fix: return clean errors and refund quota on AI provider failures

AI routes had no consistent error handling — a provider failure (e.g. OpenRouter returning a degraded-model error) crashed the route as an uncaught 500 and, worse, still charged the user's monthly aiCall quota for a request that never succeeded. Adds withAiQuota()/aiErrorResponse() (lib/ai/ai-error.ts) and applies them across all 12 AI generation routes: charges the quota, runs the AI call, refunds the credit and returns a clean user-facing message if it throws. Frontend needs no changes — existing dialogs already toast whatever `error` string comes back. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-07-02 12:32:31 +02:00
parent e5d1080fb9
commit 524310433c
16 changed files with 325 additions and 165 deletions
@@ -0,0 +1,55 @@
+import { NextResponse } from "next/server";
+import { APICallError } from "ai";
+import { checkAndIncrementTierLimit, refundAiCall, TierLimitError } from "@/lib/tiers";
+
+/**
+ * Maps an AI-call failure to a clean JSON response instead of letting the
+ * raw provider error (which can include internal provider names/payloads)
+ * reach the client or crash the route as an uncaught 500.
+ */
+export function aiErrorResponse(err: unknown): NextResponse {
+  if (APICallError.isInstance(err)) {
+    return NextResponse.json(
+      {
+        error: err.isRetryable
+          ? "The AI provider is temporarily unavailable. Please try again in a moment."
+          : "The AI provider rejected this request. Try switching models in Settings.",
+        retryable: err.isRetryable,
+      },
+      { status: err.isRetryable ? 503 : 502 }
+    );
+  }
+
+  return NextResponse.json({ error: "AI request failed. Please try again." }, { status: 502 });
+}
+
+type QuotaResult<T> = { ok: true; data: T } | { ok: false; response: NextResponse };
+
+/**
+ * Charges one aiCall credit, runs `fn`, and refunds the credit if `fn`
+ * throws — so a provider outage never silently burns a user's quota.
+ * Centralizes the TierLimitError → 403 and AI-failure → clean-JSON mapping
+ * that every AI route needs instead of repeating try/catch per route.
+ */
+export async function withAiQuota<T>(
+  userId: string,
+  tier: "free" | "pro",
+  fn: () => Promise<T>
+): Promise<QuotaResult<T>> {
+  try {
+    await checkAndIncrementTierLimit(userId, tier, "aiCall");
+  } catch (err) {
+    if (err instanceof TierLimitError) {
+      return { ok: false, response: NextResponse.json({ error: "AI call limit reached for your tier" }, { status: 403 }) };
+    }
+    throw err;
+  }
+
+  try {
+    const data = await fn();
+    return { ok: true, data };
+  } catch (err) {
+    await refundAiCall(userId);
+    return { ok: false, response: aiErrorResponse(err) };
+  }
+}