'use strict';

const NOTES_MAX_LENGTH = 5000;

const toNonNegativeNumber = (value) => {
  const n = Number(value);
  if (!Number.isFinite(n) || n < 0) return 0;
  return n;
};

const normalizeDiscount = (discount, amount) => {
  return Math.min(toNonNegativeNumber(discount), toNonNegativeNumber(amount));
};

const getPayableAmount = (payment = {}) => {
  const amount = toNonNegativeNumber(payment.amount);
  return amount - normalizeDiscount(payment.discount, amount);
};

const sanitizeNotes = (notes) => {
  if (notes == null) return '';
  return String(notes).trim().slice(0, NOTES_MAX_LENGTH);
};

const rialsToToman = (value) => Math.floor(toNonNegativeNumber(value) / 10);

const isPaidTransaction = (trx = {}) => {
  const status = String(trx.status || '').toLowerCase();
  if (status === 'pending') return false;
  if (status === 'paid') return true;
  return Boolean(trx.date);
};

const sumPaidTransactions = (transactions = []) => {
  if (!Array.isArray(transactions)) return 0;
  return transactions.reduce((sum, trx) => {
    if (!isPaidTransaction(trx)) return sum;
    return sum + toNonNegativeNumber(trx.amount);
  }, 0);
};

const remainingPayable = (payment = {}, transactions = []) => {
  return Math.max(0, getPayableAmount(payment) - sumPaidTransactions(transactions));
};

module.exports = {
  NOTES_MAX_LENGTH,
  getPayableAmount,
  normalizeDiscount,
  sanitizeNotes,
  rialsToToman,
  isPaidTransaction,
  sumPaidTransactions,
  remainingPayable
};