From c1602d7ea8d8a5ef4928875b8026b08b0770e287 Mon Sep 17 00:00:00 2001
From: "Patrick W. Healy" <patrick.healy@microsoft.com>
Date: Wed, 16 Sep 2026 22:05:15 +0000
Subject: [PATCH] refactor(net): share exact status diagnostic counting rules

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: d2243398-6c36-4c3d-969e-7ed7bfb5b459
---
 internal/net/status/diagnostics.go      | 60 +++++++++++++++++++
 internal/net/status/diagnostics_test.go | 78 +++++++++++++++++++++++++
 2 files changed, 138 insertions(+)
 create mode 100644 internal/net/status/diagnostics.go
 create mode 100644 internal/net/status/diagnostics_test.go

diff --git a/internal/net/status/diagnostics.go b/internal/net/status/diagnostics.go
new file mode 100644
index 000000000..04e86932c
--- /dev/null
+++ b/internal/net/status/diagnostics.go
@@ -0,0 +1,60 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0
+
+package status
+
+import (
+	"strings"
+	"time"
+
+	"github.com/Azure/unbounded/internal/net/status/v1alpha1"
+)
+
+// PeerLinkHealthyForDiagnostics preserves the problem list's normalized probe
+// rules. Unlike PeerHealthyForOverview, a nonempty status enables probe checks
+// even when Enabled is false. Each tunnel link is counted, not each node name.
+func PeerLinkHealthyForDiagnostics(peer *v1alpha1.PeerStatus, now time.Time) bool {
+	checkStatus := ""
+	if peer.HealthCheck != nil {
+		checkStatus = strings.ToLower(strings.TrimSpace(peer.HealthCheck.Status))
+	}
+
+	if (peer.HealthCheck != nil && peer.HealthCheck.Enabled) || checkStatus != "" {
+		return checkStatus == "up"
+	}
+
+	lastHandshake := peer.Tunnel.LastHandshake
+
+	return !lastHandshake.IsZero() && now.Sub(lastHandshake) < 3*time.Minute
+}
+
+// UnhealthyPeerLinkCount counts unhealthy links without deduplicating peer names.
+func UnhealthyPeerLinkCount(peers []v1alpha1.PeerStatus, now time.Time) int {
+	count := 0
+
+	for i := range peers {
+		if !PeerLinkHealthyForDiagnostics(&peers[i], now) {
+			count++
+		}
+	}
+
+	return count
+}
+
+// RouteMismatchCount counts every annotated expected/present next-hop mismatch.
+func RouteMismatchCount(routes []v1alpha1.RouteEntry) int {
+	count := 0
+
+	for _, route := range routes {
+		for _, hop := range route.NextHops {
+			expected := hop.Expected != nil && *hop.Expected
+
+			present := hop.Present != nil && *hop.Present
+			if expected != present {
+				count++
+			}
+		}
+	}
+
+	return count
+}
diff --git a/internal/net/status/diagnostics_test.go b/internal/net/status/diagnostics_test.go
new file mode 100644
index 000000000..426377e28
--- /dev/null
+++ b/internal/net/status/diagnostics_test.go
@@ -0,0 +1,78 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0
+
+package status
+
+import (
+	"testing"
+	"time"
+
+	"github.com/Azure/unbounded/internal/net/status/v1alpha1"
+)
+
+func TestPeerLinkHealthyForDiagnostics(t *testing.T) {
+	now := time.Unix(1000, 0)
+	for _, tc := range []struct {
+		name      string
+		check     *v1alpha1.HealthCheckPeerStatus
+		handshake time.Time
+		healthy   bool
+	}{
+		{"unknown", nil, time.Time{}, false},
+		{"recent", nil, now.Add(-time.Minute), true},
+		{"boundary", nil, now.Add(-3 * time.Minute), false},
+		{"future", nil, now.Add(time.Minute), true},
+		{"normalized up", &v1alpha1.HealthCheckPeerStatus{Enabled: true, Status: " UP "}, time.Time{}, true},
+		{"disabled nonempty up", &v1alpha1.HealthCheckPeerStatus{Status: " up "}, time.Time{}, true},
+		{"disabled nonempty down", &v1alpha1.HealthCheckPeerStatus{Status: " DOWN "}, now, false},
+		{"enabled empty", &v1alpha1.HealthCheckPeerStatus{Enabled: true}, now, false},
+		{"disabled whitespace uses handshake", &v1alpha1.HealthCheckPeerStatus{Status: "  "}, now, true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			peer := v1alpha1.PeerStatus{HealthCheck: tc.check, Tunnel: v1alpha1.PeerTunnelStatus{LastHandshake: tc.handshake}}
+			if got := PeerLinkHealthyForDiagnostics(&peer, now); got != tc.healthy {
+				t.Fatalf("healthy=%v, want %v", got, tc.healthy)
+			}
+		})
+	}
+}
+
+func TestUnhealthyPeerLinkCountKeepsDistinctLinks(t *testing.T) {
+	now := time.Unix(1000, 0)
+
+	peers := []v1alpha1.PeerStatus{
+		{Name: "same", HealthCheck: &v1alpha1.HealthCheckPeerStatus{Enabled: true, Status: "DOWN"}},
+		{Name: "same", HealthCheck: &v1alpha1.HealthCheckPeerStatus{Status: " down "}, Tunnel: v1alpha1.PeerTunnelStatus{LastHandshake: now}},
+		{Name: "same", HealthCheck: &v1alpha1.HealthCheckPeerStatus{Status: " UP "}},
+	}
+	if got := UnhealthyPeerLinkCount(peers, now); got != 2 {
+		t.Fatalf("unhealthy links=%d, want 2", got)
+	}
+
+	if got := UnhealthyPeerLinkCount(nil, now); got != 0 {
+		t.Fatalf("empty links=%d, want 0", got)
+	}
+}
+
+func TestRouteMismatchCountIncludesEveryHop(t *testing.T) {
+	yes, no := true, false
+
+	routes := []v1alpha1.RouteEntry{
+		{NextHops: []v1alpha1.NextHop{
+			{Expected: &yes},
+			{Present: &yes},
+			{Expected: &yes, Present: &no},
+			{Expected: &yes, Present: &yes},
+			{Expected: &no},
+			{},
+		}},
+		{NextHops: []v1alpha1.NextHop{{Expected: &no, Present: &yes}}},
+	}
+	if got := RouteMismatchCount(routes); got != 4 {
+		t.Fatalf("mismatched hops=%d, want 4", got)
+	}
+
+	if got := RouteMismatchCount(nil); got != 0 {
+		t.Fatalf("empty routes=%d, want 0", got)
+	}
+}