from binascii import hexlify
import time

from addresses import calculateInventoryHash
from debug import logger
from inventory import Inventory
from network.dandelion import Dandelion
import protocol
import state
import workprover.utils
import defaults

class BMObjectInsufficientPOWError(Exception):
    errorCodes = ("Insufficient proof of work")


class BMObjectInvalidDataError(Exception):
    errorCodes = ("Data invalid")


class BMObjectExpiredError(Exception):
    errorCodes = ("Object expired")


class BMObjectUnwantedStreamError(Exception):
    errorCodes = ("Object in unwanted stream")


class BMObjectInvalidError(Exception):
    errorCodes = ("Invalid object")


class BMObjectAlreadyHaveError(Exception):
    errorCodes = ("Already have this object")


class BMObject(object):
    # max TTL, 28 days and 3 hours
    maxTTL = 28 * 24 * 60 * 60 + 10800
    # min TTL, 3 hour (in the past
    minTTL = -3600

    def __init__(self, nonce, expiresTime, objectType, version, streamNumber, data, payloadOffset):
        self.nonce = nonce
        self.expiresTime = expiresTime
        self.objectType = objectType
        self.version = version
        self.streamNumber = streamNumber
        self.inventoryHash = calculateInventoryHash(data)
        # copy to avoid memory issues
        self.data = bytearray(data)
        # Doesn't matter if the payload is shorter, old version "getpubkey" objects must have 20-byte tags
        self.tag = self.data[payloadOffset:payloadOffset+32]

    def checkProofOfWorkSufficient(self):
        # Let us check to make sure that the proof of work is sufficient.
        if not workprover.utils.checkWorkSufficient(
            self.data,
            defaults.networkDefaultProofOfWorkNonceTrialsPerByte,
            defaults.networkDefaultPayloadLengthExtraBytes
        ):
            logger.info('Proof of work is insufficient.')
            raise BMObjectInsufficientPOWError()

    def checkEOLSanity(self):
        # EOL sanity check
        if self.expiresTime - int(time.time()) > BMObject.maxTTL:
            logger.info('This object\'s End of Life time is too far in the future. Ignoring it. Time is %i', self.expiresTime)
            # TODO: remove from download queue
            raise BMObjectExpiredError()

        if self.expiresTime - int(time.time()) < BMObject.minTTL:
            logger.info('This object\'s End of Life time was too long ago. Ignoring the object. Time is %i', self.expiresTime)
            # TODO: remove from download queue
            raise BMObjectExpiredError()

    def checkStream(self):
        if self.streamNumber not in state.streamsInWhichIAmParticipating:
            logger.debug('The streamNumber %i isn\'t one we are interested in.', self.streamNumber)
            raise BMObjectUnwantedStreamError()

    def checkAlreadyHave(self):
        # if it's a stem duplicate, pretend we don't have it
        if Dandelion().hasHash(self.inventoryHash):
            return
        if self.inventoryHash in Inventory():
            raise BMObjectAlreadyHaveError()

    def checkObjectByType(self):
        if self.objectType == protocol.OBJECT_GETPUBKEY:
            self.checkGetpubkey()
        elif self.objectType == protocol.OBJECT_PUBKEY:
            self.checkPubkey()
        elif self.objectType == protocol.OBJECT_MSG:
            self.checkMessage()
        elif self.objectType == protocol.OBJECT_BROADCAST:
            self.checkBroadcast()
        # other objects don't require other types of tests

    def checkMessage(self):
        return

    def checkGetpubkey(self):
        if len(self.data) < 42:
            logger.info('getpubkey message doesn\'t contain enough data. Ignoring.')
            raise BMObjectInvalidError()

    def checkPubkey(self):
        if len(self.data) < 146 or len(self.data) > 440:  # sanity check
            logger.info('pubkey object too short or too long. Ignoring.')
            raise BMObjectInvalidError()

    def checkBroadcast(self):
        if len(self.data) < 180:
            logger.debug('The payload length of this broadcast packet is unreasonably low. Someone is probably trying funny business. Ignoring message.')
            raise BMObjectInvalidError()

        # this isn't supported anymore
        if self.version < 2:
            raise BMObjectInvalidError()