account.py

import os
import time
import json
import logging
import typing
import asyncio
import random
from hashlib import sha256
from string import hexdigits
from typing import Type, Dict, Tuple, Optional, Any, List

from lbry.error import InvalidPasswordError
from lbry.crypto.crypt import aes_encrypt, aes_decrypt

from .bip32 import PrivateKey, PublicKey, KeyPath, from_extended_key_string
from .mnemonic import Mnemonic
from .constants import COIN, TXO_TYPES
from .transaction import Transaction, Input, Output

if typing.TYPE_CHECKING:
    from .ledger import Ledger
    from .wallet import Wallet

log = logging.getLogger(__name__)


def validate_claim_id(claim_id):
    if not len(claim_id) == 40:
        raise Exception("Incorrect claimid length: %i" % len(claim_id))
    if isinstance(claim_id, bytes):
        claim_id = claim_id.decode('utf-8')
    if set(claim_id).difference(hexdigits):
        raise Exception("Claim id is not hex encoded")


class DeterministicChannelKeyManager:

    def __init__(self, account: 'Account'):
        self.account = account
        self.last_known = 0
        self.cache = {}
        self._private_key: Optional[PrivateKey] = None

    @property
    def private_key(self):
        if self._private_key is None:
            if self.account.private_key is not None:
                self._private_key = self.account.private_key.child(KeyPath.CHANNEL)
        return self._private_key

    def maybe_generate_deterministic_key_for_channel(self, txo):
        if self.private_key is None:
            return
        next_private_key = self.private_key.child(self.last_known)
        public_key = next_private_key.public_key
        public_key_bytes = public_key.pubkey_bytes
        if txo.claim.channel.public_key_bytes == public_key_bytes:
            self.cache[public_key.address] = next_private_key
            self.last_known += 1

    async def ensure_cache_primed(self):
        if self.private_key is not None:
            await self.generate_next_key()

    async def generate_next_key(self) -> PrivateKey:
        db = self.account.ledger.db
        while True:
            next_private_key = self.private_key.child(self.last_known)
            public_key = next_private_key.public_key
            self.cache[public_key.address] = next_private_key
            if not await db.is_channel_key_used(self.account, public_key):
                return next_private_key
            self.last_known += 1

    def get_private_key_from_pubkey_hash(self, pubkey_hash) -> PrivateKey:
        return self.cache.get(pubkey_hash)


class AddressManager:

    name: str

    __slots__ = 'account', 'public_key', 'chain_number', 'address_generator_lock'

    def __init__(self, account, public_key, chain_number):
        self.account = account
        self.public_key = public_key
        self.chain_number = chain_number
        self.address_generator_lock = asyncio.Lock()

    @classmethod
    def from_dict(cls, account: 'Account', d: dict) \
            -> Tuple['AddressManager', 'AddressManager']:
        raise NotImplementedError

    @classmethod
    def to_dict(cls, receiving: 'AddressManager', change: 'AddressManager') -> Dict:
        d: Dict[str, Any] = {'name': cls.name}
        receiving_dict = receiving.to_dict_instance()
        if receiving_dict:
            d['receiving'] = receiving_dict
        change_dict = change.to_dict_instance()
        if change_dict:
            d['change'] = change_dict
        return d

    def merge(self, d: dict):
        pass

    def to_dict_instance(self) -> Optional[dict]:
        raise NotImplementedError

    def _query_addresses(self, **constraints):
        return self.account.ledger.db.get_addresses(
            read_only=constraints.pop("read_only", False),
            accounts=[self.account],
            chain=self.chain_number,
            **constraints
        )

    def get_private_key(self, index: int) -> PrivateKey:
        raise NotImplementedError

    def get_public_key(self, index: int) -> PublicKey:
        raise NotImplementedError

    async def get_max_gap(self):
        raise NotImplementedError

    async def ensure_address_gap(self):
        raise NotImplementedError

    def get_address_records(self, only_usable: bool = False, **constraints):
        raise NotImplementedError

