters
    ----------
    iprange: str.
        An IPv4 range formatted as 'x.x.x.x/y'.
        The last 2 digits of the ip can be set to anything,
        they will be ignored.
    callback: Callable.
        Arbitrary postprocessing function.
    nameservers: List[str].
        Optional list of DNS servers.

    Returns
    -------
    out: None.
    """
    loop = asyncio.get_event_loop()
    __resolver = DNSResolver(loop=loop, timeout=8, nameservers=nameservers)
    for __ip in list_ips_in_network_range(iprange):
        log_query(__ip)
        __host = await reverse_single_ip(ip=__ip, resolver=__resolver)
        callback(__host)
        log_result(__host)


#####################################################################
# IO
#####################################################################


def log_query(ip: str) -> None:
    """
    Display the current query in the console.

    Parameters
    ----------
    ip: str.
        Queried ip.

    Results
    -------
    out: None.
    """
    sys.stdout.write(chr(27) + '[2K' + chr(27) + '[G')
    sys.stdout.write('\r' + ip + ' - ')
    sys.stdout.flush()


def log_result(host: str) -> None:
    """
    Display the query result in the console.

    Parameters
    ----------
    host: str.
        Host name returned by the DNS query.

    Results
    -------
    out: None.
    """
    if host:
        print(host)


def generate_postprocessing_callback(target: str, **allhosts: list[str]) -> Callable:
    """
    Postprocess the query results asynchronously too, instead of waiting for
    the querying stage to be completely finished.

    Parameters
    ----------
    target: str.
        The domain wanted as TLD.
    allhosts: List.
        A collection of all the subdomains -of target- found so far.

    Returns
    -------
    out: Callable.
        A function that will update the collection of target subdomains
        when the query result is satisfying.
    """

    def append_matching_hosts(host: str) -> None:
        if host and target in host:
            for __name, __hosts in allhosts.items():
                if host not in __hosts:
                    __hosts.append(host)

    return append_matching_hosts
