"""
 This file is part of nucypher.

 nucypher is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 nucypher is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
"""

import tempfile
from contextlib import contextmanager
from unittest.mock import patch

from nucypher.network.server import make_rest_app
from tests.mock.serials import good_serials
from umbral.config import default_params
from umbral.keys import UmbralPublicKey
from umbral.signing import Signature

mock_cert_storage = patch("nucypher.config.storages.ForgetfulNodeStorage.store_node_certificate",
                          new=lambda *args, **kwargs: "this_might_normally_be_a_filepath")
mock_message_verification = patch('nucypher.characters.lawful.Alice.verify_from', new=lambda *args, **kwargs: None)


def fake_keep_learning(selfish, learner=None, *args, **kwargs):
    return None


mock_keep_learning = patch('nucypher.network.nodes.Learner.keep_learning_about_nodes', new=fake_keep_learning)

mock_record_fleet_state = patch("nucypher.acumen.perception.FleetSensor.record_fleet_state",
                                new=lambda *args, **kwargs: None)

"""
Some hairy stuff ahead.  We want 5,000 Ursulas for some of these tests.  OK, so what effect does that have?  For one thing, if you generate 5k Ursulas, you end up generate some 20k keypairs (validating, signing, delegating, and TLSHosting for each of the 5k Ursulas). That causes this test to go from taking about 7s total (on jMyles' laptop) to about 2min. So that's obviously unacceptable.

Instead, we generate mock keys in serial, and then, when Alice chooses her 8 Ursulas (out of the 4000 about whom she has learned, out of the 5000 that we have made), she verifies them, and at this stage, we're no longer mocking out, which causes the bytes of the key to be cast back into a real key.

The problem is that, for any mock key string, there are going to be some bytes that aren't properly formatted to be a real key. So, I have included all of the numbers which ultimately produce bytes which can't be used as a public key.

The only other obvious way to have a test this fast is to hardcode 20k keypairs into the codebase (and even then, it will be far, far less performant than this).
"""


class NotAPublicKey:
    _serial_bytes_length = 5
    _serial = 10000

    _umbral_pubkey_from_bytes = UmbralPublicKey.from_bytes

    def _tick():
        for serial in good_serials:
            yield serial
    tick = _tick()

    def __init__(self, serial=None):
        if serial is None:
            serial_int = next(self.tick)
            self.serial = serial_int.to_bytes(self._serial_bytes_length, byteorder="big")
        else:
            self.serial = serial

    def __bytes__(self):
        return b"\x03\ not a compress publickey:" + self.serial

    @classmethod
    def reset(cls):
        cls.tick = cls._tick()

    @classmethod
    def from_bytes(cls, some_bytes):
        return cls(serial=some_bytes[-5:])

    @classmethod
    def from_int(cls, serial):
        return cls(serial.to_bytes(cls._serial_bytes_length, byteorder="big"))

    def to_bytes(self, *args, **kwargs):
        return b"this is not a public key... but it is 64 bytes.. so, ya know" + self.serial

    def i_want_to_be_a_real_boy(self):
        _umbral_pubkey = self._umbral_pubkey_from_bytes(bytes(self))
        self.__dict__ = _umbral_pubkey.__dict__
        self.__class__ = _umbral_pubkey.__class__

    def to_cryptography_pubkey(self):
        self.i_want_to_be_a_real_boy()
        return self.to_cryptography_pubkey()

    @property
    def params(self):
        # Holy heck, metamock hacking.
        self.i_want_to_be_a_real_boy()
        return self.params

    def __eq__(self, other):
        return bytes(self) == bytes(other)


class NotAPrivateKey:
    params = default_params()

    fake_signature = Signature.from_bytes(
        b'@\xbfS&\x97\xb3\x9e\x9e\xd3\\j\x9f\x0e\x8fY\x0c\xbeS\x08d\x0b%s\xf6\x17\xe2\xb6\xcd\x95u\xaapON\xd9E\xb3\x10M\xe1\xf4u\x0bL\x99q\xd6\r\x8e_\xe5I\x1e\xe5\xa2\xcf\xe5\x8be_\x077Gz'
    )

    def public_key(self):
        return NotAPublicKey()

    def get_pubkey(self, *args, **kwargs):
        return self.public_key()

    def to_cryptography_privkey(self, *args, **kwargs):
        return self

    def sign(self, *args, **kwargs):
        return b'0D\x02 @\xbfS&\x97\xb3\x9e\x9e\xd3\\j\x9f\x0e\x8fY\x0c\xbeS\x08d\x0b%s\xf6\x17\xe2\xb6\xcd\x95u\xaap\x02 ON\xd9E\xb3\x10M\xe1\xf4u\x0bL\x99q\xd6\r\x8e_\xe5I\x1e\xe5\xa2\xcf\xe5\x8be_\x077Gz'

    @classmethod
    def stamp(cls, *args, **kwargs):
        return cls.fake_signature

