pallectrum/electrum/plugins/psbt_nostr/qt.py

#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2014 The Electrum Developers
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import asyncio
import time
from contextlib import asynccontextmanager
from typing import TYPE_CHECKING, Union, List, Tuple, Dict, Optional
import ssl
import json

from PyQt6.QtCore import QObject, pyqtSignal
from PyQt6.QtWidgets import QPushButton

import electrum_ecc as ecc
import electrum_aionostr as aionostr
from electrum_aionostr.key import PrivateKey

from electrum.crypto import sha256
from electrum import util
from electrum.transaction import Transaction, PartialTransaction, tx_from_any, SerializationError
from electrum.bip32 import BIP32Node
from electrum.plugin import BasePlugin, hook
from electrum.i18n import _
from electrum.wallet import Multisig_Wallet, Abstract_Wallet
from electrum.logging import Logger
from electrum.network import Network
from electrum.util import log_exceptions, OldTaskGroup, UserCancelled, ca_path
from electrum.gui.qt.transaction_dialog import show_transaction, TxDialog
from electrum.gui.qt.util import WaitingDialog

if TYPE_CHECKING:
    from electrum.gui.qt import ElectrumGui
    from electrum.gui.qt.main_window import ElectrumWindow

# event kind used for nostr messages (with expiration tag)
NOSTR_EVENT_KIND = 4

now = lambda: int(time.time())

class QReceiveSignalObject(QObject):
    cosigner_receive_signal = pyqtSignal(object, object, object)


class Plugin(BasePlugin):

    def __init__(self, parent, config, name):
        BasePlugin.__init__(self, parent, config, name)
        self._init_qt_received = False
        self.cosigner_wallets = {}  # type: Dict[Abstract_Wallet, CosignerWallet]


    @hook
    def load_wallet(self, wallet: 'Abstract_Wallet', window: 'ElectrumWindow'):
        if type(wallet) != Multisig_Wallet:
            return
        self.cosigner_wallets[wallet] = CosignerWallet(wallet, window)

    @hook
    def on_close_window(self, window):
        wallet = window.wallet
        if cw := self.cosigner_wallets.get(wallet):
            cw.close()
            self.cosigner_wallets.pop(wallet)

    def is_available(self):
        return True

    @hook
    def transaction_dialog(self, d: 'TxDialog'):
        if cw := self.cosigner_wallets.get(d.wallet):
            cw.hook_transaction_dialog(d)

    @hook
    def transaction_dialog_update(self, d: 'TxDialog'):
        if cw := self.cosigner_wallets.get(d.wallet):
            cw.hook_transaction_dialog_update(d)


class CosignerWallet(Logger):
    # one for each open window
    # if user signs a tx, we have the password
    # if user receives a dm? needs to enter password first

    KEEP_DELAY = 24*60*60

    def __init__(self, wallet: 'Multisig_Wallet', window: 'ElectrumWindow'):
        assert isinstance(wallet, Multisig_Wallet)
        self.wallet = wallet
        self.network = window.network
        self.config = self.wallet.config
        self.window = window

        Logger.__init__(self)
        self.known_events = wallet.db.get_dict('cosigner_events')
        for k, v in list(self.known_events.items()):
            if v < now() - self.KEEP_DELAY:
                self.logger.info(f'deleting old event {k}')
                self.known_events.pop(k)
        self.relays = self.config.NOSTR_RELAYS.split(',')
        self.ssl_context = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH, cafile=ca_path)
        self.logger.info(f'relays {self.relays}')
        self.obj = QReceiveSignalObject()
        self.obj.cosigner_receive_signal.connect(self.on_receive)

        self.cosigner_list = []  # type: List[Tuple[str, bytes, str]]
        self.nostr_pubkey = None

        for key, keystore in wallet.keystores.items():
            xpub = keystore.get_master_public_key()  # type: str
            privkey = sha256('nostr_psbt:' + xpub)
            pubkey = ecc.ECPrivkey(privkey).get_public_key_bytes()[1:]
            if self.nostr_pubkey is None and not keystore.is_watching_only():
                self.nostr_privkey = privkey.hex()
                self.nostr_pubkey = pubkey.hex()
                self.logger.info(f'nostr pubkey: {self.nostr_pubkey}')
            else:
                self.cosigner_list.append((xpub, pubkey.hex()))

        self.messages = asyncio.Queue()
        self.taskgroup = OldTaskGroup()
        if self.network and self.nostr_pubkey:
            asyncio.run_coroutine_threadsafe(self.main_loop(), self.network.asyncio_loop)

    @log_exceptions
    async def main_loop(self):
        self.logger.info("starting taskgroup.")
        try:
            async with self.taskgroup as group:
                await group.spawn(self.check_direct_messages())
        except Exception as e:
            self.logger.exception("taskgroup died.")
        finally:
            self.logger.info("taskgroup stopped.")

    async def stop(self):
        await self.taskgroup.cancel_remaining()

