fix: persist active_remote_id in state for remote session restore

Remote sessions failed to reconnect after page refresh because
restoreState() and renderSheetList() didn't pass remoteId to
openSession(). Fix:

- state.py: add active_remote_id field to empty_state()
- main.py: extend StatePatch model to accept active_session and
  active_remote_id; update PATCH /api/state to selectively update
  only fields explicitly provided (using model_fields_set)
- app.js restoreState(): read state.active_remote_id and pass it
  as remoteId option so page-refresh reconnects remote sessions
- app.js openSession(): fire-and-forget PATCH /api/state to persist
  active_session + active_remote_id after successful connect
- app.js closeSession(): fire-and-forget PATCH /api/state to clear
  both fields so refresh doesn't try to reopen a closed session
- app.js renderSheetList(): add data-remote-id to sheet items and
  pass remoteId in click handler (previously called openSession(name)
  with no remoteId, routing remote sessions to local 404 endpoint)

Fixes: POST /api/sessions/paperclip-adapter/connect 404 when clicking
a remote session from the mobile bottom sheet or after page refresh.

muxplex/frontend/app.js

@@ -219,7 +219,10 @@ async function restoreState() {
     const res = await api('GET', '/api/state');
     const state = await res.json();
     if (state.active_session) {
-      await openSession(state.active_session, { skipAnimation: true });
+      await openSession(state.active_session, {
+        skipAnimation: true,
+        remoteId: state.active_remote_id || '',
+      });
     }
   } catch (err) {
     console.warn('[restoreState] could not restore previous session:', err);
@@ -1241,6 +1244,9 @@ async function openSession(name, opts = {}) {
     return closeSession();
   }
 
+  // Persist active_remote_id so restoreState() can reopen remote sessions after page refresh
+  api('PATCH', '/api/state', { active_session: name, active_remote_id: _remoteId || null }).catch(function() {});
+
   // Fire-and-forget bell-clear for remote sessions — acknowledge bells on the remote server
   if (_remoteId !== '') {
     api('POST', '/api/federation/' + encodeURIComponent(_remoteId) + '/sessions/' + encodeURIComponent(name) + '/bell/clear').catch(function() {});
@@ -1267,6 +1273,8 @@ function closeSession() {
   if (_viewingRemoteId === '') {
     api('DELETE', '/api/sessions/current').catch(function() {});
   }
+  // Clear active_remote_id so a page refresh does not attempt to reopen the remote session
+  api('PATCH', '/api/state', { active_session: null, active_remote_id: null }).catch(function() {});
   _viewingRemoteId = '';
 
   const expanded = $('view-expanded');
@@ -1857,8 +1865,9 @@ function renderSheetList() {
       (s.bell.seen_at === null || s.bell.last_fired_at > s.bell.seen_at);
     var isActive = s.name === _viewingSession;
     var escapedName = escapeHtml(s.name || '');
+    var remoteIdAttr = s.remoteId ? ' data-remote-id="' + escapeHtml(s.remoteId) + '"' : '';
     return '<li class="sheet-item' + (isActive ? ' sheet-item--active' : '') + '"' +
-      ' data-session="' + escapedName + '" role="option">' +
+      ' data-session="' + escapedName + '"' + remoteIdAttr + ' role="option">' +
       '<span class="sheet-item__name">' + escapedName + '</span>' +
       (hasBell ? '<span class="sheet-item__bell">\uD83D\uDD14</span>' : '') +
       '<span class="sheet-item__time">' + formatTimestamp(s.bell && s.bell.last_fired_at) + '</span>' +
@@ -1869,7 +1878,8 @@ function renderSheetList() {
     item.addEventListener('click', function() {
       closeBottomSheet();
       var name = item.dataset.session;
-      if (name !== _viewingSession) openSession(name);
+      var remoteId = item.dataset.remoteId || '';
+      if (name !== _viewingSession) openSession(name, { remoteId: remoteId });
     });
   });
 }

