Add photo search with Boolean operators

- Server-side search index built from all album.json files + people.json,
  cached in memory for 5 minutes.  Each photo document includes filename,
  album path words, title, caption, camera, date parts (year/month-name/
  full date), and person names.
- Recursive-descent Boolean parser: AND (explicit or implicit between
  consecutive terms), OR, NOT, with standard precedence.
- GET /search?q=... returns a photo grid (max 300 results) linking each
  photo back to its album lightbox.
- Search box added to the site header; hidden on mobile.
- Results show filename, date, person names, and album path per photo.

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

4 files changed, 242 insertions, 0 deletions

diff --git a/app.rb b/app.rb
index 5172eeb..3978c54 100644
--- a/app.rb
+++ b/app.rb
@@ -18,6 +18,11 @@ THUMB_SIZE  = 300
 UPDATE_JOBS       = {}
 UPDATE_JOBS_MUTEX = Mutex.new
 
+SEARCH_TTL   = 300  # seconds before rebuilding search index
+MONTH_NAMES  = %w[january february march april may june july
+                  august september october november december].freeze
+$search_cache = { index: nil, built_at: nil, 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
@@ -270,6 +275,142 @@ helpers do
   end
 end
 
+# ── Search index ──────────────────────────────────────────────────────────────
+
+def search_index
+  $search_cache[:mutex].synchronize do
+    if $search_cache[:index].nil? ||
+       (Time.now - $search_cache[:built_at]) > SEARCH_TTL
+      $search_cache[:index]    = build_search_index
+      $search_cache[:built_at] = Time.now
+    end
+    $search_cache[:index]
+  end
+end
+
+def build_search_index
+  # people lookup: rel → [person name, ...]
+  people_by_rel = {}
+  (load_people_data['people'] || {}).each do |_, p|
+    next unless p['name']
+    (p['members'] || []).each do |m|
+      (people_by_rel[m['rel']] ||= []) << p['name']
+    end
+  end
+
+  docs = []
+  dirs = [MEDIA_ROOT] + Dir.glob("#{MEDIA_ROOT}/**/*/").sort
+  dirs.each do |dir|
+    dir_rel     = dir.delete_prefix(MEDIA_ROOT).delete_prefix('/')
+    data        = load_album(dir)
+    dir_words   = dir_rel.split('/').flat_map { |s| s.downcase.split(/[-_]/) }
+    album_title = (data['title'] || (dir_rel.empty? ? '' : File.basename(dir))).downcase
+    album_vis   = data['visible'] != false
+
+    (data['files'] || {}).each do |filename, meta|
+      meta ||= {}
+      rel   = dir_rel.empty? ? filename : "#{dir_rel}/#{filename}"
+
+      parts = (dir_words + [album_title,
+               filename.downcase,
+               File.basename(filename, '.*').downcase,
+               meta['title'].to_s.downcase,
+               meta['caption'].to_s.downcase,
+               meta['camera'].to_s.downcase]).reject(&:empty?)
+
+      if (ts = meta['taken_at'])
+        parts << ts[0..3]
+        if ts.length >= 7
+          m_idx = ts[5..6].to_i - 1
+          parts << ts[5..6]
+          parts << MONTH_NAMES[m_idx] if m_idx.between?(0, 11)
+        end
+        parts << ts[0..9] if ts.length >= 10
+      end
+
+      names = people_by_rel[rel] || []
+      parts.concat(names.map(&:downcase))
+
+      docs << {
+        rel:      rel,
+        filename: filename,
+        dir_rel:  dir_rel,
+        text:     parts.join(' '),
+        taken_at: meta['taken_at'],
+        people:   names,
+        visible:  album_vis && meta.fetch('visible', true) != false,
+      }
+    end
+  end
+  docs
+end
+
+# ── Boolean query parser ───────────────────────────────────────────────────────
+# Grammar: expr = or_expr
+#          or_expr  = and_expr  ('OR'  and_expr)*
+#          and_expr = not_expr  ('AND'? not_expr)*   ← AND implicit between terms
+#          not_expr = 'NOT' not_expr | atom
+#          atom     = TERM
+
+def search_tokenize(query)
+  query.downcase.scan(/\S+/).map do |t|
+    case t.upcase
+    when 'AND' then :AND
+    when 'OR'  then :OR
+    when 'NOT' then :NOT
+    else t
+    end
+  end
+end
+
+def search_parse(query)
+  toks = search_tokenize(query)
+  pos  = [0]
+  search_or(toks, pos)
+end
+
+def search_or(toks, pos)
+  left = search_and(toks, pos)
+  while toks[pos[0]] == :OR
+    pos[0] += 1
+    left = [:or, left, search_and(toks, pos)]
+  end
+  left
+end
+
+def search_and(toks, pos)
+  left = search_not(toks, pos)
+  loop do
+    t = toks[pos[0]]
+    break if t.nil? || t == :OR
+    pos[0] += 1 if t == :AND  # consume explicit AND; implicit falls through
+    left = [:and, left, search_not(toks, pos)]
+  end
+  left
+end
+
+def search_not(toks, pos)
+  if toks[pos[0]] == :NOT
+    pos[0] += 1
+    [:not, search_not(toks, pos)]
+  else
+    t = toks[pos[0]]
+    return [:lit, true] if t.nil? || %i[AND OR NOT].include?(t)
+    pos[0] += 1
+    [:term, t]
+  end
+end
+
+def eval_search(node, text)
+  case node[0]
+  when :or   then eval_search(node[1], text) || eval_search(node[2], text)
+  when :and  then eval_search(node[1], text) && eval_search(node[2], text)
+  when :not  then !eval_search(node[1], text)
+  when :term then text.include?(node[1])
+  when :lit  then node[1]
+  end
+end
+
 # ── Public routes ──────────────────────────────────────────────────────────────
 