    async def get_addresses(self, only_usable: bool = False, **constraints) -> List[str]:
        records = await self.get_address_records(only_usable=only_usable, **constraints)
        return [r['address'] for r in records]

    async def get_or_create_usable_address(self) -> str:
        async with self.address_generator_lock:
            addresses = await self.get_addresses(only_usable=True, limit=10)
        if addresses:
            return random.choice(addresses)
        addresses = await self.ensure_address_gap()
        return addresses[0]


class HierarchicalDeterministic(AddressManager):
    """ Implements simple version of Bitcoin Hierarchical Deterministic key management. """

    name: str = "deterministic-chain"

    __slots__ = 'gap', 'maximum_uses_per_address'

    def __init__(self, account: 'Account', chain: int, gap: int, maximum_uses_per_address: int) -> None:
        super().__init__(account, account.public_key.child(chain), chain)
        self.gap = gap
        self.maximum_uses_per_address = maximum_uses_per_address

    @classmethod
    def from_dict(cls, account: 'Account', d: dict) -> Tuple[AddressManager, AddressManager]:
        return (
            cls(account, KeyPath.RECEIVE, **d.get('receiving', {'gap': 20, 'maximum_uses_per_address': 1})),
            cls(account, KeyPath.CHANGE, **d.get('change', {'gap': 6, 'maximum_uses_per_address': 1}))
        )

    def merge(self, d: dict):
        self.gap = d.get('gap', self.gap)
        self.maximum_uses_per_address = d.get('maximum_uses_per_address', self.maximum_uses_per_address)

    def to_dict_instance(self):
        return {'gap': self.gap, 'maximum_uses_per_address': self.maximum_uses_per_address}

    def get_private_key(self, index: int) -> PrivateKey:
        return self.account.private_key.child(self.chain_number).child(index)

    def get_public_key(self, index: int) -> PublicKey:
        return self.account.public_key.child(self.chain_number).child(index)

    async def get_max_gap(self) -> int:
        addresses = await self._query_addresses(order_by="n asc")
        max_gap = 0
        current_gap = 0
        for address in addresses:
            if address['used_times'] == 0:
                current_gap += 1
            else:
                max_gap = max(max_gap, current_gap)
                current_gap = 0
        return max_gap

    async def ensure_address_gap(self) -> List[str]:
        async with self.address_generator_lock:
            addresses = await self._query_addresses(limit=self.gap, order_by="n desc")

            existing_gap = 0
            for address in addresses:
                if address['used_times'] == 0:
                    existing_gap += 1
                else:
                    break

            if existing_gap == self.gap:
                return []

            start = addresses[0]['pubkey'].n+1 if addresses else 0
            end = start + (self.gap - existing_gap)
            new_keys = await self._generate_keys(start, end-1)
            await self.account.ledger.announce_addresses(self, new_keys)
            return new_keys

    async def _generate_keys(self, start: int, end: int) -> List[str]:
        if not self.address_generator_lock.locked():
            raise RuntimeError('Should not be called outside of address_generator_lock.')
        keys = [self.public_key.child(index) for index in range(start, end+1)]
        await self.account.ledger.db.add_keys(self.account, self.chain_number, keys)
        return [key.address for key in keys]

    def get_address_records(self, only_usable: bool = False, **constraints):
        if only_usable:
            constraints['used_times__lt'] = self.maximum_uses_per_address
        if 'order_by' not in constraints:
            constraints['order_by'] = "used_times asc, n asc"
        return self._query_addresses(**constraints)


class SingleKey(AddressManager):
    """ Single Key address manager always returns the same address for all operations. """

    name: str = "single-address"

