// ============================================
// STATE & VARIABLES
// ============================================
let currentEditingId = null;
let datePicker = null;
let startTimePicker = null;
let endTimePicker = null;
let filterFromPicker = null;
let filterToPicker = null;
let manualStartTimePicker = null;

// Timer state
let timerInterval = null;
let timerStartTime = null;
let timerPausedDuration = 0; // Total paused time in seconds
let isPaused = false;
let pauseTimeout = null;
let currentEntryId = null; // ID of today's entry being timed

// Current month display state
let displayYear = new Date().getFullYear();
let displayMonth = new Date().getMonth(); // 0-11

// Current view state
let currentView = 'monthly'; // 'monthly' or 'filter'
let currentFilterFrom = null;
let currentFilterTo = null;

// Bulk edit state
let bulkEditMode = false;
let selectedEntries = new Set();

// Settings state
let currentBundesland = 'BW'; // Default: Baden-Württemberg
let totalVacationDays = 30; // Default vacation days per year

// ============================================
// UTILITY FUNCTIONS
// ============================================

/**
 * Format date from YYYY-MM-DD to DD.MM.YYYY
 */
function formatDateDisplay(dateStr) {
  const [year, month, day] = dateStr.split('-');
  return `${day}.${month}.${year}`;
}

/**
 * Format date from DD.MM.YYYY to YYYY-MM-DD
 */
function formatDateISO(dateStr) {
  const [day, month, year] = dateStr.split('.');
  return `${year}-${month}-${day}`;
}

/**
 * Get today's date in YYYY-MM-DD format
 */
function getTodayISO() {
  const today = new Date();
  const year = today.getFullYear();
  const month = String(today.getMonth() + 1).padStart(2, '0');
  const day = String(today.getDate()).padStart(2, '0');
  return `${year}-${month}-${day}`;
}

/**
 * Round time down to nearest 15 minutes
 */
function roundDownTo15Min(date) {
  const minutes = date.getMinutes();
  const roundedMinutes = Math.floor(minutes / 15) * 15;
  date.setMinutes(roundedMinutes);
  date.setSeconds(0);
  date.setMilliseconds(0);
  return date;
}

/**
 * Round time up to nearest 15 minutes
 */
function roundUpTo15Min(date) {
  const minutes = date.getMinutes();
  const roundedMinutes = Math.ceil(minutes / 15) * 15;
  date.setMinutes(roundedMinutes);
  date.setSeconds(0);
  date.setMilliseconds(0);
  return date;
}

/**
 * Format time as HH:MM
 */
function formatTime(date) {
  const hours = String(date.getHours()).padStart(2, '0');
  const minutes = String(date.getMinutes()).padStart(2, '0');
  return `${hours}:${minutes}`;
}

/**
 * Format seconds to HH:MM:SS
 */
function formatDuration(seconds) {
  const hrs = Math.floor(seconds / 3600);
  const mins = Math.floor((seconds % 3600) / 60);
  const secs = seconds % 60;
  return `${String(hrs).padStart(2, '0')}:${String(mins).padStart(2, '0')}:${String(secs).padStart(2, '0')}`;
}

/**
 * Show toast notification
 */
function showNotification(message, type = 'info') {
  const container = document.getElementById('toastContainer');
  
  // Create toast element
  const toast = document.createElement('div');
  toast.className = `toast toast-${type}`;
  
  // Icon based on type
  const icons = {
    success: '✓',
    error: '✕',
    info: 'ℹ'
  };
  
  toast.innerHTML = `
    <span class="toast-icon">${icons[type] || 'ℹ'}</span>
    <span>${message}</span>
  `;
  
  container.appendChild(toast);
  
  // Auto-remove after 3 seconds
  setTimeout(() => {
    toast.classList.add('hiding');
    setTimeout(() => {
      container.removeChild(toast);
    }, 300);
  }, 3000);
}

/**
 * Get day of week abbreviation in German
 */
function getDayOfWeek(date) {
  const days = ['So', 'Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa'];
  return days[date.getDay()];
}

/**
 * Check if date is weekend
 */
function isWeekend(date) {
  const day = date.getDay();
  return day === 0 || day === 6; // Sunday or Saturday
}

/**
 * Calculate Easter Sunday for a given year (Gauss algorithm)
 */
function getEasterSunday(year) {
  const a = year % 19;
  const b = Math.floor(year / 100);
  const c = year % 100;
  const d = Math.floor(b / 4);
  const e = b % 4;
  const f = Math.floor((b + 8) / 25);
  const g = Math.floor((b - f + 1) / 3);
  const h = (19 * a + b - d - g + 15) % 30;
  const i = Math.floor(c / 4);
  const k = c % 4;
  const l = (32 + 2 * e + 2 * i - h - k) % 7;
  const m = Math.floor((a + 11 * h + 22 * l) / 451);
  const month = Math.floor((h + l - 7 * m + 114) / 31);
  const day = ((h + l - 7 * m + 114) % 31) + 1;
  return new Date(year, month - 1, day);
}

/**
 * Get all public holidays for a given year and Bundesland
 */
function getPublicHolidays(year, bundesland = currentBundesland) {
  const holidays = [];
  
  // Fixed holidays (all states)
  holidays.push({ date: new Date(year, 0, 1), name: 'Neujahr' });
  holidays.push({ date: new Date(year, 4, 1), name: 'Tag der Arbeit' });
  holidays.push({ date: new Date(year, 9, 3), name: 'Tag der Deutschen Einheit' });
  holidays.push({ date: new Date(year, 11, 25), name: '1. Weihnachtstag' });
  holidays.push({ date: new Date(year, 11, 26), name: '2. Weihnachtstag' });
  
  // Heilige Drei Könige (BW, BY, ST)
  if (['BW', 'BY', 'ST'].includes(bundesland)) {
    holidays.push({ date: new Date(year, 0, 6), name: 'Heilige Drei Könige' });
  }
  
  // Internationaler Frauentag (BE, MV since 2023)
  if (['BE'].includes(bundesland) || (bundesland === 'MV' && year >= 2023)) {
    holidays.push({ date: new Date(year, 2, 8), name: 'Internationaler Frauentag' });
  }
  
  // Weltkindertag (TH since 2019)
  if (bundesland === 'TH' && year >= 2019) {
    holidays.push({ date: new Date(year, 8, 20), name: 'Weltkindertag' });
  }
  
  // Reformationstag (BB, MV, SN, ST, TH, + HB, HH, NI, SH since 2018)
  const reformationstagStates = ['BB', 'MV', 'SN', 'ST', 'TH'];
  if (year >= 2018) {
    reformationstagStates.push('HB', 'HH', 'NI', 'SH');
  }
  if (reformationstagStates.includes(bundesland)) {
    holidays.push({ date: new Date(year, 9, 31), name: 'Reformationstag' });
  }
  
  // Allerheiligen (BW, BY, NW, RP, SL)
  if (['BW', 'BY', 'NW', 'RP', 'SL'].includes(bundesland)) {
    holidays.push({ date: new Date(year, 10, 1), name: 'Allerheiligen' });
  }
  
  // Buß- und Bettag (only SN)
  if (bundesland === 'SN') {
    // Buß- und Bettag is the Wednesday before November 23
    let bussbettag = new Date(year, 10, 23);
    while (bussbettag.getDay() !== 3) { // 3 = Wednesday
      bussbettag.setDate(bussbettag.getDate() - 1);
    }
    bussbettag.setDate(bussbettag.getDate() - 7); // One week before
    holidays.push({ date: bussbettag, name: 'Buß- und Bettag' });
  }
  
  // Easter-dependent holidays
  const easter = getEasterSunday(year);
  
  // Karfreitag (Good Friday) - 2 days before Easter (all states)
  const goodFriday = new Date(easter);
  goodFriday.setDate(easter.getDate() - 2);
  holidays.push({ date: goodFriday, name: 'Karfreitag' });
  
  // Ostermontag (Easter Monday) - 1 day after Easter (all states)
  const easterMonday = new Date(easter);
  easterMonday.setDate(easter.getDate() + 1);
  holidays.push({ date: easterMonday, name: 'Ostermontag' });
  
  // Christi Himmelfahrt (Ascension Day) - 39 days after Easter (all states)
  const ascension = new Date(easter);
  ascension.setDate(easter.getDate() + 39);
  holidays.push({ date: ascension, name: 'Christi Himmelfahrt' });
  
  // Pfingstmontag (Whit Monday) - 50 days after Easter (all states)
  const whitMonday = new Date(easter);
  whitMonday.setDate(easter.getDate() + 50);
  holidays.push({ date: whitMonday, name: 'Pfingstmontag' });
  
  // Fronleichnam (Corpus Christi) - 60 days after Easter (BW, BY, HE, NW, RP, SL, + some communities in SN, TH)
  if (['BW', 'BY', 'HE', 'NW', 'RP', 'SL'].includes(bundesland)) {
    const corpusChristi = new Date(easter);
    corpusChristi.setDate(easter.getDate() + 60);
    holidays.push({ date: corpusChristi, name: 'Fronleichnam' });
  }
  
  // Mariä Himmelfahrt (Assumption of Mary) - August 15 (BY in some communities, SL)
  if (['SL'].includes(bundesland)) {
    holidays.push({ date: new Date(year, 7, 15), name: 'Mariä Himmelfahrt' });
  }
  
  return holidays;
}

/**
 * Check if date is a public holiday
 * Returns the holiday name or null
 */
function getHolidayName(date) {
  const year = date.getFullYear();
  const holidays = getPublicHolidays(year, currentBundesland);
  
  const dateStr = date.toISOString().split('T')[0];
  const holiday = holidays.find(h => {
    return h.date.toISOString().split('T')[0] === dateStr;
  });
  
  return holiday ? holiday.name : null;
}

/**
 * Check if date is a public holiday in Baden-Württemberg
 */
function isPublicHoliday(date) {
  return getHolidayName(date) !== null;
}

/**
 * Check if date is weekend or public holiday
 */
function isWeekendOrHoliday(date) {
  return isWeekend(date) || isPublicHoliday(date);
}

/**
 * Get month name in German
 */
function getMonthName(month) {
  const months = [
    'Januar', 'Februar', 'März', 'April', 'Mai', 'Juni',
    'Juli', 'August', 'September', 'Oktober', 'November', 'Dezember'
  ];
  return months[month];
}

/**
 * Update month display
 */
function updateMonthDisplay() {
  const monthName = getMonthName(displayMonth);
  const displayText = `${monthName} ${displayYear}`;
  document.getElementById('currentMonthDisplay').textContent = displayText;
  
  // Always show next month button (allow navigation to future)
  const nextBtn = document.getElementById('btnNextMonth');
  nextBtn.style.visibility = 'visible';
}

/**
 * Navigate to previous month
 */
function handlePrevMonth() {
  if (displayMonth === 0) {
    displayMonth = 11;
    displayYear--;
  } else {
    displayMonth--;
  }
  loadMonthlyView();
}

/**
 * Navigate to next month
 */
function handleNextMonth() {
  // Allow navigation to future months
  if (displayMonth === 11) {
    displayMonth = 0;
    displayYear++;
  } else {
    displayMonth++;
  }
  loadMonthlyView();
}

