/**
 * LandveX Finance — Utilities
 * Sprint 3: UI-refaktorering
 */

export const MN = ['Jan', 'Feb', 'Mar', 'Apr', 'Maj', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dec'];

// ── Formatering ──
export function fmt(v) {
  const a = Math.abs(v);
  return (v < 0 ? '−' : '') + Math.round(a).toLocaleString('sv-SE') + ' kr';
}

export function fmtNumber(v, decimals = 0) {
  return Number(v).toLocaleString('sv-SE', {
    minimumFractionDigits: decimals,
    maximumFractionDigits: decimals,
  });
}

export function fmtPercent(v, decimals = 1) {
  return Number(v).toLocaleString('sv-SE', {
    minimumFractionDigits: decimals,
    maximumFractionDigits: decimals,
  }) + ' %';
}

export function fmtDate(d) {
  if (!d) return '—';
  const date = new Date(d);
  return date.toLocaleDateString('sv-SE');
}

// ── Escape ──
export function esc(s) {
  return String(s || '')
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;');
}

// ── Datum ──
export function today() {
  return new Date().toISOString().slice(0, 10);
}

export function now() {
  return new Date();
}

export function curPeriod() {
  const d = new Date();
  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}`;
}

// ── Period-hjälpare ──
export function pLabel(p) {
  if (!p) return '—';
  if (/^Q[1-4]-\d{4}$/.test(p)) {
    const q = p[1];
    const y = p.split('-')[1];
    return `Q${q} ${['Jan–Mar', 'Apr–Jun', 'Jul–Sep', 'Okt–Dec'][q - 1]} ${y}`;
  }
  if (p.includes(':')) {
    const [a, b] = p.split(':');
    return `${pLabel(a)} → ${pLabel(b)}`;
  }
  const [y, m] = p.split('-');
  return `${MN[parseInt(m) - 1]} ${y}`;
}

export function pParam(p) {
  if (!p) return '';
  if (/^Q[1-4]-\d{4}$/.test(p)) {
    const q = parseInt(p[1]) - 1;
    const y = p.split('-')[1];
    return `&period_from=${y}-${String(q * 3 + 1).padStart(2, '0')}&period_to=${y}-${String(q * 3 + 3).padStart(2, '0')}`;
  }
  if (p.includes(':')) {
    const [f, t] = p.split(':');
    return `&period_from=${f}&period_to=${t}`;
  }
  return `&period=${p}`;
}

// ── Konto-hjälpare ──
export function acname(a) {
  return a?.account_name || a?.name || '';
}

export function fbal(a) {
  return parseFloat(a?.balance || 0);
}

export function fdeb(a) {
  return parseFloat(a?.total_debit || a?.debit || 0);
}

export function fcrd(a) {
  return parseFloat(a?.total_credit || a?.credit || 0);
}

// ── Kvitto-hjälpare ──
const EXPENSE_PFX = ['4', '5', '6'];
const PAYROLL_PFX = ['7'];
const INTERNAL_KW = ['omvänd skatt', 'moms', 'justering', 'stämning', 'rättelse', 'avskrivning', 'överbetald', 'kursvinst', 'kursförlust', 'kursdiff', 'ingående balans', 'period close', 'opening'];

export function needsReceipt(e) {
  if (e?.source_type === 'bank') return false;
  const desc = (e?.description || '').toLowerCase();
  if (INTERNAL_KW.some(k => desc.includes(k))) return false;
  const accts = (e?.lines || []).map(l => l?.account_number || '');
  return accts.some(a => EXPENSE_PFX.includes(a[0]) || PAYROLL_PFX.includes(a[0]));
}

export function rcptBadge(e) {
  if (!needsReceipt(e)) {
    return '<span style="font-size:.68rem;color:var(--muted)">☑ auto</span>';
  }
  const n = (e?.metadata?.receipts || []).length;
  return n > 0
    ? `<span style="font-size:.68rem;font-weight:700;color:var(--green)">✅ ${n} kvitto${n > 1 ? 'n' : ''}</span>`
    : '<span style="font-size:.68rem;font-weight:700;color:var(--red)">❌ Saknar</span>';
}

// ── DOM-hjälpare ──
export function $(id) {
  return document.getElementById(id);
}

export function $$$(selector, context = document) {
  return context.querySelector(selector);
}

export function $$$(selector, context = document) {
  return Array.from(context.querySelectorAll(selector));
}

export function empty(el) {
  if (typeof el === 'string') el = $(el);
  if (el) el.innerHTML = '';
}

export function show(el) {
  if (typeof el === 'string') el = $(el);
  if (el) el.style.display = '';
}

export function hide(el) {
  if (typeof el === 'string') el = $(el);
  if (el) el.style.display = 'none';
}

// ── Event-hjälpare ──
export function on(el, event, fn) {
  if (typeof el === 'string') el = $(el);
  if (el) el.addEventListener(event, fn);
}

export function off(el, event, fn) {
  if (typeof el === 'string') el = $(el);
  if (el) el.removeEventListener(event, fn);
}

// ── Debounce ──
export function debounce(fn, ms) {
  let t;
  return (...args) => {
    clearTimeout(t);
    t = setTimeout(() => fn(...args), ms);
  };
}

// ── Throttle ──
export function throttle(fn, ms) {
  let last = 0;
  return (...args) => {
    const now = Date.now();
    if (now - last >= ms) {
      last = now;
      fn(...args);
    }
  };
}

// ── LocalStorage ──
export function lsGet(key, fallback = null) {
  try {
    const v = localStorage.getItem(`landvex:${key}`);
    return v ? JSON.parse(v) : fallback;
  } catch {
    return fallback;
  }
}

export function lsSet(key, value) {
  try {
    localStorage.setItem(`landvex:${key}`, JSON.stringify(value));
  } catch { /* ignore */ }
}

// ── Download helper ──
export function downloadBlob(blob, filename) {
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = filename;
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
}

export function downloadText(text, filename, type = 'text/plain') {
  const blob = new Blob([text], { type });
  downloadBlob(blob, filename);
}