    __slots__ = ()

    @classmethod
    def from_dict(cls, account: 'Account', d: dict) \
            -> Tuple[AddressManager, AddressManager]:
        same_address_manager = cls(account, account.public_key, KeyPath.RECEIVE)
        return same_address_manager, same_address_manager

    def to_dict_instance(self):
        return None

    def get_private_key(self, index: int) -> PrivateKey:
        return self.account.private_key

    def get_public_key(self, index: int) -> PublicKey:
        return self.account.public_key

    async def get_max_gap(self) -> int:
        return 0

    async def ensure_address_gap(self) -> List[str]:
        async with self.address_generator_lock:
            exists = await self.get_address_records()
            if not exists:
                await self.account.ledger.db.add_keys(self.account, self.chain_number, [self.public_key])
                new_keys = [self.public_key.address]
                await self.account.ledger.announce_addresses(self, new_keys)
                return new_keys
            return []

    def get_address_records(self, only_usable: bool = False, **constraints):
        return self._query_addresses(**constraints)


class Account:

    address_generators: Dict[str, Type[AddressManager]] = {
        SingleKey.name: SingleKey,
        HierarchicalDeterministic.name: HierarchicalDeterministic,
    }

    def __init__(self, ledger: 'Ledger', wallet: 'Wallet', name: str,
                 seed: str, private_key_string: str, encrypted: bool,
                 private_key: Optional[PrivateKey], public_key: PublicKey,
                 address_generator: dict, modified_on: float, channel_keys: dict) -> None:
        self.ledger = ledger
        self.wallet = wallet
        self.id = public_key.address
        self.name = name
        self.seed = seed
        self.modified_on = modified_on
        self.private_key_string = private_key_string
        self.init_vectors: Dict[str, bytes] = {}
        self.encrypted = encrypted
        self.private_key: Optional[PrivateKey] = private_key
        self.public_key: PublicKey = public_key
        generator_name = address_generator.get('name', HierarchicalDeterministic.name)
        self.address_generator = self.address_generators[generator_name]
        self.receiving, self.change = self.address_generator.from_dict(self, address_generator)
        self.address_managers = {am.chain_number: am for am in (self.receiving, self.change)}
        self.channel_keys = channel_keys
        self.deterministic_channel_keys = DeterministicChannelKeyManager(self)
        ledger.add_account(self)
        wallet.add_account(self)

    def get_init_vector(self, key) -> Optional[bytes]:
        init_vector = self.init_vectors.get(key, None)
        if init_vector is None:
            init_vector = self.init_vectors[key] = os.urandom(16)
        return init_vector

    @classmethod
    def generate(cls, ledger: 'Ledger', wallet: 'Wallet',
                 name: str = None, address_generator: dict = None):
        return cls.from_dict(ledger, wallet, {
            'name': name,
            'seed': Mnemonic().make_seed(),
            'address_generator': address_generator or {}
        })

    @classmethod
    def get_private_key_from_seed(cls, ledger: 'Ledger', seed: str, password: str):
        return PrivateKey.from_seed(
            ledger, Mnemonic.mnemonic_to_seed(seed, password or 'lbryum')
        )

    @classmethod
    def keys_from_dict(cls, ledger: 'Ledger', d: dict) \
            -> Tuple[str, Optional[PrivateKey], PublicKey]:
        seed = d.get('seed', '')
        private_key_string = d.get('private_key', '')
        private_key = None
        public_key = None
        encrypted = d.get('encrypted', False)
        if not encrypted:
            if seed:
                private_key = cls.get_private_key_from_seed(ledger, seed, '')
                public_key = private_key.public_key
            elif private_key_string:
                private_key = from_extended_key_string(ledger, private_key_string)
                public_key = private_key.public_key
        if public_key is None:
            public_key = from_extended_key_string(ledger, d['public_key'])
        return seed, private_key, public_key

