from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import jwt
from pydantic import ValidationError
from sqlalchemy.orm import Session

from app.core.config import settings
from app.core.database import get_db
from app.core.security import ALGORITHM
from app.models.user import User
from app.schemas.token import TokenPayload
from app.services import user as user_service

# OAuth2 scheme for token authentication
oauth2_scheme = OAuth2PasswordBearer(tokenUrl=settings.TOKEN_URL)


def get_current_user(
    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
) -> User:
    """
    Get current user based on JWT token
    """
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[ALGORITHM]
        )
        token_data = TokenPayload(**payload)
    except (jwt.JWTError, ValidationError):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    user = user_service.get_by_id(db, user_id=token_data.sub)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="User not found"
        )
    return user


def get_current_active_user(
    current_user: User = Depends(get_current_user),
) -> User:
    """
    Get current active user
    """
    if not user_service.is_active(current_user):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Inactive user"
        )
    return current_user


def get_current_active_superuser(
    current_user: User = Depends(get_current_active_user),
) -> User:
    """
    Get current active superuser
    """
    if not user_service.is_superuser(current_user):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="The user doesn't have enough privileges"
        )
    return current_user