Work through TODO fixes

internal/app/timers.go

@@ -55,9 +55,10 @@ type pendingTimer struct {
 type timerManager struct {
 	sess *Session
 
-	mu     sync.Mutex
-	nextID int
-	timers map[string]*pendingTimer
+	mu      sync.Mutex
+	nextID  int
+	timers  map[string]*pendingTimer
+	changes chan struct{}
 
 	// fireFn is the callback used to deliver the body to the owning
 	// process. Decoupled so tests can substitute a recorder. Defaults
@@ -67,13 +68,25 @@ type timerManager struct {
 
 func newTimerManager(sess *Session) *timerManager {
 	m := &timerManager{
-		sess:   sess,
-		timers: make(map[string]*pendingTimer),
+		sess:    sess,
+		timers:  make(map[string]*pendingTimer),
+		changes: make(chan struct{}, 1),
 	}
 	m.fireFn = defaultFireFn
 	return m
 }
 
+func (m *timerManager) changeEvents() <-chan struct{} {
+	return m.changes
+}
+
+func (m *timerManager) notifyChanged() {
+	select {
+	case m.changes <- struct{}{}:
+	default:
+	}
+}
+
 func defaultFireFn(owner *Child, body, label string) {
 	if owner == nil || !owner.IsLive() {
 		return
@@ -121,6 +134,7 @@ func (m *timerManager) TimerSet(ownerID string, body, label string, seconds floa
 	m.timers[id] = t
 	m.mu.Unlock()
 	t.rt = time.AfterFunc(d, func() { m.fireDelay(id) })
+	m.notifyChanged()
 	return id, nil
 }
 
@@ -136,6 +150,7 @@ func (m *timerManager) fireDelay(id string) {
 	body, label := t.body, t.label
 	delete(m.timers, id)
 	m.mu.Unlock()
+	m.notifyChanged()
 	m.fireFn(owner, body, label)
 }
 
@@ -214,6 +229,7 @@ func (m *timerManager) registerIdleTimer(kind pendingTimerKind, ownerID, body, l
 	}
 	m.timers[id] = t
 	m.mu.Unlock()
+	m.notifyChanged()
 	resp.ID = id
 	resp.Status = "pending"
 	return resp, nil
@@ -231,6 +247,7 @@ func (m *timerManager) fireIdleMaxWait(id string) {
 	body, label := t.body, t.label
 	delete(m.timers, id)
 	m.mu.Unlock()
+	m.notifyChanged()
 	m.fireFn(owner, body, label)
 }
 
@@ -291,6 +308,9 @@ func (m *timerManager) onChildStateChanged(childID string, state IdleState) {
 		delete(m.timers, id)
 	}
 	m.mu.Unlock()
+	if len(firedIDs) > 0 {
+		m.notifyChanged()
+	}
 	for _, f := range fires {
 		m.fireFn(f.owner, f.body, f.label)
 	}
@@ -320,7 +340,7 @@ func (m *timerManager) onChildStateChanged(childID string, state IdleState) {
 // legitimate fire and leave the parent never notified.
 func (m *timerManager) onChildClosed(childID string) {
 	m.mu.Lock()
-	defer m.mu.Unlock()
+	changed := false
 	for id, t := range m.timers {
 		if t.ownerID == childID {
 			if t.rt != nil {
@@ -329,6 +349,7 @@ func (m *timerManager) onChildClosed(childID string) {
 			}
 			t.status = timerStatusCanceled
 			delete(m.timers, id)
+			changed = true
 			continue
 		}
 		if !contains(t.watched, childID) {
@@ -344,6 +365,7 @@ func (m *timerManager) onChildClosed(childID string) {
 		if t.idleBaseline != nil {
 			delete(t.idleBaseline, childID)
 		}
+		changed = true
 		if len(t.watched) == 0 {
 			if t.rt != nil {
 				t.rt.Stop()
@@ -353,6 +375,10 @@ func (m *timerManager) onChildClosed(childID string) {
 			delete(m.timers, id)
 		}
 	}
+	m.mu.Unlock()
+	if changed {
+		m.notifyChanged()
+	}
 }
 
