from passlib.context import CryptContext
from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt

# Configuration
SECRET_KEY = "super-secret-key-please-change-in-production"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 3000 # Long expiry for convenience

# Changed to pbkdf2_sha256 to avoid bcrypt dependency issues on Windows
pwd_context = CryptContext(schemes=["pbkdf2_sha256"], deprecated="auto")

def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password):
    return pwd_context.hash(password)

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=15)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from database import get_db
import models

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/biblejyuku/api/token")

def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
    except jwt.JWTError:
        raise credentials_exception
    
    user = db.query(models.User).filter(models.User.username == username).first()
    if user is None:
        raise credentials_exception
    return user