From e8bef1ac7c37aa89cddf59ae1dde6f959c2f3ef7 Mon Sep 17 00:00:00 2001
From: Brian Harrison <brianharrison02@gmail.com>
Date: Mon, 13 Apr 2026 22:34:28 -0400
Subject: [PATCH] feat: add waveform viewer endpoint and enhance UI with new
 tabs for history, units, monitor log, and sessions

---
 sfm/server.py            |   6 +
 sfm/sfm_webapp.html      | 562 ++++++++++++++++++++++++++++++++++++++-
 sfm/waveform_viewer.html |   5 +-
 3 files changed, 570 insertions(+), 3 deletions(-)

diff --git a/sfm/server.py b/sfm/server.py
index 58e49a9..0ed47ad 100644
--- a/sfm/server.py
+++ b/sfm/server.py
@@ -402,6 +402,12 @@ def webapp():
     return str(Path(__file__).parent / "sfm_webapp.html")
 
 
+@app.get("/waveform", response_class=FileResponse)
+def waveform_viewer():
+    """Serve the standalone waveform viewer."""
+    return str(Path(__file__).parent / "waveform_viewer.html")
+
+
 @app.get("/device/info")
 def device_info(
     port:     Optional[str] = Query(None,             description="Serial port (e.g. COM5, /dev/ttyUSB0)"),
diff --git a/sfm/sfm_webapp.html b/sfm/sfm_webapp.html
index 904842c..5db6746 100644
--- a/sfm/sfm_webapp.html
+++ b/sfm/sfm_webapp.html
@@ -448,6 +448,143 @@
       font-size: 14px;
       margin-top: 40px;
     }
+
+    /* ── DB tabs (History / Units / Monitor Log / Sessions) ── */
+    .db-tab-pane { padding: 0; display: flex; flex-direction: column; overflow: hidden; }
+    .db-tab-pane.active { display: flex; }
+
+    .db-toolbar {
+      background: var(--surface);
+      border-bottom: 1px solid var(--border2);
+      padding: 8px 18px;
+      display: flex;
+      align-items: center;
+      gap: 10px;
+      flex-wrap: wrap;
+      flex-shrink: 0;
+    }
+    .db-toolbar label { color: var(--text-dim); font-size: 11px; white-space: nowrap; }
+    .db-toolbar input[type="text"],
+    .db-toolbar input[type="date"],
+    .db-toolbar select { font-size: 12px; padding: 4px 8px; }
+    .db-toolbar select#db-serial-filter { width: 120px; }
+    .db-toolbar input.date-input { width: 130px; }
+    .db-toolbar-spacer { flex: 1; }
+    .db-count-badge {
+      color: var(--text-mute);
+      font-size: 11px;
+      white-space: nowrap;
+    }
+
+    .db-scroll { flex: 1; overflow-y: auto; padding: 14px 18px; }
+
+    .db-table-wrap {
+      border: 1px solid var(--border);
+      border-radius: 8px;
+      overflow: hidden;
+      max-width: 100%;
+    }
+    table.db-table {
+      width: 100%;
+      border-collapse: collapse;
+      font-size: 12px;
+    }
+    table.db-table thead th {
+      background: var(--surface2);
+      color: var(--text-dim);
+      font-size: 10px;
+      font-weight: 700;
+      letter-spacing: 0.06em;
+      text-transform: uppercase;
+      padding: 7px 12px;
+      text-align: left;
+      border-bottom: 1px solid var(--border);
+      white-space: nowrap;
+    }
+    table.db-table tbody tr { border-bottom: 1px solid var(--border2); }
+    table.db-table tbody tr:last-child { border-bottom: none; }
+    table.db-table tbody tr:nth-child(even) { background: var(--surface); }
+    table.db-table tbody tr:hover { background: var(--surface2); }
+    table.db-table tbody td {
+      padding: 7px 12px;
+      color: var(--text);
+      white-space: nowrap;
+      font-family: monospace;
+      font-size: 12px;
+    }
+    table.db-table tbody td.td-text {
+      font-family: inherit;
+      max-width: 180px;
+      overflow: hidden;
+      text-overflow: ellipsis;
+    }
