electrum

Electrum Bitcoin wallet
git clone https://git.parazyd.org/electrum
Log | Files | Refs | Submodules

exchange_rate.py (23164B)


      1 import asyncio
      2 from datetime import datetime
      3 import inspect
      4 import sys
      5 import os
      6 import json
      7 import time
      8 import csv
      9 import decimal
     10 from decimal import Decimal
     11 from typing import Sequence, Optional
     12 
     13 from aiorpcx.curio import timeout_after, TaskTimeout, TaskGroup
     14 import aiohttp
     15 
     16 from . import util
     17 from .bitcoin import COIN
     18 from .i18n import _
     19 from .util import (ThreadJob, make_dir, log_exceptions,
     20                    make_aiohttp_session, resource_path)
     21 from .network import Network
     22 from .simple_config import SimpleConfig
     23 from .logging import Logger
     24 
     25 
     26 DEFAULT_ENABLED = False
     27 DEFAULT_CURRENCY = "EUR"
     28 DEFAULT_EXCHANGE = "CoinGecko"  # default exchange should ideally provide historical rates
     29 
     30 
     31 # See https://en.wikipedia.org/wiki/ISO_4217
     32 CCY_PRECISIONS = {'BHD': 3, 'BIF': 0, 'BYR': 0, 'CLF': 4, 'CLP': 0,
     33                   'CVE': 0, 'DJF': 0, 'GNF': 0, 'IQD': 3, 'ISK': 0,
     34                   'JOD': 3, 'JPY': 0, 'KMF': 0, 'KRW': 0, 'KWD': 3,
     35                   'LYD': 3, 'MGA': 1, 'MRO': 1, 'OMR': 3, 'PYG': 0,
     36                   'RWF': 0, 'TND': 3, 'UGX': 0, 'UYI': 0, 'VND': 0,
     37                   'VUV': 0, 'XAF': 0, 'XAU': 4, 'XOF': 0, 'XPF': 0}
     38 
     39 
     40 class ExchangeBase(Logger):
     41 
     42     def __init__(self, on_quotes, on_history):
     43         Logger.__init__(self)
     44         self.history = {}
     45         self.quotes = {}
     46         self.on_quotes = on_quotes
     47         self.on_history = on_history
     48 
     49     async def get_raw(self, site, get_string):
     50         # APIs must have https
     51         url = ''.join(['https://', site, get_string])
     52         network = Network.get_instance()
     53         proxy = network.proxy if network else None
     54         async with make_aiohttp_session(proxy) as session:
     55             async with session.get(url) as response:
     56                 response.raise_for_status()
     57                 return await response.text()
     58 
     59     async def get_json(self, site, get_string):
     60         # APIs must have https
     61         url = ''.join(['https://', site, get_string])
     62         network = Network.get_instance()
     63         proxy = network.proxy if network else None
     64         async with make_aiohttp_session(proxy) as session:
     65             async with session.get(url) as response:
     66                 response.raise_for_status()
     67                 # set content_type to None to disable checking MIME type
     68                 return await response.json(content_type=None)
     69 
     70     async def get_csv(self, site, get_string):
     71         raw = await self.get_raw(site, get_string)
     72         reader = csv.DictReader(raw.split('\n'))
     73         return list(reader)
     74 
     75     def name(self):
     76         return self.__class__.__name__
     77 
     78     async def update_safe(self, ccy):
     79         try:
     80             self.logger.info(f"getting fx quotes for {ccy}")
     81             self.quotes = await self.get_rates(ccy)
     82             self.logger.info("received fx quotes")
     83         except asyncio.CancelledError:
     84             # CancelledError must be passed-through for cancellation to work
     85             raise
     86         except aiohttp.ClientError as e:
     87             self.logger.info(f"failed fx quotes: {repr(e)}")
     88             self.quotes = {}
     89         except Exception as e:
     90             self.logger.exception(f"failed fx quotes: {repr(e)}")
     91             self.quotes = {}
     92         self.on_quotes()
     93 
     94     def read_historical_rates(self, ccy, cache_dir) -> Optional[dict]:
     95         filename = os.path.join(cache_dir, self.name() + '_'+ ccy)
