import { renderEmployees } from './employees.js';
import { renderCalendar } from './calendar.js';
import { renderDataTab } from './history.js';
import { normalizeEmployees } from './data.js';

const STORAGE_KEY = 'morning-planner-state';

// Shared mutable state — imported by all other modules
export const state = {
  employees: [],
  calendar: { holidays: [], companyClosures: [] },
  history: [],
  settings: { moderatorsPerDay: 1 }
};

// Load persisted state from localStorage on startup
try {
  const saved = localStorage.getItem(STORAGE_KEY);
  if (saved) {
    const parsed = JSON.parse(saved);
    if (Array.isArray(parsed.employees)) state.employees = normalizeEmployees(parsed.employees);
    if (parsed.calendar) state.calendar = parsed.calendar;
    if (Array.isArray(parsed.history)) state.history = parsed.history;
    if (parsed.settings && Number.isInteger(parsed.settings.moderatorsPerDay)
        && parsed.settings.moderatorsPerDay >= 1 && parsed.settings.moderatorsPerDay <= 5) {
      state.settings = { moderatorsPerDay: parsed.settings.moderatorsPerDay };
    }
  }
} catch {
  // Corrupt storage — start fresh
}

// Persist immediately. Used by the debounced saveState and the flush handlers.
let storageWarned = false;
let saveTimer = null;
function writeState() {
  if (saveTimer !== null) { clearTimeout(saveTimer); saveTimer = null; }
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify({
      employees: state.employees,
      calendar: state.calendar,
      history: state.history,
      settings: state.settings
    }));
  } catch (e) {
    // Storage full or unavailable — warn once so the user can react (export data)
    console.warn('Speichern in localStorage fehlgeschlagen:', e);
    if (!storageWarned) {
      storageWarned = true;
      alert('Achtung: Änderungen konnten nicht gespeichert werden ' +
        '(Speicher voll oder nicht verfügbar). Bitte exportiere deine Daten ' +
        'als JSON, um Datenverlust zu vermeiden.');
    }
  }
}

// Call after any state mutation. Debounced to coalesce rapid changes; a pending
// write is flushed on page hide/unload so the last change is never lost.
export function saveState() {
  if (saveTimer !== null) clearTimeout(saveTimer);
  saveTimer = setTimeout(writeState, 400);
}

const flushPending = () => { if (saveTimer !== null) writeState(); };
window.addEventListener('beforeunload', flushPending);
document.addEventListener('visibilitychange', () => {
  if (document.visibilityState === 'hidden') flushPending();
});

// Tab switching
document.querySelectorAll('.tab-btn').forEach(btn => {
  btn.addEventListener('click', () => {
    const tab = btn.dataset.tab;
    document.querySelectorAll('.tab-btn').forEach(b => b.classList.remove('active'));
    document.querySelectorAll('.tab-content').forEach(s => s.classList.add('hidden'));
    btn.classList.add('active');
    document.getElementById('tab-' + tab).classList.remove('hidden');
    if (tab === 'planning') renderCalendar();
    if (tab === 'data') renderDataTab();
  });
});

renderEmployees();