fix(kafka): improve message browsing and topic navigation

apps/desktop/src/lib/__tests__/mq/kafkaTopicStats.spec.ts

@@ -0,0 +1,22 @@
+import { describe, expect, it } from "vitest";
+import { extractKafkaPartitionRows, isKafkaStatsPayload } from "@/lib/mq/kafkaTopicStats";
+
+describe("Kafka topic stats", () => {
+  it("normalizes and sorts partition rows", () => {
+    expect(
+      extractKafkaPartitionRows({
+        partitionStats: [{ partition: 2, beginOffset: 8, endOffset: 20, messageCount: 12, leader: 3, replicas: [3, 4], isr: [3] }, { partition: 0, beginOffset: 1, endOffset: 4, messageCount: 3 }, null],
+      }),
+    ).toEqual([
+      { partition: 0, beginOffset: 1, endOffset: 4, messageCount: 3, leader: -1, replicas: [], isr: [] },
+      { partition: 2, beginOffset: 8, endOffset: 20, messageCount: 12, leader: 3, replicas: [3, 4], isr: [3] },
+    ]);
+  });
+
+  it("recognizes Kafka summaries and rejects unrelated payloads", () => {
+    expect(isKafkaStatsPayload({ partitionStats: [] })).toBe(true);
+    expect(isKafkaStatsPayload({ partitions: 2, replicationFactor: 1, totalMessages: 4 })).toBe(true);
+    expect(isKafkaStatsPayload({ partitions: 2 })).toBe(false);
+    expect(extractKafkaPartitionRows(undefined)).toEqual([]);
+  });
+});

apps/desktop/src/lib/mq/__tests__/mqConsoleDefaults.spec.ts

@@ -77,6 +77,13 @@ describe("mqConsoleDefaults", () => {
     expect(defaultMqCapabilitiesForSystemKind("pulsar").supportsClientConnections).toBeFalsy();
   });
 
+  it("exposes Kafka message browsing through peek capability without query capability", () => {
+    const caps = { ...defaultMqCapabilitiesForSystemKind("kafka"), supportsSendMessage: false };
+    expect(caps.supportsPeekMessages).toBe(true);
+    expect(caps.supportsMessageQuery).toBe(false);
+    expect(resolveAvailableMqTabs({ systemKind: "kafka", capabilities: caps })).toContain("messages");
+  });
+
   it("exposes the namespaces tab for RabbitMQ vhost management", () => {
     const caps = defaultMqCapabilitiesForSystemKind("rabbitmq");
     expect(resolveAvailableMqTabs({ systemKind: "rabbitmq", capabilities: caps })).toEqual(["namespaces", "topics", "subscriptions", "monitoring", "clients", "messages", "broker", "policies", "permissions"]);

apps/desktop/src/lib/mq/kafkaTopicStats.ts

@@ -0,0 +1,49 @@
+export interface KafkaPartitionStatsRow {
+  partition: number;
+  beginOffset: number;
+  endOffset: number;
+  messageCount: number;
+  leader: number;
+  replicas: number[];
+  isr: number[];
+}
+
+export function extractKafkaPartitionRows(raw: unknown): KafkaPartitionStatsRow[] {
+  return arrayObjects(objectRecord(raw).partitionStats)
+    .map((body) => ({
+      partition: numberField(body.partition) ?? 0,
+      beginOffset: numberField(body.beginOffset) ?? 0,
+      endOffset: numberField(body.endOffset) ?? 0,
+      messageCount: numberField(body.messageCount) ?? 0,
+      leader: numberField(body.leader) ?? -1,
+      replicas: numberArrayField(body.replicas),
+      isr: numberArrayField(body.isr),
+    }))
+    .sort((left, right) => left.partition - right.partition);
+}
+
+export function isKafkaStatsPayload(raw: unknown): boolean {
+  const root = objectRecord(raw);
+  return Array.isArray(root.partitionStats) || (numberField(root.partitions) !== undefined && numberField(root.replicationFactor) !== undefined && numberField(root.totalMessages) !== undefined);
+}
+
+function objectRecord(value: unknown): Record<string, unknown> {
+  return value && typeof value === "object" && !Array.isArray(value) ? (value as Record<string, unknown>) : {};
+}
+
+function arrayObjects(value: unknown): Record<string, unknown>[] {
+  return Array.isArray(value) ? value.filter((item): item is Record<string, unknown> => !!item && typeof item === "object" && !Array.isArray(item)) : [];
+}
+
+function numberField(value: unknown): number | undefined {
+  if (typeof value === "number" && Number.isFinite(value)) return value;
+  if (typeof value === "string" && value.trim()) {
+    const parsed = Number(value);
+    return Number.isFinite(parsed) ? parsed : undefined;
+  }
+  return undefined;
+}
+
+function numberArrayField(value: unknown): number[] {
+  return Array.isArray(value) ? value.map(numberField).filter((item): item is number => item !== undefined) : [];
+}

apps/desktop/src/lib/mq/mqConsoleDefaults.ts

@@ -177,7 +177,7 @@ export function resolveAvailableMqTabs(options: { systemKind?: MqSystemKind; cap
   if (capabilities.supportsSubscriptions) tabs.push("subscriptions");
   tabs.push("monitoring");
   tabs.push("clients");
-  if (capabilities.supportsSendMessage) tabs.push("messages");
+  if (capabilities.supportsSendMessage || (systemKind === "kafka" && capabilities.supportsPeekMessages)) tabs.push("messages");
   tabs.push("broker");
   // RabbitMQ lights this tab via virtual-host policies instead of Pulsar rates/quotas.
   if (capabilities.supportsRateLimits || capabilities.supportsBacklogQuota || capabilities.supportsRetention || capabilities.supportsPolicies) {