feat: add mobile swipe triage UI with HammerJS and undo stack

On viewports < 768px, show a Tinder-style card UI instead of the photo
grid. Cards show one untagged photo at a time with swipe gestures
(right=journal, left=skip, up=story), colour overlays during drag, tap
buttons as alternatives, a progress bar, and a 10-deep undo stack.
Desktop grid is unchanged, wrapped in #desktop-view.

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

services/travel-memories/app/templates/phase2.html

@@ -13,6 +13,9 @@
         {{ state.photos | selectattr('tag', 'ne', 'untagged') | list | length }}
         / {{ state.photos | length }} tagged
       </span>
+      <button class="btn btn-ghost btn-sm" @click="skipUntagged()">
+        Skip untagged
+      </button>
       <button id="done-btn"
               class="btn btn-primary btn-sm"
               {% if not all_tagged %}disabled{% endif %}
@@ -22,42 +25,90 @@
     </div>
   </div>
 
-  {% for day, photos in photos_by_day.items() %}
-  <div class="day-group mb-6">
-    <h2 class="sticky top-16 z-20 bg-base-200 py-1 text-sm font-semibold opacity-70">{{ day }}</h2>
-    <div class="grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-2 mt-2">
-      {% for photo in photos %}
-      <div class="photo-card relative cursor-pointer rounded-lg overflow-hidden border-4
-                  {% if photo.tag == 'journal' %}border-success
-                  {% elif photo.tag == 'story' %}border-info
-                  {% elif photo.tag == 'skip' %}border-base-300 opacity-40
-                  {% else %}border-transparent{% endif %}"
-           data-asset-id="{{ photo.id }}"
-           data-tag="{{ photo.tag }}"
-           tabindex="0"
-           @click="select($el)"
-           @focus="select($el)">
-        <img src="/proxy/thumb/{{ photo.id }}"
-             class="w-full aspect-square object-cover" loading="lazy" alt="">
-        <div class="absolute bottom-0 left-0 right-0 text-[10px] text-white bg-black/40 px-1">
-          {{ photo.local_datetime[11:16] }}
+  {# ── Desktop grid (hidden on mobile) ── #}
+  <div id="desktop-view">
+    {% for day, photos in photos_by_day.items() %}
+    <div class="day-group mb-6">
+      <h2 class="sticky top-16 z-20 bg-base-200 py-1 text-sm font-semibold opacity-70">{{ day }}</h2>
+      <div class="grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-2 mt-2">
+        {% for photo in photos %}
+        <div class="photo-card relative cursor-pointer rounded-lg overflow-hidden border-4
+                    {% if photo.tag == 'journal' %}border-success
+                    {% elif photo.tag == 'story' %}border-info
+                    {% elif photo.tag == 'skip' %}border-base-300 opacity-40
+                    {% else %}border-transparent{% endif %}"
+             data-asset-id="{{ photo.id }}"
+             data-tag="{{ photo.tag }}"
+             tabindex="0"
+             @click="select($el)"
+             @focus="select($el)">
