from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from fastapi import HTTPException, status, Depends
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session

from ..database.config import settings
from ..models.user import User
from ..schemas.token import TokenData
from ..database.database import get_db

security = HTTPBearer()


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
    return encoded_jwt


def verify_token(token: str, credentials_exception):
    try:
        payload = jwt.decode(token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
    return token_data


async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: Session = Depends(get_db)
):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    
    token_data = verify_token(credentials.credentials, credentials_exception)
    
    user = db.query(User).filter(User.username == token_data.username).first()
    if user is None:
        raise credentials_exception
    return user


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