bambuddy/backend/app/api/routes/auth.py

from datetime import timedelta

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from backend.app.core.auth import (
    ACCESS_TOKEN_EXPIRE_MINUTES,
    authenticate_user,
    create_access_token,
    get_current_active_user,
    get_password_hash,
    get_user_by_username,
)
from backend.app.core.database import get_db
from backend.app.models.settings import Settings
from backend.app.models.user import User
from backend.app.schemas.auth import LoginRequest, LoginResponse, SetupRequest, SetupResponse, UserResponse

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


async def is_auth_enabled(db: AsyncSession) -> bool:
    """Check if authentication is enabled."""
    result = await db.execute(select(Settings).where(Settings.key == "auth_enabled"))
    setting = result.scalar_one_or_none()
    return setting and setting.value.lower() == "true"


async def set_auth_enabled(db: AsyncSession, enabled: bool) -> None:
    """Set authentication enabled status."""
    from sqlalchemy import func
    from sqlalchemy.dialects.sqlite import insert as sqlite_insert

    stmt = sqlite_insert(Settings).values(key="auth_enabled", value="true" if enabled else "false")
    stmt = stmt.on_conflict_do_update(index_elements=["key"], set_={"value": "true" if enabled else "false", "updated_at": func.now()})
    await db.execute(stmt)
    # Note: Don't commit here - let get_db handle it or commit explicitly in the route


@router.post("/setup", response_model=SetupResponse)
async def setup_auth(request: SetupRequest, db: AsyncSession = Depends(get_db)):
    """First-time setup: enable/disable authentication and create admin user."""
    import logging
    
    logger = logging.getLogger(__name__)
    
    try:
        # Check if auth is already configured (prevent re-setup)
        result = await db.execute(select(Settings).where(Settings.key == "auth_enabled"))
        existing_setting = result.scalar_one_or_none()
        
        # Check if users exist
        user_count_result = await db.execute(select(User))
        user_count = len(user_count_result.scalars().all())

        if existing_setting and user_count > 0:
            # Auth already configured and users exist - prevent re-setup
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Authentication is already configured. Use user management to modify users.",
            )
        
        # If auth_enabled is true but no users exist, allow re-setup (recovery scenario)

        admin_created = False

        if request.auth_enabled:
            if not request.admin_username or not request.admin_password:
                raise HTTPException(
                    status_code=status.HTTP_400_BAD_REQUEST,
                    detail="Admin username and password are required when enabling authentication",
                )

            # Check if admin already exists
            existing_admin = await get_user_by_username(db, request.admin_username)
            if existing_admin:
                raise HTTPException(
                    status_code=status.HTTP_400_BAD_REQUEST,
                    detail="Admin user already exists",
                )

            # Create admin user FIRST (before enabling auth)
            try:
                logger.info(f"Creating admin user: {request.admin_username}")
                admin_user = User(
                    username=request.admin_username,
                    password_hash=get_password_hash(request.admin_password),
                    role="admin",
                    is_active=True,
                )
                db.add(admin_user)
                logger.info(f"Admin user added to session: {request.admin_username}")
                admin_created = True
            except Exception as e:
                await db.rollback()
                logger.error(f"Failed to create admin user: {e}", exc_info=True)
                raise HTTPException(
                    status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                    detail=f"Failed to create admin user: {str(e)}",
                )

        # Set auth enabled and commit everything together
        await set_auth_enabled(db, request.auth_enabled)
        await db.commit()
        
        if admin_created:
            await db.refresh(admin_user)
            logger.info(f"Admin user created successfully: {admin_user.id}")

        return SetupResponse(auth_enabled=request.auth_enabled, admin_created=admin_created)
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Setup error: {e}", exc_info=True)
        await db.rollback()
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Setup failed: {str(e)}",
        )


@router.get("/status")
async def get_auth_status(db: AsyncSession = Depends(get_db)):
    """Get authentication status (public endpoint)."""
    auth_enabled = await is_auth_enabled(db)
    return {"auth_enabled": auth_enabled, "requires_setup": not auth_enabled}


@router.post("/disable", response_model=dict)
async def disable_auth(
    current_user: User = Depends(get_current_active_user),
    db: AsyncSession = Depends(get_db),
):
    """Disable authentication (admin only)."""
    import logging
    
    logger = logging.getLogger(__name__)
    
    # Only admins can disable authentication
    if current_user.role != "admin":
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Only admins can disable authentication",
        )
    
    try:
        await set_auth_enabled(db, False)
        await db.commit()
        logger.info(f"Authentication disabled by admin user: {current_user.username}")
        return {"message": "Authentication disabled successfully", "auth_enabled": False}
    except Exception as e:
        await db.rollback()
        logger.error(f"Failed to disable authentication: {e}", exc_info=True)
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Failed to disable authentication: {str(e)}",
        )


@router.post("/login", response_model=LoginResponse)
async def login(request: LoginRequest, db: AsyncSession = Depends(get_db)):
    """Login and get access token."""
    # Check if auth is enabled
    auth_enabled = await is_auth_enabled(db)
    if not auth_enabled:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Authentication is not enabled",
        )

    user = await authenticate_user(db, request.username, request.password)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
            headers={"WWW-Authenticate": "Bearer"},
        )

    access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    access_token = create_access_token(data={"sub": user.username}, expires_delta=access_token_expires)

    return LoginResponse(
        access_token=access_token,
        token_type="bearer",
        user=UserResponse(
            id=user.id,
            username=user.username,
            role=user.role,
            is_active=user.is_active,
            created_at=user.created_at.isoformat(),
        ),
    )


@router.get("/me", response_model=UserResponse)
async def get_current_user_info(current_user: User = Depends(get_current_active_user)):
    """Get current user information."""
    return UserResponse(
        id=current_user.id,
        username=current_user.username,
        role=current_user.role,
        is_active=current_user.is_active,
        created_at=current_user.created_at.isoformat(),
    )


@router.post("/logout")
async def logout():
    """Logout (client should discard token)."""
    return {"message": "Logged out successfully"}