import { getDecimalPlaces } from '$shared/lib/utils';

/**
 * Round a value to the precision of the given step
 *
 * This fixes floating-point precision errors that occur with decimal steps.
 * For example, with step=0.05, adding it repeatedly can produce values like
 * 1.3499999999999999 instead of 1.35.
 *
 * We use toFixed() to round to the appropriate decimal places instead of
 * Math.round(value / step) * step, which doesn't always work correctly
 * due to floating-point arithmetic errors.
 *
 * @param value - The value to round
 * @param step - The step to round to (defaults to 1)
 * @returns The rounded value
 */
export function roundToStepPrecision(value: number, step: number = 1): number {
    if (step <= 0) {
        return value;
    }
    const decimals = getDecimalPlaces(step);
    return parseFloat(value.toFixed(decimals));
}