import { BadRequestException } from '@nestjs/common';

export const MONEY_UNITS_PER_YUAN = 10_000;

export function moneyToNumber(value: number | bigint | null | undefined) {
  if (value === null || value === undefined) return 0;
  const result = typeof value === 'bigint' ? Number(value) : value;
  if (!Number.isSafeInteger(result)) {
    throw new RangeError('金额超过 JavaScript 安全整数范围');
  }
  return result;
}

export function moneyUnitsToYuan(value: number | bigint | null | undefined) {
  return moneyToNumber(value) / MONEY_UNITS_PER_YUAN;
}

export function moneyUnitsToFixedYuan(value: number | bigint | null | undefined) {
  return moneyUnitsToYuan(value).toFixed(4);
}

export function assertMoneyUnits(
  value: number,
  label: string,
  options: { allowNegative?: boolean; allowZero?: boolean } = {},
) {
  if (!Number.isSafeInteger(value)) {
    throw new BadRequestException(`${label}最多支持人民币小数点后 4 位，且不能超过安全金额范围`);
  }
  if (!options.allowNegative && value < 0) {
    throw new BadRequestException(`${label}不能为负数`);
  }
  if (options.allowZero === false && value === 0) {
    throw new BadRequestException(`${label}不能为 0`);
  }
}