    @classmethod
    def from_dict(cls, ledger: 'Ledger', wallet: 'Wallet', d: dict):
        seed, private_key, public_key = cls.keys_from_dict(ledger, d)
        name = d.get('name')
        if not name:
            name = f'Account #{public_key.address}'
        return cls(
            ledger=ledger,
            wallet=wallet,
            name=name,
            seed=seed,
            private_key_string=d.get('private_key', ''),
            encrypted=d.get('encrypted', False),
            private_key=private_key,
            public_key=public_key,
            address_generator=d.get('address_generator', {}),
            modified_on=int(d.get('modified_on', time.time())),
            channel_keys=d.get('certificates', {})
        )

    def to_dict(self, encrypt_password: str = None, include_channel_keys: bool = True):
        private_key_string, seed = self.private_key_string, self.seed
        if not self.encrypted and self.private_key:
            private_key_string = self.private_key.extended_key_string()
        if not self.encrypted and encrypt_password:
            if private_key_string:
                private_key_string = aes_encrypt(
                    encrypt_password, private_key_string, self.get_init_vector('private_key')
                )
            if seed:
                seed = aes_encrypt(encrypt_password, self.seed, self.get_init_vector('seed'))
        d = {
            'ledger': self.ledger.get_id(),
            'name': self.name,
            'seed': seed,
            'encrypted': bool(self.encrypted or encrypt_password),
            'private_key': private_key_string,
            'public_key': self.public_key.extended_key_string(),
            'address_generator': self.address_generator.to_dict(self.receiving, self.change),
            'modified_on': self.modified_on
        }
        if include_channel_keys:
            d['certificates'] = self.channel_keys
        return d

    def merge(self, d: dict):
        if d.get('modified_on', 0) > self.modified_on:
            self.name = d['name']
            self.modified_on = int(d.get('modified_on', time.time()))
            assert self.address_generator.name == d['address_generator']['name']
            for chain_name in ('change', 'receiving'):
                if chain_name in d['address_generator']:
                    chain_object = getattr(self, chain_name)
                    chain_object.merge(d['address_generator'][chain_name])
        self.channel_keys.update(d.get('certificates', {}))

    @property
    def hash(self) -> bytes:
        assert not self.encrypted, "Cannot hash an encrypted account."
        h = sha256(json.dumps(self.to_dict(include_channel_keys=False)).encode())
        for cert in sorted(self.channel_keys.keys()):
            h.update(cert.encode())
        return h.digest()

    async def get_details(self, show_seed=False, **kwargs):
        satoshis = await self.get_balance(**kwargs)
        details = {
            'id': self.id,
            'name': self.name,
            'ledger': self.ledger.get_id(),
            'coins': round(satoshis/COIN, 2),
            'satoshis': satoshis,
            'encrypted': self.encrypted,
            'public_key': self.public_key.extended_key_string(),
            'address_generator': self.address_generator.to_dict(self.receiving, self.change)
        }
        if show_seed:
            details['seed'] = self.seed
        details['certificates'] = len(self.channel_keys)
        return details

    def decrypt(self, password: str) -> bool:
        assert self.encrypted, "Key is not encrypted."
        try:
            seed = self._decrypt_seed(password)
        except (ValueError, InvalidPasswordError):
            return False
        try:
            private_key = self._decrypt_private_key_string(password)
        except (TypeError, ValueError, InvalidPasswordError):
            return False
        self.seed = seed
        self.private_key = private_key
        self.private_key_string = ""
        self.encrypted = False
        return True

    def _decrypt_private_key_string(self, password: str) -> Optional[PrivateKey]:
        if not self.private_key_string:
            return None
        private_key_string, self.init_vectors['private_key'] = aes_decrypt(password, self.private_key_string)
        if not private_key_string:
            return None
        return from_extended_key_string(
            self.ledger, private_key_string
        )

    def _decrypt_seed(self, password: str) -> str:
        if not self.seed:
            return ""
        seed, self.init_vectors['seed'] = aes_decrypt(password, self.seed)
        if not seed:
            return ""
        try:
            Mnemonic().mnemonic_decode(seed)
        except IndexError:
            # failed to decode the seed, this either means it decrypted and is invalid
            # or that we hit an edge case where an incorrect password gave valid padding
            raise ValueError("Failed to decode seed.")
        return seed