     96         if not os.path.exists(filename):
     97             return None
     98         timestamp = os.stat(filename).st_mtime
     99         try:
    100             with open(filename, 'r', encoding='utf-8') as f:
    101                 h = json.loads(f.read())
    102         except:
    103             return None
    104         if not h:  # e.g. empty dict
    105             return None
    106         h['timestamp'] = timestamp
    107         self.history[ccy] = h
    108         self.on_history()
    109         return h
    110 
    111     @log_exceptions
    112     async def get_historical_rates_safe(self, ccy, cache_dir):
    113         try:
    114             self.logger.info(f"requesting fx history for {ccy}")
    115             h = await self.request_history(ccy)
    116             self.logger.info(f"received fx history for {ccy}")
    117         except aiohttp.ClientError as e:
    118             self.logger.info(f"failed fx history: {repr(e)}")
    119             return
    120         except Exception as e:
    121             self.logger.exception(f"failed fx history: {repr(e)}")
    122             return
    123         filename = os.path.join(cache_dir, self.name() + '_' + ccy)
    124         with open(filename, 'w', encoding='utf-8') as f:
    125             f.write(json.dumps(h))
    126         h['timestamp'] = time.time()
    127         self.history[ccy] = h
    128         self.on_history()
    129 
    130     def get_historical_rates(self, ccy, cache_dir):
    131         if ccy not in self.history_ccys():
    132             return
    133         h = self.history.get(ccy)
    134         if h is None:
    135             h = self.read_historical_rates(ccy, cache_dir)
    136         if h is None or h['timestamp'] < time.time() - 24*3600:
    137             asyncio.get_event_loop().create_task(self.get_historical_rates_safe(ccy, cache_dir))
    138 
    139     def history_ccys(self):
    140         return []
    141 
    142     def historical_rate(self, ccy, d_t):
    143         return self.history.get(ccy, {}).get(d_t.strftime('%Y-%m-%d'), 'NaN')
    144 
    145     async def request_history(self, ccy):
    146         raise NotImplementedError()  # implemented by subclasses
    147 
    148     async def get_rates(self, ccy):
    149         raise NotImplementedError()  # implemented by subclasses
    150 
    151     async def get_currencies(self):
    152         rates = await self.get_rates('')
    153         return sorted([str(a) for (a, b) in rates.items() if b is not None and len(a)==3])
    154 
    155 
    156 class BitcoinAverage(ExchangeBase):
    157     # note: historical rates used to be freely available
    158     # but this is no longer the case. see #5188
    159 
    160     async def get_rates(self, ccy):
    161         json = await self.get_json('apiv2.bitcoinaverage.com', '/indices/global/ticker/short')
    162         return dict([(r.replace("BTC", ""), Decimal(json[r]['last']))
    163                      for r in json if r != 'timestamp'])
    164 
    165 
    166 class Bitcointoyou(ExchangeBase):
    167 
    168     async def get_rates(self, ccy):
    169         json = await self.get_json('bitcointoyou.com', "/API/ticker.aspx")
    170         return {'BRL': Decimal(json['ticker']['last'])}
    171 
    172 
    173 class BitcoinVenezuela(ExchangeBase):
    174 
    175     async def get_rates(self, ccy):
    176         json = await self.get_json('api.bitcoinvenezuela.com', '/')
    177         rates = [(r, json['BTC'][r]) for r in json['BTC']
    178                  if json['BTC'][r] is not None]  # Giving NULL for LTC
    179         return dict(rates)
    180 
    181     def history_ccys(self):
    182         return ['ARS', 'EUR', 'USD', 'VEF']
    183 
    184     async def request_history(self, ccy):
    185         json = await self.get_json('api.bitcoinvenezuela.com',
    186                              "/historical/index.php?coin=BTC")
    187         return json[ccy +'_BTC']
    188 
    189 
    190 class Bitbank(ExchangeBase):
    191 
    192     async def get_rates(self, ccy):
    193         json = await self.get_json('public.bitbank.cc', '/btc_jpy/ticker')