+    table.db-table tbody td.td-dim { color: var(--text-mute); }
+    table.db-table tbody td.td-key { color: var(--blue-lt); }
+
+    /* PPV color tiers: green < 0.5, amber < 2.0, red ≥ 2.0 in/s */
+    .ppv-ok   { color: var(--green-lt); font-weight: 600; }
+    .ppv-warn { color: var(--yellow);   font-weight: 600; }
+    .ppv-high { color: var(--red);      font-weight: 600; }
+
+    .ft-badge {
+      background: rgba(248,81,73,0.15);
+      border: 1px solid rgba(248,81,73,0.4);
+      border-radius: 4px;
+      color: var(--red);
+      font-family: inherit;
+      font-size: 10px;
+      font-weight: 700;
+      letter-spacing: 0.05em;
+      padding: 1px 6px;
+    }
+    .ft-toggle-btn {
+      background: none;
+      border: 1px solid var(--border);
+      border-radius: var(--radius);
+      color: var(--text-dim);
+      cursor: pointer;
+      font-size: 11px;
+      padding: 2px 8px;
+    }
+    .ft-toggle-btn:hover { border-color: var(--red); color: var(--red); }
+    .ft-toggle-btn.flagged { border-color: var(--red); color: var(--red); background: rgba(248,81,73,0.1); }
+
+    .db-empty {
+      color: var(--text-mute);
+      font-size: 13px;
+      padding: 40px 0;
+      text-align: center;
+    }
+
+    /* Units tab cards */
+    .units-grid {
+      display: grid;
+      grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
+      gap: 12px;
+      max-width: 900px;
+    }
+    .unit-card {
+      background: var(--surface);
+      border: 1px solid var(--border);
+      border-radius: 8px;
+      padding: 14px 16px;
+      cursor: pointer;
+    }
+    .unit-card:hover { border-color: var(--blue-lt); }
+    .unit-card .uc-serial {
+      font-size: 16px;
+      font-weight: 700;
+      font-family: monospace;
+      color: var(--blue-lt);
+      margin-bottom: 8px;
+    }
+    .unit-card .uc-stat {
+      display: flex;
+      justify-content: space-between;
+      margin-bottom: 4px;
+    }
+    .unit-card .uc-label { font-size: 11px; color: var(--text-mute); }
+    .unit-card .uc-val   { font-size: 12px; color: var(--text); font-family: monospace; }
   </style>
 </head>
 <body>
@@ -538,6 +675,10 @@
   <button class="tab-btn active" onclick="switchTab('device')">Device</button>
   <button class="tab-btn"        onclick="switchTab('events')">Events</button>
   <button class="tab-btn"        onclick="switchTab('config')">Config</button>
+  <button class="tab-btn"        onclick="switchTab('history')">History</button>
+  <button class="tab-btn"        onclick="switchTab('units')">Units</button>
+  <button class="tab-btn"        onclick="switchTab('monlog')">Monitor Log</button>
+  <button class="tab-btn"        onclick="switchTab('sessions')">Sessions</button>
 </div>
 
 <!-- ════════════════════════════════════════════════════════════════
@@ -678,6 +819,138 @@
 
 </div>
 
+<!-- ════════════════════════════════════════════════════════════════
+     TAB: History  (events from DB)
+═══════════════════════════════════════════════════════════════════ -->
+<div id="tab-history" class="tab-pane db-tab-pane">
+  <div class="db-toolbar">
+    <label>Serial</label>
+    <select id="hist-serial-filter" onchange="loadHistory()">
+      <option value="">All units</option>
+    </select>
+    <label>From</label>
+    <input type="date" class="date-input" id="hist-from" onchange="loadHistory()" />
+    <label>To</label>
+    <input type="date" class="date-input" id="hist-to"   onchange="loadHistory()" />
+    <label style="display:flex;align-items:center;gap:5px;cursor:pointer;">
