from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from jose import JWTError, jwt
from ..db.database import get_db
from ..db.models import User
from ..core.config import settings

oauth2_scheme = OAuth2PasswordBearer(tokenUrl=f"{settings.API_V1_STR}/auth/login")

async def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: AsyncSession = Depends(get_db)
):
    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])
        user_id: str = payload.get("sub")
        if user_id is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception
    
    stmt = select(User).where(User.id == int(user_id))
    result = await db.execute(stmt)
    user = result.scalar_one_or_none()
    
    if user is None:
        raise credentials_exception
    return user

async def get_current_active_user(
    current_user: User = Depends(get_current_user)
):
    if not current_user.is_active:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user

async def get_current_superuser(
    current_user: User = Depends(get_current_user)
):
    if not current_user.is_superuser:
        raise HTTPException(
            status_code=403, detail="The user doesn't have enough privileges"
        )
    return current_user