feat: add support for multi-disc albums

app/api/analyze/route.ts

@@ -61,9 +61,13 @@ export async function POST(request: Request) {
         // Calculate total size
         const totalSize = tracks.reduce((acc, track) => acc + (track.size || 0), 0);
 
-        // Sort tracks by track number if available, else by filename
+        // Sort tracks by disc number first, then track number, else by filename
         tracks.sort((a, b) => {
             if ('error' in a || 'error' in b) return 0; // Keep order if error
+            const discA = a.common?.disk?.no ?? 1;
+            const discB = b.common?.disk?.no ?? 1;
+            if (discA !== discB) return discA - discB;
+
             const trackA = a.common?.track?.no ?? 0;
             const trackB = b.common?.track?.no ?? 0;
             if (trackA && trackB) return trackA - trackB;
@@ -95,6 +99,11 @@ export async function POST(request: Request) {
             }
         });
 
+        const discNumbers = new Set(
+            tracks.map(t => ('error' in t ? 1 : (t.common?.disk?.no || 1)))
+        );
+        const isMultiDisc = discNumbers.size > 1 || Array.from(discNumbers).some(d => d > 1);
+
         if (sampleRates.size > 1 || bitDepths.size > 1) {
             mixed = true;
             qualityDetails = `NOTE: Mixed formats. Sample Rates: ${Array.from(sampleRates).join(', ')} Hz. Bit Depths: ${Array.from(bitDepths).join(', ')} bit.`;
@@ -102,7 +111,13 @@ export async function POST(request: Request) {
             // Generate detailed message for mixed content
             const mixedDetails = tracks.map(t => {
                 if ('error' in t) return `${t.filename}: Error`;
-                return `Track ${t.common?.track?.no || '?'}: ${t.format?.bitsPerSample}bit / ${t.format?.sampleRate}Hz`;
+                const discNo = t.common?.disk?.no || 1;
+                const trackNo = t.common?.track?.no;
+                let trackStr = trackNo !== undefined && trackNo !== null ? String(trackNo).padStart(2, '0') : '?';
+                if (isMultiDisc) {
+                    trackStr = `${discNo}-${trackStr}`;
+                }
+                return `Track ${trackStr}: ${t.format?.bitsPerSample}bit / ${t.format?.sampleRate}Hz`;
             }).join('\n');
 
             qualityDetails += '\n' + mixedDetails;