feat：新增大屏存取发布接口

app/services/conversation_mongo.py

@@ -45,6 +45,8 @@ class MongoConversationStore:
         await self._conversations.create_index("created_at")
         # 按用户查询会话
         await self._conversations.create_index("user_id")
+        # 按大屏过滤会话
+        await self._conversations.create_index([("user_id", ASCENDING), ("screen_id", ASCENDING)])
 
     async def _purge_expired(self) -> None:
         # 只清理没有任何轮次且超过保留时长的空会话，有对话的会话不受影响
@@ -66,12 +68,17 @@ class MongoConversationStore:
         if empty:
             await self._conversations.delete_many({"_id": {"$in": empty}})
 
-    async def create(self, user_id: int) -> str:
+    async def create(self, user_id: int, screen_id: str | None = None) -> str:
         await self._purge_expired()
         conversation_id = str(uuid4())
         # user_id 来自用户中心，会话只对创建者可见
         await self._conversations.insert_one(
-            {"_id": conversation_id, "created_at": _now(), "user_id": user_id}
+            {
+                "_id": conversation_id,
+                "created_at": _now(),
+                "user_id": user_id,
+                "screen_id": screen_id,
+            }
         )
         return conversation_id
 
@@ -121,12 +128,13 @@ class MongoConversationStore:
             upsert=True,
         )
 
-    async def list_by_user(
-        self, user_id: int, limit: int, offset: int
-    ) -> list[ConversationSummary]:
+    def _with_stats(self, user_id: int, screen_id: str | None) -> list[dict]:
+        match: dict = {"user_id": user_id}
+        if screen_id is not None:
+            match["screen_id"] = screen_id
         # $unwind 会丢弃没有任何轮次的空会话
-        pipeline = [
-            {"$match": {"user_id": user_id}},
+        return [
+            {"$match": match},
             {
                 "$lookup": {
                     "from": self._turns.name,
@@ -146,6 +154,13 @@ class MongoConversationStore:
                 }
             },
             {"$unwind": "$stats"},
+        ]
+
+    async def list_by_user(
+        self, user_id: int, limit: int, offset: int, screen_id: str | None = None
+    ) -> list[ConversationSummary]:
+        pipeline = [
+            *self._with_stats(user_id, screen_id),
             {"$sort": {"stats.updated_at": -1, "_id": -1}},
             {"$skip": offset},
             {"$limit": limit},
@@ -154,8 +169,30 @@ class MongoConversationStore:
         return [
             ConversationSummary(
                 conversation_id=item["_id"],
-                title=make_title(item["stats"]["first_prompt"]),
+                title=item.get("title") or make_title(item["stats"]["first_prompt"]),
+                screen_id=item.get("screen_id"),
                 updated_at=item["stats"]["updated_at"],
             )
             for item in await cursor.to_list()
         ]
+
+    async def count_by_user(self, user_id: int, screen_id: str | None = None) -> int:
+        pipeline = [*self._with_stats(user_id, screen_id), {"$count": "total"}]
+        cursor = await self._conversations.aggregate(pipeline)
+        counted = await cursor.to_list()
+        return counted[0]["total"] if counted else 0
+
+    async def rename(self, conversation_id: str, user_id: int, title: str) -> bool:
+        if not await self.exists(conversation_id, user_id):
+            return False
+        await self._conversations.update_one(
+            {"_id": conversation_id, "user_id": user_id}, {"$set": {"title": title}}
+        )
+        return True
+
+    async def delete(self, conversation_id: str, user_id: int) -> bool:
+        if not await self.exists(conversation_id, user_id):
+            return False
+        await self._turns.delete_many({"conversation_id": conversation_id})
+        await self._conversations.delete_one({"_id": conversation_id, "user_id": user_id})
+        return True