+          <img src="/proxy/thumb/{{ photo.id }}"
+               class="w-full aspect-square object-cover" loading="lazy" alt="">
+          <div class="absolute bottom-0 left-0 right-0 text-[10px] text-white bg-black/40 px-1">
+            {{ photo.local_datetime[11:16] }}
+          </div>
+          {% if photo.tag != 'untagged' and photo.tag != 'skip' %}
+          <div class="absolute top-1 right-1 badge badge-xs
+                      {% if photo.tag == 'journal' %}badge-success{% else %}badge-info{% endif %}">
+            {{ photo.tag[0] | upper }}
+          </div>
+          {% endif %}
         </div>
-        {% if photo.tag != 'untagged' and photo.tag != 'skip' %}
-        <div class="absolute top-1 right-1 badge badge-xs
-                    {% if photo.tag == 'journal' %}badge-success{% else %}badge-info{% endif %}">
-          {{ photo.tag[0] | upper }}
-        </div>
-        {% endif %}
+        {% endfor %}
       </div>
-      {% endfor %}
+    </div>
+    {% endfor %}
+  </div>
+
+  {# ── Mobile card UI (hidden on desktop) ── #}
+  <div id="mobile-view" style="display:none">
+    {# Progress bar #}
+    <div class="mb-3">
+      <div class="flex justify-between text-xs opacity-60 mb-1">
+        <span id="m-progress-text">0 / {{ state.photos | length }} tagged</span>
+        <span id="m-undo-btn-wrap" style="display:none">
+          <button id="m-undo-btn" class="btn btn-ghost btn-xs">&#8592; Back</button>
+        </span>
+      </div>
+      <div class="w-full bg-base-300 rounded-full h-1.5">
+        <div id="m-progress-bar" class="bg-primary h-1.5 rounded-full transition-all" style="width:0%"></div>
+      </div>
+    </div>
+
+    {# Card stack #}
+    <div id="m-card-area" class="relative w-full" style="height:70vh">
+      {# Card is injected by JS #}
+      <div id="m-completion" style="display:none"
+           class="flex flex-col items-center justify-center h-full gap-4 text-center">
+        <div class="text-4xl">&#10003;</div>
+        <p class="text-lg font-semibold">All tagged!</p>
+        <button class="btn btn-primary" onclick="document.getElementById('done-btn').click()">
+          Done triaging &rarr;
+        </button>
+      </div>
+    </div>
+
+    {# Action buttons #}
+    <div id="m-buttons" class="flex justify-center gap-6 mt-4">
+      <button id="m-btn-skip"
+              class="btn btn-circle btn-lg btn-ghost border-2 border-base-300 text-2xl"
+              onclick="mobileApp && mobileApp.doTag('skip')">&#10005;</button>
+      <button id="m-btn-journal"
+              class="btn btn-circle btn-lg btn-ghost border-2 border-success text-2xl"
+              onclick="mobileApp && mobileApp.doTag('journal')">J</button>
+      <button id="m-btn-story"
+              class="btn btn-circle btn-lg btn-ghost border-2 border-info text-2xl"
+              onclick="mobileApp && mobileApp.doTag('story')">S</button>
     </div>
   </div>
-  {% endfor %}
+
 </div>
 {% endblock %}
 
