# [File: auth_utils.py]
import os
import jwt
import bcrypt
import random
import string
from fastapi import HTTPException, Depends, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from dotenv import load_dotenv

# 1. Thêm import Database để lấy thông tin User
from backend.app.database import users_collection
from backend.auth.config import JWT_ALGORITHM, JWT_SECRET

load_dotenv()

SECRET_KEY = JWT_SECRET
security = HTTPBearer()

# --- Helper Functions ---

def hash_password(password: str) -> str:
    return bcrypt.hashpw(password.encode('utf-8'), bcrypt.gensalt()).decode('utf-8')

def verify_password(plain_password: str, hashed_password: str) -> bool:
    return bcrypt.checkpw(plain_password.encode('utf-8'), hashed_password.encode('utf-8'))

# Dependency: Giải mã Token lấy Email
def verify_token(credentials: HTTPAuthorizationCredentials = Depends(security)) -> str:
    try:
        payload = jwt.decode(credentials.credentials, SECRET_KEY, algorithms=[JWT_ALGORITHM])
        return payload.get("email")
    except Exception:
        raise HTTPException(status_code=401, detail="Token invalid")

# 🔥 [MỚI] Dependency: Lấy Full User Info từ Token
# Hàm này sẽ được dùng trong Nutrition Routes
def get_current_user(email: str = Depends(verify_token)):
    user = users_collection.find_one({"email": email})
    if not user:
        raise HTTPException(status_code=401, detail="User not found")
    return user

# Hàm tạo OTP 6 số
def generate_otp(length=6) -> str:
    return ''.join(random.choices(string.digits, k=length))