scroll position save fix attempt no. 1 feat. 'What happens next…?' text at bottom of scroll; buffer added to scroll, accounter for in FTs

src/functional_tests/test_billboard.py

@@ -154,15 +154,17 @@ class BillscrollPositionTest(FunctionalTest):
         )
 
         # 2. Force the element scrollable (CSS not served by StaticLiveServerTestCase),
-        #    set position, and dispatch scroll event to trigger the debounced save
-        target = 100
+        #    set position, and dispatch scroll event to trigger the debounced save.
+        #    JS saves scrollTop + clientHeight (bottom-of-viewport); forced height is 150px.
+        scroll_top = 100
+        forced_height = 150
         self.browser.execute_script("""
             var el = arguments[0];
             el.style.overflow = 'auto';
             el.style.height = '150px';
             el.scrollTop = arguments[1];
             el.dispatchEvent(new Event('scroll'));
-        """, scroll_el, target)
+        """, scroll_el, scroll_top)
 
         # 3. Wait for debounce (800ms) + fetch to complete
         time.sleep(3)
@@ -178,8 +180,11 @@ class BillscrollPositionTest(FunctionalTest):
         scroll_el = self.wait_for(
             lambda: self.browser.find_element(By.ID, "id_drama_scroll")
         )
+        buffer_px = self.browser.execute_script(
+            "return Math.round(parseFloat(getComputedStyle(document.documentElement).fontSize) * 2.5)"
+        )
         restored = int(scroll_el.get_attribute("data-scroll-position"))
-        self.assertEqual(restored, target)
+        self.assertEqual(restored, scroll_top + forced_height + buffer_px)
 
 
 class BillboardAppletsTest(FunctionalTest):

src/static_src/scss/_billboard.scss

@@ -57,6 +57,31 @@ body.page-billscroll {
             flex: 1;
             min-height: 0;
             overflow-y: auto;
+
+            .scroll-buffer {
+                display: flex;
+                justify-content: center;
+                align-items: baseline;
+                padding: 2rem 0 1rem;
+                opacity: 0.4;
+                font-size: 0.8rem;
+                text-transform: uppercase;
+
+                .scroll-buffer-text {
+                    letter-spacing: 0.33em;
+                }
+
+                .scroll-buffer-dots {
+                    display: inline-flex;
+                    letter-spacing: 0;
+
+                    span {
+                        display: inline-block;
+                        width: 0.7em;
+                        text-align: center;
+                    }
+                }
+            }
         }
     }
 }

src/templates/apps/billboard/_partials/_applet-billboard-scroll.html

@@ -7,23 +7,48 @@
     var scroll = document.getElementById('id_drama_scroll');
     if (!scroll) return;
 
-    // Restore saved position
-    scroll.scrollTop = {{ scroll_position }};
+    // Push buffer so its top aligns with the bottom of the aperture when all
+    // events fit within the viewport (no natural scrolling).  For longer scrolls
+    // the buffer top naturally appears at the aperture bottom when the last event
+    // clears the top of the visible area.
+    var buffer = scroll.querySelector('.scroll-buffer');
+    if (buffer) {
+        var eventsHeight = scroll.scrollHeight - buffer.offsetHeight;
+        var gap = scroll.clientHeight - eventsHeight;
+        if (gap > 0) {
+            buffer.style.marginTop = gap + 'px';
+        }
+    }
 
-    // Debounced save on scroll
+    // Restore: position stored is bottom-of-viewport; subtract clientHeight to align it
+    scroll.scrollTop = Math.max(0, {{ scroll_position }} - scroll.clientHeight);
+
+    // Animate "What happens next. . . ?" buffer dots — 4th span shows '?'
+    var dotsWrap = scroll.querySelector('.scroll-buffer-dots');
+    if (dotsWrap) {
+        var dots = dotsWrap.querySelectorAll('span');
+        var n = 0;
+        setInterval(function() {
+            dots.forEach(function(d, i) { d.textContent = i < n ? (i === 3 ? '?' : '.') : ''; });
+            n = (n + 1) % 5;
+        }, 400);
+    }
+
+    // Debounced save on scroll — store bottom-of-viewport so the last-read line is restored
     var saveTimer;
     scroll.addEventListener('scroll', function() {
         clearTimeout(saveTimer);
         saveTimer = setTimeout(function() {
             var csrfToken = document.querySelector('[name=csrfmiddlewaretoken]');
             var token = csrfToken ? csrfToken.value : '';
+            var remPx = parseFloat(getComputedStyle(document.documentElement).fontSize);
             fetch("{% url 'billboard:save_scroll_position' room.id %}", {
                 method: 'POST',
                 headers: {
                     'Content-Type': 'application/x-www-form-urlencoded',
                     'X-CSRFToken': token,
                 },
-                body: 'position=' + Math.round(scroll.scrollTop),
+                body: 'position=' + Math.round(scroll.scrollTop + scroll.clientHeight + remPx * 2.5),
             });
         }, 800);
     });

src/templates/core/_partials/_scroll.html

@@ -13,4 +13,12 @@
     {% empty %}
         <p class="event-empty"><small>No events yet.</small></p>
     {% endfor %}
+    <div class="scroll-buffer" aria-hidden="true">
+        <span class="scroll-buffer-text">What</span>
+        <span class="scroll-buffer-text quaUser">&nbsp;happens</span>
+        <span class="scroll-buffer-text terUser">&nbsp;next</span>
+        <span class="scroll-buffer-dots">
+            <span></span><span></span><span></span><span></span>
+        </span>
+    </div>
 </section>