improve loading speed

frontend/app/api/classes/route.ts

@@ -137,6 +137,7 @@ export async function GET(request: Request) {
   }
 
   const { searchParams } = new URL(request.url);
+  const classIdParam = searchParams.get("id")?.trim() || null;
   const limitParam = searchParams.get("limit");
   const offsetParam = searchParams.get("offset");
   const departmentParamRaw = searchParams.get("department")?.trim() || null;
@@ -145,6 +146,34 @@ export async function GET(request: Request) {
   const limit = paginated ? Math.min(Math.max(1, parseInt(limitParam, 10) || PAGE_SIZE), 1000) : PAGE_SIZE;
   const offset = paginated ? Math.max(0, parseInt(offsetParam ?? "0", 10)) : 0;
 
+  if (classIdParam) {
+    const { data: course, error } = await supabase
+      .from("courses")
+      .select("id, title, department, course_number, term, year")
+      .eq("id", classIdParam)
+      .maybeSingle();
+
+    if (error) {
+      return NextResponse.json({ error: error.message }, { status: 500 });
+    }
+
+    if (!course) {
+      return NextResponse.json({ error: "Course not found" }, { status: 404 });
+    }
+
+    const classes = buildClasses([course as CourseRow], new Map<string, number>());
+
+    return NextResponse.json(
+      { classes, hasMore: false },
+      {
+        status: 200,
+        headers: {
+          "Cache-Control": "private, max-age=300, stale-while-revalidate=600",
+        },
+      }
+    );
+  }
+
   if (paginated) {
     let query = supabase
       .from("courses")

frontend/app/api/notes/route.ts

@@ -1,7 +1,7 @@
 import { NextResponse } from "next/server";
 import { headers } from "next/headers";
 import { createClient as createSupabaseClient } from "@supabase/supabase-js";
-import { generateSignedUrl } from "@/lib/storage";
+import { generateSignedUrls } from "@/lib/storage";
 import { createClient } from "@/utils/supabaseServerClient";
 
 type ResourceRow = {
@@ -102,7 +102,6 @@ export async function GET(req: Request) {
         download_cost,
         profiles ( display_name )
       `,
-      { count: "exact" },
     )
     .eq("status", "active"); // Only show active (approved) notes on dashboard
 
@@ -125,17 +124,19 @@ export async function GET(req: Request) {
     query = query.eq("course_id", classId);
   }
 
-  query = query.range(from, to);
+  // Over-fetch one row to compute hasMore without expensive exact counts.
+  query = query.range(from, to + 1);
 
-  const { data, error, count } = await query.returns<ResourceRow[]>();
+  const { data, error } = await query.returns<ResourceRow[]>();
 
   if (error) {
     return NextResponse.json({ error: error.message }, { status: 500 });
   }
 
-  const total = count ?? 0;
-  const hasMore = to + 1 < total;
-  const ids = data?.map((row) => row.id) ?? [];
+  const rows = data ?? [];
+  const hasMore = rows.length > pageSize;
+  const pageRows = hasMore ? rows.slice(0, pageSize) : rows;
+  const ids = pageRows.map((row) => row.id);
 
   let voteStats: VoteStatRow[] = [];
   if (ids.length > 0) {
@@ -183,49 +184,52 @@ export async function GET(req: Request) {
     });
   }
 
-  const normalized = data
-    ? await Promise.all(
-        data.map(async (row) => {
-          const stats = voteMap.get(row.id) ?? { upvotes: 0, downvotes: 0, score: 0 };
-          const myVote = myVoteMap.get(row.id) ?? null;
-          const base = {
-            id: row.id,
-            title: row.title,
-            class_id: row.course_id,
-            created_at: row.created_at,
-            description: row.description ?? null,
-            storage_path: row.file_key,
-            profile_display_name: row.profiles?.display_name ?? null,
-            upvote_count: stats.upvotes,
-            downvote_count: stats.downvotes,
-            score: stats.score,
-            my_vote: myVote,
-            download_cost: row.download_cost ?? 0,
-            downloaded: downloadedIds.has(row.id),
-          };
-
-          const path = row.preview_key ?? row.file_key;
-          if (!path) {
-            return { ...base, previewUrl: null };
-          }
-
-          let previewUrl: string | null = null;
-          try {
-            previewUrl = await generateSignedUrl("resources", path);
-          } catch {
-            previewUrl = null;
-          }
-          return { ...base, previewUrl };
-        }),
-      )
-    : [];
+  const previewPaths = Array.from(
+    new Set(
+      pageRows
+        .map((row) => row.preview_key ?? row.file_key)
+        .filter((path): path is string => Boolean(path)),
+    ),
+  );
+
+  let previewUrlMap = new Map<string, string>();
+  if (previewPaths.length > 0) {
+    try {
+      previewUrlMap = await generateSignedUrls("resources", previewPaths);
+    } catch {
+      previewUrlMap = new Map<string, string>();
+    }
+  }
+
+  const normalized = pageRows.map((row) => {
+    const stats = voteMap.get(row.id) ?? { upvotes: 0, downvotes: 0, score: 0 };
+    const myVote = myVoteMap.get(row.id) ?? null;
+    const path = row.preview_key ?? row.file_key;
+
+    return {
+      id: row.id,
+      title: row.title,
+      class_id: row.course_id,
+      created_at: row.created_at,
+      description: row.description ?? null,
+      storage_path: row.file_key,
+      profile_display_name: row.profiles?.display_name ?? null,
+      upvote_count: stats.upvotes,
+      downvote_count: stats.downvotes,
+      score: stats.score,
+      my_vote: myVote,
+      download_cost: row.download_cost ?? 0,
+      downloaded: downloadedIds.has(row.id),
+      previewUrl: path ? previewUrlMap.get(path) ?? null : null,
+    };
+  });
 
   return NextResponse.json(
     {
       notes: normalized,
       page,
       pageSize,
-      total,
+      total: null,
       hasMore,
     },
     {

frontend/app/auth/page.tsx

@@ -31,7 +31,7 @@ export default function AuthPage() {
     };
 
     checkSession();
-  }, [router]);
+  }, [router, redirectTo]);
 
   const content = checking ? (
     <p className="auth-loading">Checking your session…</p>