import os
import bcrypt
from datetime import datetime, timedelta, timezone
from jose import jwt, JWTError
from fastapi import HTTPException, Security, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials

SECRET_KEY = os.getenv("SECRET_KEY", "el_puro_secret_key_change_in_production_jwt_99_1_pure")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_DAYS = 365

security = HTTPBearer()

def hash_password(password: str) -> str:
    # Truncate password to 72 bytes as per bcrypt spec
    pwd_bytes = password.encode('utf-8')[:72]
    salt = bcrypt.gensalt()
    return bcrypt.hashpw(pwd_bytes, salt).decode('utf-8')

def verify_password(plain_password: str, hashed_password: str) -> bool:
    pwd_bytes = plain_password.encode('utf-8')[:72]
    hashed_bytes = hashed_password.encode('utf-8')
    return bcrypt.checkpw(pwd_bytes, hashed_bytes)

def create_access_token(data: dict) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + timedelta(days=ACCESS_TOKEN_EXPIRE_DAYS)
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

def get_current_user_id(credentials: HTTPAuthorizationCredentials = Security(security)) -> int:
    token = credentials.credentials
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id = payload.get("sub")
        if user_id is None:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="Invalid authentication token",
            )
        return int(user_id)
    except (JWTError, ValueError):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
        )