from PyQt4.QtGui import *
from PyQt4.QtCore import *

import datetime
import decimal
import httplib
import json
import threading
import time
import re
from decimal import Decimal
from ssl import SSLError

from electrum.plugins import BasePlugin, hook
from electrum.i18n import _
from electrum_gui.qt.util import *
from electrum_gui.qt.amountedit import AmountEdit


EXCHANGES = ["BitcoinAverage",
             "BitcoinVenezuela",
             "BTCParalelo",
             "Bitcurex",
             "Bitmarket",
             "BitPay",
             "Blockchain",
             "BTCChina",
             "CaVirtEx",
             "Coinbase",
             "CoinDesk",
             "itBit",
             "LocalBitcoins",
             "Winkdex"]

EXCH_SUPPORT_HIST = [("CoinDesk", "USD"),
                     ("Winkdex", "USD"),
                     ("BitcoinVenezuela", "ARS"),
                     ("BitcoinVenezuela", "VEF")]

class Exchanger(threading.Thread):

    def __init__(self, parent):
        threading.Thread.__init__(self)
        self.daemon = True
        self.parent = parent
        self.quote_currencies = None
        self.lock = threading.Lock()
        self.query_rates = threading.Event()
        self.use_exchange = self.parent.config.get('use_exchange', "Blockchain")
        self.parent.exchanges = EXCHANGES
        self.parent.win.emit(SIGNAL("refresh_exchanges_combo()"))
        self.parent.win.emit(SIGNAL("refresh_currencies_combo()"))
        self.is_running = False

    def get_json(self, site, get_string):
        try:
            connection = httplib.HTTPSConnection(site)
            connection.request("GET", get_string, headers={"User-Agent":"Electrum"})
        except Exception:
            raise
        resp = connection.getresponse()
        if resp.reason == httplib.responses[httplib.NOT_FOUND]:
            raise
        try:
            json_resp = json.loads(resp.read())
        except Exception:
            raise
        return json_resp
        
    def get_json_insecure(self, site, get_string):
        """ get_json_insecure shouldn't be used in production releases
        It doesn't use SSL, and so prices could be manipulated by a middle man
        This should be used ONLY when developing plugins when you don't have a
        SSL certificate that validates against HTTPSConnection
        """
        try:
            connection = httplib.HTTPConnection(site)
            connection.request("GET", get_string, headers={"User-Agent":"Electrum"})
        except Exception:
            raise
        resp = connection.getresponse()
        if resp.reason == httplib.responses[httplib.NOT_FOUND]:
            raise
        try:
            json_resp = json.loads(resp.read())
        except Exception:
            raise
        return json_resp


    def exchange(self, btc_amount, quote_currency):
        with self.lock:
            if self.quote_currencies is None:
                return None
            quote_currencies = self.quote_currencies.copy()
        if quote_currency not in quote_currencies:
            return None
        return btc_amount * decimal.Decimal(str(quote_currencies[quote_currency]))

    def stop(self):
        self.is_running = False

    def update_rate(self):
        self.use_exchange = self.parent.config.get('use_exchange', "Blockchain")
        update_rates = {
            "BitcoinAverage": self.update_ba,
            "BitcoinVenezuela": self.update_bv,
            "BTCParalelo": self.update_bpl,
            "Bitcurex": self.update_bx,
            "Bitmarket": self.update_bm,
            "BitPay": self.update_bp,
            "Blockchain": self.update_bc,
            "BTCChina": self.update_CNY,
            "CaVirtEx": self.update_cv,
            "CoinDesk": self.update_cd,
            "Coinbase": self.update_cb,
            "itBit": self.update_ib,
            "LocalBitcoins": self.update_lb,
            "Winkdex": self.update_wd,
        }
        try:
            update_rates[self.use_exchange]()
        except KeyError:
            return

    def run(self):
        self.is_running = True
        while self.is_running:
            self.query_rates.clear()
            self.update_rate()
            self.query_rates.wait(150)


    def update_cd(self):
        try:
            resp_currencies = self.get_json('api.coindesk.com', "/v1/bpi/supported-currencies.json")
        except SSLError:
            print("SSL Error when accesing coindesk")
            return
        except Exception:
            return

        quote_currencies = {}
        for cur in resp_currencies:
            quote_currencies[str(cur["currency"])] = 0.0