+      <input type="checkbox" id="hist-hide-ft" onchange="loadHistory()" />
+      Hide false triggers
+    </label>
+    <div class="db-toolbar-spacer"></div>
+    <button class="btn btn-ghost" onclick="loadHistory()">↻ Refresh</button>
+    <span class="db-count-badge" id="hist-count"></span>
+  </div>
+  <div class="db-scroll" id="hist-scroll">
+    <div class="db-empty" id="hist-empty" style="display:none">No events found.</div>
+    <div class="db-table-wrap" id="hist-table-wrap" style="display:none">
+      <table class="db-table" id="hist-table">
+        <thead>
+          <tr>
+            <th>Timestamp</th>
+            <th>Serial</th>
+            <th>Tran (in/s)</th>
+            <th>Vert (in/s)</th>
+            <th>Long (in/s)</th>
+            <th>PVS (in/s)</th>
+            <th>Mic</th>
+            <th>Project</th>
+            <th>Client</th>
+            <th>Type</th>
+            <th>Key</th>
+            <th></th>
+          </tr>
+        </thead>
+        <tbody id="hist-tbody"></tbody>
+      </table>
+    </div>
+  </div>
+</div>
+
+<!-- ════════════════════════════════════════════════════════════════
+     TAB: Units
+═══════════════════════════════════════════════════════════════════ -->
+<div id="tab-units" class="tab-pane db-tab-pane">
+  <div class="db-toolbar">
+    <div class="db-toolbar-spacer"></div>
+    <button class="btn btn-ghost" onclick="loadUnits()">↻ Refresh</button>
+    <span class="db-count-badge" id="units-count"></span>
+  </div>
+  <div class="db-scroll">
+    <div class="db-empty" id="units-empty" style="display:none">No units in database yet.</div>
+    <div class="units-grid" id="units-grid"></div>
+  </div>
+</div>
+
+<!-- ════════════════════════════════════════════════════════════════
+     TAB: Monitor Log
+═══════════════════════════════════════════════════════════════════ -->
+<div id="tab-monlog" class="tab-pane db-tab-pane">
+  <div class="db-toolbar">
+    <label>Serial</label>
+    <select id="monlog-serial-filter" onchange="loadMonitorLog()">
+      <option value="">All units</option>
+    </select>
+    <label>From</label>
+    <input type="date" class="date-input" id="monlog-from" onchange="loadMonitorLog()" />
+    <label>To</label>
+    <input type="date" class="date-input" id="monlog-to"   onchange="loadMonitorLog()" />
+    <div class="db-toolbar-spacer"></div>
+    <button class="btn btn-ghost" onclick="loadMonitorLog()">↻ Refresh</button>
+    <span class="db-count-badge" id="monlog-count"></span>
+  </div>
+  <div class="db-scroll" id="monlog-scroll">
+    <div class="db-empty" id="monlog-empty" style="display:none">No monitor log entries found.</div>
+    <div class="db-table-wrap" id="monlog-table-wrap" style="display:none">
+      <table class="db-table" id="monlog-table">
+        <thead>
+          <tr>
+            <th>Start Time</th>
+            <th>Stop Time</th>
+            <th>Duration</th>
+            <th>Serial</th>
+            <th>Geo Threshold</th>
+            <th>Key</th>
+          </tr>
+        </thead>
+        <tbody id="monlog-tbody"></tbody>
+      </table>
+    </div>
+  </div>
+</div>
+
+<!-- ════════════════════════════════════════════════════════════════
+     TAB: Sessions
+═══════════════════════════════════════════════════════════════════ -->
+<div id="tab-sessions" class="tab-pane db-tab-pane">
+  <div class="db-toolbar">
+    <label>Serial</label>
+    <select id="sess-serial-filter" onchange="loadSessions()">
