Fastapi Endpoint

from pydantic import BaseModel, ConfigDict
from datetime import datetime
from uuid import UUID

class ResourceBase(BaseModel):
    """Shared fields between create and response."""
    name: str
    # ... fields from interview

class ResourceCreate(ResourceBase):
    """Fields required to create the resource."""
    pass

class ResourceUpdate(BaseModel):
    """All fields optional for partial updates."""
    name: str | None = None

class ResourceResponse(ResourceBase):
    """Full resource with DB-generated fields."""
    model_config = ConfigDict(from_attributes=True)
    id: UUID
    created_at: datetime
    updated_at: datetime

class ResourceListResponse(BaseModel):
    """Paginated list response."""
    data: list[ResourceResponse]
    next_cursor: str | None = None
    has_more: bool

from sqlalchemy import Column, String, DateTime, func
from sqlalchemy.dialects.postgresql import UUID as PG_UUID
import uuid
from app.database import Base

class Resource(Base):
    __tablename__ = "resources"

    id = Column(PG_UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    name = Column(String, nullable=False, index=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from uuid import UUID

async def get_resource(db: AsyncSession, resource_id: UUID) -> Resource | None:
    result = await db.execute(select(Resource).where(Resource.id == resource_id))
    return result.scalar_one_or_none()

async def list_resources(
    db: AsyncSession,
    cursor: str | None = None,
    limit: int = 20,
) -> tuple[list[Resource], str | None]:
    query = select(Resource).order_by(Resource.created_at.desc()).limit(limit + 1)
    if cursor:
        query = query.where(Resource.created_at < decode_cursor(cursor))
    result = await db.execute(query)
    items = list(result.scalars().all())
    next_cursor = encode_cursor(items[-1].created_at) if len(items) > limit else None
    return items[:limit], next_cursor

async def create_resource(db: AsyncSession, data: ResourceCreate) -> Resource:
    resource = Resource(**data.model_dump())
    db.add(resource)
    await db.commit()
    await db.refresh(resource)
    return resource

async def update_resource(
    db: AsyncSession, resource_id: UUID, data: ResourceUpdate
) -> Resource | None:
    resource = await get_resource(db, resource_id)
    if not resource:
        return None
    for field, value in data.model_dump(exclude_unset=True).items():
        setattr(resource, field, value)
    await db.commit()
    await db.refresh(resource)
    return resource

async def delete_resource(db: AsyncSession, resource_id: UUID) -> bool:
    resource = await get_resource(db, resource_id)
    if not resource:
        return False
    await db.delete(resource)
    await db.commit()
    return True

from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy.ext.asyncio import AsyncSession
from uuid import UUID

router = APIRouter(prefix="/resources", tags=["resources"])

@router.get("", response_model=ResourceListResponse)
async def list_resources_endpoint(
    cursor: str | None = Query(None),
    limit: int = Query(20, ge=1, le=100),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),  # if auth required
):
    items, next_cursor = await list_resources(db, cursor=cursor, limit=limit)
    return ResourceListResponse(
        data=items,
        next_cursor=next_cursor,
        has_more=next_cursor is not None,
    )

@router.get("/{resource_id}", response_model=ResourceResponse)
async def get_resource_endpoint(
    resource_id: UUID,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    resource = await get_resource(db, resource_id)
    if not resource:
        raise HTTPException(status_code=404, detail="Resource not found")
    return resource

@router.post("", response_model=ResourceResponse, status_code=status.HTTP_201_CREATED)
async def create_resource_endpoint(
    data: ResourceCreate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    return await create_resource(db, data)

@router.patch("/{resource_id}", response_model=ResourceResponse)
async def update_resource_endpoint(
    resource_id: UUID,
    data: ResourceUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    resource = await update_resource(db, resource_id, data)
    if not resource:
        raise HTTPException(status_code=404, detail="Resource not found")
    return resource