    @classmethod
    def signature_bytes(cls, *args, **kwargs):
        return b'@\xbfS&\x97\xb3\x9e\x9e\xd3\\j\x9f\x0e\x8fY\x0c\xbeS\x08d\x0b%s\xf6\x17\xe2\xb6\xcd\x95u\xaapON\xd9E\xb3\x10M\xe1\xf4u\x0bL\x99q\xd6\r\x8e_\xe5I\x1e\xe5\xa2\xcf\xe5\x8be_\x077Gz'


class NotACert:
    class Subject:
        def get_attributes_for_oid(self, *args, **kwargs):
            class Pseudonym:
                value = "0x51347fF6eb8F1D39B83B5e9c244Dc2E1E9EB14B4"

            return Pseudonym(), "Or whatever?"

    subject = Subject()

    def public_bytes(self, does_not_matter):
        return b"this is not a cert."

    def public_key(self):
        return NotAPublicKey()


mock_cert_loading = patch("nucypher.characters.lawful.load_pem_x509_certificate",
                          new=lambda *args, **kwargs: NotACert())


def do_not_create_cert(*args, **kwargs):
    return NotACert(), NotAPrivateKey()


def simple_remember(ursula, node, *args, **kwargs):
    address = node.checksum_address
    ursula.known_nodes[address] = node


class NotARestApp:
    testing = True
    _actual_rest_apps = []
    _replaced_routes = {}

    def __init__(self, this_node, *args, **kwargs):
        self._actual_rest_app = None
        self.this_node = this_node

    @classmethod
    def create_with_not_a_datastore(cls, *args, **kwargs):
        return cls(*args, **kwargs), "this is not a datastore."

    @classmethod
    @contextmanager
    def replace_route(cls, route_name, new_route):
        cls._replaced_routes[route_name] = new_route
        yield
        del cls._replaced_routes[route_name]

    class _ViewFunctions:
        def __init__(self, _old_view_functions=None):
            self._view_functions_registry = _old_view_functions or {}

        def __getitem__(self, route_name):
            try:
                return NotARestApp._replaced_routes[route_name]
            except KeyError:
                return self._view_functions_registry[route_name]

    def actual_rest_app(self):
        if self._actual_rest_app is None:
            self._actual_rest_app, _datastore = make_rest_app(db_filepath=tempfile.mkdtemp(),
                                                             this_node=self.this_node,
                                                             serving_domains=(None,))
            _new_view_functions = self._ViewFunctions(self._actual_rest_app.view_functions)
            self._actual_rest_app.view_functions = _new_view_functions
            self._actual_rest_apps.append(
                self._actual_rest_app)  # Remember now, we're appending to the class-bound list.
        return self._actual_rest_app

    def test_client(self):
        rest_app = self.actual_rest_app()
        return rest_app.test_client()


class VerificationTracker:
    node_verifications = 0
    metadata_verifications = 0

    @classmethod
    def fake_verify_node(cls, *args, **kwargs):
        cls.node_verifications += 1

    @classmethod
    def fake_verify_metadata(cls, *args, **kwargs):
        cls.metadata_verifications += 1


mock_cert_generation = patch("nucypher.crypto.api.generate_self_signed_certificate", new=do_not_create_cert)
mock_rest_app_creation = patch("nucypher.characters.lawful.make_rest_app",
                               new=NotARestApp.create_with_not_a_datastore)

mock_remember_node = patch("nucypher.characters.lawful.Ursula.remember_node", new=simple_remember)
mock_verify_node = patch("nucypher.characters.lawful.Ursula.verify_node", new=VerificationTracker.fake_verify_node)

mock_metadata_validation = patch("nucypher.network.nodes.Teacher.validate_metadata",
                                 new=VerificationTracker.fake_verify_metadata)


@contextmanager
def mock_secret_source(*args, **kwargs):
    with patch("nucypher.datastore.keypairs.Keypair._private_key_source", new=lambda *args, **kwargs: NotAPrivateKey()):
        yield
    NotAPublicKey.reset()


@contextmanager
def mock_pubkey_from_bytes(*args, **kwargs):
    with patch('umbral.keys.UmbralPublicKey.from_bytes', NotAPublicKey.from_bytes):
        yield
    NotAPublicKey.reset()


mock_stamp_call = patch('nucypher.crypto.signing.SignatureStamp.__call__', new=NotAPrivateKey.stamp)
mock_signature_bytes = patch('umbral.signing.Signature.__bytes__', new=NotAPrivateKey.signature_bytes)


def _determine_good_serials(start, end):
    '''
    Figure out which serials are good to use in mocks because they won't result in non-viable public keys.
    '''
    good_serials = []
    for i in range(start, end):
        try:
            NotAPublicKey.from_int(i).i_want_to_be_a_real_boy()
        except Exception as e:
            continue
        else:
            good_serials.append(i)
    return good_serials