+      <option value="">All units</option>
+    </select>
+    <div class="db-toolbar-spacer"></div>
+    <button class="btn btn-ghost" onclick="loadSessions()">↻ Refresh</button>
+    <span class="db-count-badge" id="sess-count"></span>
+  </div>
+  <div class="db-scroll" id="sess-scroll">
+    <div class="db-empty" id="sess-empty" style="display:none">No ACH sessions recorded yet.</div>
+    <div class="db-table-wrap" id="sess-table-wrap" style="display:none">
+      <table class="db-table" id="sess-table">
+        <thead>
+          <tr>
+            <th>Session Time</th>
+            <th>Serial</th>
+            <th>Peer</th>
+            <th>Events DL'd</th>
+            <th>Monitor Entries</th>
+            <th>Duration (s)</th>
+          </tr>
+        </thead>
+        <tbody id="sess-tbody"></tbody>
+      </table>
+    </div>
+  </div>
+</div>
+
 <!-- ── Script ─────────────────────────────────────────────────────── -->
 <script>
 'use strict';
@@ -721,10 +994,11 @@ function deviceParams() {
 }
 
 // ── Tab switching ──────────────────────────────────────────────────────────────
+const TAB_NAMES = ['device','events','config','history','units','monlog','sessions'];
+
 function switchTab(name) {
   document.querySelectorAll('.tab-btn').forEach((b, i) => {
-    const names = ['device','events','config'];
-    b.classList.toggle('active', names[i] === name);
+    b.classList.toggle('active', TAB_NAMES[i] === name);
   });
   document.querySelectorAll('.tab-pane').forEach(p => {
     p.classList.remove('active');
@@ -733,9 +1007,16 @@ function switchTab(name) {
   const pane = document.getElementById(`tab-${name}`);
   if (pane.id === 'tab-events') {
     pane.style.display = 'flex';
+  } else if (pane.classList.contains('db-tab-pane')) {
+    pane.style.display = 'flex';
   } else {
     pane.classList.add('active');
   }
+  // Auto-load DB tabs on first switch
+  if (name === 'history')  { if (!histLoaded)  loadHistory(); }
+  if (name === 'units')    { if (!unitsLoaded) loadUnits(); }
+  if (name === 'monlog')   { if (!monlogLoaded) loadMonitorLog(); }
+  if (name === 'sessions') { if (!sessLoaded)  loadSessions(); }
 }
 
 // ── Connect ────────────────────────────────────────────────────────────────────
@@ -1261,6 +1542,283 @@ function renderWaveform(data) {
   }
 }
 
+// ── DB tabs ────────────────────────────────────────────────────────────────────
+let histLoaded   = false;
+let unitsLoaded  = false;
+let monlogLoaded = false;
+let sessLoaded   = false;
+
+// Shared serial filter options — populated from /db/units
+const _unitSerials = new Set();
+
+function _ppvClass(v) {
+  if (v == null) return '';
+  if (v >= 2.0)  return 'ppv-high';
+  if (v >= 0.5)  return 'ppv-warn';
+  return 'ppv-ok';
+}
+function _ppvFmt(v) {
+  return v != null ? v.toFixed(5) : '—';
+}
+function _fmtTs(ts) {
+  if (!ts) return '—';
+  // ts is ISO string; show date + time, strip trailing seconds if all zeros
+  const d = new Date(ts);
+  return d.toLocaleString();
+}
+function _fmtDur(sec) {
+  if (sec == null) return '—';
+  const h = Math.floor(sec / 3600);
+  const m = Math.floor((sec % 3600) / 60);
+  const s = Math.floor(sec % 60);
+  if (h > 0) return `${h}h ${m}m ${s}s`;
+  if (m > 0) return `${m}m ${s}s`;
+  return `${s}s`;
+}
+
+function _populateSerialDropdown(selectId, currentVal) {
+  const sel = document.getElementById(selectId);
+  const prev = currentVal ?? sel.value;
+  sel.innerHTML = '<option value="">All units</option>';
+  for (const sn of [..._unitSerials].sort()) {