        current_cur = self.parent.config.get("currency", "EUR")
        if current_cur in quote_currencies:
            try:
                resp_rate = self.get_json('api.coindesk.com', "/v1/bpi/currentprice/" + str(current_cur) + ".json")
                quote_currencies[str(current_cur)] = decimal.Decimal(str(resp_rate["bpi"][str(current_cur)]["rate_float"]))
            except Exception:
                return
        with self.lock:
            self.quote_currencies = quote_currencies
        self.parent.set_currencies(quote_currencies)

    def update_ib(self):
        available_currencies = ["USD", "EUR", "SGD"]
        quote_currencies = {}
        for cur in available_currencies:
            quote_currencies[cur] = 0.0
        current_cur = self.parent.config.get("currency", "EUR")
        if current_cur in available_currencies:
            try:
                resp_rate = self.get_json('api.itbit.com', "/v1/markets/XBT" + str(current_cur) + "/ticker")
                quote_currencies[str(current_cur)] = decimal.Decimal(str(resp_rate["lastPrice"]))
            except SSLError:
                print("SSL Error when accesing itbit")
                return
            except Exception:
                return
        with self.lock:
            self.quote_currencies = quote_currencies
        self.parent.set_currencies(quote_currencies)

    def update_wd(self):
        try:
            winkresp = self.get_json('winkdex.com', "/api/v0/price")
        except SSLError:
            print("SSL Error when accesing winkdex")
            return
        except Exception:
            return
        quote_currencies = {"USD": 0.0}
        usdprice = decimal.Decimal(str(winkresp["price"]))/decimal.Decimal("100.0")
        try:
            quote_currencies["USD"] = usdprice
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_cv(self):
        try:
            jsonresp = self.get_json('www.cavirtex.com', "/api/CAD/ticker.json")
        except SSLError:
            print("SSL Error when accesing cavirtex")
            return
        except Exception:
            return
        quote_currencies = {"CAD": 0.0}
        cadprice = jsonresp["last"]
        try:
            quote_currencies["CAD"] = decimal.Decimal(str(cadprice))
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_bm(self):
        try:
            jsonresp = self.get_json('www.bitmarket.pl', "/json/BTCPLN/ticker.json")
        except SSLError:
            print("SSL Error when accesing bitmarket")
            return
        except Exception:
            return
        quote_currencies = {"PLN": 0.0}
        pln_price = jsonresp["last"]
        try:
            quote_currencies["PLN"] = decimal.Decimal(str(pln_price))
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_bx(self):
        try:
            jsonresp = self.get_json('pln.bitcurex.com', "/data/ticker.json")
        except SSLError:
            print("SSL Error when accesing bitcurex")
            return
        except Exception:
            return
        quote_currencies = {"PLN": 0.0}
        pln_price = jsonresp["last"]
        try:
            quote_currencies["PLN"] = decimal.Decimal(str(pln_price))
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_CNY(self):
        try:
            jsonresp = self.get_json('data.btcchina.com', "/data/ticker")
        except SSLError:
            print("SSL Error when accesing btcchina")
            return
        except Exception:
            return
        quote_currencies = {"CNY": 0.0}
        cnyprice = jsonresp["ticker"]["last"]
        try:
            quote_currencies["CNY"] = decimal.Decimal(str(cnyprice))
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_bp(self):
        try:
            jsonresp = self.get_json('bitpay.com', "/api/rates")
        except SSLError:
            print("SSL Error when accesing bitpay")
            return
        except Exception:
            return
        quote_currencies = {}
        try:
            for r in jsonresp:
                quote_currencies[str(r["code"])] = decimal.Decimal(r["rate"])
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_cb(self):
        try:
            jsonresp = self.get_json('coinbase.com', "/api/v1/currencies/exchange_rates")
        except SSLError:
            print("SSL Error when accesing coinbase")
            return
        except Exception:
            return

        quote_currencies = {}
        try:
            for r in jsonresp:
                if r[:7] == "btc_to_":
                    quote_currencies[r[7:].upper()] = self._lookup_rate_cb(jsonresp, r)
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)


