Refactor ZHA (#18629)

* refactor ZHA

* lint

* review request

* Exclude more zha modules from coverage

homeassistant/components/zha/entities/entity.py

@@ -0,0 +1,89 @@
+"""
+Entity for Zigbee Home Automation.
+
+For more details about this component, please refer to the documentation at
+https://home-assistant.io/components/zha/
+"""
+from homeassistant.helpers import entity
+from homeassistant.util import slugify
+from homeassistant.core import callback
+
+
+class ZhaEntity(entity.Entity):
+    """A base class for ZHA entities."""
+
+    _domain = None  # Must be overridden by subclasses
+
+    def __init__(self, endpoint, in_clusters, out_clusters, manufacturer,
+                 model, application_listener, unique_id, **kwargs):
+        """Init ZHA entity."""
+        self._device_state_attributes = {}
+        ieee = endpoint.device.ieee
+        ieeetail = ''.join(['%02x' % (o, ) for o in ieee[-4:]])
+        if manufacturer and model is not None:
+            self.entity_id = "{}.{}_{}_{}_{}{}".format(
+                self._domain,
+                slugify(manufacturer),
+                slugify(model),
+                ieeetail,
+                endpoint.endpoint_id,
+                kwargs.get('entity_suffix', ''),
+            )
+            self._device_state_attributes['friendly_name'] = "{} {}".format(
+                manufacturer,
+                model,
+            )
+        else:
+            self.entity_id = "{}.zha_{}_{}{}".format(
+                self._domain,
+                ieeetail,
+                endpoint.endpoint_id,
+                kwargs.get('entity_suffix', ''),
+            )
+
+        self._endpoint = endpoint
+        self._in_clusters = in_clusters
+        self._out_clusters = out_clusters
+        self._state = None
+        self._unique_id = unique_id
+
+        # Normally the entity itself is the listener. Sub-classes may set this
+        # to a dict of cluster ID -> listener to receive messages for specific
+        # clusters separately
+        self._in_listeners = {}
+        self._out_listeners = {}
+
+        self._initialized = False
+        application_listener.register_entity(ieee, self)
+
+    async def async_added_to_hass(self):
+        """Handle entity addition to hass.
+
+        It is now safe to update the entity state
+        """
+        for cluster_id, cluster in self._in_clusters.items():
+            cluster.add_listener(self._in_listeners.get(cluster_id, self))
+        for cluster_id, cluster in self._out_clusters.items():
+            cluster.add_listener(self._out_listeners.get(cluster_id, self))
+
+        self._initialized = True
+
+    @property
+    def unique_id(self) -> str:
+        """Return a unique ID."""
+        return self._unique_id
+
+    @property
+    def device_state_attributes(self):
+        """Return device specific state attributes."""
+        return self._device_state_attributes
+
+    @callback
+    def attribute_updated(self, attribute, value):
+        """Handle an attribute updated on this cluster."""
+        pass
+
+    @callback
+    def zdo_command(self, tsn, command_id, args):
+        """Handle a ZDO command received on this cluster."""
+        pass