+    const opt = document.createElement('option');
+    opt.value = sn; opt.textContent = sn;
+    sel.appendChild(opt);
+  }
+  if (prev) sel.value = prev;
+}
+
+async function _fetchUnits() {
+  try {
+    const r = await fetch(`${api()}/db/units`);
+    if (!r.ok) return [];
+    return await r.json();
+  } catch { return []; }
+}
+
+// ── History tab ────────────────────────────────────────────────────────────────
+async function loadHistory() {
+  histLoaded = true;
+  const serial  = document.getElementById('hist-serial-filter').value;
+  const from_dt = document.getElementById('hist-from').value;
+  const to_dt   = document.getElementById('hist-to').value;
+  const hideFT  = document.getElementById('hist-hide-ft').checked;
+
+  let url = `${api()}/db/events?limit=500`;
+  if (serial)  url += `&serial=${encodeURIComponent(serial)}`;
+  if (from_dt) url += `&from_dt=${encodeURIComponent(from_dt)}`;
+  if (to_dt)   url += `&to_dt=${encodeURIComponent(to_dt + 'T23:59:59')}`;
+
+  let data;
+  try {
+    const r = await fetch(url);
+    if (!r.ok) throw new Error(r.statusText);
+    data = await r.json();
+  } catch (e) {
+    document.getElementById('hist-count').textContent = `Error: ${e.message}`;
+    return;
+  }
+
+  let events = data.events || [];
+  if (hideFT) events = events.filter(ev => !ev.false_trigger);
+
+  // Update serial dropdowns with any new serials seen
+  events.forEach(ev => { if (ev.serial) _unitSerials.add(ev.serial); });
+  _populateSerialDropdown('hist-serial-filter');
+  _populateSerialDropdown('monlog-serial-filter');
+  _populateSerialDropdown('sess-serial-filter');
+
+  document.getElementById('hist-count').textContent = `${events.length} event${events.length !== 1 ? 's' : ''}`;
+  const tbody = document.getElementById('hist-tbody');
+  tbody.innerHTML = '';
+
+  if (events.length === 0) {
+    document.getElementById('hist-empty').style.display = 'block';
+    document.getElementById('hist-table-wrap').style.display = 'none';
+    return;
+  }
+  document.getElementById('hist-empty').style.display = 'none';
+  document.getElementById('hist-table-wrap').style.display = 'block';
+
+  for (const ev of events) {
+    const tr = document.createElement('tr');
+    const pvs = ev.peak_vector_sum;
+    const maxPPV = Math.max(ev.tran_ppv ?? 0, ev.vert_ppv ?? 0, ev.long_ppv ?? 0);
+    tr.innerHTML = `
+      <td>${_fmtTs(ev.timestamp)}</td>
+      <td class="td-key">${ev.serial ?? '—'}</td>
+      <td class="${_ppvClass(ev.tran_ppv)}">${_ppvFmt(ev.tran_ppv)}</td>
+      <td class="${_ppvClass(ev.vert_ppv)}">${_ppvFmt(ev.vert_ppv)}</td>
+      <td class="${_ppvClass(ev.long_ppv)}">${_ppvFmt(ev.long_ppv)}</td>
+      <td class="${_ppvClass(pvs)}">${_ppvFmt(pvs)}</td>
+      <td class="td-dim">${ev.mic_ppv != null ? ev.mic_ppv.toExponential(3) : '—'}</td>
+      <td class="td-text">${ev.project ?? '—'}</td>
+      <td class="td-text">${ev.client  ?? '—'}</td>
+      <td class="td-dim">${ev.record_type ?? '—'}</td>
+      <td class="td-dim" style="font-size:10px">${ev.waveform_key ?? '—'}</td>
+      <td>${ev.false_trigger ? '<span class="ft-badge">FALSE</span>' : `<button class="ft-toggle-btn" onclick="toggleFalseTrigger(${ev.id}, this)" title="Flag as false trigger">Flag</button>`}</td>
+    `;
+    tbody.appendChild(tr);
+  }
+}
+
+async function toggleFalseTrigger(id, btn) {
+  btn.disabled = true;
+  try {
+    const r = await fetch(`${api()}/db/events/${id}/false_trigger?value=true`, { method: 'PATCH' });
