Add github readme badge api (#163)

* add github readme badge api

* return error on monitorId is null

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* delete duplicated boolean check

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Refactor badge endpoint to use KV store

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

pages/api/badge.ts

@@ -0,0 +1,93 @@
+import { workerConfig } from '@/uptime.config'
+import { MonitorState } from '@/types/config'
+import { NextRequest } from 'next/server'
+
+export const runtime = 'edge'
+
+type BadgePayload = {
+  schemaVersion: 1
+  label: string
+  message: string
+  color: string
+  isError?: boolean
+}
+
+const jsonHeaders = {
+  'Content-Type': 'application/json',
+  'Cache-Control': 'no-store, max-age=0, must-revalidate',
+}
+
+function errorBadge(label: string, message: string): BadgePayload {
+  return {
+    schemaVersion: 1,
+    label,
+    message,
+    color: 'lightgrey',
+    isError: true,
+  }
+}
+
+export default async function handler(req: NextRequest): Promise<Response> {
+  try {
+    const url = new URL(req.url)
+
+    const defaultMonitorId = workerConfig.monitors[0]?.id
+    const monitorId = url.searchParams.get('id') ?? defaultMonitorId
+    const label = url.searchParams.get('label') ?? monitorId ?? 'UptimeFlare'
+
+    const upMsg = url.searchParams.get('up') ?? 'UP'
+    const downMsg = url.searchParams.get('down') ?? 'DOWN'
+    const colorUp = url.searchParams.get('colorUp') ?? 'brightgreen'
+    const colorDown = url.searchParams.get('colorDown') ?? 'red'
+
+    if (!monitorId) {
+      return new Response(JSON.stringify(errorBadge(label, 'no-monitor')), {
+        headers: jsonHeaders,
+        status: 400,
+      })
+    }
+
+    const { UPTIMEFLARE_STATE } = process.env as unknown as {
+      UPTIMEFLARE_STATE: KVNamespace
+    }
+
+    const stateStr = await UPTIMEFLARE_STATE?.get('state')
+    if (!stateStr) {
+      return new Response(JSON.stringify(errorBadge(label, 'unavailable')), {
+        headers: jsonHeaders,
+        status: 503,
+      })
+    }
+
+    const state = JSON.parse(stateStr) as MonitorState
+    const monitorIncidentHistory = state.incident?.[monitorId]
+    const hasLatencyData = Boolean(state.latency?.[monitorId]?.recent?.length)
+
+    if (!monitorIncidentHistory || monitorIncidentHistory.length === 0 || !hasLatencyData) {
+      return new Response(JSON.stringify(errorBadge(label, 'unknown')), {
+        headers: jsonHeaders,
+        status: 404,
+      })
+    }
+
+    const latestIncident = monitorIncidentHistory.slice(-1)[0]
+    const isUp = latestIncident.end !== undefined
+
+    const badge: BadgePayload = {
+      schemaVersion: 1,
+      label,
+      message: isUp ? upMsg : downMsg,
+      color: isUp ? colorUp : colorDown,
+    }
+
+    return new Response(JSON.stringify(badge), {
+      headers: jsonHeaders,
+    })
+  } catch (err) {
+    console.error('Error rendering badge API:', err)
+    return new Response(JSON.stringify(errorBadge('status', 'error')), {
+      headers: jsonHeaders,
+      status: 500,
+    })
+  }
+}