import { add, formatDecimal, multiply, subtract } from '../../common/decimal';
import { decimal } from './decimal';

describe('decimal', () => {
  it('keeps signed nanos exact without floats', () => {
    expect(formatDecimal(decimal({ units: 0, nano: -500000000 }))).toBe('-0.5');
    expect(
      formatDecimal(
        add(decimal({ units: '9007199254740993' }), decimal({ nano: 1 })),
      ),
    ).toBe('9007199254740993.000000001');
    expect(
      formatDecimal(
        subtract(decimal({ units: 1 }), decimal({ nano: 500000000 })),
      ),
    ).toBe('0.5');
    expect(
      formatDecimal(
        multiply(decimal({ units: 2 }), decimal({ nano: 500000000 })),
      ),
    ).toBe('1');
  });
});

describe('decimal formatting', () => {
  it.each([
    [120000n, 4, '12'],
    [-120030n, 4, '-12.003'],
    [1n, 4, '0.0001'],
    [0n, 4, '0'],
  ])('preserves value %s at scale %s while trimming only trailing zeros', (value, scale, expected) => {
    expect(formatDecimal({ value, scale })).toBe(expected);
  });
  it('preserves a long fraction with a trailing zero run', () => {
    const significant = '1'.repeat(10_000);
    expect(formatDecimal({ value: BigInt(significant + '0'.repeat(10_000)), scale: 20_000 })).toBe('0.' + significant);
  });
});