feat(chat): 聊天功能

core/routers/chat/services.py

@@ -0,0 +1,90 @@
+# -*- coding = utf-8 -*-
+# @Time : 2025/3/1 下午4:44
+# @File : services.py
+# @Software : PyCharm
+# @Author : xingc
+# @Desc :
+from typing import Dict
+
+from sqlalchemy import select, and_, func
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import aliased, selectinload
+
+from core.base.exceptions import WebsocketTooManyRequests
+from core.db.models import User, Chat, ReadStatus, Message
+from core.routers.auth.schema import LoginUser
+from core.utils.helper import format_date
+
+from .schema import ChatUnreadOut
+
+
+async def websocket_callback(ws, pexpire):
+    raise WebsocketTooManyRequests("Too many requests")
+
+
+async def get_user_active_direct_chats(
+        db_session: AsyncSession, current_user: User
+) -> Dict[str, int] | None:
+    """获取活跃聊天"""
+    direct_chats_dict = dict()
+    query = (
+        select(Chat)
+        .where(and_(Chat.is_deleted.is_(False), Chat.users.contains(current_user)))
+        .options(selectinload(Chat.users))
+    )
+    result = await db_session.execute(query)
+    direct_chats: list[Chat] = result.scalars().all()
+
+    if direct_chats:
+        for direct_chat in direct_chats:
+            direct_chats_dict[str(direct_chat.guid)] = direct_chat.id
+        return direct_chats_dict
+
+
+async def get_unread_messages_per_chat(
+        db_session: AsyncSession, chats: list[Chat], login_user: LoginUser
+) -> list[dict]:
+    """获取聊天未读消息数"""
+    unread_messages_info_per_chat = {chat.id: {'message_count': 0} for chat in chats}
+
+    # 查询消息情况
+    read_status_alias = aliased(ReadStatus)
+    query = (
+        select(Message.chat_id, Message.content, func.count().label("message_count"))
+        .join(
+            read_status_alias,
+            and_(read_status_alias.user_id == login_user.user_id, read_status_alias.chat_id == Message.chat_id),
+        )
+        .where(
+            and_(
+                Message.user_id != login_user.user_id,
+                Message.id > func.coalesce(read_status_alias.last_read_message_id, 0),
+                Message.chat_id.in_(unread_messages_info_per_chat),
+            )
+        )
+        .order_by(Message.created_at.desc())
+        .group_by(Message.chat_id)
+    )
+    result = await db_session.execute(query)
+    unread_messages_info = result.fetchall()
+
+    for messages_info in unread_messages_info:
+        unread_messages_info_per_chat[messages_info[0]] = {
+            'message': messages_info[1],
+            'message_count': messages_info[2],
+        }
+
+    results = []
+    for chat in chats:
+        users = [user for user in await chat.awaitable_attrs.users if user.user_id != login_user.user_id]
+        messages_info = unread_messages_info_per_chat[chat.id]
+        results.append(dict(
+            chat_guid=chat.guid,
+            created_at=format_date(chat.created_at),
+            updated_at=format_date(chat.updated_at),
+            recipient_user=users[0],
+            last_message=messages_info.get('message'),
+            unread_messages_count=messages_info.get('message_count'),
+        ))
+
+    return results