from typing import Generator

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 import crud, models, schemas
from app.core import security
from app.core.config import settings
from app.db.session import SessionLocal

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


def get_db() -> Generator:
    """
    Dependency for getting DB session
    """
    try:
        db = SessionLocal()
        yield db
    finally:
        db.close()


def get_current_user(
    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
) -> models.User:
    """
    Dependency for getting current user from JWT token
    """
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[security.ALGORITHM]
        )
        token_data = schemas.TokenPayload(**payload)
    except (JWTError, ValidationError):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Could not validate credentials",
        )
    user = crud.user.get_by_id(db, id=token_data.sub)
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    return user


def get_current_active_user(
    current_user: models.User = Depends(get_current_user),
) -> models.User:
    """
    Dependency for getting current active user
    """
    if not crud.user.is_active(current_user):
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user


def get_current_active_superuser(
    current_user: models.User = Depends(get_current_user),
) -> models.User:
    """
    Dependency for getting current superuser
    """
    if not crud.user.is_superuser(current_user):
        raise HTTPException(
            status_code=400, detail="The user doesn't have enough privileges"
        )
    return current_user