// ============================================
// TIMER FUNCTIONS
// ============================================

/**
 * Check if timer is running (on page load)
 */
async function checkRunningTimer() {
  const today = getTodayISO();
  const entries = await fetchEntries(today, today);
  
  if (entries.length > 0) {
    const todayEntry = entries[0];
    // Check if entry has start but same start and end (running timer)
    if (todayEntry.startTime === todayEntry.endTime) {
      // Timer is running
      currentEntryId = todayEntry.id;
      
      // Calculate start time from DB
      const [hours, minutes] = todayEntry.startTime.split(':').map(Number);
      const startDate = new Date();
      startDate.setHours(hours, minutes, 0, 0);
      timerStartTime = startDate.getTime();
      
      // Update UI
      const startBtn = document.getElementById('btnStartWork');
      const stopBtn = document.getElementById('btnStopWork');
      startBtn.disabled = true;
      startBtn.classList.add('opacity-50', 'cursor-not-allowed');
      startBtn.classList.remove('hover:bg-green-700');
      stopBtn.disabled = false;
      stopBtn.classList.remove('opacity-50', 'cursor-not-allowed');
      stopBtn.classList.add('hover:bg-red-700');
      document.getElementById('timerStatus').textContent = 'Läuft seit ' + todayEntry.startTime;
      document.getElementById('timerStatus').classList.remove('cursor-pointer', 'underline', 'hover:text-blue-300');
      document.getElementById('timerStatus').classList.add('cursor-default');
      
      // Start timer interval
      timerInterval = setInterval(updateTimer, 1000);
      updateTimer(); // Immediate update
      
      // Schedule automatic pauses
      const elapsed = Date.now() - timerStartTime;
      schedulePausesWithOffset(elapsed);
    }
  }
}

/**
 * Start work timer
 */
async function startWork() {
  const now = new Date();
  const roundedStart = roundDownTo15Min(new Date(now));
  const startTime = formatTime(roundedStart);
  const today = getTodayISO();
  
  // Create entry with same start and end time (indicates running)
  const entry = await createEntry(formatDateDisplay(today), startTime, startTime, null);
  
  if (!entry) {
    return;
  }
  
  currentEntryId = entry.id;
  timerStartTime = roundedStart.getTime();
  timerPausedDuration = 0;
  isPaused = false;
  
  // Update UI
  const startBtn = document.getElementById('btnStartWork');
  const stopBtn = document.getElementById('btnStopWork');
  startBtn.disabled = true;
  startBtn.classList.add('opacity-50', 'cursor-not-allowed');
  startBtn.classList.remove('hover:bg-green-700');
  stopBtn.disabled = false;
  stopBtn.classList.remove('opacity-50', 'cursor-not-allowed');
  stopBtn.classList.add('hover:bg-red-700');
  document.getElementById('timerStatus').textContent = 'Läuft seit ' + startTime;
  document.getElementById('timerStatus').classList.remove('cursor-pointer', 'underline', 'hover:text-blue-300');
  document.getElementById('timerStatus').classList.add('cursor-default');
  
  // Start timer interval
  timerInterval = setInterval(updateTimer, 1000);
  
  // Schedule automatic pauses
  schedulePausesWithOffset(0);
  
  // Reload view to show entry
  loadMonthlyView();
}

/**
 * Stop work timer
 */
async function stopWork() {
  if (!currentEntryId) {
    return;
  }
  
  clearInterval(timerInterval);
  if (pauseTimeout) clearTimeout(pauseTimeout);
  
  const now = new Date();
  const roundedEnd = roundUpTo15Min(new Date(now));
  const endTime = formatTime(roundedEnd);
  const today = getTodayISO();
  
  // Fetch the entry to get start time
  const entries = await fetchEntries(today, today);
  const entry = entries.find(e => e.id === currentEntryId);
  
  if (entry) {
    // Update entry with end time
    await updateEntry(currentEntryId, formatDateDisplay(today), entry.startTime, endTime, null);
  }
  
  // Reset timer state
  currentEntryId = null;
  timerStartTime = null;
  timerPausedDuration = 0;
  isPaused = false;
  
  // Update UI
  const startBtn = document.getElementById('btnStartWork');
  const stopBtn = document.getElementById('btnStopWork');
  startBtn.disabled = false;
  startBtn.classList.remove('opacity-50', 'cursor-not-allowed');
  startBtn.classList.add('hover:bg-green-700');
  stopBtn.disabled = true;
  stopBtn.classList.add('opacity-50', 'cursor-not-allowed');
  stopBtn.classList.remove('hover:bg-red-700');
  document.getElementById('timerDisplay').textContent = '00:00:00';
  document.getElementById('timerStatus').textContent = 'Nicht gestartet';
  document.getElementById('timerStatus').classList.add('cursor-pointer', 'underline', 'hover:text-blue-300');
  document.getElementById('timerStatus').classList.remove('cursor-default');
  
  // Reload monthly view
  loadMonthlyView();
}

/**
 * Update timer display
 */
function updateTimer() {
  if (!timerStartTime) return;
  
  const elapsed = Math.floor((Date.now() - timerStartTime) / 1000) - timerPausedDuration;
  document.getElementById('timerDisplay').textContent = formatDuration(elapsed);
}

/**
 * Schedule automatic pauses at 6h and 9h with offset for existing elapsed time
 */
function schedulePausesWithOffset(elapsedMs) {
  const sixHoursMs = 6 * 60 * 60 * 1000;
  const nineHoursMs = 9 * 60 * 60 * 1000;
  
  // Pause at 6 hours for 30 minutes
  if (elapsedMs < sixHoursMs) {
    setTimeout(() => {
      if (timerStartTime && !isPaused) {
        pauseTimer(30 * 60); // 30 minutes
        showNotification('⏸️ Automatische Pause: 30 Minuten (nach 6 Stunden)', 'info');
      }
    }, sixHoursMs - elapsedMs);
  }
  
  // Additional pause at 9 hours for 15 minutes
  if (elapsedMs < nineHoursMs) {
    setTimeout(() => {
      if (timerStartTime && !isPaused) {
        pauseTimer(15 * 60); // 15 minutes
        showNotification('⏸️ Automatische Pause: 15 Minuten (nach 9 Stunden)', 'info');
      }
    }, nineHoursMs - elapsedMs);
  }
}

/**
 * Pause timer for specified duration
 */
function pauseTimer(durationSeconds) {
  isPaused = true;
  document.getElementById('timerStatus').textContent = `Pause (${Math.floor(durationSeconds / 60)} Min)...`;
  
  pauseTimeout = setTimeout(() => {
    timerPausedDuration += durationSeconds;
    isPaused = false;
    document.getElementById('timerStatus').textContent = 'Läuft...';
  }, durationSeconds * 1000);
}

/**
 * Fetch entries from the backend
 */
async function fetchEntries(fromDate = null, toDate = null) {
  try {
    let url = '/api/entries';
    const params = new URLSearchParams();
    
    if (fromDate) params.append('from', fromDate);
    if (toDate) params.append('to', toDate);
    
    if (params.toString()) {
      url += '?' + params.toString();
    }
    
    const response = await fetch(url);
    
    if (!response.ok) {
      throw new Error('Failed to fetch entries');
    }
    
    const entries = await response.json();
    return entries;
  } catch (error) {
    console.error('Error fetching entries:', error);
    showNotification('Fehler beim Laden der Einträge', 'error');
    return [];
  }
}

/**
 * Create a new entry
 */
async function createEntry(date, startTime, endTime, pauseMinutes, location) {
  try {
    const body = {
      date: formatDateISO(date),
      startTime,
      endTime,
      location: location || 'office'
    };
    
    // Only include pauseMinutes if explicitly provided (not empty)
    if (pauseMinutes !== null && pauseMinutes !== undefined && pauseMinutes !== '') {
      body.pauseMinutes = parseInt(pauseMinutes);
    }
    
    const response = await fetch('/api/entries', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify(body)
    });
    
    if (!response.ok) {
      const error = await response.json();
      throw new Error(error.error || 'Failed to create entry');
    }
    
    const entry = await response.json();
    return entry;
  } catch (error) {
    console.error('Error creating entry:', error);
    showNotification(error.message || 'Fehler beim Erstellen des Eintrags', 'error');
    return null;
  }
}

/**
 * Update an existing entry
 */
async function updateEntry(id, date, startTime, endTime, pauseMinutes, location) {
  try {
    const body = {
      date: formatDateISO(date),
      startTime,
      endTime,
      location: location || 'office'
    };
    
    // Only include pauseMinutes if explicitly provided (not empty)
    if (pauseMinutes !== null && pauseMinutes !== undefined && pauseMinutes !== '') {
      body.pauseMinutes = parseInt(pauseMinutes);
    }
    
    const response = await fetch(`/api/entries/${id}`, {
      method: 'PUT',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify(body)
    });
    
    if (!response.ok) {
      const error = await response.json();
      throw new Error(error.error || 'Failed to update entry');
    }
    
    const entry = await response.json();
    return entry;
  } catch (error) {
    console.error('Error updating entry:', error);
    showNotification(error.message || 'Fehler beim Aktualisieren des Eintrags', 'error');
    return null;
  }
}

/**
 * Delete an entry
 */
async function deleteEntry(id) {
  try {
    const response = await fetch(`/api/entries/${id}`, {
      method: 'DELETE'
    });
    
    if (!response.ok) {
      throw new Error('Failed to delete entry');
    }
    
    return true;
  } catch (error) {
    console.error('Error deleting entry:', error);
    showNotification('Fehler beim Löschen des Eintrags', 'error');
    return false;
  }
}

/**
 * Get a setting by key
 */
async function getSetting(key) {
  try {
    const response = await fetch(`/api/settings/${key}`);
    
    if (!response.ok) {
      if (response.status === 404) {
        return null; // Setting doesn't exist yet
      }
      throw new Error('Failed to get setting');
    }
    
    const data = await response.json();
    return data.value;
  } catch (error) {
    console.error('Error getting setting:', error);
    return null;
  }
}

/**
 * Set a setting
 */
async function setSetting(key, value) {
  try {
    const response = await fetch('/api/settings', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({ key, value })
    });
    
    if (!response.ok) {
      throw new Error('Failed to set setting');
    }
    
    return true;
  } catch (error) {
    console.error('Error setting setting:', error);
    showNotification('Fehler beim Speichern der Einstellung', 'error');
    return false;
  }
}

/**
 * Export entries as CSV
 */
async function exportEntries(fromDate = null, toDate = null) {
  try {
    let url = '/api/export';
    const params = new URLSearchParams();
    
    if (fromDate) params.append('from', fromDate);
    if (toDate) params.append('to', toDate);
    
    if (params.toString()) {
      url += '?' + params.toString();
    }
    
    const response = await fetch(url);
    
    if (!response.ok) {
      throw new Error('Failed to export entries');
    }
    
    const blob = await response.blob();
    const downloadUrl = window.URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = downloadUrl;
    a.download = 'zeiterfassung.csv';
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    window.URL.revokeObjectURL(downloadUrl);
    
    showNotification('Export erfolgreich', 'success');
  } catch (error) {
    console.error('Error exporting entries:', error);
    showNotification('Fehler beim Exportieren', 'error');
  }
}

