Add folder rename and background update trigger to admin UI

- Admin edit form: "Folder name" field renames the directory on save;
  also moves the thumbnail cache subtree to match the new path
- Admin edit page: "Run Update" button spawns update.rb in a background
  thread, streams output into a terminal-style log panel via 1.5s polling;
  shows Done/Error status when complete

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 145 insertions, 0 deletions

diff --git a/app.rb b/app.rb
index 5aba1b4..0678c67 100644
--- a/app.rb
+++ b/app.rb
@@ -15,6 +15,9 @@ CACHE_ROOT  = (ENV['CACHE_ROOT']  || '/opt/albumen/cache/thumbs').freeze
 CONFIG_PATH = (ENV['CONFIG_PATH'] || '/opt/albumen/config.yml').freeze
 THUMB_SIZE  = 300
 
+UPDATE_JOBS       = {}
+UPDATE_JOBS_MUTEX = Mutex.new
+
 IMAGE_EXTS = %w[jpg jpeg png gif webp heic heif tiff bmp].freeze
 VIDEO_EXTS = %w[mp4 mov avi mkv webm m4v ogv].freeze
 AUDIO_EXTS = %w[mp3 flac ogg wav m4a aac].freeze
@@ -409,6 +412,28 @@ post '/admin/edit/*' do
   require_admin!
   rel = params[:splat].first.chomp('/')
   dir = resolve_dir(rel)
+
+  unless rel.empty?
+    new_name = params['folder_name'].to_s.strip
+    new_name = '' if new_name.include?('/') || new_name.include?("\x00") ||
+                     new_name == '.' || new_name == '..'
+    old_name = File.basename(dir)
+    if !new_name.empty? && new_name != old_name
+      parent_dir = File.dirname(dir)
+      new_dir    = File.join(parent_dir, new_name)
+      unless File.exist?(new_dir)
+        parent_rel = rel.include?('/') ? rel.split('/')[0..-2].join('/') : ''
+        new_rel    = parent_rel.empty? ? new_name : "#{parent_rel}/#{new_name}"
+        old_cache  = File.join(CACHE_ROOT, rel)
+        new_cache  = File.join(CACHE_ROOT, new_rel)
+        FileUtils.mv(old_cache, new_cache) if File.directory?(old_cache)
+        FileUtils.mv(dir, new_dir)
+        save_edits(new_rel, new_dir)
+        redirect "/admin/edit/#{new_rel}"
+      end
+    end
+  end
+
   save_edits(rel, dir)
   redirect "/admin/edit/#{rel}"
 end
@@ -435,6 +460,48 @@ def save_edits(rel, dir)
   atomic_write(File.join(dir, 'album.json'), JSON.pretty_generate(data))
 end
 
+# ── Background update ─────────────────────────────────────────────────────────
+
+post '/admin/update' do
+  require_admin!
+  rel    = params[:rel].to_s.chomp('/')
+  job_id = SecureRandom.hex(8)
+  script = File.join(__dir__, 'scripts', 'update.rb')
+  cmd    = rel.empty? ? ['ruby', script] : ['ruby', script, rel]
+
+  UPDATE_JOBS_MUTEX.synchronize do
+    UPDATE_JOBS[job_id] = { status: :running, lines: [] }
+  end
+
+  Thread.new do
+    begin
+      IO.popen(cmd, err: [:child, :out]) do |io|
+        io.each_line do |line|
+          UPDATE_JOBS_MUTEX.synchronize { UPDATE_JOBS[job_id][:lines] << line.chomp }
+        end
+      end
+      code = $?.exitstatus
+      UPDATE_JOBS_MUTEX.synchronize { UPDATE_JOBS[job_id][:status] = code == 0 ? :done : :error }
+    rescue => e
+      UPDATE_JOBS_MUTEX.synchronize do
+        UPDATE_JOBS[job_id][:status] = :error
+        UPDATE_JOBS[job_id][:lines] << "Error: #{e.message}"
+      end
+    end
+  end
+
+  content_type :json
+  { job_id: job_id }.to_json
+end
+
+get '/admin/update/:id' do
+  require_admin!
+  job = UPDATE_JOBS_MUTEX.synchronize { UPDATE_JOBS[params[:id]]&.dup }
+  halt 404 unless job
+  content_type :json
+  { status: job[:status], lines: job[:lines] }.to_json
+end
+
 # ── Thumbnail generation ───────────────────────────────────────────────────────
 
