from fastapi import Depends, HTTPException, status, Query
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session
from jose import JWTError, jwt
from database import get_db, SECRET_KEY, ALGORITHM
from models import User

security = HTTPBearer()


async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: Session = Depends(get_db)
) -> User:
    """Validate JWT token and return current user."""
    token = credentials.credentials
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Invalid or expired token",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id_str = payload.get("sub")
        if user_id_str is None:
            raise credentials_exception
        try:
            user_id = int(user_id_str)
        except (ValueError, TypeError):
            raise credentials_exception
    except JWTError:
        raise credentials_exception
    
    user = db.query(User).filter(User.id == user_id, User.is_active == True).first()
    if user is None:
        raise credentials_exception
    return user


async def get_current_admin(current_user: User = Depends(get_current_user)) -> User:
    """Ensure current user is an admin."""
    if current_user.role != "admin":
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Admin access required"
        )
    return current_user


async def get_current_user_from_query(
    token: str = Query(...),
    db: Session = Depends(get_db)
) -> User:
    """Validate JWT token from query parameter and return current user."""
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Invalid or expired token",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id_str = payload.get("sub")
        if user_id_str is None:
            raise credentials_exception
        user_id = int(user_id_str)
    except (JWTError, ValueError, TypeError):
        raise credentials_exception
    
    user = db.query(User).filter(User.id == user_id, User.is_active == True).first()
    if user is None:
        raise credentials_exception
    return user