Add advanced gallery features: lazy loading, sorting, and loading animations

- Implement lazy loading for video thumbnails using Intersection Observer
  - Only load thumbnails when they enter viewport (50px margin)
  - Smooth fade-in transition when thumbnails load
  - Significantly reduces initial page load time

- Add shimmer loading animation for thumbnail containers
  - Gradient shimmer effect while videos are loading
  - Automatic removal once content loads
  - Professional loading state feedback

- Add video sorting functionality
  - Sort by: Newest/Oldest, Name (A-Z/Z-A), Size (Largest/Smallest)
  - Client-side sorting for instant results
  - Maintains lazy loading when re-rendering sorted videos

- Improve error handling
  - Graceful fallback with placeholder icon for failed thumbnails
  - Better UX when videos fail to load

Performance improvements especially noticeable with large video collections.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

worker/video-server-enhanced.js

@@ -610,6 +610,30 @@ async function handlePublicGallery(bucket, kv, corsHeaders) {
     header { text-align: center; margin-bottom: 40px; padding: 20px; }
     h1 { font-size: 2.5rem; margin-bottom: 10px; }
     .subtitle { color: #aaa; font-size: 1.1rem; }
+    .controls {
+      display: flex;
+      justify-content: center;
+      gap: 15px;
+      margin-top: 20px;
+      flex-wrap: wrap;
+    }
+    .sort-select {
+      padding: 10px 20px;
+      background: #1a1a1a;
+      border: 1px solid #3a3a3a;
+      border-radius: 6px;
+      color: white;
+      font-size: 0.95rem;
+      cursor: pointer;
+      transition: border-color 0.2s;
+    }
+    .sort-select:hover {
+      border-color: #3ea6ff;
+    }
+    .sort-select:focus {
+      outline: none;
+      border-color: #3ea6ff;
+    }
     .video-grid {
       display: grid;
       grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
@@ -631,15 +655,30 @@ async function handlePublicGallery(bucket, kv, corsHeaders) {
       position: relative;
       width: 100%;
       aspect-ratio: 16/9;
-      background: #000;
+      background: linear-gradient(90deg, #1a1a1a 0%, #2a2a2a 50%, #1a1a1a 100%);
+      background-size: 200% 100%;
+      animation: shimmer 1.5s infinite;
       cursor: pointer;
       overflow: hidden;
     }
+    @keyframes shimmer {
+      0% { background-position: -200% 0; }
+      100% { background-position: 200% 0; }
+    }
+    .video-thumbnail.loaded {
+      animation: none;
+      background: #000;
+    }
     .video-thumbnail video {
       width: 100%;
       height: 100%;
       object-fit: cover;
       pointer-events: none;
+      opacity: 0;
+      transition: opacity 0.3s;
+    }
+    .video-thumbnail video.loaded {
+      opacity: 1;
     }
     .play-overlay {
       position: absolute;
@@ -706,11 +745,33 @@ async function handlePublicGallery(bucket, kv, corsHeaders) {
   <header>
     <h1>🎥 Video Gallery</h1>
     <p class="subtitle">${shareableVideos.length} video${shareableVideos.length === 1 ? '' : 's'} available</p>
+    ${shareableVideos.length > 0 ? `
+    <div class="controls">
+      <select class="sort-select" id="sortSelect" onchange="sortVideos(this.value)">
+        <option value="newest">Newest First</option>
+        <option value="oldest">Oldest First</option>
+        <option value="name-asc">Name (A-Z)</option>
+        <option value="name-desc">Name (Z-A)</option>
+        <option value="size-desc">Largest First</option>
+        <option value="size-asc">Smallest First</option>
+      </select>
+    </div>
+    ` : ''}
   </header>
-  <div class="video-grid">
+  <div class="video-grid" id="videoGrid">
     ${emptyState}
   </div>
   <script>
+    // Store videos for sorting
+    let allVideos = ${JSON.stringify(shareableVideos.map(v => ({
+      key: v.key,
+      size: v.size,
+      uploaded: v.uploaded,
+      sizeInMB: (v.size / (1024 * 1024)).toFixed(2),
+      uploadDate: new Date(v.uploaded).toLocaleDateString(),
+      encodedKey: encodeURIComponent(v.key)
+    })))};
+
     function playVideo(encodedKey) {
       window.location.href = '/watch/' + encodedKey;
     }
@@ -720,28 +781,130 @@ async function handlePublicGallery(bucket, kv, corsHeaders) {
       navigator.clipboard.writeText(url).then(() => alert('Link copied!'));
     }
 
