Simplify package structure

tfw/components/frontend/__init__.py

@@ -0,0 +1,2 @@
+from .frontend_handler import FrontendHandler
+from .message_sender import MessageSender

tfw/components/frontend/frontend_handler.py

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+from tfw.internals.networking import Scope
+
+from .message_storage import FrontendMessageStorage
+
+
+class FrontendHandler:
+    keys = ['message', 'queueMessages', 'dashboard', 'console']
+
+    def __init__(self):
+        self.server_connector = None
+        self.keys = [*type(self).keys, 'recover']
+        self._frontend_message_storage = FrontendMessageStorage(type(self).keys)
+
+    def send_message(self, message):
+        self.server_connector.send_message(message, scope=Scope.WEBSOCKET)
+
+    def handle_event(self, message, _):
+        self._frontend_message_storage.save_message(message)
+        if message['key'] == 'recover':
+            self.recover_frontend()
+        self.send_message(message)
+
+    def recover_frontend(self):
+        for message in self._frontend_message_storage.messages:
+            self.send_message(message)

tfw/components/frontend/message_sender.py

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+class MessageSender:
+    """
+    Provides mechanisms to send messages to our frontend messaging component.
+    """
+    def __init__(self, uplink):
+        self.uplink = uplink
+        self.key = 'message'
+        self.queue_key = 'queueMessages'
+
+    def send(self, originator, message):
+        """
+        Sends a message.
+        :param originator: name of sender to be displayed on the frontend
+        :param message: message to send
+        """
+        message = {
+            'key': self.key,
+            'data': {
+                'originator': originator,
+                'message': message
+            }
+        }
+        self.uplink.send_message(message)
+
+    def queue_messages(self, originator, messages):
+        """
+        Queues a list of messages to be displayed in a chatbot-like manner.
+        :param originator: name of sender to be displayed on the frontend
+        :param messages: list of messages to queue
+        """
+        message = {
+            'key': self.queue_key,
+            'data': {
+                'messages': [
+                    {'message': message, 'originator': originator}
+                    for message in messages
+                ]
+            }
+        }
+        self.uplink.send_message(message)
+
+    @staticmethod
+    def generate_messages_from_queue(queue_message):
+        for message in queue_message['data']['messages']:
+            yield {
+                'key': 'message',
+                'data': message
+            }

tfw/components/frontend/message_storage.py

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+from abc import ABC, abstractmethod
+from contextlib import suppress
+
+from .message_sender import MessageSender
+
+
+class MessageStorage(ABC):
+    def __init__(self):
+        self._messages = []
+
+    def save_message(self, message):
+        with suppress(KeyError, AttributeError):
+            if self._filter_message(message):
+                self._messages.extend(self._transform_message(message))
+
+    @abstractmethod
+    def _filter_message(self, message):
+        raise NotImplementedError
+
+    def _transform_message(self, message):   # pylint: disable=no-self-use
+        yield message
+
+    def clear(self):
+        self._messages.clear()
+
+    @property
+    def messages(self):
+        yield from self._messages
+
+
+class FrontendMessageStorage(MessageStorage):
+    def __init__(self, keys):
+        self._keys = keys
+        super().__init__()
+
+    def _filter_message(self, message):
+        key = message['key']
+        return key in self._keys
+
+    def _transform_message(self, message):
+        if message['key'] == 'queueMessages':
+            yield from MessageSender.generate_messages_from_queue(message)
+        else:
+            yield message