Cash Accounts Implementation + Many Bug Fixes (#1505)

Closes #1035 .

The main UI components to it are in:

- **Contacts tab**
- Addresses tab, right click -> Register new.. (to register to a specific address)
- Tools -> Lookup Cash Account
- Receive tab (to register a cash account on the fly to the receive address there in the tab)

What it has:

- *Full verification* -- users are never presented with any results unless they are first SPV verified. They are also warned when a cash account in the contacts tab is no longer verified (due to reorg?) and won't offer it as an option for pay-to.

- Cash Account Registration Auto-Detection™ - Detects cash accounts related to the wallet (that is, registration tx's for the wallet) whenever it "sees" a tx. This can either be a tx that came through the normal wallet "add_transaction" path or if the user explicitly opens a tx, etc.

- The lookup facility is pretty robust and resilient to all sorts of shenanigans.

What it lacks:

- 100% Send tab niceties: Right now the only way to send to a cash account from the send tab is to **first** add it as a contact in the contacts tab.


This last Send Tab bit is a somewhat complex UI flow but I will do it.  I just wanted to get this PR merged in.

As I was working on this I fixed/found/cleaned up a ton of bugs and made the code tighter overall.

This PR includes all of that as well, so I would like to merge it fairly soon and move forward from master with work on Cash Accounts send tab perfection.

gui/qt/__init__.py

@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+# -*- coding: utf-8 -*-
 #
 # Electrum - lightweight Bitcoin client
 # Copyright (C) 2012 thomasv@gitorious
@@ -393,9 +394,10 @@ def on_focus_change(self, ignored, new_focus_widget):
         closed.'''
         if not new_focus_widget:
             return
-        window = QWidget.window(new_focus_widget)  # call base class because some widgets may actually override 'window' with Python attributes.
-        if isinstance(window, ElectrumWindow):
-            self._last_active_window = Weak.ref(window)
+        if isinstance(new_focus_widget, QWidget):
+            window = QWidget.window(new_focus_widget)  # call base class because some widgets may actually override 'window' with Python attributes.
+            if isinstance(window, ElectrumWindow):
+                self._last_active_window = Weak.ref(window)
 
     def start_new_window(self, path, uri):
         '''Raises the window for the wallet if it is open. Otherwise
@@ -736,6 +738,31 @@ def set_cashaddr_status_button_hidden(self, b):
             self.config.set_key('hide_cashaddr_button', bool(b))
             self.cashaddr_status_button_hidden_signal.emit(b)
 
+    def test_emoji_fonts(self) -> bool:
+        ''' Returns True if we can render all of the emoji fonts we need,
+        False otherwise. This needs to be called after the QApplication has
+        already been instantiated, which is why it's an instance method. Even
+        though this contains a loop over many characters we need, it ends up
+        having the following performance: first run is ~130 msec, subsequent
+        runs are ~10 msec total (on moderate hardware).'''
+        from electroncash import cashacct
+        #from . import network_dialog as nd
+
+        fontm = QFontMetrics(QFont())
+        fontm_mono = QFontMetrics(QFont(MONOSPACE_FONT))
+
+        emojis = set(cashacct.emoji_list)
+        # Note the below characters are not emojis, so they do not need to
+        # be included in this test. The rationale is these characters for
+        # the network dialog are not 100% critical to the UI, and they also
+        # are not in the solution we will recommend:install NotoColorEmoji.ttf.
+        # Uncomment if you wish to also check for these characters, however.
+        #emojis |= set(ord(ch) for ch in nd.ServerFlag.Symbol + nd.ServerFlag.UnSymbol if ch)
+        for uval in emojis:
+            if not fontm.inFontUcs4(uval) or not fontm_mono.inFontUcs4(uval):
+                return False
+        return True
+
     def main(self):
         try:
             self.init_network()

gui/qt/address_dialog.py

@@ -25,6 +25,7 @@
 
 from electroncash.i18n import _
 from electroncash.address import Address
+from electroncash.util import PrintError
 
 from PyQt5.QtCore import *
 from PyQt5.QtGui import *
@@ -33,9 +34,13 @@
 from .util import *
 from .history_list import HistoryList
 from .qrtextedit import ShowQRTextEdit
+from . import cashacctqt
 
 
-class AddressDialog(WindowModalDialog):
+class AddressDialog(PrintError, WindowModalDialog):
+
+    MIN_WIDTH_NO_FX_HIST = 700
+    MIN_WIDTH_FX_HIST = MIN_WIDTH_NO_FX_HIST + 75
 
     def __init__(self, parent, address, *, windowParent=None):
         assert isinstance(address, Address)
@@ -48,7 +53,7 @@ def __init__(self, parent, address, *, windowParent=None):
         self.app = parent.app
         self.saved = True
 
-        self.setMinimumWidth(700)
+        self.setMinimumWidth(self.MIN_WIDTH_FX_HIST if self.parent.fx and self.parent.fx.show_history() else self.MIN_WIDTH_NO_FX_HIST)
         vbox = QVBoxLayout()
         self.setLayout(vbox)
 
@@ -89,6 +94,22 @@ def __init__(self, parent, address, *, windowParent=None):
             redeem_e.addCopyButton()
             vbox.addWidget(redeem_e)
 
+        # Cash Accounts
+        ca_infos = self.wallet.cashacct.get_cashaccounts(self.get_domain())
+        vbox.addSpacing(10)
+        self.cashacct_gb = gb = cashacctqt.InfoGroupBox(self, self.parent, show_addresses=False)
+        self.update_cash_accounts(ca_infos)
+        def on_button_click():
+            item = gb.selectedItem()
+            if item:
+                info, ch, mch = item
+                self.wallet.cashacct.set_address_default(info)
+                QToolTip.showText(QCursor.pos(), _("Cash Account has been made the default for this address"), gb)
+                self.parent.address_list.update()
+        gb.buttonGroup().buttonClicked.connect(on_button_click)
+        vbox.addWidget(gb)
+        # /Cash Accounts
+
         vbox.addWidget(QLabel(_("History")))
         self.hw = HistoryList(self.parent)
         self.hw.get_domain = self.get_domain
@@ -116,12 +137,30 @@ def disconnect_signals(self):
         except TypeError: pass
 
     def got_verified_tx(self, event, args):
-        if event == 'verified':
-            self.hw.update_item(*args)
+        if event == 'verified2' and args[0] is self.wallet:
+            self.hw.update_item(*args[1:])
+        elif event in ('ca_verified_tx', 'ca_verification_failed') and args[0] == self.wallet.cashacct and args[1].address == self.address:
+            self.update_cash_accounts()
 
     def update_addr(self):
         self.addr_e.setText(self.address.to_full_ui_string())
 
+    def update_cash_accounts(self, ca_infos=None):
+        gb = self.cashacct_gb
+        ca_infos = ca_infos or self.wallet.cashacct.get_cashaccounts(self.get_domain())
+        tups = []
+        for info in ca_infos:
+            tups.append((info, self.wallet.cashacct.get_minimal_chash(info.name, info.number, info.collision_hash)))
+        default = self.wallet.cashacct.get_address_default(ca_infos)
+        gb.setItems(tups)
+        if tups:
+            gb.checkItemWithInfo(default)
+            if not gb.selectedItem():
+                gb.checkItemWithInfo(ca_infos[-1])
+            gb.setHidden(False)
+        else:
+            gb.setHidden(True)
+
     def get_domain(self):
         return [self.address]