import { Numeric, NumberToDelimitedOptions } from "../typing";
import { parseBigNumber } from "./parseBigNumber";

/**
 * Formats a number with grouped thousands using delimiter (e.g., 12,324).
 *
 * @private
 *
 * @param {Numeric} input The number that will be formatted.
 *
 * @param {NumberToDelimitedOptions} options The formatting options.
 *
 * @return {string} The formatted number.
 */
export function numberToDelimited(
  input: Numeric,
  options: NumberToDelimitedOptions,
): string {
  const numeric = parseBigNumber(input, options.raise);

  if (!numeric.isFinite()) {
    return input.toString();
  }

  if (!options.delimiterPattern.global) {
    throw new Error(
      `options.delimiterPattern must be a global regular expression; received ${options.delimiterPattern}`,
    );
  }

  // eslint-disable-next-line prefer-const
  let [left, right] = numeric.toString().split(".");

  left = left.replace(
    options.delimiterPattern,
    (digitToDelimiter) => `${digitToDelimiter}${options.delimiter}`,
  );

  return [left, right].filter(Boolean).join(options.separator);
}