const KEYS = {
  data:     "wbjw_data",
  evRows:   "ev_voortgang_rows",
  users:    "wbjw_users",
  exitplan: "exitplan_data",
  // Weergavevoorkeuren: per browser, net als de kolombreedtes. Ze staan bewust
  // los van de financiële data, dus ze gaan niet mee in de backup-ZIP.
  thema:    "vibefinance_thema",
  darkMode: "vibefinance_darkmode",
};

export function loadFromStorage(key) {
  try {
    const raw = localStorage.getItem(KEYS[key] ?? key);
    return raw ? JSON.parse(raw) : null;
  } catch { return null; }
}

export function saveToStorage(key, value) {
  try { localStorage.setItem(KEYS[key] ?? key, JSON.stringify(value)); } catch {}
}

export function clearStorage(key) {
  try { localStorage.removeItem(KEYS[key] ?? key); } catch {}
}

/** Exporteer alle data als JSON-backup blob */
export function buildBackup() {
  return {
    wbjw_data:          localStorage.getItem(KEYS.data),
    ev_voortgang_rows:  localStorage.getItem(KEYS.evRows),
    wbjw_users:         localStorage.getItem(KEYS.users),
    exitplan_data:      localStorage.getItem(KEYS.exitplan),
    datum:              new Date().toISOString(),
    versie:             "2.0",
  };
}

/** Herstel een backup-object naar localStorage */
export function restoreBackup(backup) {
  if (backup.wbjw_data)         localStorage.setItem(KEYS.data,     backup.wbjw_data);
  if (backup.ev_voortgang_rows) localStorage.setItem(KEYS.evRows,   backup.ev_voortgang_rows);
  if (backup.wbjw_users)        localStorage.setItem(KEYS.users,    backup.wbjw_users);
  if (backup.exitplan_data)     localStorage.setItem(KEYS.exitplan, backup.exitplan_data);
}

/** Migreer oud schuld-formaat naar blokken-formaat */
export function migrateData(parsed) {
  if (parsed.schuld && !parsed.schuld.blokken) {
    const h  = parsed.schuld.hypotheek       || {};
    const b  = parsed.schuld.belastingdienst || {};
    const ex = parsed.schuld.extra           || [];
    parsed.schuld.blokken = [
      {
        id: "s1", naam: "Hypotheek", color: "#ef4444",
        items: Object.entries({
          deel1: "Leningdeel 1", deel2: "Leningdeel 2",
          deel3: "Leningdeel 3", deel4: "Leningdeel 4",
          deel5: "Sub-categorie 5",
        }).map(([k, n], i) => ({ id: `s1i${i + 1}`, naam: n, waarde: h[k] || 0 })),
      },
      {
        id: "s2", naam: "Belastingdienst", color: "#f97316",
        items: Object.entries({
          sub1: "Kinderopvangtoeslag", sub2: "Sub-categorie 2",
          sub3: "Sub-categorie 3",    sub4: "Sub-categorie 4",
          sub5: "Sub-categorie 5",
        }).map(([k, n], i) => ({ id: `s2i${i + 1}`, naam: n, waarde: b[k] || 0 })),
      },
      ...ex.map((cat, ci) => ({ ...cat, id: `s${ci + 3}` })),
    ];
    delete parsed.schuld.hypotheek;
    delete parsed.schuld.belastingdienst;
    delete parsed.schuld.extra;
  }
  if (!parsed.schuld.schuldHistory)  parsed.schuld.schuldHistory  = [];
  if (!parsed.schuld.initieleSchuld) parsed.schuld.initieleSchuld = 303000;
  return parsed;
}