+    if (!r.ok) throw new Error(r.statusText);
+    btn.outerHTML = '<span class="ft-badge">FALSE</span>';
+  } catch (e) {
+    btn.disabled = false;
+    alert(`Failed to flag: ${e.message}`);
+  }
+}
+
+// ── Units tab ──────────────────────────────────────────────────────────────────
+async function loadUnits() {
+  unitsLoaded = true;
+  const units = await _fetchUnits();
+
+  units.forEach(u => { if (u.serial) _unitSerials.add(u.serial); });
+  _populateSerialDropdown('hist-serial-filter');
+  _populateSerialDropdown('monlog-serial-filter');
+  _populateSerialDropdown('sess-serial-filter');
+
+  document.getElementById('units-count').textContent = `${units.length} unit${units.length !== 1 ? 's' : ''}`;
+  const grid = document.getElementById('units-grid');
+  grid.innerHTML = '';
+
+  if (units.length === 0) {
+    document.getElementById('units-empty').style.display = 'block';
+    return;
+  }
+  document.getElementById('units-empty').style.display = 'none';
+
+  for (const u of units) {
+    const card = document.createElement('div');
+    card.className = 'unit-card';
+    card.title = 'Click to filter History by this unit';
+    card.onclick = () => {
+      _populateSerialDropdown('hist-serial-filter', u.serial);
+      switchTab('history');
+      loadHistory();
+    };
+    const lastSeen = u.last_seen ? new Date(u.last_seen).toLocaleDateString() : '—';
+    card.innerHTML = `
+      <div class="uc-serial">${u.serial}</div>
+      <div class="uc-stat"><span class="uc-label">Events</span><span class="uc-val">${u.total_events ?? 0}</span></div>
+      <div class="uc-stat"><span class="uc-label">Monitor entries</span><span class="uc-val">${u.total_monitor_entries ?? 0}</span></div>
+      <div class="uc-stat"><span class="uc-label">Sessions</span><span class="uc-val">${u.total_sessions ?? 0}</span></div>
+      <div class="uc-stat"><span class="uc-label">Last seen</span><span class="uc-val">${lastSeen}</span></div>
+    `;
+    grid.appendChild(card);
+  }
+}
+
+// ── Monitor Log tab ────────────────────────────────────────────────────────────
+async function loadMonitorLog() {
+  monlogLoaded = true;
+  const serial  = document.getElementById('monlog-serial-filter').value;
+  const from_dt = document.getElementById('monlog-from').value;
+  const to_dt   = document.getElementById('monlog-to').value;
+
+  let url = `${api()}/db/monitor_log?`;
+  if (serial)  url += `serial=${encodeURIComponent(serial)}&`;
+  if (from_dt) url += `from_dt=${encodeURIComponent(from_dt)}&`;
+  if (to_dt)   url += `to_dt=${encodeURIComponent(to_dt + 'T23:59:59')}&`;
+
+  let data;
+  try {
+    const r = await fetch(url);
+    if (!r.ok) throw new Error(r.statusText);
+    data = await r.json();
+  } catch (e) {
+    document.getElementById('monlog-count').textContent = `Error: ${e.message}`;
+    return;
+  }
+
+  const entries = data.entries || [];
+  entries.forEach(e => { if (e.serial) _unitSerials.add(e.serial); });
+  _populateSerialDropdown('hist-serial-filter');
+  _populateSerialDropdown('monlog-serial-filter');
+  _populateSerialDropdown('sess-serial-filter');
+
+  document.getElementById('monlog-count').textContent = `${entries.length} entr${entries.length !== 1 ? 'ies' : 'y'}`;
+  const tbody = document.getElementById('monlog-tbody');
+  tbody.innerHTML = '';
+
+  if (entries.length === 0) {
+    document.getElementById('monlog-empty').style.display = 'block';
+    document.getElementById('monlog-table-wrap').style.display = 'none';
+    return;
