/**
 * Attendance Fullscreen JavaScript
 * Handles fullscreen toggle and optimization for iPad viewing
 * static/js/attendance_fullscreen.js
 */

// Fullscreen state management
let isFullscreen = false;

// Touch event handlers
let touchStartY = 0;
let touchStartX = 0;

/**
 * Toggle fullscreen mode for attendance report
 */
function toggleFullscreen() {
  const container = document.getElementById('attendanceReportContainer');
  const icon = document.getElementById('fullscreenIcon');
  const body = document.body;

  if (!container || !icon) {
    console.error('Fullscreen elements not found');
    return;
  }

  isFullscreen = !isFullscreen;

  if (isFullscreen) {
    enterFullscreen(container, icon, body);
  } else {
    exitFullscreen(container, icon, body);
  }

  // Log fullscreen action
  logFullscreenAction(isFullscreen ? 'enter' : 'exit');
}

/**
 * Prevent swipe gestures from interfering with fullscreen on touch devices
 */
function preventSwipeGestures(container, enable) {
  if (enable) {
    // Prevent pull-to-refresh and other touch gestures
    container.addEventListener('touchstart', handleTouchStart, { passive: false });
    container.addEventListener('touchmove', handleTouchMove, { passive: false });
    container.addEventListener('touchend', handleTouchEnd, { passive: false });
    
    // Prevent overscroll
    document.body.style.overscrollBehavior = 'none';
    container.style.overscrollBehavior = 'none';
    
    console.log('Swipe gestures prevented for fullscreen mode');
  } else {
    // Re-enable normal touch behavior
    container.removeEventListener('touchstart', handleTouchStart);
    container.removeEventListener('touchmove', handleTouchMove);
    container.removeEventListener('touchend', handleTouchEnd);
    
    // Restore overscroll
    document.body.style.overscrollBehavior = '';
    container.style.overscrollBehavior = '';
    
    console.log('Swipe gestures re-enabled');
  }
}

function handleTouchStart(e) {
  touchStartY = e.touches[0].clientY;
  touchStartX = e.touches[0].clientX;
}

function handleTouchMove(e) {
  if (!isFullscreen) return;
  
  const touchY = e.touches[0].clientY;
  const touchX = e.touches[0].clientX;
  const deltaY = touchY - touchStartY;
  const deltaX = touchX - touchStartX;
  
  const container = document.getElementById('attendanceReportContainer');
  const scrollTop = container.scrollTop;
  const scrollHeight = container.scrollHeight;
  const clientHeight = container.clientHeight;
  const isAtTop = scrollTop === 0;
  const isAtBottom = scrollTop + clientHeight >= scrollHeight - 1;
  
  // Prevent pull-down-to-refresh when at top
  if (isAtTop && deltaY > 0) {
    e.preventDefault();
    return false;
  }
  
  // Prevent overscroll at bottom
  if (isAtBottom && deltaY < 0) {
    e.preventDefault();
    return false;
  }
  
  // Allow normal scrolling within the container
}

function handleTouchEnd(e) {
  touchStartY = 0;
  touchStartX = 0;
}

/**
 * Enter fullscreen mode
 */
function enterFullscreen(container, icon, body) {
  // Add fullscreen classes
  container.classList.add('fullscreen-mode');
  body.classList.add('fullscreen-active');

  // Change icon
  icon.classList.remove('fa-expand');
  icon.classList.add('fa-compress');

  // Update button title
  const button = document.getElementById('fullscreenToggle');
  if (button) {
    button.setAttribute('title', 'Exit Fullscreen');
  }

  // Detect if device is touch-enabled (iPad/tablet)
  const isTouchDevice = 'ontouchstart' in window || navigator.maxTouchPoints > 0;
  
  // Only use native fullscreen API on non-touch devices
  // This prevents swipe-down gesture from exiting fullscreen on iPad
  if (!isTouchDevice) {
    // Try to use native fullscreen API for desktop browsers
    if (container.requestFullscreen) {
      container.requestFullscreen().catch(err => {
        console.log('Native fullscreen not available, using CSS fullscreen');
      });
    } else if (container.webkitRequestFullscreen) {
      container.webkitRequestFullscreen().catch(err => {
        console.log('Native fullscreen not available, using CSS fullscreen');
      });
    } else if (container.mozRequestFullScreen) {
      container.mozRequestFullScreen().catch(err => {
        console.log('Native fullscreen not available, using CSS fullscreen');
      });
    } else if (container.msRequestFullscreen) {
      container.msRequestFullscreen().catch(err => {
        console.log('Native fullscreen not available, using CSS fullscreen');
      });
    }
  } else {
    console.log('Touch device detected - using CSS-only fullscreen to prevent swipe-down exit');
  }