 get '/' do
@@ -402,6 +543,22 @@ def slideshow_view(rel)
   erb :slideshow, layout: false
 end
 
+get '/search' do
+  q             = params[:q].to_s.strip
+  @title        = q.empty? ? 'Search' : "Search: #{q}"
+  @search_query = q
+
+  unless q.empty?
+    ast      = search_parse(q)
+    index    = search_index
+    all      = index.select { |d| (admin? || d[:visible]) && eval_search(ast, d[:text]) }
+    @total   = all.length
+    @results = all.first(300)
+  end
+
+  erb :search
+end
+
 # ── Admin routes ───────────────────────────────────────────────────────────────
 
 get '/admin' do
diff --git a/public/css/style.css b/public/css/style.css
index ba9b822..47147f4 100644
--- a/public/css/style.css
+++ b/public/css/style.css
@@ -366,6 +366,32 @@ legend { padding: 0 8px; color: var(--text-dim); font-size: .85rem; }
 .sub-album-list { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; }
 .sub-album-list a { padding: 4px 12px; background: var(--bg2); border: 1px solid var(--border); border-radius: var(--radius); font-size: .9rem; }
 
+/* ── Header search ─────────────────────────────────────────────────────── */
+.header-search { flex: 1; display: flex; justify-content: center; padding: 0 20px; }
+.header-search-input {
+  width: 200px;
+  background: var(--bg3); border: 1px solid var(--border); border-radius: var(--radius);
+  color: var(--text); padding: 5px 12px; font-size: .85rem;
+  transition: width .2s, border-color .15s;
+}
+.header-search-input:focus { width: 300px; border-color: var(--accent); outline: none; }
+
+/* ── Search results page ────────────────────────────────────────────────── */
+.search-form  { display: flex; gap: 8px; margin: 14px 0 8px; }
+.search-input {
+  flex: 1; max-width: 540px;
+  background: var(--bg3); border: 1px solid var(--border); border-radius: var(--radius);
+  color: var(--text); padding: 8px 12px; font-size: 1rem;
+}
+.search-input:focus  { border-color: var(--accent); outline: none; }
+.search-hint         { font-size: .8rem; color: var(--text-dim); margin: 0 0 18px; }
+.search-hint code    { background: var(--bg3); padding: 1px 5px; border-radius: 3px; font-size: .85em; }
+.search-card .card-meta { padding: 6px 8px 8px; }
+.search-album-path   { font-size: .72rem; color: var(--text-dim); margin-top: 3px;
+                       overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.search-album-path a { color: var(--text-dim); }
+.search-album-path a:hover { color: var(--accent); }
+
 /* ── Responsive ────────────────────────────────────────────────────────── */
 @media (max-width: 600px) {
   :root { --thumb: 140px; --gap: 8px; }
@@ -373,6 +399,7 @@ legend { padding: 0 8px; color: var(--text-dim); font-size: .85rem; }
   .lb-prev { left: 4px; }
   .lb-next { right: 4px; }
   .files-table { font-size: .78rem; }
+  .header-search { display: none; }
 }
 
