fix(webui): multi-pass snap to bottom; image onload re-pin; dynamic header/footer height measurement; disable native scrollRestoration

internal/httpapi/static/app.js

@@ -1,11 +1,21 @@
 // Shared state
 const st = { tailLoading: false, atBottom: true, current: '#', earliest: null, sse: null, channels: [] };
 
+function measureBars(){
+  const hdr = document.querySelector('header.nav');
+  const ftr = document.querySelector('footer');
+  if(hdr){ document.documentElement.style.setProperty('--headerH', hdr.getBoundingClientRect().height+'px'); }
+  if(ftr){ document.documentElement.style.setProperty('--footerH', ftr.getBoundingClientRect().height+'px'); }
+}
+
 function colorFor(nick){ let h=0; for(let i=0;i<nick.length;i++){ h=(h*31+nick.charCodeAt(i))>>>0 } return 'hsl('+(h%360)+',60%,'+(window.matchMedia('(prefers-color-scheme: dark)').matches? '70%':'35%')+')'; }
 function escapeHtml(s){ return s.replace(/[&<>"]/g, c=>({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;'}[c])); }
 function linkify(t){ return t.replace(/https?:\/\/\S+/g, function(u){ return '<a href="' + u + '" target="_blank" rel="noopener">' + u + '</a>'; }); }
 function lineHTML(m){ const ts = '<span class=ts>[' + m.time + ']</span>'; const nick = '<b style="color:' + colorFor(m.author) + '">' + m.author + '</b>'; const body = escapeHtml(m.body); return ts + ' ' + nick + ': ' + linkify(body); }
 
+function snapBottom(){ window.scrollTo(0, document.documentElement.scrollHeight); }
+function pinBottomMulti(){ if(!st.atBottom) return; [0,16,64,200].forEach(d=> setTimeout(()=>requestAnimationFrame(snapBottom), d)); }
+
 async function api(path, params){
   const url = new URL(path, window.location.origin);
   if(params && params.query){ Object.entries(params.query).forEach(([k,v])=>url.searchParams.set(k,v)); }
@@ -16,9 +26,8 @@ async function api(path, params){
   return res.text();
 }
 
-function appendBatch(arr){ const el=document.getElementById('tail'); const frag=document.createDocumentFragment(); arr.forEach(m=>{ const div=document.createElement('div'); div.className='msg'; div.innerHTML=lineHTML(m); frag.appendChild(div); processLinks(div); }); el.appendChild(frag); if(st.atBottom){ requestAnimationFrame(()=>{ window.scrollTo({top: document.documentElement.scrollHeight, behavior: 'instant'}); }); } }
+function appendBatch(arr){ const el=document.getElementById('tail'); const frag=document.createDocumentFragment(); arr.forEach(m=>{ const div=document.createElement('div'); div.className='msg'; div.innerHTML=lineHTML(m); frag.appendChild(div); processLinks(div); }); el.appendChild(frag); pinBottomMulti(); }
-function prependBatch(arr){ const el=document.getElementById('tail'); const oldTop=el.firstChild; const beforeTop = oldTop ? oldTop.getBoundingClientRect().top : 0; const frag=document.createDocumentFragment(); arr.forEach(m=>{ const div=document.createElement('div'); div.className='msg'; div.innerHTML=lineHTML(m); frag.appendChild(div); processLinks(div); }); el.insertBefore(frag, el.firstChild); // preserve visual position
+function prependBatch(arr){ const el=document.getElementById('tail'); const oldTop=el.firstChild; const beforeTop = oldTop ? oldTop.getBoundingClientRect().top : 0; const frag=document.createDocumentFragment(); arr.forEach(m=>{ const div=document.createElement('div'); div.className='msg'; div.innerHTML=lineHTML(m); frag.appendChild(div); processLinks(div); }); el.insertBefore(frag, el.firstChild); if(oldTop){ const afterTop = oldTop.getBoundingClientRect().top; const delta = afterTop - beforeTop; window.scrollBy(0, delta); } }
-  if(oldTop){ const afterTop = oldTop.getBoundingClientRect().top; const delta = afterTop - beforeTop; window.scrollBy({top: delta, left: 0, behavior: 'instant'}); } }
 
