'use strict';

const { describe, it } = require('node:test');
const assert = require('node:assert/strict');
const {
  getPayableAmount,
  normalizeDiscount,
  sanitizeNotes,
  NOTES_MAX_LENGTH
} = require('./paymentAmount');

describe('payment amount helpers', () => {
  it('returns the original amount when there is no discount', () => {
    assert.equal(getPayableAmount({ amount: 1_000_000 }), 1_000_000);
    assert.equal(getPayableAmount({ amount: 1_000_000, discount: 0 }), 1_000_000);
  });

  it('subtracts a discount from the total', () => {
    assert.equal(getPayableAmount({ amount: 1_000_000, discount: 150_000 }), 850_000);
  });

  it('never returns a negative payable amount', () => {
    assert.equal(getPayableAmount({ amount: 100, discount: 250 }), 0);
  });

  it('treats missing or invalid values as zero', () => {
    assert.equal(getPayableAmount({}), 0);
    assert.equal(getPayableAmount({ amount: 'abc', discount: 'x' }), 0);
    assert.equal(normalizeDiscount(-50, 1000), 0);
    assert.equal(normalizeDiscount('not-a-number', 1000), 0);
  });

  it('clamps discount so it cannot exceed the total', () => {
    assert.equal(normalizeDiscount(2_000, 1_000), 1_000);
    assert.equal(normalizeDiscount(200, 1_000), 200);
  });
});

describe('sanitizeNotes', () => {
  it('trims notes and caps length', () => {
    assert.equal(sanitizeNotes('  hello  '), 'hello');
    assert.equal(sanitizeNotes(null), '');
    assert.equal(sanitizeNotes(undefined), '');
    assert.equal(sanitizeNotes('a'.repeat(NOTES_MAX_LENGTH + 10)).length, NOTES_MAX_LENGTH);
  });
});