Add IM event python codegen

src/app/zap-templates/templates/app/cluster-objects.zapt

@@ -195,8 +195,8 @@ enum class Fields {
 struct Type
 {
 public:
-    static constexpr PriorityLevel priorityLevel = PriorityLevel::{{asUpperCamelCase priority}};
-    static constexpr EventId eventId = {{asMEI manufacturerCode code}};
+    static constexpr PriorityLevel GetPriorityLevel() { return kPriorityLevel; }
+    static constexpr EventId GetEventId() { return kEventId; }
     static constexpr ClusterId GetClusterId() { return Clusters::{{asUpperCamelCase parent.name}}::Id; }
 
     {{#zcl_event_fields}}

src/controller/python/chip/clusters/ClusterObjects.py

@@ -275,3 +275,59 @@ def _cluster_object(cls) -> ClusterObject:
                                   )
                               ],
                               bases=(ClusterObject,))
+
+
+class ClusterEventDescriptor:
+    '''
+    The ClusterEventDescriptor is used for holding an event's metadata like its cluster id, event id and its type.
+
+    Users should not initialize an object based on this class. Instead, users should pass the subclass objects to tell some methods what they want.
+
+    The implementation of this functions is quite tricky, it will create a cluster object on-the-fly, and use it for actual encode / decode routine to save lines of code.
+    '''
+    @classmethod
+    def ToTLV(cls, tag: Union[int, None], value):
+        writer = tlv.TLVWriter()
+        wrapped_value = cls._cluster_object(Value=value)
+        cls.event_type.PutFieldToTLV(tag,
+                                     asdict(wrapped_value)['Value'], writer, '')
+        return writer.encoding
+
+    @classmethod
+    def FromTLV(cls, tlvBuffer: bytes):
+        obj_class = cls._cluster_object
+        return obj_class.FromDict(obj_class.descriptor.TagDictToLabelDict('', {0: tlv.TLVReader(tlvBuffer).get().get('Any', {})})).Value
+
+    @classmethod
+    def FromTagDictOrRawValue(cls, val: Any):
+        obj_class = cls._cluster_object
+        return obj_class.FromDict(obj_class.descriptor.TagDictToLabelDict('', {0: val})).Value
+
+    @ChipUtility.classproperty
+    def cluster_id(self) -> int:
+        raise NotImplementedError()
+
+    @ChipUtility.classproperty
+    def event_id(self) -> int:
+        raise NotImplementedError()
+
+    @ChipUtility.classproperty
+    def event_type(cls) -> ClusterObjectFieldDescriptor:
+        raise NotImplementedError()
+
+    @ChipUtility.classproperty
+    def _cluster_object(cls) -> ClusterObject:
+        return make_dataclass('InternalClass',
+                              [
+                                  ('Value', List[cls.event_type.Type]
+                                   if cls.event_type.IsArray else cls.event_type.Type, field(default=None)),
+                                  ('descriptor', ClassVar[ClusterObjectDescriptor],
+                                   field(
+                                       default=ClusterObjectDescriptor(
+                                           Fields=[ClusterObjectFieldDescriptor(
+                                               Label='Value', Tag=0, Type=cls.event_type.Type, IsArray=cls.event_type.IsArray)]
+                                       )
+                                  )
+                                  )
+                              ],
+                              bases=(ClusterObject,))