-    // Load thumbnails on page load
-    document.addEventListener('DOMContentLoaded', function() {
+    function sortVideos(sortBy) {
+      const sorted = [...allVideos];
+
+      switch(sortBy) {
+        case 'newest':
+          sorted.sort((a, b) => new Date(b.uploaded) - new Date(a.uploaded));
+          break;
+        case 'oldest':
+          sorted.sort((a, b) => new Date(a.uploaded) - new Date(b.uploaded));
+          break;
+        case 'name-asc':
+          sorted.sort((a, b) => a.key.localeCompare(b.key));
+          break;
+        case 'name-desc':
+          sorted.sort((a, b) => b.key.localeCompare(a.key));
+          break;
+        case 'size-desc':
+          sorted.sort((a, b) => b.size - a.size);
+          break;
+        case 'size-asc':
+          sorted.sort((a, b) => a.size - b.size);
+          break;
+      }
+
+      renderVideos(sorted);
+    }
+
+    function renderVideos(videos) {
+      const grid = document.getElementById('videoGrid');
+      grid.innerHTML = videos.map(obj => \`
+        <div class="video-item">
+          <div class="video-thumbnail" onclick="playVideo('\${obj.encodedKey}')">
+            <video id="thumb-\${obj.encodedKey}" preload="metadata" muted>
+              <source src="/\${obj.key}#t=0.5" type="\${getContentType(obj.key)}">
+            </video>
+            <div class="play-overlay">
+              <div class="play-button">▶</div>
+            </div>
+          </div>
+          <div class="video-info">
+            <h3 onclick="playVideo('\${obj.encodedKey}')" style="cursor: pointer;">\${obj.key}</h3>
+            <p>Size: \${obj.sizeInMB} MB | Uploaded: \${obj.uploadDate}</p>
+            <div class="button-group">
+              <button onclick="playVideo('\${obj.encodedKey}')">Watch</button>
+              <button onclick="copyLink('\${obj.key}')">Copy Link</button>
+            </div>
+          </div>
+        </div>
+      \`).join('\\n');
+
+      // Re-initialize lazy loading for new thumbnails
+      initLazyLoading();
+    }
+
+    function getContentType(filename) {
+      const ext = filename.split('.').pop().toLowerCase();
+      const types = {
+        'mp4': 'video/mp4',
+        'mkv': 'video/x-matroska',
+        'mov': 'video/quicktime',
+        'avi': 'video/x-msvideo',
+        'webm': 'video/webm',
+        'flv': 'video/x-flv',
+        'wmv': 'video/x-ms-wmv'
+      };
+      return types[ext] || 'video/mp4';
+    }
+
+    // Lazy load thumbnails using Intersection Observer
+    function initLazyLoading() {
       const videos = document.querySelectorAll('.video-thumbnail video');
-      videos.forEach(video => {
-        // Set up error handling for videos that fail to load
-        video.addEventListener('error', function() {
-          // Hide the video element and show a placeholder
-          const thumbnail = this.closest('.video-thumbnail');
-          const overlay = thumbnail.querySelector('.play-overlay');
-          this.style.display = 'none';
-          thumbnail.style.background = 'linear-gradient(135deg, #1a1a1a 0%, #2a2a2a 100%)';
 
-          // Add a video icon placeholder
-          const icon = document.createElement('div');
-          icon.style.cssText = 'position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); font-size: 3rem; opacity: 0.3;';
-          icon.textContent = '🎬';
-          thumbnail.insertBefore(icon, overlay);
+      // Create intersection observer for lazy loading
+      const observerOptions = {
+        root: null,
+        rootMargin: '50px',
+        threshold: 0.01
+      };
+
+      const videoObserver = new IntersectionObserver((entries, observer) => {
+        entries.forEach(entry => {
+          if (entry.isIntersecting) {
+            const video = entry.target;
+
+            // Set up error handling for videos that fail to load
+            video.addEventListener('error', function() {
+              // Hide the video element and show a placeholder
+              const thumbnail = this.closest('.video-thumbnail');
+              const overlay = thumbnail.querySelector('.play-overlay');
+              this.style.display = 'none';
+              thumbnail.style.background = 'linear-gradient(135deg, #1a1a1a 0%, #2a2a2a 100%)';
+
+              // Add a video icon placeholder
+              const icon = document.createElement('div');
+              icon.style.cssText = 'position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); font-size: 3rem; opacity: 0.3;';
+              icon.textContent = '🎬';
+              thumbnail.insertBefore(icon, overlay);
+            });
+
+            // Show video when loaded
+            video.addEventListener('loadeddata', function() {
+              this.classList.add('loaded');
+              const thumbnail = this.closest('.video-thumbnail');
+              thumbnail.classList.add('loaded');
+            });
+
+            // Try to load the video
+            video.load();
+
+            // Stop observing this video
+            observer.unobserve(video);
+          }
         });
+      }, observerOptions);
 
-        // Try to load the video
-        video.load();
+      // Observe all video elements
+      videos.forEach(video => {
+        videoObserver.observe(video);
       });
+    }
+
+    // Initialize on page load
+    document.addEventListener('DOMContentLoaded', function() {
+      initLazyLoading();
     });
   </script>
 </body>