    194         return {'JPY': Decimal(json['data']['last'])}
    195 
    196 
    197 class BitFlyer(ExchangeBase):
    198 
    199     async def get_rates(self, ccy):
    200         json = await self.get_json('bitflyer.jp', '/api/echo/price')
    201         return {'JPY': Decimal(json['mid'])}
    202 
    203 
    204 class BitPay(ExchangeBase):
    205 
    206     async def get_rates(self, ccy):
    207         json = await self.get_json('bitpay.com', '/api/rates')
    208         return dict([(r['code'], Decimal(r['rate'])) for r in json])
    209 
    210 
    211 class Bitso(ExchangeBase):
    212 
    213     async def get_rates(self, ccy):
    214         json = await self.get_json('api.bitso.com', '/v2/ticker')
    215         return {'MXN': Decimal(json['last'])}
    216 
    217 
    218 class BitStamp(ExchangeBase):
    219 
    220     async def get_currencies(self):
    221         return ['USD', 'EUR']
    222 
    223     async def get_rates(self, ccy):
    224         if ccy in CURRENCIES[self.name()]:
    225             json = await self.get_json('www.bitstamp.net', f'/api/v2/ticker/btc{ccy.lower()}/')
    226             return {ccy: Decimal(json['last'])}
    227         return {}
    228 
    229 
    230 class Bitvalor(ExchangeBase):
    231 
    232     async def get_rates(self,ccy):
    233         json = await self.get_json('api.bitvalor.com', '/v1/ticker.json')
    234         return {'BRL': Decimal(json['ticker_1h']['total']['last'])}
    235 
    236 
    237 class BlockchainInfo(ExchangeBase):
    238 
    239     async def get_rates(self, ccy):
    240         json = await self.get_json('blockchain.info', '/ticker')
    241         return dict([(r, Decimal(json[r]['15m'])) for r in json])
    242 
    243 
    244 class Bylls(ExchangeBase):
    245 
    246     async def get_rates(self, ccy):
    247         json = await self.get_json('bylls.com', '/api/price?from_currency=BTC&to_currency=CAD')
    248         return {'CAD': Decimal(json['public_price']['to_price'])}
    249 
    250 
    251 class Coinbase(ExchangeBase):
    252 
    253     async def get_rates(self, ccy):
    254         json = await self.get_json('api.coinbase.com',
    255                              '/v2/exchange-rates?currency=BTC')
    256         return {ccy: Decimal(rate) for (ccy, rate) in json["data"]["rates"].items()}
    257 
    258 
    259 class CoinCap(ExchangeBase):
    260 
    261     async def get_rates(self, ccy):
    262         json = await self.get_json('api.coincap.io', '/v2/rates/bitcoin/')
    263         return {'USD': Decimal(json['data']['rateUsd'])}
    264 
    265     def history_ccys(self):
    266         return ['USD']
    267 
    268     async def request_history(self, ccy):
    269         # Currently 2000 days is the maximum in 1 API call
    270         # (and history starts on 2017-03-23)
    271         history = await self.get_json('api.coincap.io',
    272                                       '/v2/assets/bitcoin/history?interval=d1&limit=2000')
    273         return dict([(datetime.utcfromtimestamp(h['time']/1000).strftime('%Y-%m-%d'), h['priceUsd'])
    274                      for h in history['data']])
    275 
    276 
    277 class CoinDesk(ExchangeBase):
    278 
    279     async def get_currencies(self):
    280         dicts = await self.get_json('api.coindesk.com',
    281                               '/v1/bpi/supported-currencies.json')
    282         return [d['currency'] for d in dicts]
    283 
    284     async def get_rates(self, ccy):
    285         json = await self.get_json('api.coindesk.com',
    286                              '/v1/bpi/currentprice/%s.json' % ccy)
    287         result = {ccy: Decimal(json['bpi'][ccy]['rate_float'])}
    288         return result
    289 
    290     def history_starts(self):
    291         return { 'USD': '2012-11-30', 'EUR': '2013-09-01' }
    292 
    293     def history_ccys(self):
    294         return self.history_starts().keys()
    295 
    296     async def request_history(self, ccy):
    297         start = self.history_starts()[ccy]
    298         end = datetime.today().strftime('%Y-%m-%d')
    299         # Note ?currency and ?index don't work as documented.  Sigh.
