Initial commit — AI-powered coding tutor (Professor)

Next.js 16, React 19, Monaco editor, Anthropic SDK, multi-provider AI,
Wandbox Python execution, iframe HTML preview, SQLite auth + session persistence.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/models/route.ts

@@ -0,0 +1,84 @@
+import { NextRequest, NextResponse } from 'next/server';
+import type { ProviderId } from '@/types';
+import { PROVIDER_MAP } from '@/lib/providers';
+
+interface ModelsRequestBody {
+  provider: ProviderId;
+  apiKey?: string;
+  baseUrl?: string;
+}
+
+export async function POST(req: NextRequest) {
+  let body: ModelsRequestBody;
+  try {
+    body = await req.json();
+  } catch {
+    return NextResponse.json({ error: 'Invalid JSON' }, { status: 400 });
+  }
+
+  const { provider, apiKey, baseUrl } = body;
+  const def = PROVIDER_MAP[provider];
+  const base = baseUrl?.trim() || def.defaultBaseUrl;
+
+  try {
+    let models: string[] = [];
+
+    if (provider === 'anthropic') {
+      const key = apiKey?.trim() || process.env.ANTHROPIC_API_KEY;
+      if (!key) {
+        return NextResponse.json({ error: 'No API key — enter one above or set ANTHROPIC_API_KEY in .env.local' }, { status: 400 });
+      }
+      const res = await fetch('https://api.anthropic.com/v1/models?limit=100', {
+        headers: {
+          'x-api-key': key,
+          'anthropic-version': '2023-06-01',
+        },
+      });
+      if (!res.ok) {
+        const text = await res.text().catch(() => '');
+        return NextResponse.json({ error: `Anthropic: ${res.status} ${text}` }, { status: res.status });
+      }
+      const data = await res.json();
+      models = (data.data ?? []).map((m: { id: string }) => m.id);
+    }
+
+    else if (provider === 'openrouter') {
+      const headers: Record<string, string> = {};
+      if (apiKey?.trim()) headers['Authorization'] = `Bearer ${apiKey.trim()}`;
+
+      const res = await fetch('https://openrouter.ai/api/v1/models', { headers });
+      if (!res.ok) {
+        const text = await res.text().catch(() => '');
+        return NextResponse.json({ error: `OpenRouter: ${res.status} ${text}` }, { status: res.status });
+      }
+      const data = await res.json();
+      // Sort by id for easier browsing
+      models = (data.data ?? [])
+        .map((m: { id: string }) => m.id)
+        .sort((a: string, b: string) => a.localeCompare(b));
+    }
+
+    else {
+      // LM Studio and Ollama — OpenAI-compatible /v1/models
+      const res = await fetch(`${base}/models`, {
+        headers: { Authorization: 'Bearer none' },
+        signal: AbortSignal.timeout(5000),
+      });
+      if (!res.ok) {
+        const text = await res.text().catch(() => '');
+        return NextResponse.json({ error: `${def.label}: ${res.status} ${text || 'Connection refused'}` }, { status: res.status });
+      }
+      const data = await res.json();
+      models = (data.data ?? []).map((m: { id: string }) => m.id);
+    }
+
+    return NextResponse.json({ models });
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : 'Unknown error';
+    const isTimeout = msg.includes('timeout') || msg.includes('abort');
+    return NextResponse.json(
+      { error: isTimeout ? `Could not reach ${def.label} — is it running?` : msg },
+      { status: 500 }
+    );
+  }
+}