feat: add validated llm json helper

src/lib/llm/client.ts

@@ -1,4 +1,5 @@
 import OpenAI from "openai";
+import type { z } from "zod";
 
 export interface GenerateInput {
   system?: string;
@@ -7,6 +8,10 @@ export interface GenerateInput {
   temperature?: number;
 }
 
+export interface GenerateValidatedJsonInput<T> extends GenerateInput {
+  schema: z.ZodType<T>;
+}
+
 export interface LlmProviderStatus {
   provider: "deepseek" | "openai";
   configured: boolean;
@@ -106,6 +111,31 @@ export async function generateJson<T>(input: GenerateInput): Promise<T> {
   }
 }
 
+export let generateJsonForValidation: <T>(input: GenerateInput) => Promise<T> =
+  generateJson;
+
+export function setGenerateJsonForValidation(
+  generator: typeof generateJsonForValidation,
+) {
+  generateJsonForValidation = generator;
+}
+
+export async function generateValidatedJson<T>({
+  schema,
+  ...input
+}: GenerateValidatedJsonInput<T>): Promise<T | null> {
+  if (!isLlmConfigured()) {
+    return null;
+  }
+
+  try {
+    const generated = await generateJsonForValidation<unknown>(input);
+    return schema.parse(generated);
+  } catch {
+    return null;
+  }
+}
+
 function normalizeLlmError(error: unknown) {
   const message = error instanceof Error ? error.message : "Unknown LLM error";
   return new Error(`LLM provider error: ${message}`);