    300         query = ('/v1/bpi/historical/close.json?start=%s&end=%s'
    301                  % (start, end))
    302         json = await self.get_json('api.coindesk.com', query)
    303         return json['bpi']
    304 
    305 
    306 class CoinGecko(ExchangeBase):
    307 
    308     async def get_rates(self, ccy):
    309         json = await self.get_json('api.coingecko.com', '/api/v3/exchange_rates')
    310         return dict([(ccy.upper(), Decimal(d['value']))
    311                      for ccy, d in json['rates'].items()])
    312 
    313     def history_ccys(self):
    314         # CoinGecko seems to have historical data for all ccys it supports
    315         return CURRENCIES[self.name()]
    316 
    317     async def request_history(self, ccy):
    318         history = await self.get_json('api.coingecko.com',
    319                                       '/api/v3/coins/bitcoin/market_chart?vs_currency=%s&days=max' % ccy)
    320 
    321         return dict([(datetime.utcfromtimestamp(h[0]/1000).strftime('%Y-%m-%d'), h[1])
    322                      for h in history['prices']])
    323 
    324 
    325 class CointraderMonitor(ExchangeBase):
    326 
    327     async def get_rates(self, ccy):
    328         json = await self.get_json('cointradermonitor.com', '/api/pbb/v1/ticker')
    329         return {'BRL': Decimal(json['last'])}
    330 
    331 
    332 class itBit(ExchangeBase):
    333 
    334     async def get_rates(self, ccy):
    335         ccys = ['USD', 'EUR', 'SGD']
    336         json = await self.get_json('api.itbit.com', '/v1/markets/XBT%s/ticker' % ccy)
    337         result = dict.fromkeys(ccys)
    338         if ccy in ccys:
    339             result[ccy] = Decimal(json['lastPrice'])
    340         return result
    341 
    342 
    343 class Kraken(ExchangeBase):
    344 
    345     async def get_rates(self, ccy):
    346         ccys = ['EUR', 'USD', 'CAD', 'GBP', 'JPY']
    347         pairs = ['XBT%s' % c for c in ccys]
    348         json = await self.get_json('api.kraken.com',
    349                              '/0/public/Ticker?pair=%s' % ','.join(pairs))
    350         return dict((k[-3:], Decimal(float(v['c'][0])))
    351                      for k, v in json['result'].items())
    352 
    353 
    354 class LocalBitcoins(ExchangeBase):
    355 
    356     async def get_rates(self, ccy):
    357         json = await self.get_json('localbitcoins.com',
    358                              '/bitcoinaverage/ticker-all-currencies/')
    359         return dict([(r, Decimal(json[r]['rates']['last'])) for r in json])
    360 
    361 
    362 class MercadoBitcoin(ExchangeBase):
    363 
    364     async def get_rates(self, ccy):
    365         json = await self.get_json('api.bitvalor.com', '/v1/ticker.json')
    366         return {'BRL': Decimal(json['ticker_1h']['exchanges']['MBT']['last'])}
    367 
    368 
    369 class TheRockTrading(ExchangeBase):
    370 
    371     async def get_rates(self, ccy):
    372         json = await self.get_json('api.therocktrading.com',
    373                              '/v1/funds/BTCEUR/ticker')
    374         return {'EUR': Decimal(json['last'])}
    375 
    376 
    377 class Winkdex(ExchangeBase):
    378 
    379     async def get_rates(self, ccy):
    380         json = await self.get_json('winkdex.com', '/api/v0/price')
    381         return {'USD': Decimal(json['price'] / 100.0)}
    382 
    383     def history_ccys(self):
    384         return ['USD']
    385 
    386     async def request_history(self, ccy):
    387         json = await self.get_json('winkdex.com',
    388                              "/api/v0/series?start_time=1342915200")
    389         history = json['series'][0]['results']
    390         return dict([(h['timestamp'][:10], h['price'] / 100.0)
    391                      for h in history])
    392 
    393 
    394 class Zaif(ExchangeBase):
