feat: 实现MongoDB URI方式连接，并统一数据库连接代码。

src/common/database.py

@@ -6,20 +6,44 @@ from pymongo import MongoClient
 class Database:
     _instance: Optional["Database"] = None
     
-    def __init__(self, host: str, port: int, db_name: str, username: Optional[str] = None, password: Optional[str] = None, auth_source: Optional[str] = None):
-        if username and password:
+    def __init__(
+        self,
+        host: str,
+        port: int,
+        db_name: str,
+        username: Optional[str] = None,
+        password: Optional[str] = None,
+        auth_source: Optional[str] = None,
+        uri: Optional[str] = None,
+    ):
+        if uri and uri.startswith("mongodb://"):
+            # 优先使用URI连接
+            self.client = MongoClient(uri)
+        elif username and password:
             # 如果有用户名和密码，使用认证连接
-            # TODO: 复杂情况直接支持URI吧
-            self.client = MongoClient(host, port, username=username, password=password, authSource=auth_source)
+            self.client = MongoClient(
+                host, port, username=username, password=password, authSource=auth_source
+            )
         else:
             # 否则使用无认证连接
             self.client = MongoClient(host, port)
         self.db = self.client[db_name]
         
     @classmethod
-    def initialize(cls, host: str, port: int, db_name: str, username: Optional[str] = None, password: Optional[str] = None, auth_source: Optional[str] = None) -> "Database":
+    def initialize(
+        cls,
+        host: str,
+        port: int,
+        db_name: str,
+        username: Optional[str] = None,
+        password: Optional[str] = None,
+        auth_source: Optional[str] = None,
+        uri: Optional[str] = None,
+    ) -> "Database":
         if cls._instance is None:
-            cls._instance = cls(host, port, db_name, username, password, auth_source)
+            cls._instance = cls(
+                host, port, db_name, username, password, auth_source, uri
+            )
         return cls._instance
         
     @classmethod