  // Adjust table layout for better viewing
  adjustTableForFullscreen(true);

  // Save fullscreen preference
  saveFullscreenPreference(true);
  
  // Prevent default touch behaviors that might interfere
  preventSwipeGestures(container, true);
}

/**
 * Exit fullscreen mode
 */
function exitFullscreen(container, icon, body) {
  // Remove fullscreen classes
  container.classList.remove('fullscreen-mode');
  body.classList.remove('fullscreen-active');

  // Change icon back
  icon.classList.remove('fa-compress');
  icon.classList.add('fa-expand');

  // Update button title
  const button = document.getElementById('fullscreenToggle');
  if (button) {
    button.setAttribute('title', 'Toggle Fullscreen');
  }

  // Exit native fullscreen if active (only for desktop)
  const isTouchDevice = 'ontouchstart' in window || navigator.maxTouchPoints > 0;
  
  if (!isTouchDevice) {
    if (document.exitFullscreen) {
      document.exitFullscreen().catch(err => {
        console.log('Native fullscreen exit not needed');
      });
    } else if (document.webkitExitFullscreen) {
      document.webkitExitFullscreen().catch(err => {
        console.log('Native fullscreen exit not needed');
      });
    } else if (document.mozCancelFullScreen) {
      document.mozCancelFullScreen().catch(err => {
        console.log('Native fullscreen exit not needed');
      });
    } else if (document.msExitFullscreen) {
      document.msExitFullscreen().catch(err => {
        console.log('Native fullscreen exit not needed');
      });
    }
  }

  // Restore table layout
  adjustTableForFullscreen(false);

  // Save fullscreen preference
  saveFullscreenPreference(false);
  
  // Re-enable default touch behaviors
  preventSwipeGestures(container, false);
}

/**
 * Adjust table columns visibility based on fullscreen and device
 */
function adjustTableForFullscreen(isFullscreen) {
  const table = document.getElementById('attendanceTable');
  if (!table) return;

  const viewport = {
    width: window.innerWidth,
    height: window.innerHeight,
    orientation: window.innerWidth > window.innerHeight ? 'landscape' : 'portrait'
  };

  // Log viewport info for debugging
  console.log('Adjusting table for fullscreen:', {
    isFullscreen,
    viewport
  });

  // Additional optimizations can be added here
  // The CSS already handles most responsive adjustments
}

/**
 * Save fullscreen preference to localStorage and URL
 */
function saveFullscreenPreference(isFullscreen) {
  try {
    localStorage.setItem('attendance_fullscreen_preference', isFullscreen ? 'true' : 'false');
    
    // Also update the hidden form field if it exists
    const fullscreenInput = document.getElementById('fullscreenState');
    if (fullscreenInput) {
      fullscreenInput.value = isFullscreen ? '1' : '';
    }
    
    console.log('Fullscreen preference saved:', isFullscreen);
  } catch (e) {
    console.warn('Could not save fullscreen preference:', e);
  }
}

/**
 * Load fullscreen preference from localStorage
 */
function loadFullscreenPreference() {
  try {
    const preference = localStorage.getItem('attendance_fullscreen_preference');
    return preference === 'true';
  } catch (e) {
    console.warn('Could not load fullscreen preference:', e);
    return false;
  }
}

/**
 * Log fullscreen action for analytics
 */
function logFullscreenAction(action) {
  const logData = {
    action: action,
    timestamp: new Date().toISOString(),
    viewport: {
      width: window.innerWidth,
      height: window.innerHeight,
      orientation: window.innerWidth > window.innerHeight ? 'landscape' : 'portrait'
    },
    userAgent: navigator.userAgent,
    isIPad: /iPad/.test(navigator.userAgent) || (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1)
  };

  console.log('Fullscreen action logged:', logData);

  // You can send this to your backend for analytics if needed
  // fetch('/api/log-fullscreen', {
  //   method: 'POST',
  //   headers: { 'Content-Type': 'application/json' },
  //   body: JSON.stringify(logData)
  // });
}

/**
 * Handle native fullscreen change events (only for desktop)
 */
function handleFullscreenChange() {
  // Skip handling on touch devices since we're not using native fullscreen there
  const isTouchDevice = 'ontouchstart' in window || navigator.maxTouchPoints > 0;
  if (isTouchDevice) {
    return;
  }
  
  const isNativeFullscreen = !!(
    document.fullscreenElement ||
    document.webkitFullscreenElement ||
    document.mozFullScreenElement ||
    document.msFullscreenElement
  );