    395     async def get_rates(self, ccy):
    396         json = await self.get_json('api.zaif.jp', '/api/1/last_price/btc_jpy')
    397         return {'JPY': Decimal(json['last_price'])}
    398 
    399 
    400 class Bitragem(ExchangeBase):
    401 
    402     async def get_rates(self,ccy):
    403         json = await self.get_json('api.bitragem.com', '/v1/index?asset=BTC&market=BRL')
    404         return {'BRL': Decimal(json['response']['index'])}
    405 
    406 
    407 class Biscoint(ExchangeBase):
    408 
    409     async def get_rates(self,ccy):
    410         json = await self.get_json('api.biscoint.io', '/v1/ticker?base=BTC&quote=BRL')
    411         return {'BRL': Decimal(json['data']['last'])}
    412 
    413 
    414 class Walltime(ExchangeBase):
    415 
    416     async def get_rates(self, ccy):
    417         json = await self.get_json('s3.amazonaws.com', 
    418                              '/data-production-walltime-info/production/dynamic/walltime-info.json')
    419         return {'BRL': Decimal(json['BRL_XBT']['last_inexact'])}
    420 
    421 
    422 def dictinvert(d):
    423     inv = {}
    424     for k, vlist in d.items():
    425         for v in vlist:
    426             keys = inv.setdefault(v, [])
    427             keys.append(k)
    428     return inv
    429 
    430 def get_exchanges_and_currencies():
    431     # load currencies.json from disk
    432     path = resource_path('currencies.json')
    433     try:
    434         with open(path, 'r', encoding='utf-8') as f:
    435             return json.loads(f.read())
    436     except:
    437         pass
    438     # or if not present, generate it now.
    439     print("cannot find currencies.json. will regenerate it now.")
    440     d = {}
    441     is_exchange = lambda obj: (inspect.isclass(obj)
    442                                and issubclass(obj, ExchangeBase)
    443                                and obj != ExchangeBase)
    444     exchanges = dict(inspect.getmembers(sys.modules[__name__], is_exchange))
    445 
    446     async def get_currencies_safe(name, exchange):
    447         try:
    448             d[name] = await exchange.get_currencies()
    449             print(name, "ok")
    450         except:
    451             print(name, "error")
    452 
    453     async def query_all_exchanges_for_their_ccys_over_network():
    454         async with timeout_after(10):
    455             async with TaskGroup() as group:
    456                 for name, klass in exchanges.items():
    457                     exchange = klass(None, None)
    458                     await group.spawn(get_currencies_safe(name, exchange))
    459     loop = asyncio.get_event_loop()
    460     try:
    461         loop.run_until_complete(query_all_exchanges_for_their_ccys_over_network())
    462     except Exception as e:
    463         pass
    464     with open(path, 'w', encoding='utf-8') as f:
    465         f.write(json.dumps(d, indent=4, sort_keys=True))
    466     return d
    467 
    468 
    469 CURRENCIES = get_exchanges_and_currencies()
    470 
    471 
    472 def get_exchanges_by_ccy(history=True):
    473     if not history:
    474         return dictinvert(CURRENCIES)
    475     d = {}
    476     exchanges = CURRENCIES.keys()
    477     for name in exchanges:
    478         klass = globals()[name]
    479         exchange = klass(None, None)
    480         d[name] = exchange.history_ccys()
    481     return dictinvert(d)
    482 
    483 
    484 class FxThread(ThreadJob):
    485 
    486     def __init__(self, config: SimpleConfig, network: Optional[Network]):
    487         ThreadJob.__init__(self)
    488         self.config = config
    489         self.network = network
    490         util.register_callback(self.set_proxy, ['proxy_set'])
    491         self.ccy = self.get_currency()
    492         self.history_used_spot = False
    493         self.ccy_combo = None
