text: #!/usr/bin/env python
  #
  # Electrum - Lightweight SmartCash Client
  # Copyright (C) 2015 Thomas Voegtlin
  #
  # 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.
  from collections import namedtuple
  import traceback
  import sys
  import os
  import imp
  import pkgutil
  import time
  import threading
  from typing import NamedTuple, Any, Union, TYPE_CHECKING, Optional
  
  from .util import print_error
  from .i18n import _
  from .util import profiler, PrintError, DaemonThread, UserCancelled, ThreadJob
  from . import bitcoin
  
  plugin_loaders = {}
  hook_names = set()
  hooks = {}
  
  
  class Plugins(DaemonThread):
  
      @profiler
      def __init__(self, config, is_local, gui_name):
          DaemonThread.__init__(self)
          if is_local:
              find = imp.find_module('plugins')
              plugins = imp.load_module('electrum_smart_plugins', *find)
          else:
              plugins = __import__('electrum_smart_plugins')
          self.pkgpath = os.path.dirname(plugins.__file__)
          self.config = config
          self.hw_wallets = {}
          self.plugins = {}
          self.gui_name = gui_name
          self.descriptions = {}
          self.device_manager = DeviceMgr(config)
          self.load_plugins()
          self.add_jobs(self.device_manager.thread_jobs())
          self.start()
  
      def load_plugins(self):
          for loader, name, ispkg in pkgutil.iter_modules([self.pkgpath]):
              # do not load deprecated plugins
              if name in ['plot', 'exchange_rate']:
                  continue
              m = loader.find_module(name).load_module(name)
              d = m.__dict__
              gui_good = self.gui_name in d.get('available_for', [])
              if not gui_good:
                  continue
              details = d.get('registers_wallet_type')
              if details:
                  self.register_wallet_type(name, gui_good, details)
              details = d.get('registers_keystore')
              if details:
                  self.register_keystore(name, gui_good, details)
              self.descriptions[name] = d
              if not d.get('requires_wallet_type') and self.config.get('use_' + name):
                  try:
                      self.load_plugin(name)
                  except BaseException as e:
                      traceback.print_exc(file=sys.stdout)
                      self.print_error("cannot initialize plugin %s:" % name, str(e))
  
      def get(self, name):
          return self.plugins.get(name)
  
      def count(self):
          return len(self.plugins)
  
      def load_plugin(self, name):
          if name in self.plugins:
              return self.plugins[name]
          full_name = 'electrum_smart_plugins.' + name + '.' + self.gui_name
          loader = pkgutil.find_loader(full_name)
          if not loader:
              raise RuntimeError("%s implementation for %s plugin not found"
                                 % (self.gui_name, name))
          p = loader.load_module(full_name)
          plugin = p.Plugin(self, self.config, name)
          self.add_jobs(plugin.thread_jobs())
          self.plugins[name] = plugin
          self.print_error("loaded", name)
          return plugin
  
      def close_plugin(self, plugin):
          self.remove_jobs(plugin.thread_jobs())
  
      def enable(self, name):
          self.config.set_key('use_' + name, True, True)
          p = self.get(name)
          if p:
              return p
          return self.load_plugin(name)
  
      def disable(self, name):
          self.config.set_key('use_' + name, False, True)
          p = self.get(name)
          if not p:
              return
          self.plugins.pop(name)
          p.close()
          self.print_error("closed", name)
  
      def toggle(self, name):
          p = self.get(name)
          return self.disable(name) if p else self.enable(name)
  
      def is_available(self, name, w):
          d = self.descriptions.get(name)
          if not d:
              return False
          deps = d.get('requires', [])
          for dep, s in deps:
              try:
                  __import__(dep)
              except ImportError:
                  return False
          requires = d.get('requires_wallet_type', [])
          return not requires or w.wallet_type in requires
  
      def get_hardware_support(self):
          out = []
          for name, (gui_good, details) in self.hw_wallets.items():
              if gui_good:
                  try:
                      p = self.get_plugin(name)
                      if p.is_enabled():
                          out.append([name, details[2], p])
                  except:
                      traceback.print_exc()
                      self.print_error("cannot load plugin for:", name)
          return out
  
      def register_wallet_type(self, name, gui_good, wallet_type):
          from .wallet import register_wallet_type, register_constructor
          self.print_error("registering wallet type", (wallet_type, name))
          def loader():
              plugin = self.get_plugin(name)
              register_constructor(wallet_type, plugin.wallet_class)
          register_wallet_type(wallet_type)
          plugin_loaders[wallet_type] = loader
  