muxplex/frontend/tests/test_app.mjs

@@ -4381,3 +4381,115 @@ test('showNewSessionInput device select has keydown handler for Escape', () => {
   const selectKeydownIdx = fnBody.indexOf("select.addEventListener('keydown'");
   assert.ok(selectKeydownIdx !== -1, 'select element must have a keydown handler in showNewSessionInput');
 });
+
+// --- Fix: remote sessions fail to connect because openSession call sites don't pass remoteId ---
+
+test('restoreState reads active_remote_id from state and passes it to openSession', () => {
+  const source = fs.readFileSync(new URL('../app.js', import.meta.url), 'utf8');
+  const restoreIdx = source.indexOf('async function restoreState');
+  assert.ok(restoreIdx >= 0, 'restoreState must exist');
+  const restoreEnd = source.indexOf('\n}', restoreIdx) + 2;
+  const restoreBody = source.slice(restoreIdx, restoreEnd);
+  assert.ok(
+    restoreBody.includes('active_remote_id'),
+    'restoreState must read active_remote_id from persisted state',
+  );
+  assert.ok(
+    restoreBody.includes('remoteId'),
+    'restoreState must pass remoteId to openSession so remote sessions restore correctly',
+  );
+});
+
+test('renderSheetList click handler passes remoteId to openSession', () => {
+  const source = fs.readFileSync(new URL('../app.js', import.meta.url), 'utf8');
+  const sheetIdx = source.indexOf('function renderSheetList');
+  assert.ok(sheetIdx >= 0, 'renderSheetList must exist');
+  // Extract the full function body (up to the closing brace)
+  const sheetEnd = source.indexOf('\n}', sheetIdx) + 2;
+  const sheetBody = source.slice(sheetIdx, sheetEnd);
+  assert.ok(
+    sheetBody.includes('remoteId'),
+    'renderSheetList click handler must pass remoteId to openSession',
+  );
+});
+
+test('renderSheetList item HTML includes data-remote-id attribute for remote sessions', () => {
+  let capturedHTML = '';
+  const mockList = {
+    get innerHTML() { return capturedHTML; },
+    set innerHTML(v) { capturedHTML = v; },
+    querySelectorAll: () => [],
+  };
+  const origGetById = globalThis.document.getElementById;
+  globalThis.document.getElementById = (id) => (id === 'sheet-list' ? mockList : null);
+  app._setCurrentSessions([{ name: 'remote-sess', remoteId: 'fed-abc123', bell: null }]);
+
+  app.renderSheetList();
+
+  assert.ok(
+    capturedHTML.includes('data-remote-id="fed-abc123"'),
+    'sheet item should have data-remote-id attribute for remote sessions',
+  );
+  globalThis.document.getElementById = origGetById;
+});
+
+test('openSession PATCHes /api/state with active_remote_id after successful connect', async () => {
+  const fetchCalls = [];
+  const origFetch = globalThis.fetch;
+  const origGetById = globalThis.document.getElementById;
+  const origQS = globalThis.document.querySelector;
+  const origSetTimeout = globalThis.setTimeout;
+  globalThis.fetch = async (url, opts) => { fetchCalls.push({ url, opts }); return { ok: true }; };
+  globalThis.document.getElementById = () => ({ textContent: '', style: {}, classList: { remove: () => {}, add: () => {} } });
+  globalThis.document.querySelector = () => null;
+  globalThis.setTimeout = (fn) => { fn(); };  // invoke immediately so animation resolves
+  globalThis.window._openTerminal = () => {};
+
+  await app.openSession('remote-session', { remoteId: 'fed-abc123' });
+
+  const patchCall = fetchCalls.find((c) => c.url === '/api/state' && c.opts && c.opts.method === 'PATCH');
+  assert.ok(patchCall, 'openSession should PATCH /api/state after successful connect');
+  const body = JSON.parse(patchCall.opts.body);
+  assert.strictEqual(body.active_remote_id, 'fed-abc123', 'PATCH body should include active_remote_id');
+
+  globalThis.fetch = origFetch;
+  globalThis.document.getElementById = origGetById;
+  globalThis.document.querySelector = origQS;
+  globalThis.setTimeout = origSetTimeout;
+});
+
+test('closeSession PATCHes /api/state to clear active_remote_id', async () => {
+  const origFetch = globalThis.fetch;
+  const origGetById = globalThis.document.getElementById;
+  const origQS = globalThis.document.querySelector;
+  const origSetTimeout = globalThis.setTimeout;
+
+  // Open a remote session first so _viewingRemoteId is set
+  globalThis.fetch = async () => ({ ok: true });
+  globalThis.document.getElementById = () => ({ textContent: '', style: {}, classList: { remove: () => {}, add: () => {} } });
+  globalThis.document.querySelector = () => null;
+  globalThis.setTimeout = (fn) => { fn(); };
+  globalThis.window._openTerminal = () => {};
+  globalThis.window._closeTerminal = () => {};
+
+  await app.openSession('remote-sess', { remoteId: 'fed-abc123' });
+
+  globalThis.setTimeout = origSetTimeout;
+
+  // Reset fetch tracking
+  const fetchCalls = [];
+  globalThis.fetch = async (url, opts) => { fetchCalls.push({ url, opts }); return { ok: true }; };
+
+  await app.closeSession();
+  await new Promise((r) => setTimeout(r, 0));
+
+  const patchCall = fetchCalls.find((c) => c.url === '/api/state' && c.opts && c.opts.method === 'PATCH');
+  assert.ok(patchCall, 'closeSession should PATCH /api/state to clear remote session state');
+  const body = JSON.parse(patchCall.opts.body);
+  assert.strictEqual(body.active_remote_id, null, 'PATCH should clear active_remote_id to null');
+
+  globalThis.fetch = origFetch;
+  globalThis.document.getElementById = origGetById;
+  globalThis.document.querySelector = origQS;
+  globalThis.setTimeout = origSetTimeout;
+});