 function processLinks(scope){ const links = scope.querySelectorAll('a[href]:not([data-card])'); links.forEach(a=>{ a.setAttribute('data-card','1');
   // Fetch and render card
@@ -33,6 +42,7 @@ function processLinks(scope){ const links = scope.querySelectorAll('a[href]:not(
       html += '</div>';
       const row = document.createElement('div'); row.style.display='flex'; row.style.alignItems='flex-start'; row.style.gap='.5rem'; row.innerHTML = html;
       c.appendChild(row);
+      c.querySelectorAll('img').forEach(img=> img.addEventListener('load', ()=> pinBottomMulti()));
       // Summary control row
       const ctrl = document.createElement('div'); ctrl.style.marginTop='.25rem';
       const btn = document.createElement('button'); btn.type='button'; btn.title='Summarize this link'; btn.textContent='\u25B6'; btn.style.padding='0 .4rem'; btn.style.fontSize='.9rem';
@@ -55,9 +65,7 @@ function processLinks(scope){ const links = scope.querySelectorAll('a[href]:not(
 async function loadChannels(){ try{ const data = await api('/api/channels'); st.channels = data; renderChannels(); if(data.length>0){ selectChannel(data[0]); } } catch(e){} }
 function renderChannels(){ const list=document.getElementById('chanlist'); if(!list) return; list.innerHTML=''; st.channels.forEach(c=>{ const a=document.createElement('a'); a.href='#'; a.textContent=c; a.onclick=(ev)=>{ev.preventDefault(); selectChannel(c)}; if(c===st.current) a.className='active'; list.appendChild(a); }); }
 
-async function selectChannel(ch){ if(st.sse){ st.sse.close(); st.sse=null; } st.current=ch; renderChannels(); const el=document.getElementById('tail'); if(!el) return; el.textContent=''; const data = await api('/api/tail',{query:{channel:ch,limit:50}}); appendBatch(data); // snap to bottom after initial load
+async function selectChannel(ch){ if(st.sse){ st.sse.close(); st.sse=null; } st.current=ch; renderChannels(); const el=document.getElementById('tail'); if(!el) return; el.textContent=''; const data = await api('/api/tail',{query:{channel:ch,limit:50}}); appendBatch(data); requestAnimationFrame(()=>{ snapBottom(); st.atBottom=true; }); st.earliest = data.length? data[0].time : null; startStream(); initScrollHandlers(); }
-  requestAnimationFrame(()=>{ window.scrollTo({ top: document.documentElement.scrollHeight, behavior: 'instant' }); st.atBottom=true; });
-  st.earliest = data.length? data[0].time : null; startStream(); initScrollHandlers(); }
 function initScrollHandlers(){ const el=document.getElementById('tail'); if(!el) return; const onScroll = async ()=>{ const nearBottom = (window.innerHeight + window.pageYOffset + 16) >= document.documentElement.scrollHeight; st.atBottom = nearBottom; const nearTop = window.pageYOffset <= 4; if(nearTop && st.earliest){ try{ const older = await api('/api/history',{query:{channel:st.current,before:st.earliest,limit:50}}); if(older.length){ prependBatch(older); st.earliest = older[0].time; } } catch(e){} } }; window.removeEventListener('scroll', st._scrollHandler || (()=>{})); st._scrollHandler = onScroll; window.addEventListener('scroll', onScroll, {passive:true}); }
 
 function startStream(){ const el=document.getElementById('tail'); if(!el) return; const url=new URL('/api/stream', window.location.origin); url.searchParams.set('channel', st.current); const es=new EventSource(url); st.sse=es; es.onmessage=(ev)=>{ try{ const m=JSON.parse(ev.data); appendBatch([m]); }catch(e){} }; es.onerror=()=>{ es.close(); st.sse=null; setTimeout(startStream, 3000); } }
@@ -65,13 +73,12 @@ function startStream(){ const el=document.getElementById('tail'); if(!el) return
 async function summarize(){ const ch=document.getElementById('channel'); const win=document.getElementById('window'); const push=document.getElementById('push'); const btn=document.getElementById('btn'); const out=document.getElementById('out'); if(!ch||!win||!btn||!out) return; btn.disabled=true; out.textContent=''; try{ const data = await api('/api/trigger',{query:{channel:ch.value,window:win.value||'6h',push:push && push.checked? '1':'0'}}); if(typeof data === 'string'){ out.textContent = data; } else { out.textContent = (data.summary||''); } } catch(e){ out.textContent = 'error: '+e; } btn.disabled=false; }
 
 window.addEventListener('DOMContentLoaded', ()=>{
-  // measure header/footer and set margins so last lines are visible
+  if('scrollRestoration' in history){ history.scrollRestoration = 'manual'; }
-  const hdr = document.querySelector('header.nav');
+  measureBars();
-  const ftr = document.querySelector('footer');
-  if(hdr){ document.documentElement.style.setProperty('--headerH', hdr.getBoundingClientRect().height+'px'); }
-  if(ftr){ document.documentElement.style.setProperty('--footerH', ftr.getBoundingClientRect().height+'px'); }
   if(document.getElementById('chanlist')){ loadChannels(); }
   if(document.getElementById('channel')){
     fetch('/api/channels').then(r=>r.json()).then(arr=>{ const sel=document.getElementById('channel'); arr.forEach(c=>{ const o=document.createElement('option'); o.value=c; o.textContent=c; sel.appendChild(o); }); }).catch(()=>{});
   }
 });
+window.addEventListener('load', measureBars);
+window.addEventListener('resize', ()=>{ measureBars(); if(st.atBottom) pinBottomMulti(); });