Add FastAPI backend with agent system

backend/app/agents/tools/task.py

@@ -0,0 +1,142 @@
+"""Agent 工具集 - 任务相关"""
+
+from langchain_core.tools import tool
+from app.database import async_session
+from app.models.task import Task
+from app.agents.context import get_current_user
+from sqlalchemy import select
+import asyncio
+
+_executor = None
+
+
+def _run_async(coro, timeout: int = 30):
+    try:
+        loop = asyncio.get_running_loop()
+        future = loop.run_in_executor(_executor or __import__("concurrent.futures").ThreadPoolExecutor(), lambda: asyncio.run(coro))
+        return future.result(timeout=timeout)
+    except RuntimeError:
+        return asyncio.run(coro)
+
+
+@tool
+def get_tasks(status: str | None = None, limit: int = 20) -> str:
+    """
+    获取用户当前的任务列表。
+
+    Args:
+        status: 可选，筛选任务状态 (todo/in_progress/done/blocked)
+        limit: 返回数量，默认20
+
+    Returns:
+        任务列表
+    """
+    uid = get_current_user()
+
+    async def _get():
+        async with async_session() as db:
+            from app.models.user import User
+            query = (
+                select(Task)
+                .join(User, User.id == Task.user_id)
+                .where(User.id == uid)
+            )
+            if status:
+                query = query.where(Task.status == status)
+            query = query.order_by(Task.priority.desc(), Task.updated_at.desc()).limit(limit)
+            result = await db.execute(query)
+            tasks = result.scalars().all()
+            if not tasks:
+                return "暂无任务"
+            lines = []
+            for t in tasks:
+                lines.append(
+                    f"- [{t.id[:8]}] {t.title} | "
+                    f"状态:{t.status} | 优先级:{t.priority} | 截止:{t.due_date or '无'}"
+                )
+            return "\n".join(lines)
+
+    try:
+        return _run_async(_get())
+    except Exception as e:
+        return f"获取任务失败: {str(e)}"
+
+
+@tool
+def create_task(title: str, description: str = "", priority: int = 2, due_date: str | None = None) -> str:
+    """
+    创建新任务。
+
+    Args:
+        title: 任务标题（必填）
+        description: 任务描述
+        priority: 优先级 1-4，数字越大优先级越高，默认2
+        due_date: 截止日期，格式 YYYY-MM-DD
+
+    Returns:
+        创建结果
+    """
+    uid = get_current_user()
+
+    async def _create():
+        async with async_session() as db:
+            task = Task(
+                user_id=uid,
+                title=title,
+                description=description,
+                priority=priority,
+                due_date=due_date,
+                status="todo",
+            )
+            db.add(task)
+            await db.commit()
+            await db.refresh(task)
+            return f"任务创建成功: [{task.id[:8]}] {title}"
+
+    try:
+        return _run_async(_create())
+    except Exception as e:
+        return f"创建任务失败: {str(e)}"
+
+
+@tool
+def update_task_status(task_id: str, status: str) -> str:
+    """
+    更新任务状态。
+
+    Args:
+        task_id: 任务ID（完整ID或前8位）
+        status: 新状态 (todo/in_progress/done/blocked)
+
+    Returns:
+        更新结果
+    """
+    uid = get_current_user()
+
+    async def _update():
+        async with async_session() as db:
+            from app.models.user import User
+            query = (
+                select(Task)
+                .join(User, User.id == Task.user_id)
+                .where(User.id == uid)
+            )
+            if len(task_id) == 8:
+                query = query.where(Task.id.like(f"{task_id}%"))
+            else:
+                query = query.where(Task.id == task_id)
+            result = await db.execute(query)
+            task = result.scalar_one_or_none()
+            if not task:
+                return f"任务不存在: {task_id}"
+            task.status = status
+            await db.commit()
+            return f"任务状态已更新: {task.title} -> {status}"
+
+    try:
+        return _run_async(_update())
+    except Exception as e:
+        return f"更新任务失败: {str(e)}"
+
+
+__all__ = ["get_tasks", "create_task", "update_task_status"]