    494         self.hist_checkbox = None
    495         self.cache_dir = os.path.join(config.path, 'cache')
    496         self._trigger = asyncio.Event()
    497         self._trigger.set()
    498         self.set_exchange(self.config_exchange())
    499         make_dir(self.cache_dir)
    500 
    501     def set_proxy(self, trigger_name, *args):
    502         self._trigger.set()
    503 
    504     @staticmethod
    505     def get_currencies(history: bool) -> Sequence[str]:
    506         d = get_exchanges_by_ccy(history)
    507         return sorted(d.keys())
    508 
    509     @staticmethod
    510     def get_exchanges_by_ccy(ccy: str, history: bool) -> Sequence[str]:
    511         d = get_exchanges_by_ccy(history)
    512         return d.get(ccy, [])
    513 
    514     @staticmethod
    515     def remove_thousands_separator(text):
    516         return text.replace(',', '') # FIXME use THOUSAND_SEPARATOR in util
    517 
    518     def ccy_amount_str(self, amount, commas):
    519         prec = CCY_PRECISIONS.get(self.ccy, 2)
    520         fmt_str = "{:%s.%df}" % ("," if commas else "", max(0, prec)) # FIXME use util.THOUSAND_SEPARATOR and util.DECIMAL_POINT
    521         try:
    522             rounded_amount = round(amount, prec)
    523         except decimal.InvalidOperation:
    524             rounded_amount = amount
    525         return fmt_str.format(rounded_amount)
    526 
    527     async def run(self):
    528         while True:
    529             # approx. every 2.5 minutes, refresh spot price
    530             try:
    531                 async with timeout_after(150):
    532                     await self._trigger.wait()
    533                     self._trigger.clear()
    534                 # we were manually triggered, so get historical rates
    535                 if self.is_enabled() and self.show_history():
    536                     self.exchange.get_historical_rates(self.ccy, self.cache_dir)
    537             except TaskTimeout:
    538                 pass
    539             if self.is_enabled():
    540                 await self.exchange.update_safe(self.ccy)
    541 
    542     def is_enabled(self):
    543         return bool(self.config.get('use_exchange_rate', DEFAULT_ENABLED))
    544 
    545     def set_enabled(self, b):
    546         self.config.set_key('use_exchange_rate', bool(b))
    547         self.trigger_update()
    548 
    549     def get_history_config(self, *, allow_none=False):
    550         val = self.config.get('history_rates', None)
    551         if val is None and allow_none:
    552             return None
    553         return bool(val)
    554 
    555     def set_history_config(self, b):
    556         self.config.set_key('history_rates', bool(b))
    557 
    558     def get_history_capital_gains_config(self):
    559         return bool(self.config.get('history_rates_capital_gains', False))
    560 
    561     def set_history_capital_gains_config(self, b):
    562         self.config.set_key('history_rates_capital_gains', bool(b))
    563 
    564     def get_fiat_address_config(self):
    565         return bool(self.config.get('fiat_address'))
    566 
    567     def set_fiat_address_config(self, b):
    568         self.config.set_key('fiat_address', bool(b))
    569 
    570     def get_currency(self):
    571         '''Use when dynamic fetching is needed'''
    572         return self.config.get("currency", DEFAULT_CURRENCY)
    573 
    574     def config_exchange(self):
    575         return self.config.get('use_exchange', DEFAULT_EXCHANGE)
    576 
    577     def show_history(self):
    578         return self.is_enabled() and self.get_history_config() and self.ccy in self.exchange.history_ccys()
    579 
    580     def set_currency(self, ccy: str):
    581         self.ccy = ccy
    582         self.config.set_key('currency', ccy, True)
    583         self.trigger_update()