    def update_bc(self):
        try:
            jsonresp = self.get_json('blockchain.info', "/ticker")
        except SSLError:
            print("SSL Error when accesing blockchain")
            return
        except Exception:
            return
        quote_currencies = {}
        try:
            for r in jsonresp:
                quote_currencies[r] = self._lookup_rate(jsonresp, r)
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)

    def update_lb(self):
        try:
            jsonresp = self.get_json('localbitcoins.com', "/bitcoinaverage/ticker-all-currencies/")
        except SSLError:
            print("SSL Error when accesing localbitcoins")
            return
        except Exception:
            return
        quote_currencies = {}
        try:
            for r in jsonresp:
                quote_currencies[r] = self._lookup_rate_lb(jsonresp, r)
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)


    def update_bv(self):
        try:
            jsonresp = self.get_json_insecure('api.bitcoinvenezuela.com', "/")
            print("**WARNING**: update_bv is using an insecure connection, shouldn't be used on production")
        except SSLError:
            print("SSL Error when accesing bitcoinvenezuela")
            return
        except Exception:
            return
        
        quote_currencies = {}
        try:
            for r in jsonresp["BTC"]:
                quote_currencies[r] = Decimal(jsonresp["BTC"][r])
            
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            print ("KeyError")
        self.parent.set_currencies(quote_currencies)

        
    def update_bpl(self):
        try:
            jsonresp = self.get_json_insecure('btcparalelo.com', "/api/price")
            print("**WARNING**: update_bpl is using an insecure connection, shouldn't be used on production")
        except SSLError:
            print("SSL Error when accesing btcparalelo")
            return
        except Exception:
            return
        
        
        quote_currencies = {}
        try:
            quote_currencies = {"VEF": Decimal(jsonresp["price"])}
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            print ("KeyError")
        self.parent.set_currencies(quote_currencies)
        
    def update_ba(self):
        try:
            jsonresp = self.get_json('api.bitcoinaverage.com', "/ticker/global/all")
        except SSLError:
            print("SSL Error when accesing bitcoinaverage")
            return
        except Exception:
            return
        quote_currencies = {}
        try:
            for r in jsonresp:
                if not r == "timestamp":
                    quote_currencies[r] = self._lookup_rate_ba(jsonresp, r)
            with self.lock:
                self.quote_currencies = quote_currencies
        except KeyError:
            pass
        self.parent.set_currencies(quote_currencies)


    def _lookup_rate(self, response, quote_id):
        return decimal.Decimal(str(response[str(quote_id)]["15m"]))
    def _lookup_rate_cb(self, response, quote_id):
        return decimal.Decimal(str(response[str(quote_id)]))
    def _lookup_rate_ba(self, response, quote_id):
        return decimal.Decimal(response[str(quote_id)]["last"])
    def _lookup_rate_lb(self, response, quote_id):
        return decimal.Decimal(response[str(quote_id)]["rates"]["last"])


class Plugin(BasePlugin):

    def fullname(self):
        return "Exchange rates"

    def description(self):
        return """exchange rates, retrieved from blockchain.info, CoinDesk, or Coinbase"""


    def __init__(self,a,b):
        BasePlugin.__init__(self,a,b)
        self.currencies = [self.fiat_unit()]
        self.exchanges = [self.config.get('use_exchange', "Blockchain")]
        self.exchanger = None

    @hook
    def init_qt(self, gui):
        self.gui = gui
        self.win = self.gui.main_window
        self.win.connect(self.win, SIGNAL("refresh_currencies()"), self.win.update_status)
        self.btc_rate = Decimal("0.0")
        self.resp_hist = {}
        self.tx_list = {}
        if self.exchanger is None:
            # Do price discovery
            self.exchanger = Exchanger(self)
            self.exchanger.start()
            self.gui.exchanger = self.exchanger #
            self.add_fiat_edit()
            self.win.update_status()

    def close(self):
        self.exchanger.stop()
        self.exchanger = None
        self.win.tabs.removeTab(1)
        self.win.tabs.insertTab(1, self.win.create_send_tab(), _('Send'))
        self.win.update_status()

    def set_currencies(self, currency_options):
        self.currencies = sorted(currency_options)
        self.win.emit(SIGNAL("refresh_currencies()"))
        self.win.emit(SIGNAL("refresh_currencies_combo()"))