// ============================================
// UI FUNCTIONS
// ============================================

/**
 * Render entries in the table
 */
function renderEntries(entries) {
  const tbody = document.getElementById('entriesTableBody');
  const emptyState = document.getElementById('emptyState');
  
  tbody.innerHTML = '';
  
  if (entries.length === 0) {
    emptyState.classList.remove('hidden');
    return;
  }
  
  emptyState.classList.add('hidden');
  
  entries.forEach(entry => {
    const row = document.createElement('tr');
    const dateObj = new Date(entry.date + 'T00:00:00');
    const dayOfWeek = getDayOfWeek(dateObj);
    const weekend = isWeekendOrHoliday(dateObj);
    const location = entry.location || 'office';
    
    // Row color based on location
    let rowClass = 'hover:bg-gray-700';
    if (location === 'home') {
      rowClass = 'hover:bg-green-900 bg-green-950';
    } else if (weekend) {
      rowClass = 'hover:bg-gray-700 bg-gray-700';
    }
    
    row.className = rowClass;
    row.dataset.id = entry.id;
    
    // Location icon and text
    const locationIcon = location === 'home' 
      ? '<i data-lucide="home" class="w-4 h-4 inline"></i>' 
      : '<i data-lucide="building-2" class="w-4 h-4 inline"></i>';
    const locationText = location === 'home' ? 'Home' : 'Büro';
    
    // Checkbox column (always present for consistent layout)
    const checkboxCell = bulkEditMode ? `
      <td class="px-2 py-4 whitespace-nowrap text-center">
        <input type="checkbox" class="entry-checkbox w-5 h-5 text-blue-600 bg-gray-700 border-gray-600 rounded focus:ring-blue-500" 
               data-id="${entry.id}" ${selectedEntries.has(entry.id) ? 'checked' : ''}>
      </td>
    ` : '<td class="hidden"></td>';
    
    row.innerHTML = checkboxCell + `
      <td class="px-2 py-4 whitespace-nowrap text-sm font-medium ${weekend ? 'text-blue-400' : 'text-gray-100'}">${dayOfWeek}</td>
      <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100">${formatDateDisplay(entry.date)}</td>
      <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100 editable-cell" 
          data-field="startTime" data-id="${entry.id}" data-value="${entry.startTime}">
        ${entry.startTime}
      </td>
      <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100 editable-cell" 
          data-field="endTime" data-id="${entry.id}" data-value="${entry.endTime}">
        ${entry.endTime}
      </td>
      <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100 editable-cell" 
          data-field="pauseMinutes" data-id="${entry.id}" data-value="${entry.pauseMinutes}">
        ${entry.pauseMinutes}
      </td>
      <td class="px-6 py-4 whitespace-nowrap text-sm font-semibold text-gray-100">${entry.netHours.toFixed(2)}</td>
      <td class="px-6 py-4 whitespace-nowrap text-sm text-center text-gray-100">
        <span class="text-lg">${locationIcon}</span> ${locationText}
      </td>
      <td class="px-6 py-4 whitespace-nowrap text-sm text-center">
        <div class="flex gap-2 justify-center">
          <button class="btn-edit inline-flex items-center justify-center w-8 h-8 text-blue-500 hover:text-blue-600 hover:bg-blue-500/10 rounded transition-all" data-id="${entry.id}" title="Bearbeiten">
            <i data-lucide="pencil" class="w-4 h-4"></i>
          </button>
          <button class="btn-delete inline-flex items-center justify-center w-8 h-8 text-red-500 hover:text-red-600 hover:bg-red-500/10 rounded transition-all" data-id="${entry.id}" title="Löschen">
            <i data-lucide="trash-2" class="w-4 h-4"></i>
          </button>
        </div>
      </td>
    `;
    
    tbody.appendChild(row);
  });
  
  // Reinitialize Lucide icons
  if (typeof lucide !== 'undefined') {
    lucide.createIcons();
  }
  
  // Add event listeners
  attachInlineEditListeners();
  
  document.querySelectorAll('.btn-edit').forEach(btn => {
    btn.addEventListener('click', async () => {
      const id = parseInt(btn.dataset.id);
      const entries = await fetchEntries();
      const entry = entries.find(e => e.id === id);
      if (entry) {
        openModal(entry);
      }
    });
  });
  
  document.querySelectorAll('.btn-delete').forEach(btn => {
    btn.addEventListener('click', () => handleDelete(parseInt(btn.dataset.id)));
  });
  
  // Checkbox event listeners for bulk edit
  document.querySelectorAll('.entry-checkbox').forEach(checkbox => {
    checkbox.addEventListener('change', () => {
      toggleEntrySelection(parseInt(checkbox.dataset.id));
    });
  });
}

/**
 * Render monthly view with all days
 */
function renderMonthlyView(entries) {
  const tbody = document.getElementById('entriesTableBody');
  const emptyState = document.getElementById('emptyState');
  
  tbody.innerHTML = '';
  emptyState.classList.add('hidden');
  
  const today = new Date();
  const todayYear = today.getFullYear();
  const todayMonth = today.getMonth();
  const todayDay = today.getDate();
  
  // Show all days of the month
  const lastDay = new Date(displayYear, displayMonth + 1, 0).getDate();
  
  // Create a map of entries by date
  const entriesMap = {};
  entries.forEach(entry => {
    entriesMap[entry.date] = entry;
  });
  
  // Render all days from 1st to lastDay
  for (let day = 1; day <= lastDay; day++) {
    const dateObj = new Date(displayYear, displayMonth, day);
    const dateISO = `${displayYear}-${String(displayMonth + 1).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
    const entry = entriesMap[dateISO];
    const dayOfWeek = getDayOfWeek(dateObj);
    const weekend = isWeekendOrHoliday(dateObj);
    
    // Check if this is today
    const isToday = dateISO === getTodayISO();
    
    const row = document.createElement('tr');
    
    if (entry) {
      // Day has entry
      const location = entry.location || 'office';
      const entryType = entry.entryType || 'work';
      
      // Row color based on entry type and location
      let rowClass = 'hover:bg-gray-700';
      if (entryType === 'vacation') {
        rowClass = 'hover:bg-yellow-900 bg-yellow-950';
      } else if (entryType === 'flextime') {
        rowClass = 'hover:bg-cyan-900 bg-cyan-950';
      } else if (location === 'home') {
        rowClass = 'hover:bg-green-900 bg-green-950';
      } else if (weekend) {
        rowClass = 'hover:bg-gray-700 bg-gray-700';
      }
      
      
      row.className = rowClass;
      row.dataset.id = entry.id;
      
      // Add inline border style for today
      if (isToday) {
        row.style.borderLeft = '4px solid #3b82f6'; // blue-500
      }
      
      // Icon and text based on entry type
      let displayIcon, displayText, displayTimes;
      if (entryType === 'vacation') {
        displayIcon = '<i data-lucide="plane" class="w-4 h-4 inline"></i>';
        displayText = 'Urlaub';
        displayTimes = `<td class="px-6 py-4 whitespace-nowrap text-sm text-center text-gray-400" colspan="3">
          <span class="italic">Urlaub</span>
        </td>`;
      } else if (entryType === 'flextime') {
        displayIcon = '<i data-lucide="clock" class="w-4 h-4 inline"></i>';
        displayText = 'Gleitzeit';
        displayTimes = `<td class="px-6 py-4 whitespace-nowrap text-sm text-center text-gray-400" colspan="3">
          <span class="italic">Gleittag (8h)</span>
        </td>`;
      } else {
        displayIcon = location === 'home' 
          ? '<i data-lucide="home" class="w-4 h-4 inline"></i>' 
          : '<i data-lucide="building-2" class="w-4 h-4 inline"></i>';
        displayText = location === 'home' ? 'Home' : 'Büro';
        
        // Check if timer is running (start == end time)
        const isTimerRunning = entry.startTime === entry.endTime;
        const endTimeDisplay = isTimerRunning 
          ? '<i data-lucide="clock" class="w-4 h-4 inline timer-running-icon"></i>'
          : entry.endTime;
        
        displayTimes = `
          <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100 editable-cell" 
              data-field="startTime" data-id="${entry.id}" data-value="${entry.startTime}">
            ${entry.startTime}
          </td>
          <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100 ${isTimerRunning ? '' : 'editable-cell'}" 
              ${isTimerRunning ? '' : `data-field="endTime" data-id="${entry.id}" data-value="${entry.endTime}"`}>
            ${endTimeDisplay}
          </td>
          <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100 editable-cell" 
              data-field="pauseMinutes" data-id="${entry.id}" data-value="${entry.pauseMinutes}">
            ${entry.pauseMinutes}
          </td>`;
      }
      
      // Checkbox column (always present for consistent layout)
      const checkboxCell = bulkEditMode ? `
        <td class="px-2 py-4 whitespace-nowrap text-center">
          <input type="checkbox" class="entry-checkbox w-5 h-5 text-blue-600 bg-gray-700 border-gray-600 rounded focus:ring-blue-500" 
                 data-id="${entry.id}" ${selectedEntries.has(entry.id) ? 'checked' : ''}>
        </td>
      ` : '<td class="hidden"></td>';
      
      row.innerHTML = checkboxCell + `
        <td class="px-2 py-4 whitespace-nowrap text-sm font-medium ${weekend ? 'text-blue-400' : 'text-gray-100'}">${dayOfWeek}</td>
        <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100">${formatDateDisplay(entry.date)}</td>
        ${displayTimes}
        <td class="px-6 py-4 whitespace-nowrap text-sm font-semibold text-gray-100">${entry.netHours.toFixed(2)}</td>
        <td class="px-6 py-4 whitespace-nowrap text-sm text-center text-gray-100">
          <span class="text-lg">${displayIcon}</span> ${displayText}
        </td>
        <td class="px-6 py-4 whitespace-nowrap text-sm text-center">
          <div class="flex gap-2 justify-center">
            ${entryType === 'work' ? `
              <button class="btn-edit inline-flex items-center justify-center w-8 h-8 text-blue-500 hover:text-blue-600 hover:bg-blue-500/10 rounded transition-all" data-id="${entry.id}" title="Bearbeiten">
                <i data-lucide="pencil" class="w-4 h-4"></i>
              </button>
            ` : ''}
            <button class="btn-delete inline-flex items-center justify-center w-8 h-8 text-red-500 hover:text-red-600 hover:bg-red-500/10 rounded transition-all" data-id="${entry.id}" title="Löschen">
              <i data-lucide="trash-2" class="w-4 h-4"></i>
            </button>
          </div>
        </td>
      `;
    } else {
      // Day has no entry - show add options
      const holidayName = getHolidayName(dateObj);
      const displayText = holidayName || 'Kein Eintrag';
      
      let emptyRowClass = weekend ? 'hover:bg-gray-700 bg-gray-700' : 'hover:bg-gray-700 bg-red-950/40';
      
      
      row.className = emptyRowClass;
      row.dataset.date = dateISO; // Store date for bulk operations
      