    584         self.on_quotes()
    585 
    586     def trigger_update(self):
    587         if self.network:
    588             self.network.asyncio_loop.call_soon_threadsafe(self._trigger.set)
    589 
    590     def set_exchange(self, name):
    591         class_ = globals().get(name) or globals().get(DEFAULT_EXCHANGE)
    592         self.logger.info(f"using exchange {name}")
    593         if self.config_exchange() != name:
    594             self.config.set_key('use_exchange', name, True)
    595         assert issubclass(class_, ExchangeBase), f"unexpected type {class_} for {name}"
    596         self.exchange = class_(self.on_quotes, self.on_history)  # type: ExchangeBase
    597         # A new exchange means new fx quotes, initially empty.  Force
    598         # a quote refresh
    599         self.trigger_update()
    600         self.exchange.read_historical_rates(self.ccy, self.cache_dir)
    601 
    602     def on_quotes(self):
    603         util.trigger_callback('on_quotes')
    604 
    605     def on_history(self):
    606         util.trigger_callback('on_history')
    607 
    608     def exchange_rate(self) -> Decimal:
    609         """Returns the exchange rate as a Decimal"""
    610         if not self.is_enabled():
    611             return Decimal('NaN')
    612         rate = self.exchange.quotes.get(self.ccy)
    613         if rate is None:
    614             return Decimal('NaN')
    615         return Decimal(rate)
    616 
    617     def format_amount(self, btc_balance):
    618         rate = self.exchange_rate()
    619         return '' if rate.is_nan() else "%s" % self.value_str(btc_balance, rate)
    620 
    621     def format_amount_and_units(self, btc_balance):
    622         rate = self.exchange_rate()
    623         return '' if rate.is_nan() else "%s %s" % (self.value_str(btc_balance, rate), self.ccy)
    624 
    625     def get_fiat_status_text(self, btc_balance, base_unit, decimal_point):
    626         rate = self.exchange_rate()
    627         return _("  (No FX rate available)") if rate.is_nan() else " 1 %s~%s %s" % (base_unit,
    628             self.value_str(COIN / (10**(8 - decimal_point)), rate), self.ccy)
    629 
    630     def fiat_value(self, satoshis, rate):
    631         return Decimal('NaN') if satoshis is None else Decimal(satoshis) / COIN * Decimal(rate)
    632 
    633     def value_str(self, satoshis, rate):
    634         return self.format_fiat(self.fiat_value(satoshis, rate))
    635 
    636     def format_fiat(self, value):
    637         if value.is_nan():
    638             return _("No data")
    639         return "%s" % (self.ccy_amount_str(value, True))
    640 
    641     def history_rate(self, d_t):
    642         if d_t is None:
    643             return Decimal('NaN')
    644         rate = self.exchange.historical_rate(self.ccy, d_t)
    645         # Frequently there is no rate for today, until tomorrow :)
    646         # Use spot quotes in that case
    647         if rate in ('NaN', None) and (datetime.today().date() - d_t.date()).days <= 2:
    648             rate = self.exchange.quotes.get(self.ccy, 'NaN')
    649             self.history_used_spot = True
    650         if rate is None:
    651             rate = 'NaN'
    652         return Decimal(rate)
    653 
    654     def historical_value_str(self, satoshis, d_t):
    655         return self.format_fiat(self.historical_value(satoshis, d_t))
    656 
    657     def historical_value(self, satoshis, d_t):
    658         return self.fiat_value(satoshis, self.history_rate(d_t))
    659 
    660     def timestamp_rate(self, timestamp):
    661         from .util import timestamp_to_datetime
    662         date = timestamp_to_datetime(timestamp)
    663         return self.history_rate(date)
    664 
    665 
    666 assert globals().get(DEFAULT_EXCHANGE), f"default exchange {DEFAULT_EXCHANGE} does not exist"