      def register_keystore(self, name, gui_good, details):
          from .keystore import register_keystore
          def dynamic_constructor(d):
              return self.get_plugin(name).keystore_class(d)
          if details[0] == 'hardware':
              self.hw_wallets[name] = (gui_good, details)
              self.print_error("registering hardware %s: %s" %(name, details))
              register_keystore(details[1], dynamic_constructor)
  
      def get_plugin(self, name):
          if not name in self.plugins:
              self.load_plugin(name)
          return self.plugins[name]
  
      def run(self):
          while self.is_running():
              time.sleep(0.1)
              self.run_jobs()
          self.on_stop()
  
  
  def hook(func):
      hook_names.add(func.__name__)
      return func
  
  def run_hook(name, *args):
      results = []
      f_list = hooks.get(name, [])
      for p, f in f_list:
          if p.is_enabled():
              try:
                  r = f(*args)
              except Exception:
                  print_error("Plugin error")
                  traceback.print_exc(file=sys.stdout)
                  r = False
              if r:
                  results.append(r)
  
      if results:
          assert len(results) == 1, results
          return results[0]
  
  
  class BasePlugin(PrintError):
  
      def __init__(self, parent, config, name):
          self.parent = parent  # The plugins object
          self.name = name
          self.config = config
          self.wallet = None
          # add self to hooks
          for k in dir(self):
              if k in hook_names:
                  l = hooks.get(k, [])
                  l.append((self, getattr(self, k)))
                  hooks[k] = l
  
      def __str__(self):
          return self.name
  
      def close(self):
          # remove self from hooks
          for attr_name in dir(self):
              if attr_name in hook_names:
                  # found attribute in self that is also the name of a hook
                  l = hooks.get(attr_name, [])
                  try:
                      l.remove((self, getattr(self, attr_name)))
                  except ValueError:
                      # maybe attr name just collided with hook name and was not hook
                      continue
                  hooks[attr_name] = l
          self.parent.close_plugin(self)
          self.on_close()
  
      def on_close(self):
          pass
  
      def requires_settings(self):
          return False
  
      def thread_jobs(self):
          return []
  
      def is_enabled(self):
          return self.is_available() and self.config.get('use_'+self.name) is True
  
      def is_available(self):
          return True
  
      def can_user_disable(self):
          return True
  
      def settings_dialog(self):
          pass
  
  
  class DeviceNotFoundError(Exception): pass
  class DeviceUnpairableError(Exception): pass
  class HardwarePluginLibraryUnavailable(Exception): pass
  
  
  class Device(NamedTuple):
      path: Union[str, bytes]
      interface_number: int
      id_: str
      product_key: Any   # when using hid, often Tuple[int, int]
      usage_page: int
      transport_ui_string: str
  
  
  class DeviceInfo(NamedTuple):
      device: Device
      label: Optional[str] = None
      initialized: Optional[bool] = None
      exception: Optional[Exception] = None
  
  
  class HardwarePluginToScan(NamedTuple):
      name: str
      description: str
      plugin: Optional['HW_PluginBase']
      exception: Optional[Exception]
  
  
  class DeviceMgr(ThreadJob, PrintError):
      '''Manages hardware clients.  A client communicates over a hardware
      channel with the device.
  
      In addition to tracking device HID IDs, the device manager tracks
      hardware wallets and manages wallet pairing.  A HID ID may be
      paired with a wallet when it is confirmed that the hardware device
      matches the wallet, i.e. they have the same master public key.  A
      HID ID can be unpaired if e.g. it is wiped.
  
      Because of hotplugging, a wallet must request its client
      dynamically each time it is required, rather than caching it
      itself.
  
      The device manager is shared across plugins, so just one place
      does hardware scans when needed.  By tracking HID IDs, if a device
      is plugged into a different port the wallet is automatically
      re-paired.
  
      Wallets are informed on connect / disconnect events.  It must
      implement connected(), disconnected() callbacks.  Being connected
      implies a pairing.  Callbacks can happen in any thread context,
      and we do them without holding the lock.
  
      Confusingly, the HID ID (serial number) reported by the HID system
      doesn't match the device ID reported by the device itself.  We use
      the HID IDs.
  