    def encrypt(self, password: str) -> bool:
        assert not self.encrypted, "Key is already encrypted."
        if self.seed:
            self.seed = aes_encrypt(password, self.seed, self.get_init_vector('seed'))
        if isinstance(self.private_key, PrivateKey):
            self.private_key_string = aes_encrypt(
                password, self.private_key.extended_key_string(), self.get_init_vector('private_key')
            )
            self.private_key = None
        self.encrypted = True
        return True

    async def ensure_address_gap(self):
        addresses = []
        for address_manager in self.address_managers.values():
            new_addresses = await address_manager.ensure_address_gap()
            addresses.extend(new_addresses)
        return addresses

    async def get_addresses(self, read_only=False, **constraints) -> List[str]:
        rows = await self.ledger.db.select_addresses('address', read_only=read_only, accounts=[self], **constraints)
        return [r['address'] for r in rows]

    def get_address_records(self, **constraints):
        return self.ledger.db.get_addresses(accounts=[self], **constraints)

    def get_address_count(self, **constraints):
        return self.ledger.db.get_address_count(accounts=[self], **constraints)

    def get_private_key(self, chain: int, index: int) -> PrivateKey:
        assert not self.encrypted, "Cannot get private key on encrypted wallet account."
        return self.address_managers[chain].get_private_key(index)

    def get_public_key(self, chain: int, index: int) -> PublicKey:
        return self.address_managers[chain].get_public_key(index)

    def get_balance(self, confirmations=0, include_claims=False, read_only=False, **constraints):
        if not include_claims:
            constraints.update({'txo_type__in': (TXO_TYPES['other'], TXO_TYPES['purchase'])})
        if confirmations > 0:
            height = self.ledger.headers.height - (confirmations-1)
            constraints.update({'height__lte': height, 'height__gt': 0})
        return self.ledger.db.get_balance(accounts=[self], read_only=read_only, **constraints)

    async def get_max_gap(self):
        change_gap = await self.change.get_max_gap()
        receiving_gap = await self.receiving.get_max_gap()
        return {
            'max_change_gap': change_gap,
            'max_receiving_gap': receiving_gap,
        }

    def get_txos(self, **constraints):
        return self.ledger.get_txos(wallet=self.wallet, accounts=[self], **constraints)

    def get_txo_count(self, **constraints):
        return self.ledger.get_txo_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_utxos(self, **constraints):
        return self.ledger.get_utxos(wallet=self.wallet, accounts=[self], **constraints)

    def get_utxo_count(self, **constraints):
        return self.ledger.get_utxo_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_transactions(self, **constraints):
        return self.ledger.get_transactions(wallet=self.wallet, accounts=[self], **constraints)

    def get_transaction_count(self, **constraints):
        return self.ledger.get_transaction_count(wallet=self.wallet, accounts=[self], **constraints)

    async def fund(self, to_account, amount=None, everything=False,
                   outputs=1, broadcast=False, **constraints):
        assert self.ledger == to_account.ledger, 'Can only transfer between accounts of the same ledger.'
        if everything:
            utxos = await self.get_utxos(**constraints)
            await self.ledger.reserve_outputs(utxos)
            tx = await Transaction.create(
                inputs=[Input.spend(txo) for txo in utxos],
                outputs=[],
                funding_accounts=[self],
                change_account=to_account
            )
        elif amount > 0:
            to_address = await to_account.change.get_or_create_usable_address()
            to_hash160 = to_account.ledger.address_to_hash160(to_address)
            tx = await Transaction.create(
                inputs=[],
                outputs=[
                    Output.pay_pubkey_hash(amount//outputs, to_hash160)
                    for _ in range(outputs)
                ],
                funding_accounts=[self],
                change_account=self
            )
        else:
            raise ValueError('An amount is required.')