    @hook
    def get_fiat_balance_text(self, btc_balance, r):
        # return balance as: 1.23 USD
        r[0] = self.create_fiat_balance_text(Decimal(btc_balance) / 100000000)

    def get_fiat_price_text(self, r):
        # return BTC price as: 123.45 USD
        r[0] = self.create_fiat_balance_text(1)
        quote = r[0]
        if quote:
            r[0] = "%s"%quote

    @hook
    def get_fiat_status_text(self, btc_balance, r2):
        # return status as:   (1.23 USD)    1 BTC~123.45 USD
        text = ""
        r = {}
        self.get_fiat_price_text(r)
        quote = r.get(0)
        if quote:
            price_text = "1 BTC~%s"%quote
            fiat_currency = quote[-3:]
            btc_price = self.btc_rate
            fiat_balance = Decimal(btc_price) * (Decimal(btc_balance)/100000000)
            balance_text = "(%.2f %s)" % (fiat_balance,fiat_currency)
            text = "  " + balance_text + "     " + price_text + " "
        r2[0] = text

    def create_fiat_balance_text(self, btc_balance):
        quote_currency = self.fiat_unit()
        self.exchanger.use_exchange = self.config.get("use_exchange", "Blockchain")
        cur_rate = self.exchanger.exchange(Decimal("1.0"), quote_currency)
        if cur_rate is None:
            quote_text = ""
        else:
            quote_balance = btc_balance * Decimal(cur_rate)
            self.btc_rate = cur_rate
            quote_text = "%.2f %s" % (quote_balance, quote_currency)
        return quote_text

    @hook
    def load_wallet(self, wallet):
        tx_list = {}
        for item in self.wallet.get_tx_history(self.wallet.storage.get("current_account", None)):
            tx_hash, conf, is_mine, value, fee, balance, timestamp = item
            tx_list[tx_hash] = {'value': value, 'timestamp': timestamp, 'balance': balance}

        self.tx_list = tx_list
        self.cur_exchange = self.config.get('use_exchange', "Blockchain")
        threading.Thread(target=self.request_history_rates, args=()).start()


    def requires_settings(self):
        return True


    def request_history_rates(self):
        if self.config.get('history_rates') != "checked":
            return
        if not self.tx_list:
            return

        try:
            mintimestr = datetime.datetime.fromtimestamp(int(min(self.tx_list.items(), key=lambda x: x[1]['timestamp'])[1]['timestamp'])).strftime('%Y-%m-%d')
        except Exception:
            return
        maxtimestr = datetime.datetime.now().strftime('%Y-%m-%d')

        if self.cur_exchange == "CoinDesk":
            try:
                self.resp_hist = self.exchanger.get_json('api.coindesk.com', "/v1/bpi/historical/close.json?start=" + mintimestr + "&end=" + maxtimestr)
            except Exception:
                return
        elif self.cur_exchange == "Winkdex":
            try:
                self.resp_hist = self.exchanger.get_json('winkdex.com', "/api/v0/series?start_time=1342915200")['series'][0]['results']
            except Exception:
                return
        elif self.cur_exchange == "BitcoinVenezuela":
            cur_currency = self.fiat_unit()
            if cur_currency == "VEF":
                try:
                    self.resp_hist = self.exchanger.get_json('api.bitcoinvenezuela.com', "/historical/index.php?coin=BTC")['VEF_BTC']
                except Exception:
                    return
            elif cur_currency == "ARS":
                try:
                    self.resp_hist = self.exchanger.get_json('api.bitcoinvenezuela.com', "/historical/index.php?coin=BTC")['ARS_BTC']
                except Exception:
                    return
            else:
                return

        self.win.need_update.set()

    @hook
    def history_tab_update(self):
        if self.config.get('history_rates') != "checked":
            return
        if not self.resp_hist:
            return
        if not self.wallet:
            return