      This plugin is thread-safe.  Currently only devices supported by
      hidapi are implemented.'''
  
      def __init__(self, config):
          ThreadJob.__init__(self)
          # Keyed by xpub.  The value is the device id
          # has been paired, and None otherwise.
          self.xpub_ids = {}
          # A list of clients.  The key is the client, the value is
          # a (path, id_) pair.
          self.clients = {}
          # What we recognise.  Each entry is a (vendor_id, product_id)
          # pair.
          self.recognised_hardware = set()
          # Custom enumerate functions for devices we don't know about.
          self.enumerate_func = set()
          # For synchronization
          self.lock = threading.RLock()
          self.hid_lock = threading.RLock()
          self.config = config
  
      def thread_jobs(self):
          # Thread job to handle device timeouts
          return [self]
  
      def run(self):
          '''Handle device timeouts.  Runs in the context of the Plugins
          thread.'''
          with self.lock:
              clients = list(self.clients.keys())
          cutoff = time.time() - self.config.get_session_timeout()
          for client in clients:
              client.timeout(cutoff)
  
      def register_devices(self, device_pairs):
          for pair in device_pairs:
              self.recognised_hardware.add(pair)
  
      def register_enumerate_func(self, func):
          self.enumerate_func.add(func)
  
      def create_client(self, device, handler, plugin):
          # Get from cache first
          client = self.client_lookup(device.id_)
          if client:
              return client
          client = plugin.create_client(device, handler)
          if client:
              print_error(f"Registering {client}")
              with self.lock:
                  self.clients[client] = (device.path, device.id_)
          return client
  
      def xpub_id(self, xpub):
          with self.lock:
              return self.xpub_ids.get(xpub)
  
      def xpub_by_id(self, id_):
          with self.lock:
              for xpub, xpub_id in self.xpub_ids.items():
                  if xpub_id == id_:
                      return xpub
              return None
  
      def unpair_xpub(self, xpub):
          with self.lock:
              if not xpub in self.xpub_ids:
                  return
              _id = self.xpub_ids.pop(xpub)
              self._close_client(_id)
  
      def unpair_id(self, id_):
          xpub = self.xpub_by_id(id_)
          if xpub:
              self.unpair_xpub(xpub)
          else:
              self._close_client(id_)
  
      def _close_client(self, id_):
          client = self.client_lookup(id_)
          self.clients.pop(client, None)
          if client:
              client.close()
  
      def pair_xpub(self, xpub, id_):
          with self.lock:
              self.xpub_ids[xpub] = id_
  
      def client_lookup(self, id_):
          with self.lock:
              for client, (path, client_id) in self.clients.items():
                  if client_id == id_:
                      return client
          return None
  
      def client_by_id(self, id_):
          '''Returns a client for the device ID if one is registered.  If
          a device is wiped or in bootloader mode pairing is impossible;
          in such cases we communicate by device ID and not wallet.'''
          self.scan_devices()
          return self.client_lookup(id_)
  
      def client_for_keystore(self, plugin, handler, keystore, force_pair):
          self.print_error("getting client for keystore")
          if handler is None:
              raise Exception(_("Handler not found for") + ' ' + plugin.name + '\n' + _("A library is probably missing."))
          handler.update_status(False)
          devices = self.scan_devices()
          xpub = keystore.xpub
          derivation = keystore.get_derivation()
          client = self.client_by_xpub(plugin, xpub, handler, devices)
          if client is None and force_pair:
              info = self.select_device(plugin, handler, keystore, devices)
              client = self.force_pair_xpub(plugin, handler, info, xpub, derivation, devices)
          if client:
              handler.update_status(True)
          self.print_error("end client for keystore")
          return client
  
      def client_by_xpub(self, plugin, xpub, handler, devices):
          _id = self.xpub_id(xpub)
          client = self.client_lookup(_id)
          if client:
              # An unpaired client might have another wallet's handler
              # from a prior scan.  Replace to fix dialog parenting.
              client.handler = handler
              return client
  
          for device in devices:
              if device.id_ == _id:
                  return self.create_client(device, handler, plugin)
  
  
      def force_pair_xpub(self, plugin, handler, info, xpub, derivation, devices):
          # The wallet has not been previously paired, so let the user
          # choose an unpaired device and compare its first address.
          xtype = bitcoin.xpub_type(xpub)
          client = self.client_lookup(info.device.id_)
          if client and client.is_pairable():
              # See comment above for same code
              client.handler = handler
              # This will trigger a PIN/passphrase entry request
              try:
                  client_xpub = client.get_xpub(derivation, xtype)
              except (UserCancelled, RuntimeError):
                   # Bad / cancelled PIN / passphrase
                  client_xpub = None
              if client_xpub == xpub:
                  self.pair_xpub(xpub, info.device.id_)
                  return client
  
