'use strict';

const COLUMNS = [
  'event',
  'date/time added',
  'customer',
  'item',
  'category',
  'problem',
  'status',
  'repairer',
  'outcome',
  'tools/consumables',
  'notes',
];

// Quote a field if it contains anything that would break the row, doubling any
// quotes inside it. Everything else goes out bare.
function escapeField(value) {
  const text = value === null || value === undefined ? '' : String(value);
  if (/[",\r\n]/.test(text)) return '"' + text.replace(/"/g, '""') + '"';
  return text;
}

function row(fields) {
  return fields.map(escapeField).join(',');
}

// "2026-08-15 17:14" in the server's timezone — spreadsheets read that as a
// date, which a raw UTC ISO string does not.
function localDateTime(iso) {
  const d = new Date(iso);
  if (Number.isNaN(d.getTime())) return iso;
  const pad = (n) => String(n).padStart(2, '0');
  return (
    `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ` +
    `${pad(d.getHours())}:${pad(d.getMinutes())}`
  );
}

function repairRows(event) {
  return event.repairs.map((r) =>
    row([
      event.name,
      localDateTime(r.createdAt),
      r.customer,
      r.item,
      r.category,
      r.problem,
      r.status,
      r.repairer,
      r.outcome,
      r.toolsUsed,
      (r.notes || []).map((n) => n.text).join(' | '),
    ])
  );
}

// A leading BOM so Excel reads it as UTF-8 rather than mangling accents.
function toCsv(events) {
  const lines = [row(COLUMNS)];
  for (const event of events) lines.push(...repairRows(event));
  return '' + lines.join('\r\n') + '\r\n';
}

module.exports = { toCsv, escapeField, COLUMNS };