import BigNumber from 'bignumber.js';

export const numberToString = (
  number: BigNumber | string | null,
  minDecimals: number | null = null,
  maxDecimals: number | null = null
): string => {
  if (number === null) return '';
  if (number === '') return '';
  const n = new BigNumber(number);
  const roundingMode = 1;
  let maxI = 1000;
  for (let i = 0; i < 60; i++) {
    if (new BigNumber(n.toFixed(i, roundingMode)).eq(n)) {
      maxI = i;
      break;
    }
  }

  if (n.gte(10000)) return n.toFormat(0, roundingMode);
  if (n.gte(1000))
    return n.toFormat(
      Math.min(
        maxI,
        Math.min(maxDecimals || 100, Math.max(minDecimals || 0, 1))
      ),
      roundingMode
    );
  if (n.gte(100))
    return n.toFormat(
      Math.min(
        maxI,
        Math.min(maxDecimals || 100, Math.max(minDecimals || 0, 1))
      ),
      roundingMode
    );
  if (n.gte(1))
    return n.toFormat(
      Math.min(
        maxI,
        Math.min(maxDecimals || 100, Math.max(minDecimals || 0, 2))
      ),
      roundingMode
    );
  if (n.gte(0.01))
    return n.toFormat(
      Math.min(
        maxI,
        Math.min(maxDecimals || 100, Math.max(minDecimals || 0, 4))
      ),
      roundingMode
    );
  for (let i = minDecimals || 4; i < 17; i++)
    if (n.gte(Math.pow(10, -i)))
      return n.toFormat(
        Math.min(
          maxI,
          Math.min(maxDecimals || 100, Math.max(minDecimals || 0, i))
        ),
        roundingMode
      );
  if (n.isEqualTo(0)) return '0';

  return n.toFormat(
    Math.min(maxI, Math.min(maxDecimals || 100, Math.max(minDecimals || 0, 8))),
    roundingMode
  );
};