fix: critical perf & security — rate limiting, DB indexes, N+1 query, image lazy loading

- Add in-memory rate limiter (src/lib/rateLimit.ts) to public registration endpoints
- Add DB migration #9 with 8 performance indexes on booking/registration tables
- Fix N+1 query in getUpcomingReminders() — single IN() query instead of per-title
- Add loading="lazy" to all non-hero images (MasterClasses, News, Classes, Team)
- Add sizes attribute to Classes images for better responsive loading

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/app/api/group-booking/route.ts

@@ -1,7 +1,16 @@
 import { NextRequest, NextResponse } from "next/server";
 import { addGroupBooking } from "@/lib/db";
+import { checkRateLimit, getClientIp } from "@/lib/rateLimit";
 
 export async function POST(request: NextRequest) {
+  const ip = getClientIp(request);
+  if (!checkRateLimit(ip, 5, 60_000)) {
+    return NextResponse.json(
+      { error: "Слишком много запросов. Попробуйте через минуту." },
+      { status: 429 }
+    );
+  }
+
   try {
     const body = await request.json();
     const { name, phone, groupInfo, instagram, telegram } = body;

src/app/api/master-class-register/route.ts

@@ -1,7 +1,16 @@
 import { NextResponse } from "next/server";
 import { addMcRegistration } from "@/lib/db";
+import { checkRateLimit, getClientIp } from "@/lib/rateLimit";
 
 export async function POST(request: Request) {
+  const ip = getClientIp(request);
+  if (!checkRateLimit(ip, 5, 60_000)) {
+    return NextResponse.json(
+      { error: "Слишком много запросов. Попробуйте через минуту." },
+      { status: 429 }
+    );
+  }
+
   try {
     const body = await request.json();
     const { masterClassTitle, name, phone, instagram, telegram } = body;

src/app/api/open-day-register/route.ts

@@ -5,8 +5,17 @@ import {
   getPersonOpenDayBookings,
   getOpenDayEvent,
 } from "@/lib/db";
+import { checkRateLimit, getClientIp } from "@/lib/rateLimit";
 
 export async function POST(request: NextRequest) {
+  const ip = getClientIp(request);
+  if (!checkRateLimit(ip, 10, 60_000)) {
+    return NextResponse.json(
+      { error: "Слишком много запросов. Попробуйте через минуту." },
+      { status: 429 }
+    );
+  }
+
   try {
     const body = await request.json();
     const { classId, eventId, name, phone, instagram, telegram } = body;

src/components/sections/Classes.tsx

@@ -53,6 +53,8 @@ export function Classes({ data: classes }: ClassesProps) {
                         src={item.images[0]}
                         alt={item.name}
                         fill
+                        loading="lazy"
+                        sizes="(min-width: 1024px) 60vw, 100vw"
                         className="object-cover"
                       />
                       {/* Gradient overlay */}

src/components/sections/MasterClasses.tsx

@@ -98,6 +98,7 @@ function MasterClassCard({
             src={item.image}
             alt={item.title}
             fill
+            loading="lazy"
             sizes="(min-width: 1024px) 33vw, (min-width: 640px) 50vw, 100vw"
             className="object-cover transition-transform duration-700 group-hover:scale-110"
           />

src/components/sections/News.tsx

@@ -42,6 +42,7 @@ function FeaturedArticle({
             src={item.image}
             alt={item.title}
             fill
+            loading="lazy"
             sizes="(min-width: 768px) 80vw, 100vw"
             className="object-cover transition-transform duration-700 group-hover:scale-105"
           />
@@ -84,6 +85,7 @@ function CompactArticle({
             src={item.image}
             alt={item.title}
             fill
+            loading="lazy"
             sizes="112px"
             className="object-cover transition-transform duration-500 group-hover:scale-105"
           />

src/components/sections/team/TeamCarousel.tsx

@@ -222,6 +222,7 @@ export function TeamCarousel({ members, activeIndex, onActiveChange }: TeamCarou
               src={m.image}
               alt={m.name}
               fill
+              loading="lazy"
               sizes="280px"
               className="object-cover"
               draggable={false}

