from datetime import datetime, timedelta
from passlib.context import CryptContext
from jose import jwt, JWTError
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from core.config import SECRET_KEY, ALGORITHM, ACCESS_TOKEN_EXPIRE_MINUTES
from db.mongo import users_collection

# OAuth2 setup — adjust tokenUrl if your API has a prefix like /api
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login")


# Password hashing context
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

# Hash a plain password
def hash_password(password: str) -> str:
    return pwd_context.hash(password)

# Verify a plain password against the hash
def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)

# Create a JWT access token
def create_access_token(data: dict, expires_delta: timedelta = None):
    to_encode = data.copy()
    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES))
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

async def get_current_user(token: str = Depends(oauth2_scheme)):
    logger.info(f"🔐 Authentication attempt with token: {token[:15]}...")  # Log first part of token
    
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        logger.info(f"📄 Token payload: {payload}")
        email: str = payload.get("sub")
        if email is None:
            logger.error("❌ Invalid token: subject missing")
            raise HTTPException(status_code=401, detail="Invalid token: subject missing")
    except JWTError as e:
        logger.error(f"❌ JWTError while decoding token: {str(e)}")
        raise HTTPException(status_code=401, detail="Could not validate token")

    user = await users_collection.find_one({"email": email})
    if not user:
        logger.error(f"❌ User not found for email: {email}")
        raise HTTPException(status_code=404, detail="User not found")

    logger.info(f"✅ Authenticated user: {user['email']}")
    return user