 {% block extra_scripts %}
+<script src="https://cdn.jsdelivr.net/npm/hammerjs@2.0.8/hammer.min.js"></script>
 <script>
+// ── Desktop Alpine app (unchanged) ──────────────────────────────────────────
 function triageApp(albumId) {
   return {
     focused: null,
@@ -98,6 +149,23 @@ function triageApp(albumId) {
       document.getElementById('done-btn').disabled = tagged < total;
     },
 
+    async skipUntagged() {
+      await fetch('/triage/skip-untagged', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ album_id: albumId }),
+      });
+      document.querySelectorAll('.photo-card[data-tag="untagged"]').forEach(el => {
+        el.dataset.tag = 'skip';
+        el.className = el.className
+          .split(' ')
+          .filter(c => !c.startsWith('border-') && c !== 'opacity-40')
+          .join(' ');
+        el.classList.add('border-base-300', 'opacity-40');
+      });
+      this.updateCount();
+    },
+
     async done() {
       const res = await fetch('/triage/done', {
         method: 'POST',
@@ -109,5 +177,259 @@ function triageApp(albumId) {
     },
   };
 }
+
+// ── Mobile swipe triage app ──────────────────────────────────────────────────
+let mobileApp = null;
+
+function mobileTriageApp(albumId, photos) {
+  // Build queue: only untagged photos, in their original order
+  let queue = photos
+    .filter(p => p.tag === 'untagged')
+    .slice();   // shallow copy
+
+  const total = photos.length;
+  let taggedCount = photos.filter(p => p.tag !== 'untagged').length;
+
+  // Undo stack: [{asset_id, previous_tag}, ...]  (max 10)
+  const undoStack = [];
+
+  // DOM refs
+  const cardArea   = document.getElementById('m-card-area');
+  const completion = document.getElementById('m-completion');
+  const progressBar  = document.getElementById('m-progress-bar');
+  const progressText = document.getElementById('m-progress-text');
+  const undoBtnWrap  = document.getElementById('m-undo-btn-wrap');
+  const undoBtn      = document.getElementById('m-undo-btn');
+
+  undoBtn.addEventListener('click', undo);
+
+  // ── helpers ─────────────────────────────────────────────────────────────
+
+  function updateProgress() {
+    progressText.textContent = `${taggedCount} / ${total} tagged`;
+    progressBar.style.width = total > 0 ? `${(taggedCount / total) * 100}%` : '0%';
+    undoBtnWrap.style.display = undoStack.length > 0 ? '' : 'none';
+    // Sync the shared header counter / done button
+    document.getElementById('tagged-count').textContent = `${taggedCount} / ${total} tagged`;
+    document.getElementById('done-btn').disabled = taggedCount < total;
+  }
+
+  function showCompletion() {
+    completion.style.display = '';
+    document.getElementById('m-buttons').style.display = 'none';
+  }
+
+  function makeCard(photo) {
+    const card = document.createElement('div');
+    card.id = 'm-card';
+    card.style.cssText = `
+      position: absolute; inset: 0;
+      border-radius: 16px; overflow: hidden;
+      background: #000;
+      touch-action: none;
+      user-select: none;
+      will-change: transform;
+      cursor: grab;
+    `;
+
+    const img = document.createElement('img');
+    img.src = `/proxy/thumb/${photo.id}`;
+    img.style.cssText = 'width:100%; height:100%; object-fit:cover; display:block;';
+    img.draggable = false;
+    card.appendChild(img);
+
+    // Date overlay
+    const dateOverlay = document.createElement('div');
+    dateOverlay.style.cssText = `
+      position: absolute; bottom: 0; left: 0; right: 0;
+      padding: 12px 16px;
+      background: linear-gradient(transparent, rgba(0,0,0,0.6));
+      color: #fff; font-size: 14px;
+    `;
+    dateOverlay.textContent = photo.local_datetime
+      ? photo.local_datetime.slice(0, 16).replace('T', ' ')
+      : '';
+    card.appendChild(dateOverlay);
+
+    // Colour overlay (shown during drag)
+    const colorOverlay = document.createElement('div');
+    colorOverlay.id = 'm-color-overlay';
+    colorOverlay.style.cssText = `
+      position: absolute; inset: 0;
+      opacity: 0;
+      transition: opacity 0.1s;
+      pointer-events: none;
+      border-radius: 16px;
+    `;
+    card.appendChild(colorOverlay);
+
+    return { card, colorOverlay };
+  }
+
+  function showCard() {
+    // Remove existing card if any
+    const old = document.getElementById('m-card');
+    if (old) old.remove();
+
+    if (queue.length === 0) {
+      showCompletion();
+      updateProgress();
+      return;
+    }
+
+    completion.style.display = 'none';
+    document.getElementById('m-buttons').style.display = '';
+
+    const photo = queue[0];
+    const { card, colorOverlay } = makeCard(photo);
+    cardArea.appendChild(card);
+
+    // ── HammerJS gestures ─────────────────────────────────────────────
