import struct
import hashlib
import logging
from binascii import unhexlify, hexlify

from twisted.internet import defer, error
from lbrynet.dht.encoding import Bencode
from lbrynet.dht.error import DecodeError
from lbrynet.dht.msgformat import DefaultFormat
from lbrynet.dht.msgtypes import ResponseMessage, RequestMessage, ErrorMessage
import sys
if sys.version_info > (3,):
    unicode = str

_encode = Bencode()
_datagram_formatter = DefaultFormat()

log = logging.getLogger()

MOCK_DHT_NODES = [
    unhexlify("cc8db9d0dd9b65b103594b5f992adf09f18b310958fa451d61ce8d06f3ee97a91461777c2b7dea1a89d02d2f23eb0e4f"),
    unhexlify("83a3a398eead3f162fbbe1afb3d63482bb5b6d3cdd8f9b0825c1dfa58dffd3f6f6026d6e64d6d4ae4c3dfe2262e734ba"),
    unhexlify("b6928ff25778a7bbb5d258d3b3a06e26db1654f3d2efce8c26681d43f7237cdf2e359a4d309c4473d5d89ec99fb4f573"),
]

MOCK_DHT_SEED_DNS = {  # these map to mock nodes 0, 1, and 2
    "lbrynet1.lbry.io": "10.42.42.1",
    "lbrynet2.lbry.io": "10.42.42.2",
    "lbrynet3.lbry.io": "10.42.42.3",
    "lbrynet4.lbry.io": "10.42.42.4",
    "lbrynet5.lbry.io": "10.42.42.5",
    "lbrynet6.lbry.io": "10.42.42.6",
    "lbrynet7.lbry.io": "10.42.42.7",
    "lbrynet8.lbry.io": "10.42.42.8",
    "lbrynet9.lbry.io": "10.42.42.9",
    "lbrynet10.lbry.io": "10.42.42.10",
    "lbrynet11.lbry.io": "10.42.42.11",
    "lbrynet12.lbry.io": "10.42.42.12",
    "lbrynet13.lbry.io": "10.42.42.13",
    "lbrynet14.lbry.io": "10.42.42.14",
    "lbrynet15.lbry.io": "10.42.42.15",
    "lbrynet16.lbry.io": "10.42.42.16",
}


def resolve(name, timeout=(1, 3, 11, 45)):
    if name not in MOCK_DHT_SEED_DNS:
        return defer.fail(error.DNSLookupError(name))
    return defer.succeed(MOCK_DHT_SEED_DNS[name])


class MockUDPTransport(object):
    def __init__(self, address, port, max_packet_size, protocol):
        self.address = address
        self.port = port
        self.max_packet_size = max_packet_size
        self._node = protocol._node

    def write(self, data, address):
        if address in MockNetwork.peers:
            dest = MockNetwork.peers[address][0]
            debug_kademlia_packet(data, (self.address, self.port), address, self._node)
            dest.datagramReceived(data, (self.address, self.port))
        else:  # the node is sending to an address that doesnt currently exist, act like it never arrived
            pass


class MockUDPPort(object):
    def __init__(self, protocol, remover):
        self.protocol = protocol
        self._remover = remover

    def startListening(self, reason=None):
        return self.protocol.startProtocol()

    def stopListening(self, reason=None):
        result = self.protocol.stopProtocol()
        self._remover()
        return result


class MockNetwork(object):
    peers = {}  # (interface, port): (protocol, max_packet_size)

    @classmethod
    def add_peer(cls, port, protocol, interface, maxPacketSize):
        interface = protocol._node.externalIP
        protocol.transport = MockUDPTransport(interface, port, maxPacketSize, protocol)
        cls.peers[(interface, port)] = (protocol, maxPacketSize)

        def remove_peer():
            del protocol.transport
            if (interface, port) in cls.peers:
                del cls.peers[(interface, port)]

        return remove_peer


def listenUDP(port, protocol, interface='', maxPacketSize=8192):
    remover = MockNetwork.add_peer(port, protocol, interface, maxPacketSize)
    port = MockUDPPort(protocol, remover)
    port.startListening()
    return port


def address_generator(address=(10, 42, 42, 1)):
    def increment(addr):
        value = struct.unpack("I", "".join([chr(x) for x in list(addr)[::-1]]).encode())[0] + 1
        new_addr = []
        for i in range(4):
            new_addr.append(value % 256)
            value >>= 8
        return tuple(new_addr[::-1])

    while True:
        yield "{}.{}.{}.{}".format(*address)
        address = increment(address)


def mock_node_generator(count=None, mock_node_ids=MOCK_DHT_NODES):
    if mock_node_ids is None:
        mock_node_ids = MOCK_DHT_NODES
    mock_node_ids = list(mock_node_ids)

    for num, node_ip in enumerate(address_generator()):
        if count and num >= count:
            break
        if num >= len(mock_node_ids):
            h = hashlib.sha384()
            h.update(("node %i" % num).encode())
            node_id = h.digest()
        else:
            node_id = mock_node_ids[num]
        yield (node_id, node_ip)


def debug_kademlia_packet(data, source, destination, node):
    if log.level != logging.DEBUG:
        return
    try:
        packet = _datagram_formatter.fromPrimitive(_encode.decode(data))
        if isinstance(packet, RequestMessage):
            log.debug("request %s --> %s %s (node time %s)", source[0], destination[0], packet.request,
                      node.clock.seconds())
        elif isinstance(packet, ResponseMessage):
            if isinstance(packet.response, bytes):
                log.debug("response %s <-- %s %s (node time %s)", destination[0], source[0], packet.response,
                          node.clock.seconds())
            else:
                log.debug("response %s <-- %s %i contacts (node time %s)", destination[0], source[0],
                          len(packet.response), node.clock.seconds())
        elif isinstance(packet, ErrorMessage):
            log.error("error %s <-- %s %s (node time %s)", destination[0], source[0], packet.exceptionType,
                      node.clock.seconds())
    except DecodeError:
        log.exception("decode error %s --> %s (node time %s)", source[0], destination[0], node.clock.seconds())