@router.delete("/{resource_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_resource_endpoint(
    resource_id: UUID,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    deleted = await delete_resource(db, resource_id)
    if not deleted:
        raise HTTPException(status_code=404, detail="Resource not found")

import pytest
from httpx import AsyncClient, ASGITransport
from app.main import app

@pytest.fixture
async def client():
    async with AsyncClient(
        transport=ASGITransport(app=app), base_url="http://test"
    ) as ac:
        yield ac

@pytest.mark.asyncio
async def test_create_resource(client: AsyncClient, auth_headers: dict):
    response = await client.post(
        "/resources",
        json={"name": "Test Resource"},
        headers=auth_headers,
    )
    assert response.status_code == 201
    data = response.json()
    assert data["name"] == "Test Resource"
    assert "id" in data

@pytest.mark.asyncio
async def test_get_resource_not_found(client: AsyncClient, auth_headers: dict):
    response = await client.get(
        "/resources/00000000-0000-0000-0000-000000000000",
        headers=auth_headers,
    )
    assert response.status_code == 404

@pytest.mark.asyncio
async def test_list_resources_pagination(client: AsyncClient, auth_headers: dict):
    # Create multiple resources first
    for i in range(5):
        await client.post(
            "/resources",
            json={"name": f"Resource {i}"},
            headers=auth_headers,
        )
    response = await client.get("/resources?limit=2", headers=auth_headers)
    assert response.status_code == 200
    data = response.json()
    assert len(data["data"]) == 2
    assert data["has_more"] is True
    assert data["next_cursor"] is not None

@pytest.mark.asyncio
async def test_create_resource_unauthorized(client: AsyncClient):
    response = await client.post("/resources", json={"name": "Test"})
    assert response.status_code in (401, 403)

@pytest.mark.asyncio
async def test_update_resource_partial(client: AsyncClient, auth_headers: dict):
    # Create
    create_resp = await client.post(
        "/resources",
        json={"name": "Original"},
        headers=auth_headers,
    )
    resource_id = create_resp.json()["id"]
    # Partial update
    response = await client.patch(
        f"/resources/{resource_id}",
        json={"name": "Updated"},
        headers=auth_headers,
    )
    assert response.status_code == 200
    assert response.json()["name"] == "Updated"

@pytest.mark.asyncio
async def test_delete_resource(client: AsyncClient, auth_headers: dict):
    create_resp = await client.post(
        "/resources",
        json={"name": "To Delete"},
        headers=auth_headers,
    )
    resource_id = create_resp.json()["id"]
    response = await client.delete(
        f"/resources/{resource_id}", headers=auth_headers
    )
    assert response.status_code == 204
    # Verify deleted
    get_resp = await client.get(
        f"/resources/{resource_id}", headers=auth_headers
    )
    assert get_resp.status_code == 404

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="auth/token")

async def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: AsyncSession = Depends(get_db),
) -> User:
    payload = decode_jwt(token)
    user = await db.get(User, payload["sub"])
    if not user:
        raise HTTPException(status_code=401, detail="Invalid token")
    return user

def require_role(*roles: str):
    """Factory for role-based access control."""
    async def checker(current_user: User = Depends(get_current_user)):
        if current_user.role not in roles:
            raise HTTPException(status_code=403, detail="Insufficient permissions")
        return current_user
    return checker

import base64
from datetime import datetime

def encode_cursor(dt: datetime) -> str:
    return base64.urlsafe_b64encode(dt.isoformat().encode()).decode()

def decode_cursor(cursor: str) -> datetime:
    return datetime.fromisoformat(base64.urlsafe_b64decode(cursor).decode())

# 404 — not found
raise HTTPException(status_code=404, detail="Resource not found")

# 409 — conflict (duplicate)
raise HTTPException(status_code=409, detail="Resource with this name already exists")

# 403 — forbidden
raise HTTPException(status_code=403, detail="Not allowed to modify this resource")