      // Add inline border style for today
      if (isToday) {
        row.style.borderLeft = '4px solid #3b82f6'; // blue-500
      }
      
      // Checkbox cell for empty days (in bulk edit mode)
      const checkboxCell = bulkEditMode ? `
        <td class="px-2 py-4 whitespace-nowrap text-center">
          <input type="checkbox" class="empty-day-checkbox w-5 h-5 text-blue-600 bg-gray-700 border-gray-600 rounded focus:ring-blue-500" 
                 data-date="${dateISO}" ${selectedEntries.has(dateISO) ? 'checked' : ''}>
        </td>
      ` : '<td class="hidden"></td>';
      const colspan = bulkEditMode ? '5' : '5';
      
      row.innerHTML = checkboxCell + `
        <td class="px-2 py-4 whitespace-nowrap text-sm font-medium ${weekend ? 'text-blue-400' : 'text-gray-100'}">${dayOfWeek}</td>
        <td class="px-6 py-4 whitespace-nowrap text-sm text-gray-100">${formatDateDisplay(dateISO)}</td>
        <td class="px-6 py-4 whitespace-nowrap text-sm ${holidayName ? 'text-blue-400 font-semibold' : 'text-gray-500'}" colspan="${colspan}">
          <span class="italic">${displayText}</span>
        </td>
        <td class="px-6 py-4 whitespace-nowrap text-sm text-center">
          <div class="flex gap-1 justify-center">
            <button class="btn-add-work inline-flex items-center justify-center w-7 h-7 text-indigo-500 hover:text-indigo-600 hover:bg-indigo-500/10 rounded transition-all" data-date="${dateISO}" title="Arbeit eintragen">
              <i data-lucide="plus" class="w-4 h-4"></i>
            </button>
            ${!weekend ? `
            <button class="btn-add-vacation inline-flex items-center justify-center w-7 h-7 text-amber-500 hover:text-amber-600 hover:bg-amber-500/10 rounded transition-all" data-date="${dateISO}" title="Urlaub eintragen">
              <i data-lucide="plane" class="w-4 h-4"></i>
            </button>
            <button class="btn-add-flextime inline-flex items-center justify-center w-7 h-7 text-cyan-500 hover:text-cyan-600 hover:bg-cyan-500/10 rounded transition-all" data-date="${dateISO}" title="Gleitzeit eintragen">
              <i data-lucide="clock" class="w-4 h-4"></i>
            </button>
            ` : ''}
          </div>
        </td>
      `;
    }
    
    tbody.appendChild(row);
  }
  
  // Reinitialize Lucide icons
  if (typeof lucide !== 'undefined') {
    lucide.createIcons();
  }

  // Add event listeners
  attachInlineEditListeners();
  
  document.querySelectorAll('.btn-edit').forEach(btn => {
    btn.addEventListener('click', async () => {
      const id = parseInt(btn.dataset.id);
      const entries = await fetchEntries();
      const entry = entries.find(e => e.id === id);
      if (entry) {
        openModal(entry);
      }
    });
  });
  
  document.querySelectorAll('.btn-delete').forEach(btn => {
    btn.addEventListener('click', () => handleDelete(parseInt(btn.dataset.id)));
  });
  
  // Add work entry for a specific date
  document.querySelectorAll('.btn-add-work').forEach(btn => {
    btn.addEventListener('click', () => {
      const dateISO = btn.dataset.date;
      openModalForDate(dateISO);
    });
  });
  
  // Add vacation entry for a specific date
  document.querySelectorAll('.btn-add-vacation').forEach(btn => {
    btn.addEventListener('click', async () => {
      const dateISO = btn.dataset.date;
      await addSpecialEntry(dateISO, 'vacation');
    });
  });
  
  // Add flextime entry for a specific date
  document.querySelectorAll('.btn-add-flextime').forEach(btn => {
    btn.addEventListener('click', async () => {
      const dateISO = btn.dataset.date;
      await addSpecialEntry(dateISO, 'flextime');
    });
  });
  
  // Checkbox event listeners for bulk edit (existing entries)
  document.querySelectorAll('.entry-checkbox').forEach(checkbox => {
    checkbox.addEventListener('change', () => {
      toggleEntrySelection(parseInt(checkbox.dataset.id));
    });
  });
  
  // Checkbox event listeners for bulk edit (empty days)
  document.querySelectorAll('.empty-day-checkbox').forEach(checkbox => {
    checkbox.addEventListener('change', () => {
      toggleEmptyDaySelection(checkbox.dataset.date);
    });
  });
}

/**
 * Add a special entry (vacation or flextime) for a specific date
 */
async function addSpecialEntry(dateISO, entryType) {
  const typeName = entryType === 'vacation' ? 'Urlaub' : 'Gleittag';
  
  if (!confirm(`${typeName} für ${formatDateDisplay(dateISO)} eintragen?`)) {
    return;
  }
  
  try {
    const response = await fetch('/api/entries', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        date: dateISO,
        entryType: entryType
      })
    });
    
    if (!response.ok) {
      const error = await response.json();
      throw new Error(error.error || 'Fehler beim Erstellen');
    }
    
    const message = entryType === 'vacation' ? '✅ Urlaub eingetragen (kein Arbeitstag)' : '✅ Gleittag eingetragen (8h Soll, 0h Ist)';
    showNotification(message, 'success');
    loadMonthlyView();
  } catch (error) {
    showNotification(error.message, 'error');
  }
}

/**
 * Load and display entries
 */
async function loadEntries(fromDate = null, toDate = null) {
  const entries = await fetchEntries(fromDate, toDate);
  renderEntries(entries);
}

/**
 * Load and display monthly view
 */
async function loadMonthlyView() {
  currentView = 'monthly';
  showMonthNavigation();
  
  // First day of display month
  const fromDate = `${displayYear}-${String(displayMonth + 1).padStart(2, '0')}-01`;
  
  // Last day of display month
  const lastDay = new Date(displayYear, displayMonth + 1, 0).getDate();
  const toDate = `${displayYear}-${String(displayMonth + 1).padStart(2, '0')}-${String(lastDay).padStart(2, '0')}`;
  
  const entries = await fetchEntries(fromDate, toDate);
  renderMonthlyView(entries);
  updateMonthDisplay();
  updateStatistics(entries);
}

/**
 * Reload the current view (monthly or filter)
 */
async function reloadView() {
  if (currentView === 'filter') {
    const entries = await fetchEntries(currentFilterFrom, currentFilterTo);
    renderEntries(entries);
  } else {
    await loadMonthlyView();
  }
}

/**
 * Show month navigation controls
 */
function showMonthNavigation() {
  const nav = document.getElementById('monthNavigation');
  if (nav) nav.classList.remove('hidden');
}

/**
 * Hide month navigation controls
 */
function hideMonthNavigation() {
  const nav = document.getElementById('monthNavigation');
  if (nav) nav.classList.add('hidden');
}

/**
 * Calculate and update statistics for the current month
 */
async function updateStatistics(entries) {
  const today = new Date();
  const currentYear = displayYear;
  const currentMonth = displayMonth;
  const lastDay = new Date(currentYear, currentMonth + 1, 0).getDate();
  
  // Count workdays (excluding weekends and holidays, only up to today)
  let workdaysCount = 0;
  let workdaysPassed = 0;
  let totalWorkdaysInMonth = 0; // For statistics display
  
  // Count vacation days to exclude from workdays
  const vacationDays = new Set(
    entries
      .filter(e => e.entryType === 'vacation')
      .map(e => e.date)
  );
  
  // Count flextime days (they are workdays with 0 hours worked)
  const flextimeDays = new Set(
    entries
      .filter(e => e.entryType === 'flextime')
      .map(e => e.date)
  );
  
  for (let day = 1; day <= lastDay; day++) {
    const dateObj = new Date(currentYear, currentMonth, day);
    const year = dateObj.getFullYear();
    const month = String(dateObj.getMonth() + 1).padStart(2, '0');
    const dayStr = String(dateObj.getDate()).padStart(2, '0');
    const dateISO = `${year}-${month}-${dayStr}`;
    
    const isVacation = vacationDays.has(dateISO);
    const isFlextime = flextimeDays.has(dateISO);
    const isWeekendHoliday = isWeekendOrHoliday(dateObj);
    
    if (!isWeekendHoliday && !isVacation) {
      // Normal workday (excluding vacation days)
      totalWorkdaysInMonth++;
      workdaysCount++;
      if (dateObj <= today) {
        workdaysPassed++;
      }
    } else if (isFlextime && isWeekendHoliday) {
      // Flextime on weekend/holiday counts as additional workday
      totalWorkdaysInMonth++;
      if (new Date(dateISO) <= today) {
        workdaysPassed++;
      }
    }
    // Vacation days are excluded from all counts
  }
  
  // Calculate target hours (8h per workday passed)
  const targetHours = workdaysPassed * 8;
  
  // Calculate actual hours worked (only up to today)
  let actualHours = entries
    .filter(e => new Date(e.date) <= today)
    .reduce((sum, entry) => sum + entry.netHours, 0);
  
  // Add currently running timer hours to actual hours
  if (timerStartTime) {
    const now = new Date();
    const elapsedMs = now.getTime() - timerStartTime;
    const elapsedHours = elapsedMs / (1000 * 60 * 60);
    actualHours += elapsedHours;
  }
  
  // Calculate balance for current month
  const balance = actualHours - targetHours;
  
  // Calculate previous month balance
  const previousBalance = await calculatePreviousBalance();
  
  // Total balance = previous balance + current month balance
  const totalBalance = previousBalance + balance;
  
  // Update UI
  document.getElementById('statTargetHours').textContent = targetHours.toFixed(1) + 'h';
  document.getElementById('statActualHours').textContent = actualHours.toFixed(1) + 'h';
  document.getElementById('statWorkdays').textContent = `${entries.length}/${totalWorkdaysInMonth}`;
  
  // Current month balance
  const balanceElement = document.getElementById('statBalance');
  balanceElement.textContent = (balance >= 0 ? '+' : '') + balance.toFixed(1) + 'h';
  if (balance > 0) {
    balanceElement.className = 'text-2xl font-bold text-green-400';
  } else if (balance < 0) {
    balanceElement.className = 'text-2xl font-bold text-red-400';
  } else {
    balanceElement.className = 'text-2xl font-bold text-gray-100';
  }
  
  // Previous month balance
  const prevBalanceElement = document.getElementById('statPreviousBalance');
  prevBalanceElement.textContent = (previousBalance >= 0 ? '+' : '') + previousBalance.toFixed(1) + 'h';
  
  // Total balance
  const totalBalanceElement = document.getElementById('statTotalBalance');
  totalBalanceElement.textContent = (totalBalance >= 0 ? '+' : '') + totalBalance.toFixed(1) + 'h';
  if (totalBalance > 0) {
    totalBalanceElement.className = 'text-3xl font-bold text-green-400';
  } else if (totalBalance < 0) {
    totalBalanceElement.className = 'text-3xl font-bold text-red-400';
  } else {
    totalBalanceElement.className = 'text-3xl font-bold text-gray-100';
  }
  