  // Sync our state with native fullscreen (desktop only)
  if (!isNativeFullscreen && isFullscreen) {
    // User exited native fullscreen, update our state
    const container = document.getElementById('attendanceReportContainer');
    const icon = document.getElementById('fullscreenIcon');
    const body = document.body;

    if (container && icon) {
      isFullscreen = false;
      exitFullscreen(container, icon, body);
    }
  }
}

/**
 * Handle keyboard shortcuts
 */
function handleKeyboardShortcuts(event) {
  // F11 or F for fullscreen toggle
  if (event.key === 'F11' || (event.key === 'f' && event.ctrlKey)) {
    event.preventDefault();
    toggleFullscreen();
  }

  // Escape to exit fullscreen
  if (event.key === 'Escape' && isFullscreen) {
    toggleFullscreen();
  }
}

/**
 * Detect iPad and adjust UI accordingly
 */
function detectAndOptimizeForIPad() {
  const isIPad = /iPad/.test(navigator.userAgent) || 
                 (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 0);

  if (isIPad) {
    console.log('iPad detected - optimizing UI');
    document.body.classList.add('ipad-device');

    // Add iPad-specific optimizations
    const container = document.getElementById('attendanceReportContainer');
    if (container) {
      container.classList.add('ipad-optimized');
    }
  }
}

/**
 * Restore fullscreen state from URL (CSS-only, no native fullscreen)
 */
function restoreFullscreenFromURL() {
  const urlParams = new URLSearchParams(window.location.search);
  const fullscreenParam = urlParams.get('fullscreen');
  
  if (fullscreenParam === '1' && !isFullscreen) {
    console.log('Restoring fullscreen mode from URL parameter (CSS-only)');
    
    // Use CSS-only fullscreen (no native fullscreen API call)
    const container = document.getElementById('attendanceReportContainer');
    const icon = document.getElementById('fullscreenIcon');
    const body = document.body;
    
    if (container && icon) {
      // Manually set fullscreen state without calling native API
      isFullscreen = true;
      container.classList.add('fullscreen-mode');
      body.classList.add('fullscreen-active');
      
      // Update icon
      icon.classList.remove('fa-expand');
      icon.classList.add('fa-compress');
      
      // Update button
      const button = document.getElementById('fullscreenToggle');
      if (button) {
        button.setAttribute('title', 'Exit Fullscreen');
      }
      
      // Apply touch gesture prevention
      preventSwipeGestures(container, true);
      
      // Save preference
      saveFullscreenPreference(true);
      
      console.log('Fullscreen restored successfully (CSS-only mode)');
    }
  }
}

/**
 * Initialize fullscreen functionality
 */
function initializeFullscreen() {
  console.log('Initializing fullscreen functionality');

  // Detect iPad
  detectAndOptimizeForIPad();

  // Add event listeners for native fullscreen changes (desktop only)
  document.addEventListener('fullscreenchange', handleFullscreenChange);
  document.addEventListener('webkitfullscreenchange', handleFullscreenChange);
  document.addEventListener('mozfullscreenchange', handleFullscreenChange);
  document.addEventListener('MSFullscreenChange', handleFullscreenChange);

  // Add keyboard shortcuts
  document.addEventListener('keydown', handleKeyboardShortcuts);

  // Intercept filter form submission to preserve fullscreen state
  const filterForm = document.getElementById('filterForm');
  if (filterForm) {
    filterForm.addEventListener('submit', function(e) {
      const fullscreenInput = document.getElementById('fullscreenState');
      if (fullscreenInput) {
        fullscreenInput.value = isFullscreen ? '1' : '';
        console.log('Filter form submitted with fullscreen state:', isFullscreen);
      }
    });
  }

  // Handle orientation changes
  window.addEventListener('orientationchange', function() {
    console.log('Orientation changed');
    if (isFullscreen) {
      adjustTableForFullscreen(true);
    }
  });

  // Handle window resize
  let resizeTimeout;
  window.addEventListener('resize', function() {
    clearTimeout(resizeTimeout);
    resizeTimeout = setTimeout(function() {
      if (isFullscreen) {
        adjustTableForFullscreen(true);
      }
    }, 250);
  });

  // Restore fullscreen state from URL if present
  // Use setTimeout to ensure DOM is fully loaded
  setTimeout(function() {
    restoreFullscreenFromURL();
  }, 100);

  console.log('Fullscreen functionality initialized');
}

// Initialize when DOM is ready
if (document.readyState === 'loading') {
  document.addEventListener('DOMContentLoaded', initializeFullscreen);
} else {
  initializeFullscreen();
}

// Export functions for external use
window.toggleFullscreen = toggleFullscreen;
window.isAttendanceFullscreen = function() { return isFullscreen; };