 /* ── Unplayable originals (admin-only) ─────────────────────────────────── */
diff --git a/views/layout.erb b/views/layout.erb
index e0c5399..7069e76 100644
--- a/views/layout.erb
+++ b/views/layout.erb
@@ -16,6 +16,11 @@
 <body>
   <header class="site-header">
     <a href="/browse/" class="site-logo">Albumen</a>
+    <form action="/search" method="get" class="header-search">
+      <input type="search" name="q" placeholder="Search…" autocomplete="off"
+             value="<%= defined?(@search_query) ? ERB::Util.html_escape(@search_query.to_s) : '' %>"
+             class="header-search-input">
+    </form>
     <nav class="site-nav">
       <% if FACES_ENABLED %><a href="/people">People</a><% end %>
       <% if admin? %>
diff --git a/views/search.erb b/views/search.erb
new file mode 100644
index 0000000..1010284
--- /dev/null
+++ b/views/search.erb
@@ -0,0 +1,53 @@
+<div class="album-header">
+  <h1>Search</h1>
+  <form action="/search" method="get" class="search-form">
+    <input type="search" name="q" value="<%= ERB::Util.html_escape(@search_query.to_s) %>"
+           placeholder="e.g.  ken 2004   OR   carol AND NOT vacation"
+           class="search-input" autofocus autocomplete="off">
+    <button type="submit" class="btn">Search</button>
+  </form>
+  <p class="search-hint">
+    Searches filename, album, caption, date, and people names.
+    Consecutive terms are AND'd. Operators: <code>AND</code> <code>OR</code> <code>NOT</code>.
+    Example: <code>ken OR carol AND NOT vacation</code>
+  </p>
+</div>
+
+<% if @search_query && !@search_query.empty? %>
+  <% if @results %>
+    <p class="update-hint">
+      <%= @total %> result<%= @total == 1 ? '' : 's' %>
+      <% if @total > @results.length %>(showing first <%= @results.length %>)<% end %>
+    </p>
+    <% if @results.empty? %>
+      <p class="empty-album">No photos matched "<%= ERB::Util.html_escape(@search_query) %>".</p>
+    <% else %>
+      <div class="grid">
+        <% @results.each do |r| %>
+          <% album_url = r[:dir_rel].empty? ? '/browse/' : "/browse/#{ERB::Util.html_escape(r[:dir_rel])}" %>
+          <a href="<%= album_url %>?photo=<%= ERB::Util.url_encode(r[:filename]) %>"
+             class="card search-card" style="text-decoration:none">
+            <div class="thumb-wrap">
+              <img src="/thumb/<%= ERB::Util.html_escape(r[:rel]) %>" loading="lazy"
+                   alt="<%= ERB::Util.html_escape(r[:filename]) %>">
+            </div>
+            <div class="card-meta">
+              <div class="filename"><%= ERB::Util.html_escape(r[:filename]) %></div>
+              <% if r[:taken_at] %>
+                <div class="card-caption"><%= ERB::Util.html_escape(r[:taken_at][0..9]) %></div>
+              <% end %>
+              <% unless r[:people].empty? %>
+                <div class="card-caption"><%= ERB::Util.html_escape(r[:people].join(', ')) %></div>
+              <% end %>
+              <div class="search-album-path">
+                <a href="<%= album_url %>" onclick="event.stopPropagation()">
+                  <%= ERB::Util.html_escape(r[:dir_rel].empty? ? '(root)' : r[:dir_rel]) %>
+                </a>
+              </div>
+            </div>
+          </a>
+        <% end %>
+      </div>
+    <% end %>
+  <% end %>
+<% end %>