  // Update vacation statistics
  await updateVacationStatistics();
}

/**
 * Update vacation statistics for the year
 */
async function updateVacationStatistics() {
  const currentYear = displayYear; // Use displayed year, not current calendar year
  const today = new Date();
  
  // Fetch all entries for the displayed year
  const fromDate = `${currentYear}-01-01`;
  const toDate = `${currentYear}-12-31`;
  const allEntries = await fetchEntries(fromDate, toDate);
  
  // Filter vacation entries
  const vacationEntries = allEntries.filter(e => e.entryType === 'vacation');
  
  // Calculate taken (past and today) and planned (future) vacation days
  const vacationTaken = vacationEntries.filter(e => new Date(e.date) <= today).length;
  const vacationPlanned = vacationEntries.filter(e => new Date(e.date) > today).length;
  const vacationRemaining = totalVacationDays - vacationTaken - vacationPlanned;
  
  // Update UI with dynamic year
  const vacationLabel = document.getElementById('vacationYearLabel');
  vacationLabel.innerHTML = `<i data-lucide="plane" class="w-4 h-4"></i> Urlaub ${currentYear}`;
  if (typeof lucide !== 'undefined') {
    lucide.createIcons();
  }
  document.getElementById('statVacationTaken').textContent = vacationTaken;
  document.getElementById('statVacationPlanned').textContent = vacationPlanned;
  document.getElementById('statVacationRemaining').textContent = `${vacationRemaining} / ${totalVacationDays}`;
}

/**
 * Calculate balance from all previous months (starting from first month with entries)
 */
async function calculatePreviousBalance() {
  const currentYear = displayYear;
  const currentMonth = displayMonth;
  
  // Find the first month with any entries by checking all entries
  const allEntries = await fetchEntries();
  if (allEntries.length === 0) {
    return 0;
  }
  
  // Find earliest date
  const earliestDate = allEntries.reduce((earliest, entry) => {
    const entryDate = new Date(entry.date);
    return !earliest || entryDate < earliest ? entryDate : earliest;
  }, null);
  
  if (!earliestDate) {
    return 0;
  }
  
  const firstYear = earliestDate.getFullYear();
  const firstMonth = earliestDate.getMonth();
  
  // Calculate balance from first month to previous month (not including current displayed month)
  let totalBalance = 0;
  let checkYear = firstYear;
  let checkMonth = firstMonth;
  
  const today = new Date();
  
  // Loop through all months from first entry until previous month of displayed month
  while (checkYear < currentYear || (checkYear === currentYear && checkMonth < currentMonth)) {
    const firstDay = `${checkYear}-${String(checkMonth + 1).padStart(2, '0')}-01`;
    const lastDay = new Date(checkYear, checkMonth + 1, 0).getDate();
    const lastDayStr = `${checkYear}-${String(checkMonth + 1).padStart(2, '0')}-${String(lastDay).padStart(2, '0')}`;
    
    const entries = await fetchEntries(firstDay, lastDayStr);
    
    // For past months, use full month. For current month (if displayed), limit to today
    const monthEnd = new Date(checkYear, checkMonth + 1, 0);
    const limitDate = monthEnd;  // Always use full month for previous balance calculation
    
    let workdaysPassed = 0;
    const monthLastDay = new Date(checkYear, checkMonth + 1, 0).getDate();
    
    // Count vacation days to exclude from workdays
    const vacationDays = new Set(
      entries
        .filter(e => e.entryType === 'vacation')
        .map(e => e.date)
    );
    
    // Count flextime days (they are workdays with 0 hours worked)
    const flextimeDays = new Set(
      entries
        .filter(e => e.entryType === 'flextime')
        .map(e => e.date)
    );
    
    for (let day = 1; day <= monthLastDay; day++) {
      const dateObj = new Date(checkYear, checkMonth, day);
      const year = dateObj.getFullYear();
      const month = String(dateObj.getMonth() + 1).padStart(2, '0');
      const dayStr = String(dateObj.getDate()).padStart(2, '0');
      const dateISO = `${year}-${month}-${dayStr}`;
      
      if (!isWeekendOrHoliday(dateObj)) {
        // Exclude vacation days from workdays count
        if (!vacationDays.has(dateISO)) {
          workdaysPassed++;
        }
      } else if (flextimeDays.has(dateISO)) {
        // Flextime on weekend/holiday counts as workday
        workdaysPassed++;
      }
    }
    
    const targetHours = workdaysPassed * 8;
    const actualHours = entries.reduce((sum, entry) => sum + entry.netHours, 0);
    const monthBalance = actualHours - targetHours;
    
    totalBalance += monthBalance;
    
    // Move to next month
    checkMonth++;
    if (checkMonth > 11) {
      checkMonth = 0;
      checkYear++;
    }
  }
  
  return totalBalance;
}

/**
 * Open modal for adding/editing entry
 */
function openModal(entry = null) {
  const modal = document.getElementById('entryModal');
  const modalTitle = document.getElementById('modalTitle');
  const dateInput = document.getElementById('modalDate');
  const startTimeInput = document.getElementById('modalStartTime');
  const endTimeInput = document.getElementById('modalEndTime');
  const pauseInput = document.getElementById('modalPause');
  const locationInput = document.getElementById('modalLocation');
  
  if (entry) {
    // Edit mode
    modalTitle.textContent = 'Eintrag bearbeiten';
    currentEditingId = entry.id;
    dateInput.value = formatDateDisplay(entry.date);
    startTimeInput.value = entry.startTime;
    endTimeInput.value = entry.endTime;
    pauseInput.value = entry.pauseMinutes;
    locationInput.value = entry.location || 'office';
    updateLocationButtons(entry.location || 'office');
  } else {
    // Add mode
    modalTitle.textContent = 'Neuer Eintrag';
    currentEditingId = null;
    dateInput.value = '';
    startTimeInput.value = '';
    endTimeInput.value = '';
    pauseInput.value = '';
    locationInput.value = 'office';
    updateLocationButtons('office');
  }
  
  modal.classList.remove('hidden');
}

/**
 * Open modal with pre-filled date
 */
function openModalForDate(dateISO) {
  const modal = document.getElementById('entryModal');
  const modalTitle = document.getElementById('modalTitle');
  const dateInput = document.getElementById('modalDate');
  const startTimeInput = document.getElementById('modalStartTime');
  const endTimeInput = document.getElementById('modalEndTime');
  const pauseInput = document.getElementById('modalPause');
  const locationInput = document.getElementById('modalLocation');
  
  modalTitle.textContent = 'Neuer Eintrag';
  currentEditingId = null;
  dateInput.value = formatDateDisplay(dateISO);
  startTimeInput.value = '09:00';
  endTimeInput.value = '17:30';
  pauseInput.value = '';
  locationInput.value = 'office';
  updateLocationButtons('office');
  
  modal.classList.remove('hidden');
}

/**
 * Update location button states
 */
function updateLocationButtons(location) {
  const officeBtn = document.getElementById('btnLocationOffice');
  const homeBtn = document.getElementById('btnLocationHome');
  
  if (location === 'home') {
    officeBtn.className = 'flex-1 px-4 py-3 bg-gray-700 text-gray-100 rounded-lg hover:bg-gray-600 transition-all duration-200 font-medium flex items-center justify-center gap-2';
    homeBtn.className = 'flex-1 px-4 py-3 bg-green-600 text-white rounded-lg hover:bg-green-700 transition-all duration-200 font-medium flex items-center justify-center gap-2 shadow-sm';
  } else {
    officeBtn.className = 'flex-1 px-4 py-3 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-all duration-200 font-medium flex items-center justify-center gap-2 shadow-sm';
    homeBtn.className = 'flex-1 px-4 py-3 bg-gray-700 text-gray-100 rounded-lg hover:bg-gray-600 transition-all duration-200 font-medium flex items-center justify-center gap-2';
  }
  
  // Reinitialize Lucide icons after DOM update
  if (typeof lucide !== 'undefined') {
    lucide.createIcons();
  }
}

/**
 * Close modal
 */
function closeModal() {
  const modal = document.getElementById('entryModal');
  modal.classList.add('hidden');
  currentEditingId = null;
}

/**
 * Handle form submission
 */
async function handleFormSubmit(e) {
  e.preventDefault();
  
  const date = document.getElementById('modalDate').value;
  const startTime = document.getElementById('modalStartTime').value;
  const endTime = document.getElementById('modalEndTime').value;
  const pauseInput = document.getElementById('modalPause').value;
  const location = document.getElementById('modalLocation').value;
  
  // Convert empty string or "0" to null for auto-calculation
  const pauseMinutes = (pauseInput === '' || pauseInput === '0' || parseInt(pauseInput) === 0) ? null : parseInt(pauseInput);
  
  if (!date || !startTime || !endTime) {
    showNotification('Bitte alle Felder ausfüllen', 'error');
    return;
  }
  
  if (currentEditingId) {
    // Update existing entry
    const success = await updateEntry(currentEditingId, date, startTime, endTime, pauseMinutes, location);
    if (success) {
      showNotification('Eintrag aktualisiert', 'success');
      closeModal();
      loadMonthlyView();
    }
  } else {
    // Create new entry
    const success = await createEntry(date, startTime, endTime, pauseMinutes, location);
    if (success) {
      showNotification('Eintrag erstellt', 'success');
      closeModal();
      loadMonthlyView();
    }
  }
}

/**
 * Handle delete button click
 */
async function handleDelete(id) {
  if (confirm('Möchten Sie diesen Eintrag wirklich löschen?')) {
    const success = await deleteEntry(id);
    if (success) {
      showNotification('Eintrag gelöscht', 'success');
      loadMonthlyView();
    }
  }
}

/**
 * Handle quick time button click
 * Calculates end time based on start time and target net hours
 */
function handleQuickTimeButton(netHours) {
  const startTimeInput = document.getElementById('modalStartTime');
  const endTimeInput = document.getElementById('modalEndTime');
  
  // Get start time (default to 8:30 if empty)
  let startTime = startTimeInput.value || '08:30';
  startTimeInput.value = startTime;
  
  // Parse start time
  const [startHour, startMin] = startTime.split(':').map(Number);
  const startMinutes = startHour * 60 + startMin;
  
  // Calculate required gross hours including pause
  let pauseMinutes = 0;
  let grossHours = netHours;
  
  if (netHours >= 9) {
    pauseMinutes = 45;
    grossHours = netHours + (pauseMinutes / 60);
  } else if (netHours >= 6) {
    pauseMinutes = 30;
    grossHours = netHours + (pauseMinutes / 60);
  }
  
  // Calculate end time
  const endMinutes = startMinutes + (grossHours * 60);
  const endHour = Math.floor(endMinutes / 60);
  const endMin = Math.round(endMinutes % 60);
  const endTime = `${String(endHour).padStart(2, '0')}:${String(endMin).padStart(2, '0')}`;
  
  endTimeInput.value = endTime;
}

/**
 * Auto-fill missing entries for current month with 8h net (9:00-17:30)
 */
async function handleAutoFillMonth() {
  if (!confirm('Möchten Sie alle fehlenden Arbeitstage im aktuellen Monat mit 8h (9:00-17:30) ausfüllen?\n\nWochenenden und Feiertage werden übersprungen.')) {
    return;
  }
  
  const today = new Date();
  const currentYear = displayYear;
  const currentMonth = displayMonth;
  
