from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import jwt, JWTError
from sqlalchemy.ext.asyncio import AsyncSession

from app.database import get_db
from app.config import settings
from app.models.user import User, UserRole
from app.services.auth_service import AuthService

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/v1/auth/login")

async def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: AsyncSession = Depends(get_db)
) -> User:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    
    payload = AuthService.decode_token(token)
    if payload is None:
        raise credentials_exception
        
    user_id_str = payload.get("sub")
    if user_id_str is None:
        raise credentials_exception
        
    try:
        user_id = int(user_id_str)
    except ValueError:
        raise credentials_exception
        
    user = await AuthService.get_user_by_id(db, user_id=user_id)
    if user is None:
        raise credentials_exception
        
    return user

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

async def get_current_admin_user(
    current_user: User = Depends(get_current_active_user)
) -> User:
    if current_user.role != UserRole.ADMIN:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="The user doesn't have enough privileges"
        )
    return current_user