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

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

# JWT Configuration (Consider moving to a .env file or config management)
SECRET_KEY = "your-super-secret-key"  # CHANGE THIS IN PRODUCTION!
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30 # Token validity period

def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password: str) -> str:
    return pwd_context.hash(password)

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

def decode_access_token(token: str) -> Optional[dict]:
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        return payload
    except JWTError:
        return None

class TokenPayload(BaseModel):
    sub: Optional[str] = None # 'sub' is standard for subject (e.g., user email or ID)
    exp: Optional[datetime] = None