        if broadcast:
            await self.ledger.broadcast(tx)
        else:
            await self.ledger.release_tx(tx)

        return tx

    async def generate_channel_private_key(self):
        return await self.deterministic_channel_keys.generate_next_key()

    def add_channel_private_key(self, private_key: PrivateKey):
        self.channel_keys[private_key.address] = private_key.to_pem().decode()

    async def get_channel_private_key(self, public_key_bytes) -> PrivateKey:
        channel_pubkey_hash = self.ledger.public_key_to_address(public_key_bytes)
        private_key_pem = self.channel_keys.get(channel_pubkey_hash)
        if private_key_pem:
            return PrivateKey.from_pem(self.ledger, private_key_pem)
        return self.deterministic_channel_keys.get_private_key_from_pubkey_hash(channel_pubkey_hash)

    async def maybe_migrate_certificates(self):
        if not self.channel_keys:
            return
        channel_keys = {}
        for private_key_pem in self.channel_keys.values():
            if not isinstance(private_key_pem, str):
                continue
            if not private_key_pem.startswith("-----BEGIN"):
                continue
            private_key = PrivateKey.from_pem(self.ledger, private_key_pem)
            channel_keys[private_key.address] = private_key_pem
        if self.channel_keys != channel_keys:
            self.channel_keys = channel_keys
            self.wallet.save()

    async def save_max_gap(self):
        if issubclass(self.address_generator, HierarchicalDeterministic):
            gap = await self.get_max_gap()
            gap_changed = False
            new_receiving_gap = max(20, gap['max_receiving_gap'] + 1)
            if self.receiving.gap != new_receiving_gap:
                self.receiving.gap = new_receiving_gap
                gap_changed = True
            new_change_gap = max(6, gap['max_change_gap'] + 1)
            if self.change.gap != new_change_gap:
                self.change.gap = new_change_gap
                gap_changed = True
            if gap_changed:
                self.wallet.save()

    async def get_detailed_balance(self, confirmations=0, read_only=False):
        constraints = {}
        if confirmations > 0:
            height = self.ledger.headers.height - (confirmations-1)
            constraints.update({'height__lte': height, 'height__gt': 0})
        return await self.ledger.db.get_detailed_balance(
            accounts=[self], read_only=read_only, **constraints
        )

    def get_transaction_history(self, read_only=False, **constraints):
        return self.ledger.get_transaction_history(
            read_only=read_only, wallet=self.wallet, accounts=[self], **constraints
        )

    def get_transaction_history_count(self, read_only=False, **constraints):
        return self.ledger.get_transaction_history_count(
            read_only=read_only, wallet=self.wallet, accounts=[self], **constraints
        )

    def get_claims(self, **constraints):
        return self.ledger.get_claims(wallet=self.wallet, accounts=[self], **constraints)

    def get_claim_count(self, **constraints):
        return self.ledger.get_claim_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_streams(self, **constraints):
        return self.ledger.get_streams(wallet=self.wallet, accounts=[self], **constraints)

    def get_stream_count(self, **constraints):
        return self.ledger.get_stream_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_channels(self, **constraints):
        return self.ledger.get_channels(wallet=self.wallet, accounts=[self], **constraints)

    def get_channel_count(self, **constraints):
        return self.ledger.get_channel_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_collections(self, **constraints):
        return self.ledger.get_collections(wallet=self.wallet, accounts=[self], **constraints)

    def get_collection_count(self, **constraints):
        return self.ledger.get_collection_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_supports(self, **constraints):
        return self.ledger.get_supports(wallet=self.wallet, accounts=[self], **constraints)

    def get_support_count(self, **constraints):
        return self.ledger.get_support_count(wallet=self.wallet, accounts=[self], **constraints)

    def get_support_summary(self):
        return self.ledger.db.get_supports_summary(wallet=self.wallet, accounts=[self])

    async def release_all_outputs(self):
        await self.ledger.db.release_all_outputs(self)