1.4

backend/app/services/conversation_service.py

@@ -115,6 +115,33 @@ class ConversationService:
             raise ValueError("群主不能退出，请先转让群主身份")
         member.left_at = datetime.utcnow()
 
+    async def dissolve_group(self, conv_id: str, user_id: str):
+        """解散群聊（仅群主）"""
+        member = await self._get_member(conv_id, user_id)
+        if not member:
+            raise ValueError("你不在该群中")
+        if member.role != "owner":
+            raise ValueError("只有群主可以解散群聊")
+
+        # 验证会话存在且为群聊
+        conv_result = await self.db.execute(
+            select(Conversation).where(Conversation.id == conv_id)
+        )
+        conv = conv_result.scalars().first()
+        if not conv or conv.type != "group":
+            raise ValueError("群聊不存在")
+
+        # 软删除所有成员（设置 left_at）
+        members_result = await self.db.execute(
+            select(ConversationMember).where(
+                ConversationMember.conversation_id == conv_id,
+                ConversationMember.left_at.is_(None),
+            )
+        )
+        now = datetime.utcnow()
+        for m in members_result.scalars().all():
+            m.left_at = now
+
     async def update_member_role(self, conv_id: str, user_id: str, target_user_id: str, role: str):
         """修改成员角色（仅群主）"""
         member = await self._get_member(conv_id, user_id)