src/lib/db.ts

@@ -184,6 +184,22 @@ const migrations: Migration[] = [
       }
     },
   },
+  {
+    version: 9,
+    name: "add_performance_indexes",
+    up: (db) => {
+      db.exec(`
+        CREATE INDEX IF NOT EXISTS idx_mc_registrations_title ON mc_registrations(master_class_title);
+        CREATE INDEX IF NOT EXISTS idx_mc_registrations_created ON mc_registrations(created_at DESC);
+        CREATE INDEX IF NOT EXISTS idx_group_bookings_created ON group_bookings(created_at DESC);
+        CREATE INDEX IF NOT EXISTS idx_open_day_bookings_event ON open_day_bookings(event_id);
+        CREATE INDEX IF NOT EXISTS idx_open_day_bookings_class ON open_day_bookings(class_id);
+        CREATE INDEX IF NOT EXISTS idx_open_day_bookings_phone ON open_day_bookings(event_id, phone);
+        CREATE INDEX IF NOT EXISTS idx_open_day_bookings_class_phone ON open_day_bookings(class_id, phone);
+        CREATE INDEX IF NOT EXISTS idx_open_day_classes_event ON open_day_classes(event_id);
+      `);
+    },
+  },
 ];
 
 function runMigrations(db: Database.Database) {
@@ -703,11 +719,22 @@ export function getUpcomingReminders(): ReminderItem[] {
           }
         }
       }
-      for (const { title, date, time } of upcomingTitles) {
+      if (upcomingTitles.length > 0) {
+        const uniqueTitles = [...new Set(upcomingTitles.map((t) => t.title))];
+        const placeholders = uniqueTitles.map(() => "?").join(", ");
         const rows = db.prepare(
-          "SELECT * FROM mc_registrations WHERE master_class_title = ?"
-        ).all(title) as McRegistrationRow[];
+          `SELECT * FROM mc_registrations WHERE master_class_title IN (${placeholders})`
+        ).all(...uniqueTitles) as McRegistrationRow[];
+
+        // Build a lookup: title → { date, time }
+        const titleInfo = new Map<string, { date: string; time?: string }>();
+        for (const t of upcomingTitles) {
+          titleInfo.set(t.title, { date: t.date, time: t.time });
+        }
+
         for (const r of rows) {
+          const info = titleInfo.get(r.master_class_title);
+          if (!info) continue;
           items.push({
             id: r.id,
             type: "master-class",
@@ -717,8 +744,8 @@ export function getUpcomingReminders(): ReminderItem[] {
             instagram: r.instagram ?? undefined,
             telegram: r.telegram ?? undefined,
             reminderStatus: r.reminder_status ?? undefined,
-            eventLabel: `${title}${time ? ` · ${time}` : ""}`,
-            eventDate: date,
+            eventLabel: `${r.master_class_title}${info.time ? ` · ${info.time}` : ""}`,
+            eventDate: info.date,
           });
         }
       }

src/lib/rateLimit.ts

@@ -0,0 +1,62 @@
+/**
+ * Simple in-memory rate limiter for public API endpoints.
+ * Limits requests per IP within a sliding time window.
+ */
+
+interface RateLimitEntry {
+  count: number;
+  resetAt: number;
+}
+
+const store = new Map<string, RateLimitEntry>();
+
+// Periodically clean up expired entries (every 5 minutes)
+let cleanupScheduled = false;
+function scheduleCleanup() {
+  if (cleanupScheduled) return;
+  cleanupScheduled = true;
+  setInterval(() => {
+    const now = Date.now();
+    for (const [key, entry] of store) {
+      if (now > entry.resetAt) store.delete(key);
+    }
+  }, 5 * 60 * 1000);
+}
+
+/**
+ * Check if a request is within the rate limit.
+ * @param ip - Client IP address
+ * @param limit - Max requests per window (default: 10)
+ * @param windowMs - Time window in ms (default: 60_000 = 1 minute)
+ * @returns true if allowed, false if rate limited
+ */
+export function checkRateLimit(
+  ip: string,
+  limit: number = 10,
+  windowMs: number = 60_000
+): boolean {
+  scheduleCleanup();
+
+  const now = Date.now();
+  const entry = store.get(ip);
+
+  if (!entry || now > entry.resetAt) {
+    store.set(ip, { count: 1, resetAt: now + windowMs });
+    return true;
+  }
+
+  if (entry.count >= limit) return false;
+  entry.count++;
+  return true;
+}
+
+/**
+ * Extract client IP from request headers.
+ */
+export function getClientIp(request: Request): string {
+  return (
+    request.headers.get("x-forwarded-for")?.split(",")[0]?.trim() ||
+    request.headers.get("x-real-ip") ||
+    "unknown"
+  );
+}