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

from app.core.config import settings
from app.core.security import verify_password
from app.db.session import get_db
from app.models.user import User
from app.schemas.token import TokenPayload

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

def get_current_user(
    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
) -> User:
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        token_data = TokenPayload(**payload)
    except (JWTError, ValidationError):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    user = db.query(User).filter(User.id == token_data.sub).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    return user

def authenticate_user(db: Session, email: str, password: str) -> User:
    user = db.query(User).filter(User.email == email).first()
    if not user:
        return None
    if not verify_password(password, user.hashed_password):
        return None
    return user