[1/3] Add support for multiple exchanges with ccxt (objectified version) (#585)

* remove obsolete helper functions and make _state a public member.

* remove function assertions

* revert worker() changes

* Update pytest from 3.4.2 to 3.5.0

* Adapt exchange functions to ccxt API
Remove get_market_summaries and get_wallet_health, add exception handling

* Add NetworkException

* Change pair format in constants.py

* Add tests for exchange functions that comply with ccxt

* Remove bittrex tests

* Remove Bittrex and Interface classes

* Add retrier decorator

* Remove cache from get_ticker

* Remove unused and duplicate imports

* Add keyword arguments for get_fee

* Implement 'get_pair_detail_url'

* Change get_ticker_history format to ccxt format

* Fix exchange urls dict, don't need to initialize exchanges

* Add "Using Exchange ..." logging line

freqtrade/freqtradebot.py

@@ -41,7 +41,7 @@ class FreqtradeBot(object):
         self.logger = Logger(name=__name__, level=config.get('loglevel')).get_logger()
 
         # Init bot states
-        self._state = State.STOPPED
+        self.state = State.STOPPED
 
         # Init objects
         self.config = config
@@ -71,9 +71,9 @@ class FreqtradeBot(object):
         initial_state = self.config.get('initial_state')
 
         if initial_state:
-            self.update_state(State[initial_state.upper()])
+            self.state = State[initial_state.upper()]
         else:
-            self.update_state(State.STOPPED)
+            self.state = State.STOPPED
 
     def clean(self) -> bool:
         """
@@ -82,41 +82,26 @@ class FreqtradeBot(object):
         """
         self.rpc.send_msg('*Status:* `Stopping trader...`')
         self.logger.info('Stopping trader and cleaning up modules...')
-        self.update_state(State.STOPPED)
+        self.state = State.STOPPED
         self.rpc.cleanup()
         persistence.cleanup()
         return True
 
-    def update_state(self, state: State) -> None:
-        """
-        Updates the application state
-        :param state: new state
-        :return: None
-        """
-        self._state = state
-
-    def get_state(self) -> State:
-        """
-        Gets the current application state
-        :return:
-        """
-        return self._state
-
     def worker(self, old_state: None) -> State:
         """
         Trading routine that must be run at each loop
         :param old_state: the previous service state from the previous call
         :return: current service state
         """
-        new_state = self.get_state()
         # Log state transition
-        if new_state != old_state:
-            self.rpc.send_msg('*Status:* `{}`'.format(new_state.name.lower()))
-            self.logger.info('Changing state to: %s', new_state.name)
+        state = self.state
+        if state != old_state:
+            self.rpc.send_msg('*Status:* `{}`'.format(state.name.lower()))
+            self.logger.info('Changing state to: %s', state.name)
 
-        if new_state == State.STOPPED:
+        if state == State.STOPPED:
             time.sleep(1)
-        elif new_state == State.RUNNING:
+        elif state == State.RUNNING:
             min_secs = self.config.get('internals', {}).get(
                 'process_throttle_secs',
                 Constants.PROCESS_THROTTLE_SECS
@@ -130,7 +115,7 @@ class FreqtradeBot(object):
             self._throttle(func=self._process,
                            min_secs=min_secs,
                            nb_assets=nb_assets)
-        return new_state
+        return state
 
     def _throttle(self, func: Callable[..., Any], min_secs: float, *args, **kwargs) -> Any:
         """
@@ -196,7 +181,7 @@ class FreqtradeBot(object):
                 )
             )
             self.logger.exception('OperationalException. Stopping trader ...')
-            self.update_state(State.STOPPED)
+            self.state = State.STOPPED
         return state_changed
 
     @cached(TTLCache(maxsize=1, ttl=1800))
@@ -483,8 +468,8 @@ class FreqtradeBot(object):
 
         fmt_exp_profit = round(trade.calc_profit_percent(rate=limit) * 100, 2)
         profit_trade = trade.calc_profit(rate=limit)
-        current_rate = exchange.get_ticker(trade.pair, False)['bid']
-        profit = trade.calc_profit_percent(current_rate)
+        current_rate = exchange.get_ticker(trade.pair)['bid']
+        profit = trade.calc_profit_percent(limit)
 
         message = "*{exchange}:* Selling\n" \
                   "*Current Pair:* [{pair}]({pair_url})\n" \