feat: Stellar Network Health Monitoring (#192)

app/api/stellar/health/history/route.ts

@@ -0,0 +1,29 @@
+/**
+ * GET /api/stellar/health/history
+ *
+ * Returns the outage history log for audit/debugging purposes.
+ */
+
+import { NextResponse } from "next/server";
+import { getOutageLog } from "@/lib/stellar/health-monitor";
+
+export async function GET() {
+  const log = getOutageLog();
+
+  return NextResponse.json({
+    outages: log.map((event) => ({
+      id: event.id,
+      startedAt: event.startedAt,
+      endedAt: event.endedAt,
+      durationMs: event.durationMs,
+      status: event.status,
+      error: event.error,
+      recovered: event.recovered,
+    })),
+    summary: {
+      total: log.length,
+      recovered: log.filter((o) => o.recovered).length,
+      active: log.filter((o) => !o.recovered).length,
+    },
+  });
+}

app/api/stellar/health/route.test.ts

@@ -0,0 +1,38 @@
+/**
+ * API route tests for /api/stellar/health
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { GET } from "./route";
+
+describe("GET /api/stellar/health", () => {
+  beforeEach(() => {
+    // Reset environment
+    delete process.env.STELLAR_HORIZON_URL;
+    delete process.env.STELLAR_NETWORK;
+    delete process.env.STELLAR_SOURCE_SECRET;
+  });
+
+  it("should return JSON health status", async () => {
+    const request = new Request("http://localhost/api/stellar/health");
+    const response = await GET(request);
+    const data = await response.json();
+
+    expect(response.status).toBe(200);
+    expect(data).toHaveProperty("status");
+    expect(data).toHaveProperty("latencyMs");
+    expect(data).toHaveProperty("checkedAt");
+    expect(data).toHaveProperty("outage");
+    expect(data).toHaveProperty("history");
+  });
+
+  it("should return SSE stream when Accept header is text/event-stream", async () => {
+    const request = new Request("http://localhost/api/stellar/health", {
+      headers: { Accept: "text/event-stream" },
+    });
+    const response = await GET(request);
+
+    expect(response.status).toBe(200);
+    expect(response.headers.get("content-type")).toBe("text/event-stream");
+  });
+});

app/api/stellar/health/route.ts

@@ -0,0 +1,122 @@
+/**
+ * GET /api/stellar/health
+ *
+ * Returns the current Stellar network health status.
+ * Supports Server-Sent Events (SSE) for real-time updates when
+ * the client requests streaming via Accept: text/event-stream.
+ */
+
+import { NextResponse } from "next/server";
+import {
+  checkHealth,
+  subscribe,
+  getCurrentStatus,
+  getNetworkStatus,
+  getOutageLog,
+  startMonitoring,
+  getActiveOutage,
+} from "@/lib/stellar/health-monitor";
+
+// Ensure monitoring is running on the server
+startMonitoring(30000);
+
+export async function GET(request: Request) {
+  const accept = request.headers.get("accept") || "";
+
+  // SSE streaming for real-time updates
+  if (accept.includes("text/event-stream")) {
+    const encoder = new TextEncoder();
+    const stream = new ReadableStream({
+      start(controller) {
+        const send = (data: any) => {
+          try {
+            controller.enqueue(
+              encoder.encode(`data: ${JSON.stringify(data)}\n\n`)
+            );
+          } catch {
+            // Stream closed
+          }
+        };
+
+        // Send initial state
+        const current = getCurrentStatus();
+        if (current) {
+          send({
+            type: "health_update",
+            status: current.status,
+            latencyMs: current.latencyMs,
+            ledger: current.ledger,
+            protocolVersion: current.protocolVersion,
+            network: current.network,
+            checkedAt: current.checkedAt,
+            outage: getActiveOutage(),
+          });
+        }
+
+        // Subscribe to updates
+        const unsubscribe = subscribe((result) => {
+          send({
+            type: "health_update",
+            status: result.status,
+            latencyMs: result.latencyMs,
+            ledger: result.ledger,
+            protocolVersion: result.protocolVersion,
+            network: result.network,
+            checkedAt: result.checkedAt,
+            outage: getActiveOutage(),
+          });
+        });
+
+        // Keep alive
+        const keepAlive = setInterval(() => {
+          try {
+            controller.enqueue(encoder.encode(":keepalive\n\n"));
+          } catch {
+            clearInterval(keepAlive);
+          }
+        }, 15000);
+
+        // Cleanup on close
+        request.signal.addEventListener("abort", () => {
+          unsubscribe();
+          clearInterval(keepAlive);
+        });
+      },
+    });
+
+    return new Response(stream, {
+      headers: {
+        "Content-Type": "text/event-stream",
+        "Cache-Control": "no-cache",
+        Connection: "keep-alive",
+      },
+    });
+  }
+
+  // Standard JSON response
+  const result = getCurrentStatus() || (await checkHealth());
+  const activeOutage = getActiveOutage();
+
+  return NextResponse.json({
+    status: result.status,
+    latencyMs: result.latencyMs,
+    ledger: result.ledger,
+    protocolVersion: result.protocolVersion,
+    horizonUrl: result.horizonUrl,
+    network: result.network,
+    checkedAt: result.checkedAt,
+    error: result.error,
+    outage: activeOutage
+      ? {
+          id: activeOutage.id,
+          startedAt: activeOutage.startedAt,
+          status: activeOutage.status,
+          error: activeOutage.error,
+        }
+      : null,
+    history: {
+      totalOutages: getOutageLog().length,
+      lastOutage: getOutageLog().slice(-1)[0] || null,
+    },
+  });
+}

app/chat/page.tsx

@@ -38,6 +38,7 @@ import {
   ScrollText,
   Users,
 } from "lucide-react";
+import { StellarNetworkStatus } from "@/components/stellar-network-status";
 
 type ChatPreview = {
   id: string;
@@ -488,6 +489,8 @@ export default function ChatPage() {
     <div className="min-h-screen bg-background flex flex-col">
       <Header />
 
+      <StellarNetworkStatus variant="banner" />
+
       <main className="flex-1 pt-24 pb-24 md:pb-8 px-3 sm:px-6">
         <div className="mx-auto w-full max-w-7xl h-[min(84vh,820px)] rounded-3xl border border-border/70 bg-card/90 shadow-[0_24px_64px_-24px_rgba(0,0,0,0.35)] backdrop-blur-sm overflow-hidden">
           <div className="h-full flex relative">