  // Get last day of current month
  const lastDay = new Date(currentYear, currentMonth + 1, 0).getDate();
  
  // Get existing entries for the month
  const fromDate = `${currentYear}-${String(currentMonth + 1).padStart(2, '0')}-01`;
  const toDate = `${currentYear}-${String(currentMonth + 1).padStart(2, '0')}-${String(lastDay).padStart(2, '0')}`;
  const existingEntries = await fetchEntries(fromDate, toDate);
  
  // Create a set of dates that already have entries
  const existingDates = new Set(existingEntries.map(e => e.date));
  
  let created = 0;
  let skipped = 0;
  
  // Iterate through all days in the month
  for (let day = 1; day <= lastDay; day++) {
    const dateObj = new Date(currentYear, currentMonth, day);
    const dateISO = `${currentYear}-${String(currentMonth + 1).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
    
    // Skip if entry already exists
    if (existingDates.has(dateISO)) {
      continue;
    }
    
    // Skip weekends and holidays
    if (isWeekendOrHoliday(dateObj)) {
      skipped++;
      continue;
    }
    
    // Skip future dates
    if (dateObj > today) {
      skipped++;
      continue;
    }
    
    // Create entry: 9:00-17:30 (8h net with 30min pause)
    const success = await createEntry(formatDateDisplay(dateISO), '09:00', '17:30', null);
    if (success) {
      created++;
    }
  }
  
  // Reload view
  await reloadView();
  
  showNotification(`✓ ${created} Einträge erstellt, ${skipped} Tage übersprungen`, 'success');
}

// ============================================
// BULK EDIT
// ============================================

/**
 * Toggle bulk edit mode
 */
function toggleBulkEditMode() {
  bulkEditMode = !bulkEditMode;
  selectedEntries.clear();
  
  const bulkEditBar = document.getElementById('bulkEditBar');
  const checkboxHeader = document.getElementById('checkboxHeader');
  const toggleBtn = document.getElementById('btnToggleBulkEdit');
  
  if (bulkEditMode) {
    bulkEditBar.classList.remove('hidden');
    checkboxHeader.classList.remove('hidden');
    toggleBtn.className = 'inline-flex items-center gap-2 px-4 py-2.5 bg-amber-600 text-white rounded-lg hover:bg-amber-700 transition-all duration-200 font-medium shadow-sm hover:shadow';
    toggleBtn.title = 'Mehrfachauswahl deaktivieren';
  } else {
    bulkEditBar.classList.add('hidden');
    checkboxHeader.classList.add('hidden');
    toggleBtn.className = 'inline-flex items-center gap-2 px-4 py-2.5 bg-gray-700 text-gray-100 rounded-lg hover:bg-gray-600 transition-all duration-200 font-medium shadow-sm hover:shadow';
    toggleBtn.title = 'Mehrfachauswahl aktivieren';
  }
  
  // Reload view to show/hide checkboxes
  reloadView();
}

/**
 * Toggle entry selection
 */
function toggleEntrySelection(id) {
  if (selectedEntries.has(id)) {
    selectedEntries.delete(id);
  } else {
    selectedEntries.add(id);
  }
  updateSelectedCount();
  updateCheckboxes();
}

/**
 * Toggle empty day selection (for dates without entries)
 */
function toggleEmptyDaySelection(date) {
  if (selectedEntries.has(date)) {
    selectedEntries.delete(date);
  } else {
    selectedEntries.add(date);
  }
  updateSelectedCount();
  updateCheckboxes();
}

/**
 * Select all visible entries and empty days
 */
function selectAllEntries() {
  // Select existing entries
  document.querySelectorAll('.entry-checkbox').forEach(checkbox => {
    const id = parseInt(checkbox.dataset.id);
    selectedEntries.add(id);
    checkbox.checked = true;
  });
  
  // Select empty days
  document.querySelectorAll('.empty-day-checkbox').forEach(checkbox => {
    const date = checkbox.dataset.date;
    selectedEntries.add(date);
    checkbox.checked = true;
  });
  
  updateSelectedCount();
}

/**
 * Deselect all entries
 */
function deselectAllEntries() {
  selectedEntries.clear();
  
  document.querySelectorAll('.entry-checkbox').forEach(checkbox => {
    checkbox.checked = false;
  });
  
  document.querySelectorAll('.empty-day-checkbox').forEach(checkbox => {
    checkbox.checked = false;
  });
  
  updateSelectedCount();
}

/**
 * Update selected count display
 */
function updateSelectedCount() {
  document.getElementById('selectedCount').textContent = `${selectedEntries.size} ausgewählt`;
  
  // Update master checkbox state
  const masterCheckbox = document.getElementById('masterCheckbox');
  const allCheckboxes = document.querySelectorAll('.entry-checkbox, .empty-day-checkbox');
  
  if (allCheckboxes.length === 0) {
    masterCheckbox.checked = false;
    masterCheckbox.indeterminate = false;
  } else if (selectedEntries.size === allCheckboxes.length) {
    masterCheckbox.checked = true;
    masterCheckbox.indeterminate = false;
  } else if (selectedEntries.size > 0) {
    masterCheckbox.checked = false;
    masterCheckbox.indeterminate = true;
  } else {
    masterCheckbox.checked = false;
    masterCheckbox.indeterminate = false;
  }
}

/**
 * Update checkbox states
 */
function updateCheckboxes() {
  // Update entry checkboxes (ID-based)
  document.querySelectorAll('.entry-checkbox').forEach(checkbox => {
    const id = parseInt(checkbox.dataset.id);
    checkbox.checked = selectedEntries.has(id);
  });
  
  // Update empty day checkboxes (date-based)
  document.querySelectorAll('.empty-day-checkbox').forEach(checkbox => {
    const date = checkbox.dataset.date;
    checkbox.checked = selectedEntries.has(date);
  });
  
  updateSelectedCount();
}

/**
 * Handle master checkbox toggle
 */
function handleMasterCheckboxToggle() {
  const masterCheckbox = document.getElementById('masterCheckbox');
  
  if (masterCheckbox.checked) {
    selectAllEntries();
  } else {
    deselectAllEntries();
  }
}

/**
 * Bulk set location to office
 */
async function bulkSetLocation(location) {
  if (selectedEntries.size === 0) {
    showNotification('Keine Einträge ausgewählt', 'error');
    return;
  }
  
  const locationText = location === 'home' ? 'Home Office' : 'Präsenz';
  if (!confirm(`Möchten Sie ${selectedEntries.size} Eintrag/Einträge auf "${locationText}" setzen?`)) {
    return;
  }
  
  let updated = 0;
  const entries = await fetchEntries();
  
  for (const id of selectedEntries) {
    const entry = entries.find(e => e.id === id);
    if (entry) {
      // Convert date from YYYY-MM-DD to DD.MM.YYYY for updateEntry
      const formattedDate = formatDateDisplay(entry.date);
      const success = await updateEntry(id, formattedDate, entry.startTime, entry.endTime, entry.pauseMinutes, location);
      if (success) {
        updated++;
      }
    }
  }
  
  selectedEntries.clear();
  updateSelectedCount(); // Update counter to 0
  await reloadView();
  showNotification(`✓ ${updated} Eintrag/Einträge aktualisiert`, 'success');
  toggleBulkEditMode(); // Close bulk edit mode
}

/**
 * Bulk delete entries
 */
async function bulkDeleteEntries() {
  if (selectedEntries.size === 0) {
    showNotification('Keine Einträge ausgewählt', 'error');
    return;
  }
  
  if (!confirm(`Möchten Sie wirklich ${selectedEntries.size} Eintrag/Einträge löschen?`)) {
    return;
  }
  
  let deleted = 0;
  for (const id of selectedEntries) {
    const success = await deleteEntry(id);
    if (success) {
      deleted++;
    }
  }
  
  selectedEntries.clear();
  updateSelectedCount(); // Update counter to 0
  await reloadView();
  showNotification(`${deleted} Eintrag/Einträge gelöscht`, 'success');
  toggleBulkEditMode(); // Close bulk edit mode
}

/**
 * Bulk set vacation entries
 */
async function bulkSetVacation() {
  if (selectedEntries.size === 0) {
    showNotification('Keine Einträge ausgewählt', 'error');
    return;
  }
  
  if (!confirm(`Möchten Sie ${selectedEntries.size} Eintrag/Einträge als Urlaub eintragen?`)) {
    return;
  }
  
  let created = 0;
  let updated = 0;
  let skipped = 0;
  const entries = await fetchEntries();
  
  for (const item of selectedEntries) {
    // Check if it's an ID (number) or date (string)
    if (typeof item === 'number') {
      // Update existing entry to vacation
      const entry = entries.find(e => e.id === item);
      if (entry) {
        // Skip weekends/holidays
        const dateObj = new Date(entry.date);
        if (isWeekendOrHoliday(dateObj)) {
          skipped++;
          continue;
        }
        
        try {
          const response = await fetch(`/api/entries/${item}`, {
            method: 'PUT',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
              date: entry.date,
              entryType: 'vacation'
            })
          });
          
          if (response.ok) {
            updated++;
          }
        } catch (error) {
          console.error('Error updating entry:', error);
        }
      }
    } else {
      // Create new vacation entry for empty day (item is date string)
      // Skip weekends/holidays
      const dateObj = new Date(item);
      if (isWeekendOrHoliday(dateObj)) {
        skipped++;
        continue;
      }
      
      try {
        const response = await fetch('/api/entries', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            date: item,
            entryType: 'vacation'
          })
        });
        
        if (response.ok) {
          created++;
        }
      } catch (error) {
        console.error('Error creating vacation entry:', error);
      }
    }
  }
  
  selectedEntries.clear();
  updateSelectedCount(); // Update counter to 0
  await reloadView();
  
  const message = skipped > 0 
    ? `✓ ${created} Urlaub neu eingetragen, ${updated} Einträge geändert, ${skipped} Wochenenden/Feiertage übersprungen`
    : `✓ ${created} Urlaub neu eingetragen, ${updated} Einträge geändert`;
  showNotification(message, 'success');
  toggleBulkEditMode(); // Close bulk edit mode
}