muxplex/main.py

@@ -279,7 +279,9 @@ app.add_middleware(
 
 
 class StatePatch(BaseModel):
-    session_order: list[str]
+    session_order: list[str] | None = None
+    active_session: str | None = None
+    active_remote_id: str | None = None
 
 
 class HeartbeatPayload(BaseModel):
@@ -332,10 +334,21 @@ async def get_state() -> dict:
 
 @app.patch("/api/state")
 async def patch_state(patch: StatePatch) -> dict:
-    """Update session_order in the persistent state and return the updated state."""
+    """Update fields in the persistent state and return the updated state.
+
+    Only fields explicitly included in the request body are updated;
+    omitted fields are left unchanged. Supports: session_order,
+    active_session, active_remote_id.
+    """
     async with state_lock:
         state = load_state()
+        changed = patch.model_fields_set
+        if "session_order" in changed:
             state["session_order"] = patch.session_order
+        if "active_session" in changed:
+            state["active_session"] = patch.active_session
+        if "active_remote_id" in changed:
+            state["active_remote_id"] = patch.active_remote_id
         save_state(state)
         return state
 

muxplex/state.py

@@ -59,6 +59,7 @@ def empty_state() -> dict:
     """
     return {
         "active_session": None,
+        "active_remote_id": None,
         "session_order": [],
         "sessions": {},
         "devices": {},

muxplex/tests/test_api.py

@@ -139,6 +139,66 @@ def test_patch_state_rejects_non_list_session_order(client):
     assert response.status_code == 422
 
 
+def test_patch_state_updates_active_remote_id(client):
+    """PATCH /api/state with active_remote_id persists it in state."""
+    response = client.patch(
+        "/api/state",
+        json={"active_session": "remote-sess", "active_remote_id": "fed-abc123"},
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["active_remote_id"] == "fed-abc123"
+    assert data["active_session"] == "remote-sess"
+
+
+def test_patch_state_clears_active_remote_id(client):
+    """PATCH /api/state with active_remote_id: null clears it in state."""
+    from muxplex.state import save_state
+
+    # Set up initial state with active_remote_id
+    initial = {
+        "active_session": "remote-sess",
+        "active_remote_id": "fed-abc123",
+        "session_order": [],
+        "sessions": {},
+        "devices": {},
+    }
+    save_state(initial)
+
+    response = client.patch(
+        "/api/state",
+        json={"active_session": None, "active_remote_id": None},
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["active_remote_id"] is None
+    assert data["active_session"] is None
+
+
+def test_patch_state_without_session_order_updates_active_remote_id_only(client):
+    """PATCH /api/state without session_order only updates active_remote_id."""
+    from muxplex.state import save_state
+
+    initial = {
+        "active_session": None,
+        "active_remote_id": None,
+        "session_order": ["alpha", "beta"],
+        "sessions": {},
+        "devices": {},
+    }
+    save_state(initial)
+
+    response = client.patch(
+        "/api/state",
+        json={"active_remote_id": "fed-xyz"},
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["active_remote_id"] == "fed-xyz"
+    # session_order should be unchanged
+    assert data["session_order"] == ["alpha", "beta"]
+
+
 def test_patch_state_ignores_unknown_fields(client):
     """PATCH /api/state ignores unknown fields in the request body."""
     response = client.patch(

muxplex/tests/test_state.py

@@ -68,6 +68,16 @@ def test_empty_state_devices_is_empty_dict():
     assert state["devices"] == {}
 
 
+def test_empty_state_has_active_remote_id_key():
+    state = empty_state()
+    assert "active_remote_id" in state
+
+
+def test_empty_state_active_remote_id_is_none():
+    state = empty_state()
+    assert state["active_remote_id"] is None
+
+
 def test_empty_state_returns_independent_dicts():
     """Mutating one state must not affect another."""
     s1 = empty_state()