first commit

lib/llm.ts

@@ -0,0 +1,69 @@
+import { z } from "zod";
+
+const SYSTEM_PROMPT = `You are a film research assistant for an international audience.
+You MUST respond in English with valid JSON only — no markdown fences, no commentary.
+Use a clear, neutral tone. If uncertain about a scene or timestamp, state uncertainty and set confidence to "low".
+Do not invent scenes, quotes, or timestamps. Base answers on the movie context provided.`;
+
+export async function generateStructuredResponse<T extends z.ZodType>(
+  schema: T,
+  userPrompt: string,
+): Promise<z.infer<T>> {
+  const apiKey = process.env.LLM_API_KEY;
+  if (!apiKey) {
+    throw new Error("LLM_API_KEY is not set");
+  }
+
+  const baseUrl = process.env.LLM_BASE_URL ?? "https://api.openai.com/v1";
+  const model = process.env.LLM_MODEL ?? "gpt-4o-mini";
+
+  const headers: Record<string, string> = {
+    Authorization: `Bearer ${apiKey}`,
+    "Content-Type": "application/json",
+  };
+
+  if (process.env.LLM_HTTP_REFERER) {
+    headers["HTTP-Referer"] = process.env.LLM_HTTP_REFERER;
+  }
+
+  if (process.env.LLM_APP_TITLE) {
+    headers["X-Title"] = process.env.LLM_APP_TITLE;
+  }
+
+  const response = await fetch(`${baseUrl}/chat/completions`, {
+    method: "POST",
+    headers,
+    body: JSON.stringify({
+      model,
+      temperature: 0.2,
+      response_format: { type: "json_object" },
+      messages: [
+        { role: "system", content: SYSTEM_PROMPT },
+        { role: "user", content: userPrompt },
+      ],
+    }),
+  });
+
+  if (!response.ok) {
+    const errorText = await response.text();
+    throw new Error(`LLM request failed: ${response.status} ${errorText}`);
+  }
+
+  const data = (await response.json()) as {
+    choices: Array<{ message: { content: string } }>;
+  };
+
+  const content = data.choices[0]?.message?.content;
+  if (!content) {
+    throw new Error("LLM returned empty content");
+  }
+
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(content);
+  } catch {
+    throw new Error("LLM returned invalid JSON");
+  }
+
+  return schema.parse(parsed);
+}