/**
 * Bulk set flextime entries
 */
async function bulkSetFlextime() {
  if (selectedEntries.size === 0) {
    showNotification('Keine Einträge ausgewählt', 'error');
    return;
  }
  
  if (!confirm(`Möchten Sie ${selectedEntries.size} Eintrag/Einträge als Gleitzeit eintragen?`)) {
    return;
  }
  
  let created = 0;
  let updated = 0;
  let skipped = 0;
  const entries = await fetchEntries();
  
  for (const item of selectedEntries) {
    // Check if it's an ID (number) or date (string)
    if (typeof item === 'number') {
      // Update existing entry to flextime
      const entry = entries.find(e => e.id === item);
      if (entry) {
        // Skip weekends/holidays
        const dateObj = new Date(entry.date);
        if (isWeekendOrHoliday(dateObj)) {
          skipped++;
          continue;
        }
        
        try {
          const response = await fetch(`/api/entries/${item}`, {
            method: 'PUT',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
              date: entry.date,
              entryType: 'flextime'
            })
          });
          
          if (response.ok) {
            updated++;
          }
        } catch (error) {
          console.error('Error updating entry:', error);
        }
      }
    } else {
      // Create new flextime entry for empty day (item is date string)
      // Skip weekends/holidays
      const dateObj = new Date(item);
      if (isWeekendOrHoliday(dateObj)) {
        skipped++;
        continue;
      }
      
      try {
        const response = await fetch('/api/entries', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            date: item,
            entryType: 'flextime'
          })
        });
        
        if (response.ok) {
          created++;
        }
      } catch (error) {
        console.error('Error creating flextime entry:', error);
      }
    }
  }
  
  selectedEntries.clear();
  updateSelectedCount(); // Update counter to 0
  await reloadView();
  
  const message = skipped > 0 
    ? `✓ ${created} Gleitzeit neu eingetragen, ${updated} Einträge geändert, ${skipped} Wochenenden/Feiertage übersprungen`
    : `✓ ${created} Gleitzeit neu eingetragen, ${updated} Einträge geändert`;
  showNotification(message, 'success');
  toggleBulkEditMode(); // Close bulk edit mode
}

// ============================================
// BUNDESLAND / SETTINGS
// ============================================

/**
 * Handle Bundesland change
 */
async function handleBundeslandChange(event) {
  const newBundesland = event.target.value;
  const oldBundesland = currentBundesland;
  
  // Check for conflicts with existing entries
  const entries = await fetchEntries();
  const conflicts = [];
  
  // Get old and new holidays for comparison
  const currentYear = new Date().getFullYear();
  const years = [currentYear - 1, currentYear, currentYear + 1];
  
  const oldHolidays = new Set();
  const newHolidays = new Set();
  
  years.forEach(year => {
    getPublicHolidays(year, oldBundesland).forEach(h => {
      oldHolidays.add(h.date.toISOString().split('T')[0]);
    });
    getPublicHolidays(year, newBundesland).forEach(h => {
      newHolidays.add(h.date.toISOString().split('T')[0]);
    });
  });
  
  // Find dates that are holidays in new state but not in old state, and have entries
  entries.forEach(entry => {
    if (newHolidays.has(entry.date) && !oldHolidays.has(entry.date)) {
      const dateObj = new Date(entry.date);
      // Temporarily set to new bundesland to get holiday name
      const tempBundesland = currentBundesland;
      currentBundesland = newBundesland;
      const holidayName = getHolidayName(dateObj);
      currentBundesland = tempBundesland;
      
      conflicts.push({
        date: entry.date,
        displayDate: formatDateDisplay(entry.date),
        holidayName: holidayName
      });
    }
  });
  
  // Warn user if conflicts exist
  if (conflicts.length > 0) {
    const conflictList = conflicts.map(c => `  • ${c.displayDate} (${c.holidayName})`).join('\n');
    const message = `Achtung!\n\nDie folgenden Tage werden zu Feiertagen und haben bereits Einträge:\n\n${conflictList}\n\nMöchten Sie fortfahren? Die Einträge bleiben erhalten, aber die Tage werden als Feiertage markiert.`;
    
    if (!confirm(message)) {
      // Revert selection
      event.target.value = oldBundesland;
      return;
    }
  }
  
  // Update state and save
  currentBundesland = newBundesland;
  await setSetting('bundesland', newBundesland);
  
  // Reload view to show updated holidays
  await reloadView();
  
  const bundeslandNames = {
    'BW': 'Baden-Württemberg',
    'BY': 'Bayern',
    'BE': 'Berlin',
    'BB': 'Brandenburg',
    'HB': 'Bremen',
    'HH': 'Hamburg',
    'HE': 'Hessen',
    'MV': 'Mecklenburg-Vorpommern',
    'NI': 'Niedersachsen',
    'NW': 'Nordrhein-Westfalen',
    'RP': 'Rheinland-Pfalz',
    'SL': 'Saarland',
    'SN': 'Sachsen',
    'ST': 'Sachsen-Anhalt',
    'SH': 'Schleswig-Holstein',
    'TH': 'Thüringen'
  };
  
  showNotification(`✓ Bundesland auf ${bundeslandNames[newBundesland]} gesetzt`, 'success');
}

/**
 * Load saved settings
 */
async function loadSettings() {
  const savedBundesland = await getSetting('bundesland');
  if (savedBundesland) {
    currentBundesland = savedBundesland;
    document.getElementById('bundeslandSelect').value = savedBundesland;
  }
  
  const savedVacationDays = await getSetting('vacationDays');
  if (savedVacationDays) {
    totalVacationDays = parseInt(savedVacationDays);
    document.getElementById('vacationDaysInput').value = totalVacationDays;
  }
}

/**
 * Handle vacation days input change
 */
async function handleVacationDaysChange(event) {
  const newValue = parseInt(event.target.value);
  
  if (isNaN(newValue) || newValue < 0 || newValue > 50) {
    showNotification('Bitte geben Sie eine gültige Anzahl (0-50) ein', 'error');
    event.target.value = totalVacationDays;
    return;
  }
  
  totalVacationDays = newValue;
  await setSetting('vacationDays', newValue.toString());
  await updateVacationStatistics();
  showNotification(`✓ Urlaubstage auf ${newValue} pro Jahr gesetzt`, 'success');
}

// ============================================
// INLINE EDITING
// ============================================

/**
 * Attach inline edit listeners to all editable cells
 */
function attachInlineEditListeners() {
  document.querySelectorAll('.editable-cell').forEach(cell => {
    cell.addEventListener('click', handleCellClick);
  });
}

/**
 * Handle cell click for inline editing
 */
function handleCellClick(e) {
  const cell = e.target;
  
  // Prevent editing if already editing
  if (cell.classList.contains('editing')) {
    return;
  }
  
  const field = cell.dataset.field;
  const id = parseInt(cell.dataset.id);
  const currentValue = cell.dataset.value;
  
  // Create input
  cell.classList.add('editing');
  const originalContent = cell.innerHTML;
  
  let input;
  if (field === 'pauseMinutes') {
    input = document.createElement('input');
    input.type = 'number';
    input.min = '0';
    input.step = '1';
    input.className = 'cell-input';
    input.value = currentValue;
  } else {
    // Time fields
    input = document.createElement('input');
    input.type = 'text';
    input.className = 'cell-input';
    input.value = currentValue;
    input.placeholder = 'HH:MM';
  }
  
  cell.innerHTML = '';
  cell.appendChild(input);
  input.focus();
  input.select();
  
  // Save on blur or Enter
  const saveEdit = async () => {
    const newValue = input.value.trim();
    
    if (newValue === currentValue) {
      // No change
      cell.classList.remove('editing');
      cell.innerHTML = originalContent;
      return;
    }
    
    // Validate
    if (field !== 'pauseMinutes') {
      // Validate time format
      if (!/^\d{1,2}:\d{2}$/.test(newValue)) {
        showNotification('Ungültiges Format. Bitte HH:MM verwenden.', 'error');
        cell.classList.remove('editing');
        cell.innerHTML = originalContent;
        return;
      }
    }
    
    // Get current entry data
    const row = cell.closest('tr');
    const entryId = parseInt(row.dataset.id);
    
    // Find date from row (skip weekday column, get actual date column)
    const dateCells = row.querySelectorAll('td');
    const dateText = dateCells[1].textContent; // Second column is date
    
    // Get all values from row
    const cells = row.querySelectorAll('.editable-cell');
    const values = {};
    cells.forEach(c => {
      const f = c.dataset.field;
      if (c === cell) {
        values[f] = newValue;
      } else {
        values[f] = c.dataset.value;
      }
    });
    
    // If startTime or endTime changed, set pauseMinutes to null for auto-calculation
    // If pauseMinutes was edited, keep the manual value
    let pauseToSend = values.pauseMinutes;
    if (field === 'startTime' || field === 'endTime') {
      pauseToSend = null; // Trigger auto-calculation on server
    }
    
    // Update via API
    const success = await updateEntry(
      entryId, 
      dateText, 
      values.startTime, 
      values.endTime, 
      pauseToSend
    );
    
    if (success) {
      // Update cell
      cell.dataset.value = newValue;
      cell.classList.remove('editing');
      cell.textContent = newValue;
      
      // Reload to update calculated values
      loadMonthlyView();
    } else {
      // Revert on error
      cell.classList.remove('editing');
      cell.innerHTML = originalContent;
    }
  };
  
  input.addEventListener('blur', saveEdit);
  input.addEventListener('keydown', (e) => {
    if (e.key === 'Enter') {
      e.preventDefault();
      saveEdit();
    } else if (e.key === 'Escape') {
      cell.classList.remove('editing');
      cell.innerHTML = originalContent;
    }
  });
}

/**
 * Handle filter button click
 */
function handleFilter() {
  const fromValue = document.getElementById('filterFrom').value;
  const toValue = document.getElementById('filterTo').value;
  
  const fromDate = fromValue ? formatDateISO(fromValue) : null;
  const toDate = toValue ? formatDateISO(toValue) : null;
  
  currentView = 'filter';
  currentFilterFrom = fromDate;
  currentFilterTo = toDate;
  hideMonthNavigation();
  
  loadEntries(fromDate, toDate);
}

/**
 * Handle clear filter button click
 */
function handleClearFilter() {
  document.getElementById('filterFrom').value = '';
  document.getElementById('filterTo').value = '';
  currentView = 'monthly';
  currentFilterFrom = null;
  currentFilterTo = null;
  loadMonthlyView();
}

/**
 * Handle export button click
 */
async function handleExport(onlyDeviations = false) {
  const fromValue = document.getElementById('filterFrom').value;
  const toValue = document.getElementById('filterTo').value;
  
  // Validate that both dates are set
  if (!fromValue || !toValue) {
    showNotification('Bitte beide Datumsfelder ausfüllen', 'error');
    return;
  }
  
  const fromDate = formatDateISO(fromValue);
  const toDate = formatDateISO(toValue);
  
  try {
    // Fetch entries for the date range
    let entries = await fetchEntries(fromDate, toDate);
    
    // Filter entries if only deviations are requested
    if (onlyDeviations) {
      entries = entries.filter(entry => Math.abs(entry.netHours - 8.0) > 0.01);
    }
    
    // Check if there are any entries
    if (entries.length === 0) {
      showNotification(
        onlyDeviations ? 
          'Keine Abweichungen vom 8h-Standard im gewählten Zeitraum.' : 
          'Keine Einträge im gewählten Zeitraum.',
        'error'
      );
      return;
    }
    