+  }
+  document.getElementById('monlog-empty').style.display = 'none';
+  document.getElementById('monlog-table-wrap').style.display = 'block';
+
+  for (const e of entries) {
+    const tr = document.createElement('tr');
+    tr.innerHTML = `
+      <td>${_fmtTs(e.start_time)}</td>
+      <td>${_fmtTs(e.stop_time)}</td>
+      <td>${_fmtDur(e.duration_seconds)}</td>
+      <td class="td-key">${e.serial ?? '—'}</td>
+      <td>${e.geo_threshold_ips != null ? e.geo_threshold_ips.toFixed(4) + ' in/s' : '—'}</td>
+      <td class="td-dim" style="font-size:10px">${e.key ?? '—'}</td>
+    `;
+    tbody.appendChild(tr);
+  }
+}
+
+// ── Sessions tab ───────────────────────────────────────────────────────────────
+async function loadSessions() {
+  sessLoaded = true;
+  const serial = document.getElementById('sess-serial-filter').value;
+
+  let url = `${api()}/db/sessions?limit=200`;
+  if (serial) url += `&serial=${encodeURIComponent(serial)}`;
+
+  let data;
+  try {
+    const r = await fetch(url);
+    if (!r.ok) throw new Error(r.statusText);
+    data = await r.json();
+  } catch (e) {
+    document.getElementById('sess-count').textContent = `Error: ${e.message}`;
+    return;
+  }
+
+  const sessions = data.sessions || [];
+  sessions.forEach(s => { if (s.serial) _unitSerials.add(s.serial); });
+  _populateSerialDropdown('hist-serial-filter');
+  _populateSerialDropdown('monlog-serial-filter');
+  _populateSerialDropdown('sess-serial-filter');
+
+  document.getElementById('sess-count').textContent = `${sessions.length} session${sessions.length !== 1 ? 's' : ''}`;
+  const tbody = document.getElementById('sess-tbody');
+  tbody.innerHTML = '';
+
+  if (sessions.length === 0) {
+    document.getElementById('sess-empty').style.display = 'block';
+    document.getElementById('sess-table-wrap').style.display = 'none';
+    return;
+  }
+  document.getElementById('sess-empty').style.display = 'none';
+  document.getElementById('sess-table-wrap').style.display = 'block';
+
+  for (const s of sessions) {
+    const tr = document.createElement('tr');
+    tr.innerHTML = `
+      <td>${_fmtTs(s.session_time)}</td>
+      <td class="td-key">${s.serial ?? '—'}</td>
+      <td class="td-dim">${s.peer ?? '—'}</td>
+      <td>${s.events_downloaded ?? 0}</td>
+      <td>${s.monitor_entries ?? 0}</td>
+      <td>${s.duration_seconds != null ? s.duration_seconds.toFixed(1) : '—'}</td>
+    `;
+    tbody.appendChild(tr);
+  }
+}
+
 // ── Keyboard shortcuts ─────────────────────────────────────────────────────────
 document.addEventListener('keydown', e => {
   if (e.target.tagName === 'INPUT' || e.target.tagName === 'SELECT') return;
diff --git a/sfm/waveform_viewer.html b/sfm/waveform_viewer.html
index b9d391b..8770544 100644
--- a/sfm/waveform_viewer.html
+++ b/sfm/waveform_viewer.html
@@ -183,7 +183,7 @@
   <h1>SFM Waveform Viewer</h1>
   <div class="conn-group">
     <label>API</label>
-    <input type="text" id="api-base" value="http://localhost:8200" style="width:180px" />
+    <input type="text" id="api-base" style="width:180px" />
   </div>
   <div class="conn-group">
     <label>Device host</label>
@@ -588,6 +588,9 @@
     }
   }
 
+  // Auto-detect API base from wherever this page was served from
+  document.getElementById('api-base').value = window.location.origin;
+
   // Allow Enter key on connection inputs to trigger connect
   ['api-base', 'dev-host', 'dev-tcp-port'].forEach(id => {
     document.getElementById(id).addEventListener('keydown', e => {