 // allWatchedIdleLocked reports whether every watched child is now
@@ -374,19 +400,21 @@ func (m *timerManager) allWatchedIdleLocked(t *pendingTimer) bool {
 // TimerCancel removes a pending or paused timer owned by ownerID.
 func (m *timerManager) TimerCancel(ownerID, id string) error {
 	m.mu.Lock()
-	defer m.mu.Unlock()
 	t, ok := m.timers[id]
 	if !ok {
+		m.mu.Unlock()
 		return mcp.Errorf(mcp.ErrorKindNotFound, "no such timer %q", id)
 	}
 	// Empty ownerID = top-level orchestrator caller (e.g. a non-agent
 	// MCP client); allow it to manage every timer in the session.
 	// Otherwise the caller's own id must match the timer's owner.
 	if ownerID != "" && t.ownerID != ownerID {
+		m.mu.Unlock()
 		return mcp.Errorf(mcp.ErrorKindRoleForbidden, "timer %q is not owned by caller", id)
 	}
 	if t.status == timerStatusFired || t.status == timerStatusCanceled {
 		// Cancelling a fired/cancelled timer is idempotent.
+		m.mu.Unlock()
 		return nil
 	}
 	if t.rt != nil {
@@ -395,6 +423,8 @@ func (m *timerManager) TimerCancel(ownerID, id string) error {
 	}
 	t.status = timerStatusCanceled
 	delete(m.timers, id)
+	m.mu.Unlock()
+	m.notifyChanged()
 	return nil
 }
 
@@ -402,18 +432,20 @@ func (m *timerManager) TimerCancel(ownerID, id string) error {
 // keeps the timer in the registry.
 func (m *timerManager) TimerPause(ownerID, id string) error {
 	m.mu.Lock()
-	defer m.mu.Unlock()
 	t, ok := m.timers[id]
 	if !ok {
+		m.mu.Unlock()
 		return mcp.Errorf(mcp.ErrorKindNotFound, "no such timer %q", id)
 	}
 	// Empty ownerID = top-level orchestrator caller (e.g. a non-agent
 	// MCP client); allow it to manage every timer in the session.
 	// Otherwise the caller's own id must match the timer's owner.
 	if ownerID != "" && t.ownerID != ownerID {
+		m.mu.Unlock()
 		return mcp.Errorf(mcp.ErrorKindRoleForbidden, "timer %q is not owned by caller", id)
 	}
 	if t.status != timerStatusPending {
+		m.mu.Unlock()
 		return mcp.Errorf(mcp.ErrorKindInvalidArgs, "timer %q is not pending", id)
 	}
 	if t.rt != nil {
@@ -429,6 +461,8 @@ func (m *timerManager) TimerPause(ownerID, id string) error {
 		t.pausedWasMaxWait = t.kind != timerKindDelay
 	}
 	t.status = timerStatusPaused
+	m.mu.Unlock()
+	m.notifyChanged()
 	return nil
 }
 
@@ -507,6 +541,7 @@ func (m *timerManager) TimerResume(ownerID, id string) error {
 		delete(m.timers, id)
 	}
 	m.mu.Unlock()
+	m.notifyChanged()
 	if fireNow {
 		m.fireFn(owner, body, label)
 	}
@@ -587,6 +622,56 @@ func (m *timerManager) activeForChild(id string) *mcp.TimerInfo {
 	return &info
 }
 
+const (
+	timerSidebarMinRefresh       = 50 * time.Millisecond
+	timerSidebarSubsecondRefresh = 100 * time.Millisecond
+)
+
+func nextTimerSidebarLabelChange(d time.Duration) time.Duration {
+	if d <= 0 {
+		return 0
+	}
+	if d < time.Second {
+		if d < timerSidebarSubsecondRefresh {
+			return d
+		}
+		return timerSidebarSubsecondRefresh
+	}
+
+	step := time.Second
+	if d >= time.Hour {
+		step = time.Hour
+	} else if d >= time.Minute {
+		step = time.Minute
+	}
+	wait := d % step
+	if wait <= 0 || wait < timerSidebarMinRefresh {
+		return timerSidebarMinRefresh
+	}
+	return wait
+}
+
+func (m *timerManager) nextSidebarRefreshAfter(now time.Time) (time.Duration, bool) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	var best time.Duration
+	found := false
+	for _, t := range m.timers {
+		if t.status != timerStatusPending || t.firesAt.IsZero() {
+			continue
+		}
+		wait := nextTimerSidebarLabelChange(t.firesAt.Sub(now))
+		if wait <= 0 {
+			wait = timerSidebarMinRefresh
+		}
+		if !found || wait < best {
+			best = wait
+			found = true
+		}
+	}
+	return best, found
+}
+
 func isIdleState(s IdleState) bool {
 	return s == StateIdle
 }