    // Create CSV content
    const csvHeader = 'Datum;Beginn;Ende;Pause (min);Netto (h);Arbeitsort;Abweichung (h)\n';
    const csvRows = entries.map(entry => {
      const deviation = entry.netHours - 8.0;
      const deviationStr = (deviation >= 0 ? '+' : '') + deviation.toFixed(2);
      const locationText = entry.location === 'home' ? 'Home' : 'Büro';
      
      return `${entry.date};${entry.startTime};${entry.endTime};${entry.pauseMinutes};${entry.netHours.toFixed(2)};${locationText};${deviationStr}`;
    }).join('\n');
    
    const csvContent = csvHeader + csvRows;
    
    // Create download link
    const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' });
    const link = document.createElement('a');
    const url = URL.createObjectURL(blob);
    
    const fileName = onlyDeviations ? 
      `zeiterfassung_abweichungen_${fromDate}_${toDate}.csv` :
      `zeiterfassung_${fromDate}_${toDate}.csv`;
    
    link.setAttribute('href', url);
    link.setAttribute('download', fileName);
    link.style.visibility = 'hidden';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    
    const message = onlyDeviations ?
      `${entries.length} Abweichung(en) exportiert` :
      `${entries.length} Eintrag/Einträge exportiert`;
    
    showNotification(message, 'success');
  } catch (error) {
    console.error('Error exporting CSV:', error);
    showNotification('Fehler beim CSV-Export', 'error');
  }
}

/**
 * Show a temporary notification
 */
function showNotification(message, type = 'info') {
  const notification = document.createElement('div');
  notification.className = `fixed top-4 right-4 px-6 py-3 rounded-lg shadow-lg text-white z-50 ${
    type === 'success' ? 'bg-green-600' : 
    type === 'error' ? 'bg-red-600' : 
    'bg-blue-600'
  }`;
  notification.textContent = message;
  
  document.body.appendChild(notification);
  
  setTimeout(() => {
    notification.style.transition = 'opacity 0.5s';
    notification.style.opacity = '0';
    setTimeout(() => document.body.removeChild(notification), 500);
  }, 3000);
}

// ============================================
// FLATPICKR INITIALIZATION
// ============================================

/**
 * Initialize all Flatpickr instances with optimized settings
 */
function initializeFlatpickr() {
  // German locale
  flatpickr.localize(flatpickr.l10ns.de);
  
  // Date pickers - using DD.MM.YYYY format
  const dateConfig = {
    dateFormat: 'd.m.Y',
    locale: 'de',
    allowInput: true
  };
  
  filterFromPicker = flatpickr('#filterFrom', dateConfig);
  filterToPicker = flatpickr('#filterTo', dateConfig);
  datePicker = flatpickr('#modalDate', dateConfig);
  
  // Time pickers with enhanced configuration
  // For a better "tumbler" experience on desktop, we use:
  // - enableTime: true
  // - noCalendar: true (time only)
  // - time_24hr: true (24-hour format)
  // - minuteIncrement: 15 (15-minute steps)
  // - Mobile browsers will show native time picker automatically
  
  const timeConfig = {
    enableTime: true,
    noCalendar: true,
    dateFormat: 'H:i',
    time_24hr: true,
    minuteIncrement: 15,
    allowInput: true,
    locale: 'de',
    // Mobile devices will use native picker which has wheel/tumbler interface
    // Desktop will use Flatpickr's time picker with improved UX
    static: false,
    // When opening the picker, use the current value in the input field
    onOpen: function(selectedDates, dateStr, instance) {
      const inputValue = instance.input.value;
      if (inputValue && inputValue.match(/^\d{1,2}:\d{2}$/)) {
        instance.setDate(inputValue, false);
      }
    }
  };
  
  startTimePicker = flatpickr('#modalStartTime', timeConfig);
  endTimePicker = flatpickr('#modalEndTime', timeConfig);
  
  // Initialize manual start time picker
  manualStartTimePicker = flatpickr('#manualTimeInput', {
    enableTime: true,
    noCalendar: true,
    dateFormat: 'H:i',
    time_24hr: true,
    minuteIncrement: 15,
    allowInput: true,
    locale: 'de',
    defaultHour: 9,
    defaultMinute: 0,
    onOpen: function(selectedDates, dateStr, instance) {
      const inputValue = instance.input.value;
      if (inputValue && inputValue.match(/^\d{1,2}:\d{2}$/)) {
        instance.setDate(inputValue, false);
      }
    }
  });
}

/**
 * Handle manual start time input
 */
async function handleManualStartTime(timeStr) {
  const now = new Date();
  const today = `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-${String(now.getDate()).padStart(2, '0')}`;
  
  // Parse the time
  const [hours, minutes] = timeStr.split(':').map(Number);
  const startDate = new Date(now.getFullYear(), now.getMonth(), now.getDate(), hours, minutes, 0);
  
  // Check if entry for today already exists
  const entries = await fetchEntries(today, today);
  
  if (entries.length > 0) {
    showNotification('Für heute existiert bereits ein Eintrag', 'error');
    return;
  }
  
  // Create entry with same start and end time (indicates running)
  const entry = await createEntry(formatDateDisplay(today), timeStr, timeStr, null);
  
  if (!entry) {
    return;
  }
  
  currentEntryId = entry.id;
  timerStartTime = startDate.getTime();
  timerPausedDuration = 0;
  isPaused = false;
  
  // Update UI
  const startBtn = document.getElementById('btnStartWork');
  const stopBtn = document.getElementById('btnStopWork');
  startBtn.disabled = true;
  startBtn.classList.add('opacity-50', 'cursor-not-allowed');
  startBtn.classList.remove('hover:bg-green-700');
  stopBtn.disabled = false;
  stopBtn.classList.remove('opacity-50', 'cursor-not-allowed');
  stopBtn.classList.add('hover:bg-red-700');
  document.getElementById('timerStatus').textContent = 'Läuft seit ' + timeStr;
  document.getElementById('timerStatus').classList.remove('cursor-pointer', 'underline', 'hover:text-blue-300');
  document.getElementById('timerStatus').classList.add('cursor-default');
  
  // Start timer interval
  timerInterval = setInterval(updateTimer, 1000);
  updateTimer(); // Immediate update
  
  // Calculate offset for pause scheduling
  const timeSinceStart = now.getTime() - startDate.getTime();
  const offsetMinutes = Math.floor(timeSinceStart / 60000);
  schedulePausesWithOffset(offsetMinutes);
  
  // Reload view to show entry
  await loadMonthlyView();
  
  showNotification(`Timer gestartet ab ${timeStr}`, 'success');
}

// ============================================
// EVENT LISTENERS
// ============================================

function initializeEventListeners() {
  // Auto-fill month button
  document.getElementById('btnAutoFill').addEventListener('click', handleAutoFillMonth);
  
  // Bulk edit toggle
  document.getElementById('btnToggleBulkEdit').addEventListener('click', toggleBulkEditMode);
  
  // Master checkbox
  document.getElementById('masterCheckbox').addEventListener('change', handleMasterCheckboxToggle);
  
  // Bulk edit actions
  document.getElementById('btnSelectAll').addEventListener('click', selectAllEntries);
  document.getElementById('btnDeselectAll').addEventListener('click', deselectAllEntries);
  document.getElementById('btnBulkSetOffice').addEventListener('click', () => bulkSetLocation('office'));
  document.getElementById('btnBulkSetHome').addEventListener('click', () => bulkSetLocation('home'));
  document.getElementById('btnBulkSetVacation').addEventListener('click', bulkSetVacation);
  document.getElementById('btnBulkSetFlextime').addEventListener('click', bulkSetFlextime);
  document.getElementById('btnBulkDelete').addEventListener('click', bulkDeleteEntries);
  
  // Cancel modal button
  document.getElementById('btnCancelModal').addEventListener('click', closeModal);
  
  // Location buttons
  document.getElementById('btnLocationOffice').addEventListener('click', () => {
    document.getElementById('modalLocation').value = 'office';
    updateLocationButtons('office');
  });
  
  document.getElementById('btnLocationHome').addEventListener('click', () => {
    document.getElementById('modalLocation').value = 'home';
    updateLocationButtons('home');
  });
  
  // Form submission
  document.getElementById('entryForm').addEventListener('submit', handleFormSubmit);
  
  // Filter buttons
  document.getElementById('btnFilter').addEventListener('click', handleFilter);
  document.getElementById('btnClearFilter').addEventListener('click', handleClearFilter);
  
  // Month navigation
  document.getElementById('btnPrevMonth').addEventListener('click', handlePrevMonth);
  document.getElementById('btnNextMonth').addEventListener('click', handleNextMonth);
  
  // Export buttons
  document.getElementById('btnExport').addEventListener('click', () => handleExport(false));
  document.getElementById('btnExportDeviations').addEventListener('click', () => handleExport(true));
  
  // Timer buttons
  document.getElementById('btnStartWork').addEventListener('click', startWork);
  document.getElementById('btnStopWork').addEventListener('click', stopWork);
  
  // Timer status - manual start time entry
  document.getElementById('timerStatus').addEventListener('click', () => {
    if (!timerStartTime) {
      // Show custom time picker modal
      document.getElementById('manualTimePickerModal').classList.remove('hidden');
      // Set default time to 09:00
      manualStartTimePicker.setDate('09:00', false);
    }
  });
  
  // Manual time picker - Confirm button
  document.getElementById('btnConfirmManualTime').addEventListener('click', async () => {
    const timeInput = document.getElementById('manualTimeInput');
    const timeStr = timeInput.value; // Format: HH:MM from Flatpickr
    
    if (timeStr && timeStr.match(/^\d{1,2}:\d{2}$/)) {
      await handleManualStartTime(timeStr);
      document.getElementById('manualTimePickerModal').classList.add('hidden');
    } else {
      showNotification('Bitte wählen Sie eine gültige Zeit aus', 'error');
    }
  });
  
  // Manual time picker - Cancel button
  document.getElementById('btnCancelManualTime').addEventListener('click', () => {
    document.getElementById('manualTimePickerModal').classList.add('hidden');
  });
  
  // Close manual time picker when clicking outside
  document.getElementById('manualTimePickerModal').addEventListener('click', (e) => {
    if (e.target.id === 'manualTimePickerModal') {
      document.getElementById('manualTimePickerModal').classList.add('hidden');
    }
  });
  
  // Bundesland selection
  document.getElementById('bundeslandSelect').addEventListener('change', handleBundeslandChange);
  
  // Vacation days input
  document.getElementById('vacationDaysInput').addEventListener('change', handleVacationDaysChange);
  
  // Close modal when clicking outside
  document.getElementById('entryModal').addEventListener('click', (e) => {
    if (e.target.id === 'entryModal') {
      closeModal();
    }
  });
  
  // Quick time buttons
  document.querySelectorAll('.quick-time-btn').forEach(btn => {
    btn.addEventListener('click', () => handleQuickTimeButton(parseInt(btn.dataset.hours)));
  });
}

// ============================================
// INITIALIZATION
// ============================================

document.addEventListener('DOMContentLoaded', async () => {
  initializeFlatpickr();
  initializeEventListeners();
  await loadSettings(); // Load saved settings first
  checkRunningTimer(); // Check if timer was running
  loadMonthlyView(); // Load monthly view by default
});