const VIEW_ROUTES = Object.freeze({
  dashboard: '/dashboard',
  devices: '/devices',
  zones: '/zones',
  groups: '/groups',
  schedules: '/schedules',
  automations: '/automations',
  flows: '/flows',
  simulation: '/simulation',
  night: '/night-mode',
  homeassistant: '/home-assistant',
  settings: '/settings',
  logs: '/events',
});
const ROUTE_VIEWS = Object.freeze(Object.fromEntries(Object.entries(VIEW_ROUTES).map(([view, path]) => [path, view])));
const HISTORY_TABS = Object.freeze(['overview', 'zones', 'devices', 'sensors', 'custom']);
let routerInitialized = false;

function currentHistoryPath() {
  const tab = HISTORY_TABS.includes(app.historyTab) ? app.historyTab : 'overview';
  const params = new URLSearchParams();
  const hours = $('#historyHours')?.value || new URLSearchParams(location.search).get('hours') || '24';
  if (hours !== '24') params.set('hours', hours);
  if (tab === 'zones' && app.historyZone !== 'all') params.set('zone', app.historyZone);
  if (tab === 'devices' && app.historyDevice !== 'all') params.set('device', app.historyDevice);
  if (tab === 'sensors' && app.historySensor !== 'all') params.set('sensor', app.historySensor);
  if (tab === 'custom' && app.customChartSeries.length) params.set('chart', encodeChartSpec(app.customChartSeries));
  const query = params.toString();
  return `/history/${tab}${query ? `?${query}` : ''}`;
}

function pathForView(name) {
  return name === 'history' ? currentHistoryPath() : (VIEW_ROUTES[name] || VIEW_ROUTES.dashboard);
}

function appRelativePath(pathname = location.pathname) {
  if (!APP_BASE) return pathname || '/';
  if (pathname === APP_BASE) return '/';
  if (pathname.startsWith(`${APP_BASE}/`)) return pathname.slice(APP_BASE.length) || '/';
  return pathname || '/';
}

function updateBrowserUrl(path, replace = false) {
  const normalized = path.startsWith('/') ? path : `/${path}`;
  const target = `${APP_BASE}${normalized}` || normalized;
  const current = `${location.pathname}${location.search}`;
  if (current === target) return;
  history[replace ? 'replaceState' : 'pushState']({}, '', target);
}

function restoreCurrentRoute(previousView) {
  updateBrowserUrl(previousView === 'history' ? currentHistoryPath() : pathForView(previousView), true);
}

function applyRouteFromLocation() {
  const routePath = appRelativePath();
  const parts = routePath.split('/').filter(Boolean);
  const first = parts[0] || 'dashboard';
  const params = new URLSearchParams(location.search);
  const previousView = app.currentView;

  app.standaloneSimulation = first === 'simulation' && params.get('standalone') === '1';
  document.body.classList.toggle('simulation-standalone', app.standaloneSimulation);

  if (first === 'simulation') {
    app.simulationScope = ['units', 'groups'].includes(params.get('scope')) ? params.get('scope') : 'units';
    app.simulationTarget = params.get('target') || 'all';
  }

  if (first === 'history') {
    app.historyTab = HISTORY_TABS.includes(parts[1]) ? parts[1] : 'overview';
    app.historyZone = params.get('zone') || 'all';
    app.historyDevice = params.get('device') || 'all';
    app.historySensor = params.get('sensor') || 'all';
    const hours = params.get('hours');
    if (hours && ['6', '24', '168', '720', '2160', '8760'].includes(hours) && $('#historyHours')) $('#historyHours').value = hours;
    if (app.historyTab === 'custom' && params.get('chart')) app.customChartSeries = decodeChartSpec(params.get('chart'));
    if (!showView('history', { push: false, scroll: false })) restoreCurrentRoute(previousView);
    return;
  }

  const view = first === 'index.html' ? 'dashboard' : ROUTE_VIEWS[`/${first}`];
  if (!showView(view || 'dashboard', { push: false, scroll: false })) {
    restoreCurrentRoute(previousView);
    return;
  }

  if (first === 'flows') {
    if (parts[1]) requestAnimationFrame(() => openFlowEditor(parts[1] === 'new' ? '' : parts[1], { push: false }));
    else if (!$('#flowEditor')?.hidden) closeFlowEditor({ push: false, force: true });
  }
  if (!parts.length || first === 'index.html') updateBrowserUrl(VIEW_ROUTES.dashboard, true);
}

function initRouter() {
  if (!routerInitialized) {
    window.addEventListener('popstate', applyRouteFromLocation);
    routerInitialized = true;
  }
  applyRouteFromLocation();
}