Add FastAPI backend with agent system

backend/app/routers/task.py

@@ -0,0 +1,91 @@
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select, desc
+from app.database import get_db
+from app.models.task import Task, TaskStatus
+from app.models.user import User
+from app.routers.auth import get_current_user
+from app.schemas.task import TaskCreate, TaskUpdate, TaskOut
+
+router = APIRouter(prefix="/api/tasks", tags=["看板"])
+
+
+@router.get("", response_model=list[TaskOut])
+async def list_tasks(
+    status: TaskStatus | None = None,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    query = select(Task).where(Task.user_id == current_user.id)
+    if status:
+        query = query.where(Task.status == status)
+    query = query.order_by(desc(Task.created_at))
+    result = await db.execute(query)
+    return result.scalars().all()
+
+
+@router.post("", response_model=TaskOut, status_code=201)
+async def create_task(
+    data: TaskCreate,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    import json
+    task = Task(
+        user_id=current_user.id,
+        title=data.title,
+        description=data.description,
+        priority=data.priority,
+        due_date=data.due_date,
+        tags=json.dumps(data.tags) if data.tags else None,
+    )
+    db.add(task)
+    await db.commit()
+    await db.refresh(task)
+    return task
+
+
+@router.patch("/{task_id}", response_model=TaskOut)
+async def update_task(
+    task_id: str,
+    data: TaskUpdate,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    import json
+    result = await db.execute(
+        select(Task).where(Task.id == task_id, Task.user_id == current_user.id)
+    )
+    task = result.scalar_one_or_none()
+    if not task:
+        raise HTTPException(status_code=404, detail="任务不存在")
+
+    for field, value in data.model_dump(exclude_none=True).items():
+        if field == "tags":
+            setattr(task, field, json.dumps(value))
+        elif field == "status" and value == TaskStatus.DONE:
+            from datetime import datetime
+            task.completed_at = datetime.utcnow()
+            setattr(task, field, value)
+        else:
+            setattr(task, field, value)
+
+    await db.commit()
+    await db.refresh(task)
+    return task
+
+
+@router.delete("/{task_id}", status_code=204)
+async def delete_task(
+    task_id: str,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    result = await db.execute(
+        select(Task).where(Task.id == task_id, Task.user_id == current_user.id)
+    )
+    task = result.scalar_one_or_none()
+    if not task:
+        raise HTTPException(status_code=404, detail="任务不存在")
+    await db.delete(task)
+    await db.commit()