    @asynccontextmanager
    async def nostr_manager(self):
        manager_logger = self.logger.getChild('aionostr')
        manager_logger.setLevel("INFO")  # set to INFO because DEBUG is very spammy
        async with aionostr.Manager(
                relays=self.relays,
                private_key=self.nostr_privkey,
                ssl_context=self.ssl_context,
                # todo: add proxy support, first needs:
                # https://github.com/spesmilo/electrum-aionostr/pull/8
                proxy=None,
                log=manager_logger
        ) as manager:
            yield manager

    @log_exceptions
    async def send_direct_messages(self, messages: List[Tuple[str, str]]):
        our_private_key: PrivateKey = aionostr.key.PrivateKey(bytes.fromhex(self.nostr_privkey))
        async with self.nostr_manager() as manager:
            for pubkey, msg in messages:
                encrypted_msg: str = our_private_key.encrypt_message(msg, pubkey)
                eid = await aionostr._add_event(
                    manager,
                    kind=NOSTR_EVENT_KIND,
                    content=encrypted_msg,
                    private_key=self.nostr_privkey,
                    tags=[['p', pubkey], ['expiration', str(int(now() + self.KEEP_DELAY))]])
                self.logger.info(f'message sent to {pubkey}: {eid}')

    @log_exceptions
    async def check_direct_messages(self):
        privkey = PrivateKey(bytes.fromhex(self.nostr_privkey))
        async with self.nostr_manager() as manager:
            query = {
                "kinds": [NOSTR_EVENT_KIND],
                "limit":100,
                "#p": [self.nostr_pubkey],
                "since": int(now() - self.KEEP_DELAY)
            }
            async for event in manager.get_events(query, single_event=False, only_stored=False):
                if event.id in self.known_events:
                    self.logger.info(f'known event {event.id} {util.age(event.created_at)}')
                    continue
                if event.created_at > now() + self.KEEP_DELAY:
                    # might be malicious
                    continue
                if event.created_at < now() - self.KEEP_DELAY:
                    continue
                self.logger.info(f'new event {event.id}')
                try:
                    message = privkey.decrypt_message(event.content, event.pubkey)
                except Exception as e:
                    self.logger.info(f'could not decrypt message {event.pubkey}')
                    self.known_events[event.id] = now()
                    continue
                try:
                    tx = tx_from_any(message)
                except Exception as e:
                    self.logger.info(_("Unable to deserialize the transaction:") + "\n" + str(e))
                    self.known_events[event.id] = now()
                    return
                self.logger.info(f"received PSBT from {event.pubkey}")
                self.obj.cosigner_receive_signal.emit(event.pubkey, event.id, tx)

    def diagnostic_name(self):
        return self.wallet.diagnostic_name()

    def close(self):
        self.logger.info("shutting down listener")
        asyncio.run_coroutine_threadsafe(self.stop(), self.network.asyncio_loop)

    def hook_transaction_dialog(self, d: 'TxDialog'):
        d.cosigner_send_button = b = QPushButton(_("Send to cosigner"))
        b.clicked.connect(lambda: self.do_send(d.tx))
        d.buttons.insert(0, b)
        b.setVisible(False)

    def hook_transaction_dialog_update(self, d: 'TxDialog'):
        assert self.wallet == d.wallet
        if d.tx.is_complete() or d.wallet.can_sign(d.tx):
            d.cosigner_send_button.setVisible(False)
            return
        for xpub, pubkey in self.cosigner_list:
            if self.cosigner_can_sign(d.tx, xpub):
                d.cosigner_send_button.setVisible(True)
                break
        else:
            d.cosigner_send_button.setVisible(False)

    def cosigner_can_sign(self, tx: Transaction, cosigner_xpub: str) -> bool:
        # TODO implement this properly:
        #      should return True iff cosigner (with given xpub) can sign and has not yet signed.
        #      note that tx could also be unrelated from wallet?... (not ismine inputs)
        return True

    def do_send(self, tx: Union[Transaction, PartialTransaction]):
        buffer = []
        for xpub, pubkey in self.cosigner_list:
            if not self.cosigner_can_sign(tx, xpub):
                continue
            raw_tx_bytes = tx.serialize_as_bytes()
            buffer.append((pubkey, raw_tx_bytes.hex()))
        if not buffer:
            return
        coro = self.send_direct_messages(buffer)
        text = _('Sending transaction to your Nostr relays...')
        try:
            result = self.window.run_coroutine_dialog(coro, text)
        except UserCancelled:
            return
        except asyncio.exceptions.TimeoutError:
            self.window.show_error(_('relay timeout'))
            return
        except Exception as e:
            self.window.show_error(str(e))
            return
        self.window.show_message(
            _("Your transaction was sent to your cosigners via Nostr.") + '\n\n' + tx.txid())


    def on_receive(self, pubkey, event_id, tx):
        window = self.window
        if not window.question(
                _("An transaction was received from your cosigner.") + '\n' +
                _("Do you want to open it now?")):
            return
        self.known_events[event_id] = now()
        show_transaction(tx, parent=window, prompt_if_unsaved=True)