        self.win.is_edit = True
        self.win.history_list.setColumnCount(6)
        self.win.history_list.setHeaderLabels( [ '', _('Date'), _('Description') , _('Amount'), _('Balance'), _('Fiat Amount')] )
        root = self.win.history_list.invisibleRootItem()
        childcount = root.childCount()
        for i in range(childcount):
            item = root.child(i)
            try:
                tx_info = self.tx_list[str(item.data(0, Qt.UserRole).toPyObject())]
            except Exception:
                newtx = self.wallet.get_tx_history()
                v = newtx[[x[0] for x in newtx].index(str(item.data(0, Qt.UserRole).toPyObject()))][3]
                tx_info = {'timestamp':int(time.time()), 'value': v }
                pass
            tx_time = int(tx_info['timestamp'])
            if self.cur_exchange == "CoinDesk":
                tx_time_str = datetime.datetime.fromtimestamp(tx_time).strftime('%Y-%m-%d')
                try:
                    tx_fiat_val = "%.2f %s" % (Decimal(str(tx_info['value'])) / 100000000 * Decimal(self.resp_hist['bpi'][tx_time_str]), "USD")
                except KeyError:
                    tx_fiat_val = "%.2f %s" % (self.btc_rate * Decimal(str(tx_info['value']))/100000000 , "USD")
            elif self.cur_exchange == "Winkdex":
                tx_time_str = datetime.datetime.fromtimestamp(tx_time).strftime('%Y-%m-%d') + "T16:00:00-04:00"
                try:
                    tx_rate = self.resp_hist[[x['timestamp'] for x in self.resp_hist].index(tx_time_str)]['price']
                    tx_fiat_val = "%.2f %s" % (Decimal(tx_info['value']) / 100000000 * Decimal(tx_rate)/Decimal("100.0"), "USD")
                except ValueError:
                    tx_fiat_val = "%.2f %s" % (self.btc_rate * Decimal(tx_info['value'])/100000000 , "USD")
                except KeyError:
                    tx_fiat_val = _("No data")
            elif self.cur_exchange == "BitcoinVenezuela":
                tx_time_str = datetime.datetime.fromtimestamp(tx_time).strftime('%Y-%m-%d')
                try:
                    num = self.resp_hist[tx_time_str].replace(',','')
                    tx_fiat_val = "%.2f %s" % (Decimal(str(tx_info['value'])) / 100000000 * Decimal(num), self.fiat_unit())
                except KeyError:
                    tx_fiat_val = _("No data")

            tx_fiat_val = " "*(12-len(tx_fiat_val)) + tx_fiat_val
            item.setText(5, tx_fiat_val)
            item.setFont(5, QFont(MONOSPACE_FONT))
            if Decimal(str(tx_info['value'])) < 0:
                item.setForeground(5, QBrush(QColor("#BC1E1E")))

        for i, width in enumerate(self.win.column_widths['history']):
            self.win.history_list.setColumnWidth(i, width)
        self.win.history_list.setColumnWidth(4, 140)
        self.win.history_list.setColumnWidth(5, 120)
        self.win.is_edit = False


    def settings_widget(self, window):
        return EnterButton(_('Settings'), self.settings_dialog)

    def settings_dialog(self):
        d = QDialog()
        d.setWindowTitle("Settings")
        layout = QGridLayout(d)
        layout.addWidget(QLabel(_('Exchange rate API: ')), 0, 0)
        layout.addWidget(QLabel(_('Currency: ')), 1, 0)
        layout.addWidget(QLabel(_('History Rates: ')), 2, 0)
        combo = QComboBox()
        combo_ex = QComboBox()
        hist_checkbox = QCheckBox()
        hist_checkbox.setEnabled(False)
        hist_checkbox.setChecked(self.config.get('history_rates', 'unchecked') != 'unchecked')
        ok_button = QPushButton(_("OK"))

        def on_change(x):
            try:
                cur_request = str(self.currencies[x])
            except Exception:
                return
            if cur_request != self.fiat_unit():
                self.config.set_key('currency', cur_request, True)
                cur_exchange = self.config.get('use_exchange', "Blockchain")
                if (cur_exchange, cur_request) in EXCH_SUPPORT_HIST:
                    hist_checkbox.setEnabled(True)
                else:
                    disable_check()
                self.win.update_status()
                try:
                    self.fiat_button
                except:
                    pass
                else:
                    self.fiat_button.setText(cur_request)

        def disable_check():
            hist_checkbox.setChecked(False)
            hist_checkbox.setEnabled(False)

        def on_change_ex(x):
            cur_request = str(self.exchanges[x])
            if cur_request != self.config.get('use_exchange', "Blockchain"):
                self.config.set_key('use_exchange', cur_request, True)
                self.currencies = []
                combo.clear()
                self.exchanger.query_rates.set()
                cur_currency = self.fiat_unit()
                if (cur_request, cur_currency) in EXCH_SUPPORT_HIST:
                    hist_checkbox.setEnabled(True)
                else:
                    disable_check()
                set_currencies(combo)
                self.win.update_status()