          # The user input has wrong PIN or passphrase, or cancelled input,
          # or it is not pairable
          raise DeviceUnpairableError(
              _('Electrum cannot pair with your {}.\n\n'
                'Before you request bitcoins to be sent to addresses in this '
                'wallet, ensure you can pair with your device, or that you have '
                'its seed (and passphrase, if any).  Otherwise all bitcoins you '
                'receive will be unspendable.').format(plugin.device))
  
      def unpaired_device_infos(self, handler, plugin: 'HW_PluginBase', devices=None,
                                include_failing_clients=False):
          '''Returns a list of DeviceInfo objects: one for each connected,
          unpaired device accepted by the plugin.'''
          if not plugin.libraries_available:
              message = plugin.get_library_not_available_message()
              raise HardwarePluginLibraryUnavailable(message)
          if devices is None:
              devices = self.scan_devices()
          devices = [dev for dev in devices if not self.xpub_by_id(dev.id_)]
          infos = []
          for device in devices:
              if device.product_key not in plugin.DEVICE_IDS:
                  continue
              try:
                  client = self.create_client(device, handler, plugin)
              except Exception as e:
                  print_error(f'failed to create client for {plugin.name} at {device.path}: {repr(e)}')
                  if include_failing_clients:
                      infos.append(DeviceInfo(device=device, exception=e))
                  continue
              if not client:
                  continue
              infos.append(DeviceInfo(device=device,
                                      label=client.label(),
                                      initialized=client.is_initialized()))
  
          return infos
  
      def select_device(self, plugin, handler, keystore, devices=None):
          '''Ask the user to select a device to use if there is more than one,
          and return the DeviceInfo for the device.'''
          while True:
              infos = self.unpaired_device_infos(handler, plugin, devices)
              if infos:
                  break
              msg = _('Please insert your {}').format(plugin.device)
              if keystore.label:
                  msg += ' ({})'.format(keystore.label)
              msg += '. {}\n\n{}'.format(
                  _('Verify the cable is connected and that '
                    'no other application is using it.'),
                  _('Try to connect again?')
              )
              if not handler.yes_no_question(msg):
                  raise UserCancelled()
              devices = None
          if len(infos) == 1:
              return infos[0]
          # select device by label
          for info in infos:
              if info.label == keystore.label:
                  return info
          msg = _("Please select which {} device to use:").format(plugin.device)
          descriptions = [str(info.label) + ' (%s)'%(_("initialized") if info.initialized else _("wiped")) for info in infos]
          c = handler.query_choice(msg, descriptions)
          if c is None:
              raise UserCancelled()
          info = infos[c]
          # save new label
          keystore.set_label(info.label)
          if handler.win.wallet is not None:
              handler.win.wallet.save_keystore()
          return info
  
      def _scan_devices_with_hid(self):
          try:
              import hid
          except ImportError:
              return []
  
          with self.hid_lock:
              hid_list = hid.enumerate(0, 0)
  
          devices = []
          for d in hid_list:
              product_key = (d['vendor_id'], d['product_id'])
              if product_key in self.recognised_hardware:
                  # Older versions of hid don't provide interface_number
                  interface_number = d.get('interface_number', -1)
                  usage_page = d['usage_page']
                  id_ = d['serial_number']
                  if len(id_) == 0:
                      id_ = str(d['path'])
                  id_ += str(interface_number) + str(usage_page)
                  devices.append(Device(path=d['path'],
                                        interface_number=interface_number,
                                        id_=id_,
                                        product_key=product_key,
                                        usage_page=usage_page,
                                        transport_ui_string='hid'))
          return devices
  
      def scan_devices(self):
          self.print_error("scanning devices...")
  
          # First see what's connected that we know about
          devices = self._scan_devices_with_hid()
  
          # Let plugin handlers enumerate devices we don't know about
          for f in self.enumerate_func:
              try:
                  new_devices = f()
              except BaseException as e:
                  self.print_error('custom device enum failed. func {}, error {}'
                                   .format(str(f), str(e)))
              else:
                  devices.extend(new_devices)
  
          # find out what was disconnected
          pairs = [(dev.path, dev.id_) for dev in devices]
          disconnected_ids = []
          with self.lock:
              connected = {}
              for client, pair in self.clients.items():
                  if pair in pairs and client.has_usable_connection_with_device():
                      connected[client] = pair
                  else:
                      disconnected_ids.append(pair[1])
              self.clients = connected
  
          # Unpair disconnected devices
          for id_ in disconnected_ids:
              self.unpair_id(id_)
  
          return devices
  