refactor: use enum to specify type

bridge/context.py

@@ -0,0 +1,42 @@
+# encoding:utf-8
+
+from enum import Enum
+
+class ContextType (Enum):
+    TEXT = 1         # 文本消息
+    VOICE = 2        # 音频消息
+    IMAGE_CREATE = 3 # 创建图片命令
+    
+    def __str__(self):
+        return self.name
+class Context:
+    def __init__(self, type : ContextType = None , content = None,  kwargs = dict()):
+        self.type = type
+        self.content = content
+        self.kwargs = kwargs
+    def __getitem__(self, key):
+        if key == 'type':
+            return self.type
+        elif key == 'content':
+            return self.content
+        else:
+            return self.kwargs[key]
+
+    def __setitem__(self, key, value):
+        if key == 'type':
+            self.type = value
+        elif key == 'content':
+            self.content = value
+        else:
+            self.kwargs[key] = value
+
+    def __delitem__(self, key):
+        if key == 'type':
+            self.type = None
+        elif key == 'content':
+            self.content = None
+        else:
+            del self.kwargs[key]
+    
+    def __str__(self):
+        return "Context(type={}, content={}, kwargs={})".format(self.type, self.content, self.kwargs)