        def on_change_hist(checked):
            if checked:
                self.config.set_key('history_rates', 'checked')
                self.request_history_rates()
            else:
                self.config.set_key('history_rates', 'unchecked')
                self.win.history_list.setHeaderLabels( [ '', _('Date'), _('Description') , _('Amount'), _('Balance')] )
                self.win.history_list.setColumnCount(5)
                for i,width in enumerate(self.win.column_widths['history']):
                    self.win.history_list.setColumnWidth(i, width)

        def set_hist_check(hist_checkbox):
            cur_exchange = self.config.get('use_exchange', "Blockchain")
            hist_checkbox.setEnabled(cur_exchange in ["CoinDesk", "Winkdex", "BitcoinVenezuela"])

        def set_currencies(combo):
            try:
                combo.blockSignals(True)
                current_currency = self.fiat_unit()
                combo.clear()
            except Exception:
                return
            combo.addItems(self.currencies)
            try:
                index = self.currencies.index(current_currency)
            except Exception:
                index = 0
            combo.blockSignals(False)
            combo.setCurrentIndex(index)

        def set_exchanges(combo_ex):
            try:
                combo_ex.clear()
            except Exception:
                return
            combo_ex.addItems(self.exchanges)
            try:
                index = self.exchanges.index(self.config.get('use_exchange', "Blockchain"))
            except Exception:
                index = 0
            combo_ex.setCurrentIndex(index)

        def ok_clicked():
            if self.config.get('use_exchange', "Blockchain") in ["CoinDesk", "itBit"]:
                self.exchanger.query_rates.set()
            d.accept();

        set_exchanges(combo_ex)
        set_currencies(combo)
        set_hist_check(hist_checkbox)
        combo.currentIndexChanged.connect(on_change)
        combo_ex.currentIndexChanged.connect(on_change_ex)
        hist_checkbox.stateChanged.connect(on_change_hist)
        combo.connect(self.win, SIGNAL('refresh_currencies_combo()'), lambda: set_currencies(combo))
        combo_ex.connect(d, SIGNAL('refresh_exchanges_combo()'), lambda: set_exchanges(combo_ex))
        ok_button.clicked.connect(lambda: ok_clicked())
        layout.addWidget(combo,1,1)
        layout.addWidget(combo_ex,0,1)
        layout.addWidget(hist_checkbox,2,1)
        layout.addWidget(ok_button,3,1)

        if d.exec_():
            return True
        else:
            return False

    def fiat_unit(self):
        return self.config.get("currency", "EUR")

    def add_fiat_edit(self):
        self.fiat_e = AmountEdit(self.fiat_unit)
        self.btc_e = self.win.amount_e
        grid = self.btc_e.parent()
        def fiat_changed():
            try:
                fiat_amount = Decimal(str(self.fiat_e.text()))
            except:
                self.btc_e.setText("")
                self.win.fee_e.setText("")
                return
            exchange_rate = self.exchanger.exchange(Decimal("1.0"), self.fiat_unit())
            if exchange_rate is not None:
                btc_amount = fiat_amount/exchange_rate
                self.btc_e.setAmount(int(btc_amount*Decimal(100000000)))
                self.win.update_fee(False)
        self.fiat_e.textEdited.connect(fiat_changed)
        def btc_changed():
            btc_amount = self.btc_e.get_amount()
            if btc_amount is None:
                self.fiat_e.setText("")
                return
            fiat_amount = self.exchanger.exchange(Decimal(btc_amount)/Decimal(100000000), self.fiat_unit())
            if fiat_amount is not None:
                pos = self.fiat_e.cursorPosition()
                self.fiat_e.setText("%.2f"%fiat_amount)
                self.fiat_e.setCursorPosition(pos)
        self.btc_e.textEdited.connect(btc_changed)
        self.btc_e.frozen.connect(lambda: self.fiat_e.setFrozen(self.btc_e.isReadOnly()))
        self.win.send_grid.addWidget(self.fiat_e, 4, 3, Qt.AlignHCenter)
