models/fair_odds.py

from __future__ import annotations


def probability_to_american(prob: float) -> int | None:
    if prob <= 0 or prob >= 1:
        return None

    if prob >= 0.5:
        return int(round(-(prob / (1 - prob)) * 100))
    return int(round(((1 - prob) / prob) * 100))


def american_to_probability(odds: int | float | str) -> float:
    value = int(float(odds))
    if value > 0:
        return 100.0 / (value + 100.0)
    return abs(value) / (abs(value) + 100.0)