import os
from jose import JWTError, jwt
from datetime import datetime, timedelta
from fastapi import Depends, HTTPException, Request
from sqlalchemy.orm import Session
from app import models
from app.database import get_db
from dotenv import load_dotenv

load_dotenv()

SECRET_KEY = os.getenv("SECRET_KEY", "fallback_key_if_missing")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

def create_access_token(data: dict):
    to_encode = data.copy()
    expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

def get_current_user(request: Request, db: Session = Depends(get_db)):
    auth_header = request.headers.get("Authorization")
    if not auth_header or not auth_header.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="Authorization header missing or invalid")

    token = auth_header.split(" ")[1]

    # ✅ Check if token is blacklisted
    blacklisted = db.query(models.BlacklistedToken).filter(models.BlacklistedToken.token == token).first()
    if blacklisted:
        raise HTTPException(status_code=401, detail="Please log in again.")

    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        mobile = payload.get("sub")
        if mobile is None:
            raise HTTPException(status_code=401, detail="Invalid JWT payload")

        user = db.query(models.User).filter(models.User.mobile == mobile).first()
        if user is None:
            raise HTTPException(status_code=404, detail="User not found")

        return user
    except JWTError:
        raise HTTPException(status_code=403, detail="Could not validate credentials, Token Expired")