Fix: Add batch processing to prevent timeout on large song libraries

app/api/categorize/route.ts

@@ -6,6 +6,7 @@ const prisma = new PrismaClient();
 
 const OPENROUTER_API_KEY = process.env.OPENROUTER_API_KEY;
 const OPENROUTER_MODEL = 'anthropic/claude-3.5-haiku';
+const BATCH_SIZE = 20; // Process 20 songs at a time to avoid timeouts
 
 interface CategorizeResult {
     songId: number;
@@ -14,7 +15,7 @@ interface CategorizeResult {
     assignedGenres: string[];
 }
 
-export async function POST() {
+export async function POST(request: Request) {
     try {
         if (!OPENROUTER_API_KEY) {
             return Response.json(
@@ -23,7 +24,30 @@ export async function POST() {
             );
         }
 
+        // Get offset from request body (for batch processing)
+        const body = await request.json().catch(() => ({}));
+        const offset = body.offset || 0;
+
         // Fetch all songs without genres
+        const totalUncategorized = await prisma.song.count({
+            where: {
+                genres: {
+                    none: {}
+                }
+            }
+        });
+
+        if (totalUncategorized === 0) {
+            return Response.json({
+                message: 'No uncategorized songs found',
+                results: [],
+                hasMore: false,
+                totalUncategorized: 0,
+                processed: 0
+            });
+        }
+
+        // Fetch batch of songs
         const uncategorizedSongs = await prisma.song.findMany({
             where: {
                 genres: {
@@ -32,16 +56,11 @@ export async function POST() {
             },
             include: {
                 genres: true
-            }
+            },
+            take: BATCH_SIZE,
+            skip: offset
         });
 
-        if (uncategorizedSongs.length === 0) {
-            return Response.json({
-                message: 'No uncategorized songs found',
-                results: []
-            });
-        }
-
         // Fetch all available genres
         const allGenres = await prisma.genre.findMany({
             orderBy: { name: 'asc' }
@@ -56,7 +75,7 @@ export async function POST() {
 
         const results: CategorizeResult[] = [];
 
-        // Process each song
+        // Process each song in this batch
         for (const song of uncategorizedSongs) {
             try {
                 const genreNames = allGenres.map(g => g.name);
@@ -147,10 +166,15 @@ Your response:`;
             }
         }
 
+        const newOffset = offset + BATCH_SIZE;
+        const hasMore = newOffset < totalUncategorized;
+
         return Response.json({
-            message: `Processed ${uncategorizedSongs.length} songs, categorized ${results.length}`,
-            totalProcessed: uncategorizedSongs.length,
-            totalCategorized: results.length,
+            message: `Processed ${uncategorizedSongs.length} songs in this batch, categorized ${results.length}`,
+            totalUncategorized,
+            processed: Math.min(newOffset, totalUncategorized),
+            hasMore,
+            nextOffset: hasMore ? newOffset : null,
             results
         });