+    const hammer = new Hammer(card, { recognizers: [[Hammer.Pan, { direction: Hammer.DIRECTION_ALL, threshold: 5 }]] });
+    // Also enable swipe (velocity-based)
+    hammer.get('pan').set({ direction: Hammer.DIRECTION_ALL });
+
+    let startX = 0, startY = 0;
+
+    hammer.on('panstart', () => {
+      card.style.transition = 'none';
+    });
+
+    hammer.on('panmove', (ev) => {
+      const dx = ev.deltaX;
+      const dy = ev.deltaY;
+      const tilt = dx * 0.08;   // degrees of rotation
+      card.style.transform = `translate(${dx}px, ${dy}px) rotate(${tilt}deg)`;
+
+      // Determine dominant direction for colour overlay
+      const absDx = Math.abs(dx);
+      const absDy = Math.abs(dy);
+
+      if (absDy > absDx && dy < -30) {
+        // swipe up → story (blue)
+        colorOverlay.style.background = 'rgba(56,189,248,0.35)';
+        colorOverlay.style.opacity = Math.min(absDy / 150, 0.8);
+      } else if (dx > 30) {
+        // swipe right → journal (green)
+        colorOverlay.style.background = 'rgba(74,222,128,0.35)';
+        colorOverlay.style.opacity = Math.min(absDx / 150, 0.8);
+      } else if (dx < -30) {
+        // swipe left → skip (grey)
+        colorOverlay.style.background = 'rgba(100,116,139,0.35)';
+        colorOverlay.style.opacity = Math.min(absDx / 150, 0.8);
+      } else {
+        colorOverlay.style.opacity = 0;
+      }
+    });
+
+    hammer.on('panend', (ev) => {
+      const dx = ev.deltaX;
+      const dy = ev.deltaY;
+      const absDx = Math.abs(dx);
+      const absDy = Math.abs(dy);
+      const THRESHOLD = 50;
+
+      card.style.transition = 'transform 0.3s ease, opacity 0.3s ease';
+
+      if (absDy > absDx && dy < -THRESHOLD) {
+        // Swipe up → story
+        flyOut(card, 0, -window.innerHeight, () => doTag('story'));
+      } else if (dx > THRESHOLD) {
+        // Swipe right → journal
+        flyOut(card, window.innerWidth, 0, () => doTag('journal'));
+      } else if (dx < -THRESHOLD) {
+        // Swipe left → skip
+        flyOut(card, -window.innerWidth, 0, () => doTag('skip'));
+      } else {
+        // Snap back
+        card.style.transform = 'translate(0,0) rotate(0deg)';
+        colorOverlay.style.opacity = 0;
+      }
+    });
+  }
+
+  function flyOut(card, toX, toY, callback) {
+    card.style.transform = `translate(${toX}px, ${toY}px) rotate(${toX * 0.1}deg)`;
+    card.style.opacity = '0';
+    setTimeout(() => {
+      callback();
+    }, 300);
+  }
+
+  // ── Tag action ───────────────────────────────────────────────────────
+
+  async function doTag(tag) {
+    if (queue.length === 0) return;
+
+    const photo = queue.shift();
+    const previousTag = photo.tag;
+
+    // Push to undo stack (max 10)
+    undoStack.push({ photo, previousTag });
+    if (undoStack.length > 10) undoStack.shift();
+
+    // Update local photo tag
+    photo.tag = tag;
+
+    // Increment tagged count only if previously untagged
+    if (previousTag === 'untagged') taggedCount++;
+
+    await fetch('/triage/tag', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ album_id: albumId, asset_id: photo.id, tag }),
+    });
+
+    updateProgress();
+    showCard();
+  }
+
+  // ── Undo ─────────────────────────────────────────────────────────────
+
+  async function undo() {
+    if (undoStack.length === 0) return;
+
+    const { photo, previousTag } = undoStack.pop();
+
+    // Re-insert at front of queue
+    queue.unshift(photo);
+
+    // Revert tagged count
+    if (previousTag === 'untagged' && photo.tag !== 'untagged') taggedCount--;
+    photo.tag = previousTag;
+
+    await fetch('/triage/tag', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ album_id: albumId, asset_id: photo.id, tag: previousTag }),
+    });
+
+    updateProgress();
+    showCard();
+  }
+
+  // ── Public API ───────────────────────────────────────────────────────
+  return { doTag, undo, showCard };
+}
+
+// ── View switching on load ───────────────────────────────────────────────────
+document.addEventListener('DOMContentLoaded', () => {
+  if (window.innerWidth < 768) {
+    document.getElementById('desktop-view').style.display = 'none';
+    document.getElementById('mobile-view').style.display = '';
+
+    const albumId = '{{ album_id }}';
+    const photos  = {{ state.photos | tojson }};
+
+    mobileApp = mobileTriageApp(albumId, photos);
+    // Seed initial progress
+    const taggedCount = photos.filter(p => p.tag !== 'untagged').length;
+    document.getElementById('m-progress-text').textContent = `${taggedCount} / ${photos.length} tagged`;
+    document.getElementById('m-progress-bar').style.width =
+      photos.length > 0 ? `${(taggedCount / photos.length) * 100}%` : '0%';
+    mobileApp.showCard();
+  }
+  // Desktop: nothing extra needed — Alpine handles it
+});
 </script>
 {% endblock %}