WIP checkpoint: Scaffold FastAPI backend project structure

backend/app/routers/auth.py

@@ -0,0 +1,134 @@
+"""Authentication router - login, register, token refresh."""
+
+from datetime import datetime, timedelta, timezone
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordRequestForm
+from pydantic import BaseModel, EmailStr
+
+from jose import JWTError, jwt
+from passlib.context import CryptContext
+
+from app.config import settings
+from app.database import get_db
+from app.models.user import User
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+router = APIRouter()
+
+
+# --- Pydantic schemas ---
+
+class TokenResponse(BaseModel):
+    access_token: str
+    token_type: str = "bearer"
+
+
+class RegisterRequest(BaseModel):
+    username: str
+    email: EmailStr
+    password: str
+
+
+class LoginRequest(BaseModel):
+    username: str
+    password: str
+
+
+# --- Helpers ---
+
+def _create_access_token(data: dict) -> str:
+    to_encode = data.copy()
+    expire = datetime.now(timezone.utc) + timedelta(
+        minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
+    )
+    to_encode.update({"exp": expire})
+    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+
+
+def _verify_password(plain_password: str, hashed_password: str) -> bool:
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def _get_password_hash(password: str) -> str:
+    return pwd_context.hash(password)
+
+
+# --- Endpoints ---
+
+@router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
+async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
+    """Register a new user and return an access token."""
+    # Check if username already exists
+    result = await db.execute(select(User).where(User.username == req.username))
+    if result.scalar_one_or_none():
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Username already registered",
+        )
+
+    # Check if email already exists
+    result = await db.execute(select(User).where(User.email == req.email))
+    if result.scalar_one_or_none():
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Email already registered",
+        )
+
+    user = User(
+        username=req.username,
+        email=req.email,
+        hashed_password=_get_password_hash(req.password),
+    )
+    db.add(user)
+    await db.commit()
+    await db.refresh(user)
+
+    access_token = _create_access_token({"sub": str(user.id)})
+    return TokenResponse(access_token=access_token)
+
+
+@router.post("/login", response_model=TokenResponse)
+async def login(req: LoginRequest, db: AsyncSession = Depends(get_db)):
+    """Authenticate user and return an access token."""
+    result = await db.execute(select(User).where(User.username == req.username))
+    user = result.scalar_one_or_none()
+
+    if not user or not _verify_password(req.password, user.hashed_password):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect username or password",
+        )
+
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="User account is inactive",
+        )
+
+    access_token = _create_access_token({"sub": str(user.id)})
+    return TokenResponse(access_token=access_token)
+
+
+@router.get("/me")
+async def get_current_user(
+    # In production, extract from Authorization header via OAuth2PasswordBearer
+    # For now, accept a user_id query param for simplicity
+    user_id: int,
+    db: AsyncSession = Depends(get_db),
+):
+    """Get current user profile."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+    return {
+        "id": user.id,
+        "username": user.username,
+        "email": user.email,
+        "is_active": user.is_active,
+        "created_at": user.created_at,
+    }