 def generate_thumb(source, dest, ext)
diff --git a/public/css/style.css b/public/css/style.css
index b5d713e..e6ebff3 100644
--- a/public/css/style.css
+++ b/public/css/style.css
@@ -378,3 +378,16 @@ legend { padding: 0 8px; color: var(--text-dim); font-size: .85rem; }
   .lb-stage { padding: 48px 40px; }
   .files-table { font-size: .78rem; }
 }
+
+/* ── Admin update panel ────────────────────────────────────────────────── */
+.admin-update { margin-top: 32px; }
+.admin-update h2 { font-size: 1rem; color: var(--text-dim); margin-bottom: 6px; }
+.update-hint { font-size: .85rem; color: var(--text-dim); margin: 0 0 12px; }
+.update-panel { margin-top: 12px; }
+.update-status { font-size: .9rem; font-weight: 500; margin-bottom: 6px; }
+.update-status.running { color: var(--text-dim); }
+.update-status.done    { color: #2a9d2a; }
+.update-status.error   { color: #c0392b; }
+.update-log { background: #1a1a1a; color: #e0e0e0; font-size: .8rem; line-height: 1.5;
+              padding: 12px 14px; border-radius: var(--radius); max-height: 340px;
+              overflow-y: auto; white-space: pre-wrap; word-break: break-all; margin: 0; }
diff --git a/views/admin/album.erb b/views/admin/album.erb
index 9d98c5e..49ec4ca 100644
--- a/views/admin/album.erb
+++ b/views/admin/album.erb
@@ -14,6 +14,13 @@
   <form method="post" action="/admin/edit/<%= @rel %>">
     <fieldset class="album-settings">
       <legend>Album</legend>
+      <% unless @rel.empty? %>
+      <div class="form-row">
+        <label>Folder name
+          <input type="text" name="folder_name" value="<%= File.basename(@dir) %>">
+        </label>
+      </div>
+      <% end %>
       <div class="form-row">
         <label>Title override
           <input type="text" name="album_title" value="<%= @data['title'] %>" placeholder="(use directory name)">
@@ -108,4 +115,62 @@
     </ul>
   </section>
   <% end %>
+
+  <section class="admin-update">
+    <h2>Update</h2>
+    <p class="update-hint">Scans this album for new/removed files, extracts EXIF data, and generates missing thumbnails.</p>
+    <button id="update-btn" class="btn" onclick="startUpdate()">Run Update</button>
+    <div id="update-panel" class="update-panel hidden">
+      <div id="update-status" class="update-status"></div>
+      <pre id="update-log" class="update-log"></pre>
+    </div>
+  </section>
+
+  <script>
+  async function startUpdate() {
+    const btn    = document.getElementById('update-btn');
+    const panel  = document.getElementById('update-panel');
+    const log    = document.getElementById('update-log');
+    const status = document.getElementById('update-status');
+    const rel    = <%= @rel.to_json %>;
+
+    btn.disabled = true;
+    btn.textContent = 'Running…';
+    log.textContent = '';
+    status.textContent = 'Running…';
+    status.className = 'update-status running';
+    panel.classList.remove('hidden');
+
+    const res = await fetch('/admin/update', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
+      body: new URLSearchParams({ rel })
+    });
+    const { job_id } = await res.json();
+
+    let seen = 0;
+    const poll = setInterval(async () => {
+      const r    = await fetch('/admin/update/' + job_id);
+      const data = await r.json();
+      const fresh = data.lines.slice(seen);
+      if (fresh.length) {
+        log.textContent += fresh.join('\n') + '\n';
+        log.scrollTop = log.scrollHeight;
+        seen = data.lines.length;
+      }
+      if (data.status !== 'running') {
+        clearInterval(poll);
+        btn.disabled = false;
+        btn.textContent = 'Run Update';
+        if (data.status === 'done') {
+          status.textContent = 'Done ✓';
+          status.className = 'update-status done';
+        } else {
+          status.textContent = 'Error ✗';
+          status.className = 'update-status error';
+        }
+      }
+    }, 1500);
+  }
+  </script>
 </div>