auth.py

from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from datetime import datetime, timedelta
from jose import JWTError, jwt
from passlib.context import CryptContext
from pydantic import BaseModel
from ..core.config import settings

router = APIRouter()
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/auth/token")

class Token(BaseModel):
    access_token: str
    token_type: str

class User(BaseModel):
    username: str
    role: str # 'admin', 'analyst', 'executive'
    tenant_id: str # Added Multi-Tenant support

def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password):
    return pwd_context.hash(password)

def create_access_token(data: dict, expires_delta: timedelta | None = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=15)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
    return encoded_jwt

@router.post("/token", response_model=Token)
async def login_for_access_token(form_data: OAuth2PasswordRequestForm = Depends()):
    # Mock tenant assignments for the skeleton
    tenant_id = "TENANT-ALPHA" if form_data.username == "admin" else "TENANT-BETA"

    if form_data.username in ["admin", "analyst"] and form_data.password == "password":
        access_token = create_access_token(data={"sub": form_data.username, "role": "admin", "tenant_id": tenant_id})
        return {"access_token": access_token, "token_type": "bearer"}
    raise HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Incorrect username or password",
        headers={"WWW-Authenticate": "Bearer"},
    )

async def get_current_user(token: str = Depends(oauth2_scheme)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        username: str = payload.get("sub")
        role: str = payload.get("role")
        tenant_id: str = payload.get("tenant_id")
        if username is None or tenant_id is None:
            raise credentials_exception
        return User(username=username, role=role, tenant_id=tenant_id)
    except JWTError:
        raise credentials_exception