feat: upload creates new chart from filename with duplicate handling

- POST /api/upload now creates a chart named from the CSV filename
- Duplicate names get numeric suffix (e.g., btc-daily-2)
- Candles inserted with chart_id instead of replacing all data
- Response includes chart id and name

openspec/changes/multi-chart-management/tasks.md

@@ -14,10 +14,10 @@
 
 ## 3. Upload Endpoint Changes
 
-- [ ] 3.1 Modify `POST /api/upload` to create a new chart named from the uploaded filename (strip `.csv` extension)
-- [ ] 3.2 Add duplicate name handling — append numeric suffix if chart name already exists
-- [ ] 3.3 Insert candles with the new chart's `chart_id` instead of deleting all existing candles
-- [ ] 3.4 Return chart `id` and `name` in the upload response JSON
+- [x] 3.1 Modify `POST /api/upload` to create a new chart named from the uploaded filename (strip `.csv` extension)
+- [x] 3.2 Add duplicate name handling — append numeric suffix if chart name already exists
+- [x] 3.3 Insert candles with the new chart's `chart_id` instead of deleting all existing candles
+- [x] 3.4 Return chart `id` and `name` in the upload response JSON
 
 ## 4. Candles & Annotations API Scoping
 

src/app/api/upload/route.ts

@@ -1,8 +1,28 @@
 import { NextRequest, NextResponse } from 'next/server';
 import Papa from 'papaparse';
 import { db } from '@/lib/db';
-import { candles } from '@/lib/db/schema';
-import { sql } from 'drizzle-orm';
+import { candles, charts } from '@/lib/db/schema';
+import { eq, like } from 'drizzle-orm';
+
+async function getUniqueChartName(baseName: string): Promise<string> {
+  // Check if the base name is already taken
+  const existing = await db.select().from(charts).where(eq(charts.name, baseName)).limit(1);
+  if (existing.length === 0) return baseName;
+
+  // Find existing charts with this base name pattern (e.g., "btc-daily-2", "btc-daily-3")
+  const pattern = `${baseName}-%`;
+  const suffixed = await db.select({ name: charts.name }).from(charts).where(like(charts.name, pattern));
+
+  let maxSuffix = 1;
+  for (const row of suffixed) {
+    const match = row.name.match(/-(\d+)$/);
+    if (match) {
+      maxSuffix = Math.max(maxSuffix, parseInt(match[1], 10));
+    }
+  }
+
+  return `${baseName}-${maxSuffix + 1}`;
+}
 
 export async function POST(request: NextRequest): Promise<NextResponse> {
   try {
@@ -18,6 +38,9 @@ export async function POST(request: NextRequest): Promise<NextResponse> {
 
     const text = await file.text();
 
+    // Derive chart name from filename (strip .csv extension)
+    const baseName = file.name.replace(/\.csv$/i, '');
+
     return new Promise<NextResponse>((resolve) => {
       Papa.parse(text, {
         header: true,
@@ -56,6 +79,15 @@ export async function POST(request: NextRequest): Promise<NextResponse> {
               return;
             }
 
+            // Get unique chart name (handle duplicates)
+            const chartName = await getUniqueChartName(baseName);
+
+            // Create the chart
+            const [newChart] = await db.insert(charts).values({
+              name: chartName,
+              created_at: Math.floor(Date.now() / 1000),
+            }).returning();
+
             // Parse and prepare candle data
             const candleData = rows.map((row) => {
               let timestamp: number;
@@ -75,6 +107,7 @@ export async function POST(request: NextRequest): Promise<NextResponse> {
               }
 
               return {
+                chart_id: newChart.id,
                 time: timestamp,
                 open: Number(row.open),
                 high: Number(row.high),
@@ -83,10 +116,7 @@ export async function POST(request: NextRequest): Promise<NextResponse> {
               };
             });
 
-            // Delete all old candles before inserting new ones
-            await db.delete(candles);
-
-            // Insert new candles
+            // Insert candles for this chart
             const count = candleData.length;
             if (count > 0) {
               await db.insert(candles).values(candleData);
@@ -96,6 +126,7 @@ export async function POST(request: NextRequest): Promise<NextResponse> {
               NextResponse.json({
                 success: true,
                 count,
+                chart: { id: newChart.id, name: newChart.name },
               })
             );
           } catch (error: any) {