import logging
from typing import Optional, Tuple


class MetricsCalculator:
    def __init__(self):
        self.cvd_cumulative = 0.0
        self.obi_value = 0.0

    def update_cvd_from_trade(self, side: str, size: float) -> None:
        if side == "buy":
            volume_delta = float(size)
        elif side == "sell":
            volume_delta = -float(size)
        else:
            logging.warning(f"Unknown trade side '{side}', treating as neutral")
            
        self.cvd_cumulative += volume_delta

    def update_obi_from_book(self, total_bids: float, total_asks: float) -> None:
        self.obi_value = float(total_bids - total_asks)